MRTMR Flashcards

Question

You are working in a colorectal clinic where you have seen several patients at risk of bowel malignancy. Which of these conditions does not warrant regular colonoscopies? A Familial Adenomatous Polyposis B Hereditary Non-Polyposis Colorectal Cancer C Family history of colonic cancer D Long standing Crohn's disease E Previous history of colorectal malignancy

Answer 1

The correct answer is: ### **C. Family history of colonic cancer** ### **Explanation:** While a **family history of colorectal cancer** increases an individual's risk, it does **not automatically warrant regular colonoscopies** unless specific high-risk criteria are met (e.g., **first-degree relative with early-onset cancer, multiple affected relatives, or known hereditary syndromes**). In contrast, the other options **do require regular colonoscopic surveillance** due to their significantly increased risk of malignancy: - **A. Familial Adenomatous Polyposis (FAP)** → **Mandatory surveillance** due to near-universal development of hundreds to thousands of adenomatous polyps with a 100% lifetime risk of colorectal cancer if untreated. - **B. Hereditary Non-Polyposis Colorectal Cancer (HNPCC/Lynch Syndrome)** → **High lifetime risk (up to 80%) of colorectal cancer**, requiring **colonoscopy every 1–2 years starting at age 20–25**. - **D. Long-standing Crohn’s disease** → **Increased risk of colorectal cancer after 8–10 years of disease**, especially with extensive colonic involvement (similar to ulcerative colitis). - **E. Previous history of colorectal malignancy** → **High risk of recurrence/metachronous cancers**, requiring **regular surveillance (e.g., colonoscopy at 1, 3, and 5 years post-resection)**. ### **Conclusion:** A **general family history of colorectal cancer (C)** alone does not necessitate routine colonoscopies unless additional risk factors are present (e.g., **early age at diagnosis or multiple affected relatives**). The other conditions (A, B, D, E) are well-established high-risk scenarios requiring **regular endoscopic surveillance**. Those with a strong family history of colonic cancer are advised to undergo genetic testing. In the absence of a genetic condition (such as FAP or Lynch syndrome), a colonoscopy is advised between the ages of 35 and 45. Further routine colonoscopy is only indicated in the presence of polyps or other suspicious pathology. Genetic conditions like FAP or HNPCC (aka Lynch syndrome) are associated with high risk of bowel cancer and hence managed with annual colonoscopies. Patients with IBD are also at higher risk of colonic malignancy, though the exact risk depends on a variety of factors (age, duration and severity of illness, sites affected, etc.) The screening usually starts 10 years after onset of the condition with routine colonoscopies every 1 to 5 years (depending on the risk). Previous history of colorectal malignancy also predisposes to a subsequent cancer and requires screening every few years.

Answer 2

Correct Answer: Cecum Explanation: The cecum is the most insidious site for colon cancer because: • Tumors in the cecum and ascending colon can grow large before causing symptoms due to the wide lumen and liquid stool content. • Patients often present late with iron deficiency anemia from chronic occult bleeding rather than obstructive symptoms. • Right-sided colon cancers are often diagnosed at advanced stages compared to left-sided tumors, which cause earlier symptoms like obstruction or altered bowel habits. Why Not the Other Options? • Ascending Colon – Similar to the cecum, but cecal tumors are usually more insidious. • Descending Colon – Left-sided tumors tend to present earlier with obstruction, tenesmus, or rectal bleeding. • Transverse Colon – Intermediate presentation, but not as silent as the cecum. • Sigmoid Colon – More common site for cancer, but presents earlier with obstructive symptoms due to narrower lumen. Conclusion: Cancers in the cecum grow silently for a long time, making it the most insidious site for colon cancer.

Answer 3

Giardia lamblia, also known as Giardia intestinalis and Giardia duodenalis, is a flagellated, anaerobic protozoon, which is an important cause of persistent diarrhoea or malabsorption. Giardia has an outer membrane that makes it possible to retain life even when outside of the host body which can make it tolerant to chlorine disinfection. There are multiple transmission methods including drinking infected water, which is the most common method of transmission for this parasite. It is also common in day-care centers (among children) where poor/undeveloped hygiene practices lead to feco-oral transmission. Suspect diarrhea when : • Acute diarrhea lasts more than a week • Traveller's diarrhea that has not resolved in over 10 days, and the symptoms started after return, with associated weight loss. • Diarrhea in day-care centers/ palliative care facilities. Investigation is usually via stool microscopy OC&P (ova, cysts and parasites).

Answer 4

Pathognomonic of Paget's disease is the presence of large, pale, vacuolated cells (Paget cells) in the rete pegs of the epithelium. Paget's disease may be confused with superficial spreading melanoma. Differentiation from pagetoid intrepithelial melanoma is based on the presence of S-100 antigen immunostaining in melanoma and carcinoembryonic antigen immunostaining in Paget's disease. Surgical therapy for Paget's disease may involve lumpectomy or mastectomy, depending on the extent of involvement of the nipple-areolar complex and the presence of DCIS or invasive cancer in the underlying breast parenchyma. None of the above

Answer 5

Glucagonoma syndrome is a rare syndrome, with a classic presentation of the "4 D's": diabetes, dermatitis, deep vein throm-bosis, and depression. It is also characterised by a severe catabolic state with weight loss, depletion of fat and protein stores, and associated vitamin deficiencies. The characteristic skin lesion, a necrolytic migrating erythema, is noted in approximately two thirds of patients and often appears before other symptoms of the syndrome

Answer 6

✅ Correct answer: D. Tolcapone Explanation: Catechol-O-methyltransferase (COMT) is an enzyme that breaks down catecholamines, including dopamine, in both the central and peripheral nervous systems. In Parkinson’s disease, dopamine levels are already low; therefore, inhibiting COMT helps prolong the action of levodopa by preventing its peripheral breakdown. Tolcapone (and its related drug entacapone) are COMT inhibitors used as adjuncts to levodopa/carbidopa therapy. They increase the half-life of levodopa and improve motor fluctuations (“wearing-off” effect). ⸻ Why the other options are incorrect: • A. Levodopa – Precursor of dopamine; increases dopamine synthesis, not a COMT inhibitor. • B. Trihexyphenidyl – Centrally acting antimuscarinic; used for tremor and rigidity, not dopaminergic. • C. Amantadine – Enhances dopamine release and blocks NMDA receptors; not a COMT inhibitor. • E. Ropinirole – Dopamine receptor agonist (directly stimulates dopamine receptors); does not inhibit COMT. ⸻ Key pharmacology tip for MRCS: • MAO-B inhibitors (e.g., selegiline, rasagiline) inhibit dopamine breakdown in the CNS. • COMT inhibitors (e.g., tolcapone, entacapone) inhibit peripheral dopamine and levodopa metabolism. • Tolcapone acts both centrally and peripherally, while entacapone acts only peripherally. ⸻ Mnemonic: 🧠 “COMT stops dopamine’s COMeTing down — Tolcapone helps it stay around.” Answer: D. Tolcapone • Levodopa is the single most effective agent in the treat- ment of PD.The effects of levodopa result from its decarboxylation to DA. In clinical practice, levodopa is almost always administered in combination with a peripherally acting inhibitor of AADC, such as carbidopa or benserazide, drugs that do not penetrate well into the CNS. If levodopa is administered alone, the drug is largely decarboxylated by enzymes in the intestinal mucosa and other peripheral sites so that relatively little unchanged drug reaches the cerebral circulation, and probably less than 1% penetrates the CNS. • Dopamine receptor agonists are proposed to have the potential to modify the course of PD by reducing endogenous release of DA as well as the need for exogenous levodopa, thereby reducing free-radical formation. Two orally administered DA receptor agonists are commonly used for treatment of PD: ropinirole and pramipexole.Ropinirole,pramipexole and rotigotine may produce hallucinosis or confusion, similar to that observed with levodopa, and may cause nausea and orthostatic hypotension. They should be initiated at low dose and titrated slowly to minimize these effects. • COMT inhibitors block this peripheral conversion of levodopa to 3-O-methylDOPA, increasing both the plasma t1/2 of levodopa and the fraction of each dose that reaches the CNS.The COMT inhibitors tolcapone and entacapone reduce significantly the "wearing off" symptoms in patients treated with levodopa/carbidopa. Common adverse effects of both agents include nausea, orthostatic hypotension, vivid dreams, confusion, and hallucinations. An important adverse effect associated with tolcapone is hepatotoxicity. • Selective MAO-B inhibitors are used for the treatment of PD: selegiline and rasagiline. These agents selectively and irreversibly inactivate MAO-B. Both agents exert modest beneficial effects on the symptoms of PD. Selegiline can lead to the development of stupor, rigidity, agitation, and hyperthermia when administered with the analgesic meperidine • Amantadine, an antiviral agent used for the prophylaxis and treatment of influenza A, has antiparkinsonian activity. Amantadine appears to alter DA release in the striatum, has anticholinergic properties, and blocks NMDA glutamate receptors. It is used as initial therapy of mild PD. It also may be helpful as an adjunct in patients on levodopa with dose-related fluctuations and dyskinesias. Dizziness, lethargy, anticholinergic effects, and sleep disturbance, as well as nausea and vomiting, side effects are mild and reversible. • Antimuscarinic drugs currently used in the treatment of PD include trihexyphenidyl and benztropine mesylate, as well as the antihistaminic diphenhydramine hydrochloride, which also interacts at central muscarinic receptors. The biological basis for the therapeutic actions of muscarinic antagonists is not completely understood. Adverse effects result from their anticholinergic properties. Most troublesome are sedation and mental confusion. All anti- cholinergic drugs must be used with caution in patients with narrow-angle glaucoma, and in general anticholinergics are not well tolerated in the elderly

Answer 7

Acute inflammation has three major components: • Dilation of small vessels leading to an increase in blood flow • Increased permeability of the microvasculature enabling plasma proteins and leukocytes to leave the circulation; and • Emigration of leukocytes from the microcirculation, their accumulation in the focus of injury, and their activation to eliminate the offending agent Granuloma formation is a feature of chronic inflammation.

Answer 8

This is a Bouchard node. The hard, bony growths in the PIP joint are exostoses, and are usually asymptomatic. They can occasionally cause finger tip deviation. Usually, Bouchard nodes are indicative of severe systemic osteoarthritis.

Answer 9

C. Torsion of a testicular or epididymal appendage characteristically affects boys just before puberty, possibly because of enlargement of the hydatid in response to gonadotropins. A hydatid of Morgagni is an embryological remnant found on the upper pole of the testis or epididymis. The pain often increases over a day or two. Occasionally, the torted hydatid can be felt or seen (blue dot sign). Excision of the appendage leads to rapid resolution of symptoms.

Answer 10

The correct answer is: E. Inflammation mediated by Th1 and Th17 cytokines Explanation: Ulcerative colitis (UC) is an idiopathic chronic inflammatory condition of the colon, and although the exact cause remains unclear, the pathogenesis is believed to involve a dysregulated immune response to intestinal flora in genetically susceptible individuals. The disease mechanism in UC is primarily associated with inflammatory responses mediated by Th2 and Th17 cells, though more recent research also highlights the role of Th1 and Th17 cytokines particularly in the broader category of IBD (including Crohn’s disease). • Th17 cells produce interleukin-17 (IL-17), a cytokine implicated in the recruitment of neutrophils and promotion of inflammation. • Th1 cells release interferon-gamma (IFN-γ), contributing to cellular immunity and inflammation. This immune-mediated inflammatory response leads to mucosal damage in the colon, characteristic of ulcerative colitis. The other options describe mechanisms associated with different immune conditions: • A. IgE antibodies – typical of type I hypersensitivity (e.g., allergies). • B. Antibody-mediated cellular dysfunction – seen in diseases like myasthenia gravis. • C. Antibody-mediated phagocytosis and opsonization – related to type II hypersensitivity. • D. Antigen-antibody complex deposition – hallmark of type III hypersensitivity (e.g., systemic lupus erythematosus).

Answer 11

The correct answer is: C. Endoplasmic reticulum Explanation: Döhle bodies are small, pale blue, cytoplasmic inclusions found in neutrophils. They are remnants of rough endoplasmic reticulum (RER) and are often seen in conditions involving increased neutrophil turnover or toxic granulation, such as in systemic inflammatory response syndrome (SIRS), sepsis, burns, or after administration of certain medications. These inclusions indicate accelerated neutrophil production in the bone marrow, with immature or toxic changes. Here’s why the other options are incorrect: • A. Mitochondria – do not form cytoplasmic inclusions like Döhle bodies. • B. Lysosomes – may contribute to toxic granules but not Döhle bodies. • D. Nucleus – Döhle bodies are cytoplasmic, not nuclear. • E. None of the above – incorrect because they specifically originate from RER.

Answer 12

The correct answer is: E. Stretch injury from the fracture displacement Explanation: This patient presents with a classic radial nerve palsy: • Wrist drop (inability to extend the wrist), • Loss of extension of fingers and thumb, • Numbness in the first dorsal web space (a key sensory distribution of the superficial branch of the radial nerve). The radial nerve travels in the radial (spiral) groove of the humerus, making it particularly vulnerable to injury in mid-shaft humeral fractures. Among the listed mechanisms: • Stretch injury from fracture displacement is the most common mechanism of radial nerve palsy in this context. The nerve gets stretched or entrapped by the displaced bone fragments, not necessarily cut or compressed. • Laceration by fracture fragment (A) is possible but less common than stretch injuries in closed fractures. • Direct blow (B) and crush injuries (C) might cause nerve injury but are less likely in this typical scenario. • Vascular injury (D) is unrelated to the specific nerve symptoms described.

Answer 13

The correct answer is: A. Frank-Starling law Explanation: The Frank-Starling law of the heart states that the stroke volume of the heart increases in response to an increase in the volume of blood filling the heart (the end-diastolic volume). This is due to the increased stretch of the ventricular myocardium, which optimizes the alignment of actin and myosin filaments, resulting in a stronger contraction. In simpler terms: the more the heart fills with blood during diastole, the greater the force of contraction during systole, up to a physiological limit. This ensures that the heart pumps out all the blood it receives, maintaining balance between venous return and cardiac output. Here’s why the others are incorrect: • B. Laplace law: Describes the relationship between pressure, wall tension, and radius in hollow organs. • C. Poiseuille law: Governs flow through a cylindrical vessel based on radius, viscosity, and pressure. • D. Bernoulli principle: Relates pressure and velocity in fluid dynamics.

Answer 14

The correct answer is: A. Comedo Explanation: Ductal carcinoma in situ (DCIS) is a non-invasive breast cancer confined to the ductal system. Among its various histological subtypes, the comedo type is considered the most aggressive and most likely to progress to invasive ductal carcinoma if left untreated. Comedo DCIS is characterized by: • High nuclear grade, • Central necrosis (often calcified and visible on mammography), • Rapid proliferation. The other types—micropapillary, papillary, and cribriform—tend to be lower grade and less likely to become invasive, though all forms of DCIS carry some risk. E. All of the above is incorrect because not all subtypes carry the same risk; comedo specifically stands out as the highest-risk histologic type for progression.

Answer 15

The correct answer is: A. She should ask the patient to be on the lookout for perioral tingling, ringing in the ears or excessive drowsiness. Explanation: Lignocaine toxicity can develop in case of accidental intravascular injection or loosening of a tourniquet during regional block. Symptoms include drowsiness, headache, perioral tingling, tinnitus and anxiety. Toxicity can lead to seizures, cardiovascular collapse, arrhythmias, and apnoea. If this develops, initial treatment should always follow ABC protocol - intubation may be necessary and IV fluids should be started. Treatment is mainly symptomatic and inotropic support may be needed. Incident Reports must always be filled when any avoidable error occurs in the hospital. These are used to document any problems faced in the workplace, including statements of how the problem came about and what corrective actions were taken. This is a standard procedure in hospitals in the UK. While it is crucial to monitor patients for signs of local anaesthetic systemic toxicity (LAST)—which includes symptoms like perioral tingling, tinnitus, metallic taste, dizziness, and in severe cases, seizures or cardiovascular collapse—it is not appropriate to rely on the patient to self-monitor for these signs, especially if they are sedated, anxious, or not medically trained. The appropriate course of action includes: • B. Informing nursing staff to closely observe the patient for any signs of toxicity. • C. Preparing for emergency management, including IV fluids and ICU transfer if needed. • D. Informing the anaesthetics team, as advanced airway support or lipid emulsion therapy may be required. • E. Completing an incident report, which is essential for patient safety, documentation, and reflective learning.

Answer 16

The correct answer is: D. Hypercalcemia Explanation: Massive transfusion—typically defined as the replacement of a patient’s total blood volume within 24 hours or transfusion of more than 10 units of packed red blood cells—can lead to several complications. Let’s review them: • A. Hypothermia – Stored blood is cold, and large volumes can cause hypothermia if not warmed properly. • B. Coagulopathy – Due to dilutional effects and consumption of clotting factors and platelets. • C. Hyperkalemia – Stored red cells can leak potassium, especially in older blood, which can lead to elevated serum potassium levels. • D. Hypercalcemia – This is not a complication. In fact, the opposite is true: hypocalcemia may occur because citrate used in blood products binds to calcium, reducing ionized calcium levels. So, hypercalcemia is not a complication—that makes D the correct answer here. Complications from a single transfusion It includes: • Incompatibility, haemolytic transfusion reaction; • Febrile transfusion reaction • Allergic reaction • Infection • Bacterial infection (usually due to faulty storage) • Hepatitis • HIV • Malaria • Air embolism • Thrombophlebitis • Transfusion-related acute lung injury (usually from FFP). Complications from massive transfusion: • Coagulopathy • Hypocalcaemia • Hyperkalaemia • Hypokalaemia • Hypothermia. Ref: Bailey & Love's Short Practice of Surgery, 27th Edition, Chapter 2.

Answer 17

The correct answer is: E. A, B, and C Explanation: To determine equivalent oral doses of different opioids from subcutaneous morphine, you need to consider both opioid equivalence and bioavailability. Step 1: Calculate the total daily oral morphine equivalent. • Subcutaneous morphine has higher bioavailability than oral morphine. • The usual conversion ratio is: subcutaneous morphine : oral morphine = 1 : 2. • So, 120 mg/day subcutaneous morphine = ~240 mg/day oral morphine. Step 2: Match oral alternatives. Let’s break down the options: • A. 40 mg immediate release morphine every 4 hours: • 6 doses/day → 40 mg × 6 = 240 mg/day oral morphine. Correct. • B. 120 mg sustained release oxycodone OD: • Oral oxycodone is approximately 1.5–2 times as potent as oral morphine. • So 120 mg oxycodone ≈ 180–240 mg morphine. Correct. • C. 16 mg sustained release hydromorphone BD: • Oral hydromorphone is ~5–7 times as potent as oral morphine. • 16 mg BD = 32 mg/day hydromorphone × 5–7 = 160–224 mg morphine. Correct. So, all three regimens are reasonable equivalents to 240 mg/day oral morphine, making the best answer: E. A, B, and C

Answer 18

The correct answer is: E. All of the above Explanation: Farabeuf’s triangle is an important anatomical landmark in neck surgery, particularly in vascular and lymph node dissections. It is bounded by: • Medially: Common facial vein • Laterally: Internal jugular vein (IJV) • Superiorly: Hypoglossal nerve (cranial nerve XII) Within or near this triangle, you’ll also find: • Jugulodigastric lymph node (a prominent lymph node in the upper deep cervical chain), • And the carotid bifurcation, which makes this area surgically significant. So, each structure listed: • IJV (A) – forms the lateral boundary, • Common facial vein (B) – forms the medial boundary, • Hypoglossal nerve (C) – forms the superior boundary, • Jugulodigastric node (D) – is located near/within this triangle, are indeed all related to Farabeuf’s triangle. Hence, the answer is E. All of the above.

Answer 19

The correct answer is: B. Glossopharyngeal nerve Explanation: This is a classic case of referred otalgia (ear pain) in a patient with acute tonsillitis. The glossopharyngeal nerve (cranial nerve IX) provides sensory innervation to: • The posterior third of the tongue, • The tonsils, • The oropharynx, • And importantly, the middle ear via the tympanic branch (Jacobson’s nerve). Because of this shared sensory pathway, inflammation or infection in the tonsillar region (as in tonsillitis) can refer pain to the ear, even if the ear exam is normal. Let’s rule out the others: • A. Facial nerve – primarily motor to muscles of facial expression; not involved in oropharyngeal sensation. • C. Hypoglossal nerve – motor to the tongue; no sensory role. • D. Lesser palatine nerve – sensory to soft palate, but not connected to the ear. • E. Superior laryngeal nerve – branch of the vagus nerve; sensory to the larynx above vocal cords, not the ear. So, glossopharyngeal nerve is responsible for the referred ear pain in tonsillitis.

Answer 20

The correct answer is: B. Avulsion of ureter Explanation: Percutaneous nephrolithotomy (PCNL) is a minimally invasive surgical procedure used to remove kidney stones through a small incision in the back. While it is generally safe, several complications can occur: Common complications of PCNL include: • A. Renal parenchymal haemorrhage – due to vascular injury during access or dilation. • C. Rupture of the collecting system – can occur with high-pressure irrigation or traumatic instrumentation. • D. Sepsis – due to bacteria released from infected stones or urine. • E. Pneumothorax – especially if upper pole access is attempted through the 10th or 11th intercostal space. B. Avulsion of ureter – This is not a complication of PCNL. It is typically associated with ureteroscopic procedures, especially when retrieving large or impacted stones, or during forceful stent placement. So, avulsion of the ureter is not a known risk of PCNL, making B the correct answer.

Answer 21

The correct answer is: D. Lymphangiosarcoma Explanation: This clinical scenario is classic for Stewart-Treves syndrome, which refers to the development of lymphangiosarcoma, a rare but aggressive malignant vascular tumor arising in the setting of chronic lymphoedema, often following mastectomy with axillary lymph node dissection and/or radiotherapy. Key features include: • History of breast cancer treatment (mastectomy + irradiation). • Long-standing lymphoedema in the upper limb. • Development of purple patches, nodules, or plaques on the edematous limb. • May be mistaken for bruises or hematomas initially. Let’s rule out other options: • A. Lymphoedema – is the predisposing condition but not the diagnosis in this case. • B. Thrombophlebitis – usually involves tender cords and erythema over veins. • C. DVT – uncommon in the upper limb and doesn’t present with nodules or purple patches. • E. Granulomas – are more associated with chronic inflammatory or infectious conditions, not post-radiation malignancy. Lymphangiosarcoma is a surgical emergency, as it is highly malignant and often necessitates radical surgery (like limb amputation) and/or chemotherapy.

Answer 22

The correct answer is: D. Diffuse axonal injury (DAI) Explanation: Diffuse axonal injury is a severe form of traumatic brain injury caused by shearing forces during rapid acceleration-deceleration, such as in high-speed motor vehicle accidents. It leads to widespread microscopic damage to axons, especially at the grey-white matter junction, corpus callosum, and brainstem. Key clues in this case: • High-impact trauma (car crash), • Persistent GCS of 3 despite resuscitation, • Normal CT scan initially (DAI may not show up clearly on CT; MRI is more sensitive), • No evidence of major hemorrhage or mass lesion. Why others are incorrect: • A. Concussion – usually has transient symptoms and GCS should improve. • B. Subarachnoid haemorrhage – would likely be visible on CT. • C. Intraventricular bleed – also visible on CT. • E. Alcohol induced coma – possible, but persistent GCS of 3 after resuscitation in trauma makes DAI more likely. So, the clinical picture fits diffuse axonal injury, making D the most likely diagnosis.

Answer 23

The correct answer is: E. It has no role in infectious diseases — this statement is false. Explanation: This technique is a special staining method. It detects a specific antigen using a specific antibody which is labelled with a dye and, when bound to its target antigen, is seen as a coloured stain. It determines cell type and differentiation and site of origin. The method has a role in the selection of treatment and in the prediction of prognosis. It also has a role in infections. There are antibodies to many infectious agents such as cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes virus and hepatitis B. Immunohistochemistry (IHC) is a powerful diagnostic tool that uses antibodies to detect specific antigens in tissue sections, making it valuable in both pathology and research. Let’s review each statement: • A. This is just a special staining method – True, though “just” understates its importance; IHC is a special stain using antibody-antigen interaction. • B. It relies on the use of a specific antibody – True, that’s fundamental to IHC. • C. It helps to determine cell type and differentiation – True, it’s commonly used to distinguish tumour subtypes (e.g., lymphoma vs carcinoma). • D. It has a role in the determination of treatment and prognosis – True, e.g., HER2 in breast cancer affects treatment decisions. • E. It has no role in infectious diseases – False. IHC can detect pathogens (like CMV, HSV, tuberculosis, fungi) in tissue by targeting their antigens, and is especially useful when cultures are negative or slow. Thus, E is the false statement, and therefore the correct answer.

Answer 24

The correct answer is: D. Transduction Explanation: NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) primarily act at the transduction phase of the pain pathway. Here’s how it works: Pain Pathway Steps: 1. Transduction – Conversion of a noxious stimulus (e.g., thermal or chemical from a burn) into an electrical signal at the peripheral nerve ending. NSAIDs act here by inhibiting cyclooxygenase (COX) enzymes, reducing prostaglandin production, which in turn lowers nociceptor sensitivity. 2. Transmission – The signal travels via peripheral nerves to the spinal cord and then the brain. 3. Modulation – The central nervous system modulates the pain signal through inhibitory or excitatory pathways. 4. Perception – Conscious awareness and interpretation of pain in the brain. So, NSAIDs reduce the generation of pain signals at the site of injury, specifically during transduction.

Answer 25

B. Q-angle Explanation: The Q-angle (Quadriceps angle) is a clinical measurement used to assess the alignment and biomechanics of the knee, particularly in relation to the patella and quadriceps muscle pull. The patellar ligament is the anterior ligament of the knee joint. Laterally, it receives the medial and lateral patellar retinaculum, aponeurotic expansions of the vastus medialis and lateralis and overlying deep fascia. The retinacula make up the joint capsule of the knee on each side of the patella and play an important role in maintaining alignment of the patella relative to the patellar articular surface of the femur. The oblique placement of the femur and/or line of pull of the quadriceps femoris muscle relative to the axis of the patellar tendon and tibia, assessed clinically as the Q-angle, favors lateral displacement of the patella. Key points about the Q-angle: • It represents the angle formed by: 1. A line drawn from the anterior superior iliac spine (ASIS) to the center of the patella. 2. A line from the center of the patella to the tibial tuberosity. • It reflects the lateral force vector applied by the quadriceps muscle on the patella. • Normal Q-angle: • Males: ~13° • Females: ~18° (due to wider pelvis) • Increased Q-angle can predispose to patellar subluxation/dislocation, especially laterally. Clinical relevance: This measurement is important in assessing patellofemoral pain syndrome, knee malalignment, and risk of patellar dislocation. Thus, the correct answer is B. Q-angle.

Answer 26

The correct answer is: A. Meckel’s diverticulum Explanation: In older children, the incidence of a pathologic lead point is up to 12%, and Meckel diverticulum is found to be the most common lead point for intussusception. However, other causes, such as intestinal polyps, an inflamed appendix, submucosal haemorrhage associated with Henoch-Schönlein purpura, a foreign body, ectopic pancreatic or gastric tissue, and intestinal duplication, must also be considered. Intussusception is a condition in which a segment of the intestine “telescopes” into an adjacent distal segment, leading to obstruction, ischemia, and bleeding. It is most common in infants and young children, presenting with: • Intermittent colicky abdominal pain • “Red currant jelly” stools (blood and mucus) • Palpable abdominal mass Pathological lead points: In most cases (especially under 2 years), intussusception is idiopathic and may be associated with Peyer’s patches hypertrophy (after viral infections). However, when a pathological lead point is identified, the most common cause in children is: • A. Meckel’s diverticulum – A remnant of the vitelline duct, often located in the ileum, and may contain ectopic gastric or pancreatic tissue. Other less common lead points include: • Polyps (B) – e.g., juvenile polyps, more common in older children. • Lymphoma (C) – more typical in older children and adolescents. • Duplication cyst (D) – rare congenital anomalies of the gut. So, the most common lead point in children is Meckel’s diverticulum.

Answer 27

B. Bohr effect Explanation: The Bohr effect describes the rightward shift of the oxygen-haemoglobin dissociation curve in response to a decrease in pH (acidosis) or an increase in carbon dioxide (CO₂). This shift facilitates the release of oxygen from haemoglobin in tissues where it is most needed (e.g., active muscles producing CO₂ and H⁺). Key features of the Bohr effect: • Lower pH (more acidic) → rightward shift • Increased CO₂ → rightward shift • Promotes oxygen unloading in tissues. Let’s look at the other options: • A. Haldane effect – Describes how oxygenation of blood in the lungs displaces CO₂ from haemoglobin, enhancing CO₂ removal. • C. Pasteur effect – Refers to the inhibition of glycolysis by oxygen. • D. Rebound effect – A general term not specific to respiratory physiology. • E. Breuer effect – Possibly referring to the Hering–Breuer reflex, which prevents lung overinflation. Thus, the Bohr effect is the best explanation for the rightward shift due to a fall in pH.

Answer 28

The correct answer is: C. Internal thoracic artery Explanation: In coronary artery bypass grafting (CABG), the preferred and most durable conduit is the internal thoracic artery (ITA)—specifically the left internal thoracic artery (LITA). Reasons: • Superior long-term patency rates compared to vein grafts. • Resistant to atherosclerosis. • Most commonly anastomosed to the left anterior descending artery (LAD), which is often the most critical artery in terms of myocardial perfusion. The other options: • A. Great saphenous vein – Frequently used as a secondary conduit, especially for multiple grafts, but has lower patency than ITA. • B. Short saphenous vein – Rarely used due to smaller size and variable anatomy. • D. Radial artery – A good alternative arterial conduit, used when additional arterial grafts are needed. • E. Axillary vein – Not used for CABG. So, the internal thoracic artery is the gold standard conduit for CABG. In earlier coronary artery bypass operations, a suitable length of great saphenous vein was anastomosed at one end to the ascending aorta and at the other to the appropriate coronary vessel distal to the site of blockage. The vein, of course, must be turned upside down so that any valves in the chosen segment do not obstruct the arterial flow. Current opinion now often favours the use of the internal thoracic artery, particularly for the left anterior descending artery; the proximal end remains intact at its subclavian origin and the cut lower end is anastomosed to the coronary vessel. Three or four coronary arteries may be bypassed in the same patient utilizing both internal thoracic arteries and vein grafts or free arterial segments (such as from the radial artery).

Answer 29

The correct answer is: A. Recurrent inflammation Explanation: The most important and common reason to remove a thyroglossal duct cyst is recurrent infection or inflammation. These cysts often present in childhood or adolescence as a midline neck swelling that may become tender, enlarge, or drain during episodes of infection. Why the others are incorrect: • B. Malignancy – While possible, malignancy in a thyroglossal cyst (usually papillary carcinoma) is rare (~1%). • C. Aberrant tissues – Thyroglossal cysts may contain ectopic thyroid tissue, but this alone isn’t a primary reason for removal. • D. Hyperthyroidism – Unrelated; thyroglossal cysts typically don’t secrete thyroid hormones. Surgical removal: The standard procedure is the Sistrunk operation, which involves excising the cyst, the tract, and the central portion of the hyoid bone to reduce recurrence.

Answer 30

The correct answer is: D. Lies in the middle third of a line between the intertragic notch of the auricle and the midpoint of the philtrum Explanation: The parotid (Stensen’s) duct is about 5 cm long, not 1 cm. It arises from the anterior border of the parotid gland, passes over the masseter muscle, and then pierces the buccinator muscle to open opposite the second upper molar tooth, not the first lower molar (which is the submandibular duct’s location). Importantly, it lies in the middle third of a line drawn from the intertragic notch (just below the ear) to the midpoint of the philtrum of the upper lip, which is a classic anatomical landmark used in clinical assessment and procedures involving the duct. Let’s quickly go through the other options: • A refers to the submandibular (Wharton’s) duct, not the parotid duct. • B is incorrect; the opening is opposite the second upper molar, not the first lower. • C is incorrect; the duct is approximately 5 cm long. • E is incorrect; the parotid duct does not run between the mylohyoid and hyoglossus—that’s the course of the submandibular duct.

Answer 31

The correct answer is: D. Rapid influx of sodium Explanation: Phase 0 of the cardiac action potential is characterized by a rapid depolarization of the cardiac cell membrane. This is due to the sudden influx of sodium ions (Na⁺) through fast voltage-gated sodium channels. This phase marks the upstroke of the action potential in non-pacemaker (contractile) cardiac cells such as ventricular myocytes. Here’s a quick summary of the cardiac action potential phases: • Phase 0: Rapid Na⁺ influx (depolarization) • Phase 1: Initial repolarization (brief K⁺ efflux) • Phase 2: Plateau (influx of Ca²⁺ balanced by K⁺ efflux) • Phase 3: Repolarization (K⁺ efflux) • Phase 4: Resting potential

Answer 32

The correct answer is: B. Female gender Explanation: Female gender is not considered a risk factor for ischaemic heart disease (IHD); in fact, pre-menopausal women are relatively protected due to the cardioprotective effects of estrogen. However, this protection diminishes after menopause, and the risk eventually becomes similar to that in men. Here’s how the other options relate to IHD risk: • A. Obesity: Increases risk due to its association with hypertension, diabetes, and dyslipidemia. • C. Advancing age: A well-established non-modifiable risk factor. • D. Reduced physical activity: A modifiable risk factor. • E. Smoking: A major modifiable risk factor that damages vascular endothelium and accelerates atherosclerosis.

Answer 33

The correct answer is: **B. Medulla** The **vagus nerve (CN X)** and the **hypoglossal nerve (CN XII)** nuclei are located in the **medulla oblongata** of the brainstem. - The **dorsal motor nucleus of the vagus** and the **nucleus ambiguus** (which contributes motor fibers to the vagus nerve) are found in the medulla. - The **hypoglossal nucleus** (which controls tongue movement via CN XII) is also located in the medulla. ### Breakdown of the other options: - **A. Pons** – Contains nuclei for CN V, VI, VII, and VIII, but not X or XII. - **C. Cerebrum** – Not part of the brainstem; does not contain cranial nerve nuclei. - **D. Midbrain** – Contains nuclei for CN III and IV, but not X or XII. - **E. Any of the above** – Incorrect, as only the medulla houses these nuclei. Thus, damage to the **medulla** can affect the vagus and hypoglossal nerve nuclei.

Answer 34

The correct answer is: **D. CLL (Chronic Lymphocytic Leukemia)** **Smudge cells** (also called **basket cells**) are a hallmark finding in **CLL**. They are fragile, ruptured lymphocytes that appear as smudged or broken cells on a peripheral blood smear due to their fragility during slide preparation. ### Why not the other options? - **A. CML (Chronic Myeloid Leukemia)** – Typically shows **myeloid precursors** (e.g., myelocytes, metamyelocytes) and **basophilia**, not smudge cells. - **B. AML (Acute Myeloid Leukemia)** – Presents with **myeloblasts** and **Auer rods**, not smudge cells. - **C. ALL (Acute Lymphoblastic Leukemia)** – Shows **lymphoblasts**, which are larger and more uniform, not smudge cells. - **E. Hodgkin's lymphoma** – Diagnosed by **Reed-Sternberg cells** in lymph nodes, not smudge cells in peripheral blood. ### Key Point: Smudge cells are most characteristic of **CLL**, where they result from the fragility of malignant B lymphocytes (CD5+/CD19+/CD23+). A high smudge cell count may correlate with disease burden.

Answer 35

D. It is designed to answer: “What standard does this service achieve?” Explanation: A clinical audit is a quality improvement process that seeks to improve patient care and outcomes through systematic review of care against explicit criteria and the implementation of change. The key elements involve: • Measuring current practice against a predetermined standard • Identifying areas for improvement • Implementing necessary changes • Re-auditing to assess the effect of changes Let’s review the other options: • A: Incorrect. While audits assess current care, they are also about improving care, not just judging it. • B: Incorrect. Randomisation is a feature of clinical trials, not audits. • C: Incorrect. Clinical audits may involve existing interventions, but this isn’t the defining feature. • E: Incorrect. An audit must compare current service against a set standard, not just describe it.

Answer 36

Descending thoracic aorta commences at the lower border of T4 vertebra, where the arch of the aorta ends. At first to the left of the midline, the vessel slants gradually to the midline and leaves the posterior mediastinum at the level of T12 vertebra by passing behind the diaphragm between the crura (i.e. behind the median arcuate ligament). It gives off nine pairs of posterior intercostal arteries, a pair of subcostal arteries, bronchial arteries, esophageal vessels and a few small pericardial and phrenic branches.

Answer 37

The correct answer is: B. Chronic, compensated respiratory acidosis Here’s why: Let’s interpret the blood gases step by step: • pH: 7.37 — This is within the normal range, but on the acidic side, suggesting compensation. • PaCO₂: 10 kPa — This is very high, indicating respiratory acidosis. • HCO₃⁻: 31 mmol/L — This is elevated, indicating renal compensation by retaining bicarbonate to buffer the acidosis. • PaO₂: 10 kPa — Slightly low, consistent with COPD. Conclusion: This patient with known COPD has: • A high PaCO₂, consistent with chronic CO₂ retention. • A normal pH, maintained by a raised bicarbonate, indicating the kidneys have compensated. • This is a typical picture of chronic, compensated respiratory acidosis. Other options: • A: Acute respiratory acidosis would show low pH without time for renal compensation. • C: In acute-on-chronic, you’d usually see a drop in pH due to the acute element. • D: Respiratory alkalosis would show low PaCO₂. • E: Metabolic acidosis would present with low HCO₃⁻ and low pH.

Answer 38

Solution Lobectomy. Patients with potentially resectable tumors require careful assessment of their functional status and ability to tolerate either lobectomy or pneumonectomy. The surgeon should first estimate the likelihood of pneumonectomy, lobectomy, or possibly sleeve resection, based on the CT images. A sequential process of evaluation then unfolds. A patient's history is the most important tool for gauging risk. Specific questions regarding performance status should be routinely asked. If the patient can walk on a flat surface indefinitely, without oxygen and without having to stop and rest secondary to dyspnea, he will be very likely to tolerate lobectomy. If the patient can walk up two lights on stairs (up two standard levels), without having to stop and rest secondary to dyspnea, he will likely tolerate pneumonectomy. Finally, nearly all patients, except those with carbon dioxide (CO2 ) retention on arterial blood gas analysis, will be able to tolerate periods of single-lung ventilation and wedge resection.

Answer 39

The correct answer is: B. The underlying pathology involves all layers of the bowel wall Here’s why: This patient presents with: • Left iliac fossa (LIF) pain • Fresh rectal bleeding • Longstanding constipation • No systemic symptoms like weight loss These features are most consistent with diverticular disease, likely diverticulitis or bleeding from a colonic diverticulum. Key facts about diverticular disease: • Pathology: Diverticula are mucosal herniations through the muscular layer at points of weakness — typically where vessels penetrate the bowel wall. So, A is true. • Layers involved: Diverticula are not full-thickness defects — they are false diverticula, involving mucosa and submucosa only, not all bowel layers. So, B is not true. • Common location: Most often in the sigmoid and descending colon. So, C is true. • Epidemiology: Common in Western populations, linked with low-fibre diets. So, D is true. • Rectum: Almost never affected due to stronger longitudinal muscle layer. So, E is true. Therefore: B is not true, making it the correct answer to the “not true” question.

Answer 40

The correct answer is: A. Hereditary spherocytosis Here’s why: Intravascular hemolysis occurs when red blood cells (RBCs) are destroyed within the blood vessels, leading to the release of free hemoglobin into the plasma. Let’s examine each option: • A. Hereditary spherocytosis: • This is primarily a cause of extravascular hemolysis, where spherocytes are removed by the spleen. • It does not typically cause intravascular hemolysis, hence this is the correct answer to the “except” question. • B. Prosthetic heart valves: • Can cause mechanical destruction of RBCs in circulation — a classic cause of intravascular hemolysis. • C. Thrombotic vessel (e.g., microangiopathic hemolytic anemia): • RBCs get sheared as they pass through narrowed or damaged vessels — another cause of intravascular hemolysis. • D. Marathon running: • Known to cause foot strike hemolysis, a mild form of intravascular hemolysis due to mechanical trauma. • E. All of the above: • Incorrect, as A is not a cause of intravascular hemolysis. Summary: Hereditary spherocytosis causes extravascular, not intravascular, hemolysis — making A the correct choice.

Answer 41

Solution Descending thoracic aorta commences at the lower border of T4 vertebra, where the arch of the aorta ends. At first to the left of the midline, the vessel slants gradually to the midline and leaves the posterior mediastinum at the level of T12 vertebra by passing behind the diaphragm between the crura (i.e. behind the median arcuate ligament). It gives off nine pairs of posterior intercostal arteries, a pair of subcostal arteries, bronchial arteries, esophageal vessels and a few small pericardial and phrenic branches.

Answer 42

The correct answer is: C. Relative risk Explanation: In a cohort study, participants are followed over time to see who develops the outcome of interest. This allows researchers to calculate incidence rates in both the exposed and unexposed groups. The relative risk (RR)—also called the risk ratio—is the standard outcome measure for cohort studies. It compares the probability of the outcome in the exposed group to the unexposed group. Let’s briefly review the other options: • A. Odds ratio – Typically used in case-control studies. • B. Experimental event rate – Applies to clinical trials, not observational studies. • D. Absolute risk increase – Can be calculated in cohort studies but is less commonly the primary measure. • E. Numbers needed to harm (NNH) – Derived from absolute risk measures, also more commonly associated with clinical trials. • Strength of association in a cohort study is evaluated by Relative risk (RR), Attributable risk (AR) and Population attributable risk (PAR) • Relative risk (RR) = Incidence among exposed/ Incidence among non-exposed • Interpretation of RR: Incidence of lung disease among exposed IS SO MANY TIMES HIGHER as compared to that among non-exposed • Attributable risk (AR) = (Incidence among exposed - Incidence among non- exposed) / Incidence among exposed × 100 • Interpretation of AR: So much disease can be attributed to exposure • Population attributable risk (PAR) = (Incidence among total - Incidence among non- exposed) / Incidence among total × 100 • Interpretation of PAR: If risk factor is modified or eliminated, there will be so much annual reduction in incidence of disease in the given population

Answer 43

The structures passing through the foramen magnum include: the medulla oblongata; meninges; spinal parts of the accessory nerves; meningeal branches of the upper cervical nerves; the vertebral arteries; and the anterior and posterior spinal arteries. The correct answer is: D. The medulla oblongata and the spinal accessory nerve Explanation: The foramen magnum is the largest opening in the base of the skull and serves as a passage for several critical structures: • The medulla oblongata, which continues as the spinal cord. • The spinal root of the accessory nerve (cranial nerve XI), which ascends through the foramen magnum to join its cranial component before exiting the skull via the jugular foramen. • Vertebral arteries and meninges also pass through. This question links to the clinical scenario: the inability to shrug the shoulder suggests spinal accessory nerve (CN XI) damage, which innervates the trapezius muscle. Compression or traction injury from carrying a heavy backpack could lead to this. Other nerves listed pass through different foramina: • Facial nerve (VII): stylomastoid foramen. • Hypoglossal nerve (XII): hypoglossal canal. • Optic nerve (II): optic canal. • Vestibulocochlear nerve (VIII): internal acoustic meatus.

Answer 44

Dexamethasone (Option b) is commonly used to reduce cerebral edema and manage symptoms in patients with brain metastases, providing relief from blurring of vision, headaches, and nausea.

Answer 45

It is a T cell lymphoma affecting the skin which can evolve into generalized lymphoma.tumor of CD4 + helper T cells that home to the skin. Clinically, the cutaneous lesions of mycosis fungoides typically progress through three somewhat distinct stages, an inflammatory premycotic phase, a plaque phase, and a tumor phase. Histologically, the epidermis and upper dermis are infiltrated by neoplastic T cells, which often have a cerebriform appearance due to marked infolding of the nuclear membrane. Late disease progression is characterized by extracutaneous spread, most commonly to lymph nodes and bone marrow.

Answer 46

Fall on an outstretched hand can result in scaphoid fracture. The most common symptom is pain and tenderness over the anatomic snuffbox. The pain is often mild with no noticeable deformity or swelling. The pain may even improve in the days and weeks after the fracture. Although X-rays are the primary imaging tool, these fractures may not show up on them. Therefore, if suspected clinically, immobilisation with a thumb splint should be done till repeat X-rays after 2 weeks show healing (thus making the fracture more noticeable).

Answer 47

Answer: A - Cecum Explanation: Cecal (right-sided) colon cancers, including those in the ascending colon, are often termed “insidious” because they tend to grow larger before presenting with symptoms. This is due to the larger diameter of the right colon and the more liquid nature of the fecal content, which delays the onset of obstructive symptoms. As a result, patients may not notice changes in bowel habits early. Symptoms like anemia (from chronic blood loss) and fatigue are often the first signs, rather than pain or obstruction, making them harder to detect early. In contrast, left-sided cancers (like those in the sigmoid and descending colon) more often present earlier with changes in bowel habit, obstruction, or bleeding due to the smaller lumen and more formed stool.

Answer 48

Hypoglossal nerve is a part of the anterior triangle of the neck. Nerves within the posterior triangle of the neck are: • Accessory nerve • Phrenic nerve • Three trunks of the brachial plexus • Branches of the cervical plexus: Supraclavicular nerve, transverse cervical nerve, great auricular nerve, lesser occipital nerve

Answer 49

Hormones that use the adenylyl-cyclase cAMP second messenger system are: • ACTH • Angiotensin II on epithelial cells • Calcitonin Catecholamines on beta receptor • CRH • FSH • Glucagon • HCG • LHI • PTH • Secretin • Somatostatin • TSH • Vasopressin V2 receptor on epithelial cells TRH stands for Thyrotropin Releasing Hormone which predominantly uses the phosphoinositol second messenger system.

Answer 50

Emphysema is defined by irreversible enlargement of the airspaces distal to the terminal bronchiole, accompanied by destruction of their walls. Based on the segments of the respiratory units that are involved, emphysema is subdivided into four major types: • Centriacinar • Panacinar • Paraseptal • Irregular. Centriacinar emphysema is the most common form, constituting more than 95% of clinically significant cases. It occurs predominantly in heavy smokers with COPD.

Answer 51

Colles' fracture is a transverse fracture of the radius just above the wrist, with dorsal displacement of the distal fragment. X-ray findings demonstrate a transverse fracture of the distal radius, and often the ulna styloid process is broken off. The distal fragment is: • shifted and tilted backwards (dorsally) • shifted and tilted radially • impacted, and reduction should aim to reverse these changes. Rupture of the extensor pollicis longus tendon may occur as a late complication. Most Colles' fractures are treated in plaster for six weeks, but in young patients it may be necessary to restore normal alignment by internal fixation especially when cosmetic appearances or type of occupation may be adversely affected by residual deformity or loss of movement.

Answer 52

C. Dermoid cysts arise from cystic change in epithelial remnants left behind at lines of embryological fusion. They are usually found in the midline of the scalp, neck and lower jaw. Treatment is by excision.

Answer 53

With the hypercalcemia combined with the normal albumin and PTH levels, the 2 main differentials in this patient are primary hyperparathyroidism and familial hypocalciuric hypercalcemia. Therefore, the most useful next step to differentiate between these two disorders is 24-h urinary calcium, which will be low in familial hypocalciuric hypercalcemia and high in primary hyperparathyroidism. Obtaining serum calcium values from first-degree relatives in the absence of a family history can be helpful. Ref: Afzal M, Kathuria P. Familial Hypocalciuric Hypercalcemia. [Updated 2020 Jul 20]. In: StatPearls [Internet].

Answer 54

D. This wound is an example of healing by first intention. • When the injury involves only the epithelial layer, the principal mechanism of repair is epithelial regeneration, also called primary union or healing by first intention. One of the simplest examples of this type of wound repair is the healing of a clean, uninfected surgical incision approximated by surgical sutures. • Wounding causes the rapid activation of coagulation pathways, which results in the formation of a blood clot on the wound surface • Within 24 hours, neutrophils are seen at the incision margin, migrating toward the fibrin clot. • Within 24 to 48 hours, epithelial cells from both edges have begun to migrate and proliferate along the dermis yielding a thin but continuous epithelial layer that closes the wound. • By day 3, neutrophils have been largely replaced by macrophages, and granulation tissue progressively invades the incision space. • By day 5, neovascularization reaches its peak as granulation tissue fills the incisional space. • During the second week, there is continued collagen accumulation and fibroblast proliferation. • By the end of the first month, the scar comprises a cellular connective tissue largely devoid of inflammatory cells and covered by an essentially normal epidermis. • Carefully sutured wounds have approximately 70% of the strength of normal skin, largely because of the placement of sutures. • Wound strength reaches approximately 70% to 80% of normal by 3 months but usually does not substantially improve beyond that point.

Answer 55

C. Chemotherapy has developed an increasing role over the past two decades in the treatment of head and neck SCCs. For early-stage patients, treatment consists of either radiation therapy or surgery, with chemotherapy having little to no role in the treatment. It is never used as a primary single-modality treatment for head and neck cancers with an intent to cure. For patients with advanced metastatic or recurrent disease, chemotherapy can be used in the palliative setting to inhibit tumor growth for a limited effective period. Its main role is in the treatment of locoregionally advanced stage III/IV cancer. A second role of chemotherapy in this group of patients is for organ preservation. Patients with an advanced primary T stage are best served by total laryngectomy. For advanced-stage unresectable tumors, concurrent chemoradiation therapy, compared with radiation therapy alone, has shown an improved locoregional control with a questionable overall survival benefit. Ref: Yeh SA. Radiotherapy for head and neck cancer. Semin Plast Surg. 2010;24®:127-136. doi:10.1055/s-0030-1255330

Answer 56

70-75% of the breast's drainage is laterally and superiorly into the axillary lymph nodes. Axillary LNs have 3 surgical levels: • Level 1: below the pectoralis minor • Level 2: behind the pectoralis minor • Level 3: between the upper border of pectoralis minor and lower border of the clavicle. Most of the remaining drainage is to the parasternal nodes, deep in the anterior thoracic wall. Some drainage is also covered by lateral branches of the posterior intercostal nodes

Answer 57

C Von Willebrand disease is the most common inherited bleeding disorder of humans. The bleeding tendency is usually mild and often goes unnoticed until some hemostatic stress, such as surgery or a dental procedure, reveals its presence. It is usually transmitted as an autosomal dominant disorder, but rare autosomal recessive variants also exist. Type 1 and type 3 von Willebrand disease are associated with quantitative defects in vWF. Type 2 von Willebrand disease is characterized by qualitative defects in vWF Patients with von Willebrand disease have defects in platelet function despite having normal platelet counts. Because a deficiency of VWF decreases the stability of factor VIII, type 1 and type 3 von Willebrand disease are associated with a prolonged PTT. Persons with types 1 or 2 von Willebrand disease facing hemostatic challenges (dental work, surgery) can be treated with desmopressin (which stimulates vWF release), infusions of plasma concentrates containing factor VIll and vWF, or with recombinant VWF.

Answer 58

E S/c oxycodone dose = s/c morphine dose/2 = 60 mg/day Breakthrough dose = 1/6th of daily dose = 6 mg oxycodone (or) 12 mg morphine prn (every 4 hours) Oral oxycodone dose = oral morphine dose/2 s/c morphine dose = oral morphine dose/ 2

Answer 59

D Fibrocystic breast disease, also known as fibroadenosis or fibrosclerosis, is an aberration of normal development and involution of the breast (ANDI). Symptoms vary widely, and include some combination of breast nodularity, tender lumps, cysts, and pain. Symptoms are usually cyclical and peak in the premenstrual phase (luteal phase). The upper outer quadrant is most often affected. This condition is not considered a disease, but a part of a natural physiological process caused by cumulative exposure to hormones. This is supported by the fact that it is rarely seen before 30 years, with incidence peaking in the pre-menopausal years and decreasing after menopause. It is not a malignant condition and is only considered premalignant if associated with the presence of atypia.

Answer 60

The biceps tendon inserts at the neck of the fibula in the lateral aspect of the back of the knee. Here, the common peroneal nerve winds around the neck of the fibula before dividing into superficial and deep branches. Therefore it is at risk of injury here. Piriformis m. Sciatic nerve Long head of biceps femoris Semimembranosus and semitendinosus m. Tibial nerve Common peroneal nerve Ref: Image from Sehmbi, Herman & Shah, Ushma. (2013). Ultrasound-guided Approaches to Sciatic Nerve Block. International Journal of Perioperative Ultrasound and Applied Technologies. 2. 135-137. 10.5005/jp-journals-10027-1052.

Answer 61

B Diagnostic peritoneal lavage (DPL) is a test used to assess the presence of blood or contaminants in the abdomen. A gastric tube is placed to empty the stomach and a urinary catheter is inserted to drain the bladder. A cannula is inserted below the umbilicus, directed caudally and posteriorly. The cannula is aspirated for blood (>10 mL is deemed as positive) and, following this, 1000 mL of warmed Ringer's lactate solution is allowed to run into the abdomen and is then drained out via the same route. The presence of >100000 red cells/uL or >500 white cells/uL is deemed positive (this is equivalent to 20 mL of free blood in the abdominal cavity), as is the presence of vegetable fiber or a raised amylase level. In penetrating trauma, a minimum of one tenth of the above would be regarded as evidence of peritoneal penetration or intraperitoneal injury.

Answer 62

O negative is the universal donor group. O negative blood can be transfused in anyone since it does not have any antibodies.

Answer 63

Syringomyelia patients may present with sensory disturbance, weakness of the hands, loss of pain and temperature sensation, asymmetrical abdominal reflexes or progressive kyphoscoliosis. It is associated with Arnold-Chiari malformation and spinal cord tumours. Where syringomyelia is associated with an Arnold- Chiari malformation and scoliosis, a posterior cranial fossa decompression should be carried out first to resolve the syringomyelia. The scoliosis may then be corrected at a later date.

Answer 64

Patients with scaphoid fractures will typically present following a fall on an outstretched hand. The patient exhibits several common symptoms including pain in the anatomical snuff box, between the tendons of the abductor pollicis longus, and decreased grip strength. When pain occurs in the anatomical snuff box after trauma, the injury should be treated as a scaphoid fracture until proven otherwise; initial x-rays may not reveal the fracture in up to 25% of cases.

Answer 65

JVP has 3 Upward deflections and 2 downward deflections. Upward deflections: • a wave = atrial contraction; • c wave = ventricular contraction; • v wave = atrial venous filling. Downward deflections: • x wave = atrium relaxes and tricuspid valve moves down; • y wave = ventricular filling

Answer 66

A Temporal lobe infarct - homonymous superior quadrantanopia Right lobe = Left visual field = Left homonymous superior quadrantanopia Visual field defects: 1. Monocular blindness: Lesions of the optic nerve (Relative afferent pupillary defect +) and structures anterior to it (diseases of the eyeball) 2. Bitemporal homonymous hemianopia: Lesion of optic chiasm eg. Pituitary tumours 3. Homonymous hemianopia: Lesions of the optic tract and radiating fibres leaving the lateral geniculate body. Eg. Stroke, Neoplasms. Left homonymous hemianopia = Left visual field loss = Right sided lesion They are often associated with contralateral hemiparesis 1. Homonymous superior quadrantanopia: Temporal lobe lesions (inferior optic radiating fibres) AKA Pie in the Sky (Remember: Temples reach into the sky) Seen in temporal lobe strokes (MCA territory strokes) and can be associated with audio-visual hallucinations, seizures, aphasia, or memory disturbances. Visual loss is contralateral to the side of the lesion. 1. Homonymous inferior quadrantanopia: Parietal lobe lesions (superior optic radiations) AKA Pie on the Floor (Remember: Parties happen on the floor) Seen in parietal lobe strokes/neoplasms - lesion contralateral to visual defect Dominant lobe lesion: associated with agnosia, agraphia, acalculia Non-dominant lobe: associated with contralateral hemi-neglect 1. Homonymous hemianopia with macular sparing: Occipital lobe lesions Macular region is spared because it is represented at the tip of the occipital cortex, where there is dual blood supply from MCA and PCA

Answer 67

DDH (developmental dysplasia of the hip) is a disorder that is due to abnormal development of acetabulum with or without hip dislocation. Early diagnosis and management will prevent long term complications like persistent dislocation and early hip osteoarthritis. The following are the risk factors for DDH: female sex, first-born infant, breech positioning in the third trimester, swaddling, postmaturity, LGA, conditions causing limited in utero space, and family history. Unilateral involvement in 63% and 64% involves the left side due to in utero most frequent fetal positioning (left occipitoanterior). The left hip of the fetus is adducted against the mother's lumbosacral spine. If hip examination in a newborn reveals abnormalities, then a US scan is requested. The timing of the scan is at 4-6 weeks, to reduce splint age in children that do not require it, as the majority of lax capsules will tighten up by this stage.

Answer 68

Actinomyces israelii is a gram positive bacillus and a normal colonizer of the mouth, vagina and colon. It is an anaerobe that causes a large continuously growing mass with intense fibrosis and multiple sinus tracts. Listeria monocytogenes, Bacillus cereus and Corynebacterium difficile are gram positive, aerobic bacilli. Pseudomonas aeruginosa is a gram negative aerobic bacillus that mainly affects immunocompromised hosts.

Answer 69

Staghorn calculi associated with Proteus infections are often composed of struvite (Option c). Struvite stones can form in alkaline urine and are frequently associated with urinary tract infections.

Answer 70

Lesion will potentially metastasize to: Inguinal lymph nodes

Answer 71

The caudate lobe consists of 3 portions: • The Spiegel lobe - Couinaud's segment I • The paracaval portion - Couinaud's segment IX • The caudate process

Answer 72

The long thoracic nerve (of Bell) is formed directly from the C5, C6 and C7 roots. It travels posteriorly to the C8 and T1 roots, and superficially over the serratus anterior muscle in the medial axilla where it is vulnerable to damage during axillary dissection. Damage to the long thoracic nerve leads to winging of the scapula. The brachial plexus with its main branches is shown in schematic in the image below. The three posterior divisions form the posterior cord. The medial and lateral cords form the median nerve. The C8 and T1 anterior division continues as the medial cord. A. From the superior trunk C5, C6 and C7 roots. The superior trunk gives off the suprascapular nerve, and the nerve to subclavius. The long thoracic nerve is formed directly from the B. From all three posterior divisions The long thoracic nerve is formed directly from the C5, C6 and C7 roots. The posterior divisions all unite to form the posterior cord, which gives off the upper and lower subscapular nerves, and thoracodorsal nerve and the axillary nerve before terminating as the radial nerve. C. From the medial and lateral cords The medial and lateral cords form the median nerve, with the lateral cord terminating as the musculocutaneous nerve and the medial cord terminating as the ulnar nerve. They do not contribute to the long thoracic nerve. D. From the C8 and T1 roots The long thoracic nerve is formed from the C5, C6 and C7 roots, not the C8 and T1 roots. The C8 and T1 roots contribute to the median and ulnar nerves, supplying the intrinsic muscles of the hand (via the ulnar nerve), and the thenar muscles and lateral two lumbricals (via the median nerve).

Answer 73

The surgical neck of the humerus is above the deltoid tuberosity and the anatomical neck of the humerus represents the fused epiphyseal plate. The lateral attachment of the glenohumeral joint capsule attaches to the anatomical neck of the humerus. The medial attachment of the joint capsule is the glenoid and the labrum.

Answer 74

A greenstick fracture is a partial thickness fracture where only cortex and periosteum are interrupted on one side of the bone, while they remain uninterrupted on the other side. Paediatric fracture patterns Bending force Plastic deformation of ulna Greenstick Buckle (torus) fracture radius There is a difference between buckle fracture and greenstick fractures. Buckle fractures (also called torus) are defined as a compression of the bony cortex on one side with the opposite cortex remaining intact. In contrast, a greenstick fracture the opposite cortex is not intact.

Answer 75

Isolated IgA deficiency is a common immunodeficiency caused by impaired differentiation of naïve B lymphocytes to IgA-producing plasma cells. The molecular basis of this defect in most patients is unknown; defects in a receptor for a B cell-activating cytokine, BAFF, have been described in some patients. Most individuals with IgA deficiency are asymptomatic. Because IgA is the major antibody in mucosal secretions, mucosal defenses are weakened, and infections occur in the respiratory, gastrointestinal, and urogenital tracts. Symptomatic patients commonly present with recurrent sinopulmonary infections and diarrhea. IgA-deficient patients have a high frequency of respiratory tract allergy and a variety of autoimmune diseases, particularly SLE and rheumatoid arthritis. When transfused with blood containing normal IgA, some patients develop severe, even fatal, anaphylactic reactions, because the IgA behaves like a foreign antigen.

Answer 76

B Creatinine is a by-product of muscle metabolism and is cleared from the body fluids almost entirely by glomerular filtration. Therefore, creatinine clearance can also be used to assess GFR. Because measurement of creatinine clearance does not require intravenous infusion into the patient, this method is much more widely used than inulin clearance for estimating GFR clinically. However, creatinine clearance is not a perfect marker of GFR because a small amount of it is secreted by the tubules, so the amount of creatinine excreted slightly exceeds the amount filtered. There is normally a slight error in measuring plasma creatinine that leads to an overestimation of the plasma creatinine concentration; fortuitously, these two errors tend to cancel each other. Therefore, creatinine clearance provides a reasonable estimate of GFR.

Answer 77

While all the listed pathogens are known food-borne pathogens, Listeria monocytogenes can manifest in a variety of illnesses, including meningitis, infectious abortion, perinatal septicemia, and encephalitis. Often, it is the cause of stillbirths or deaths of infants soon after birth. Surviving infants usually develop meningitis, which can be fatal or result in permanent mental retardation. Although Listeria can be inactivated by pasteurisation, it is of particular concern because it usually infects and multiplies in the cheese AFTER pasteurisation has taken place. The rich moisture content of soft cheese makes it an ideal breeding ground for this bacteria. It is for this reason that pregnant women are told to avoid soft cheeses like Brie, Camembert, Feta and Gorgonzola cheeses.

Answer 78

E Causes of raised conjugated bilirubin in infants/neonates: • Dubin Johnson syndrome • Rotor syndrome • Galactosemia • Biliary atresia • Alagille syndrome • Choledochal cyst • Primary sclerosing cholangitis • TORCH infections Causes of raised unconjugated bilirubin in infants/ neonates: • Physiological jaundice • Haemolytic conditions including G6PD deficiency • Polycythaemia • Gilbert syndrome • Crigler-Najjar syndrome

Answer 79

D Closed reduction is indicated for greenstick fractures with severe angulation deformity. In children less than 5 years of age, an angulation in the AP view > 10° (or > 30° in the lateral view) is considered unacceptable, and closed reduction must be performed. Following closed reduction, the distal radius fracture must be immobilized with a cast for about 3 weeks to stabilize the fracture site and allow the fracture to heal. A follow-up x-ray must be performed after 3-5 days in children younger than 5 years and after 7-10 days in older children.

Answer 80

The clinical picture is that of polycythemia and the patient is likely to have renal cell carcinoma.It is a paraneoplastic syndrome. Some cancer-bearing individuals develop signs and symptoms that cannot readily be explained by the anatomic distribution of the tumor or by the elaboration of hormones indigenous to the tissue from which the tumor arose; these are known as paraneoplastic syndromes. These occur in about 10% of persons with cancer.

Answer 81

Breast carcinoma can be managed with either breast conservation surgery or mastectomy. The decision on which surgery is suitable depends on several factors. Multifocal tumours are best managed with mastectomy. Solitary tumours may be suitable for wide local excision if they are of an appropriate size and location. Peripheral tumours can be managed with breast conservative surgery with better cosmetic results. Central tumours usually result in loss of tissue volume and may do better with mastectomy and use of implants/flaps for reconstruction. Tumour size is not a firm indicator for the choice of surgery. The decision will depend on tumour size relative to the breast size. A 4cm tumour in a smaller breast may need mastectomy but can be managed with conservative surgery in a larger breast.

Answer 82

The right coronary artery supplies the AV node in 85-90% of the population via the AV nodal branch

Answer 83

A CT scan of the abdomen and pelvis exposes a patient to 10 mSv of radiation, equivalent to 4.5 years of background radiation and associated with a 1 in 2000 increased lifetime additional risk of fatal cancer.

Answer 84

C The scalp consists of skin (normally hair bearing) and subcutaneous tissue that cover the neurocranium from the superior nuchal lines on the occipital bone to the supra-orbital margins of the frontal bone The scalp is composed of five layers, the first three of which are connected intimately and move as a unit (e.g., when wrinkling the forehead and moving the scalp). Each letter in the word scalp serves as a memory key for one of its five layers: • Skin: thin, except in the occipital region, contains many sweat and sebaceous glands and hair follicles. It has an abundant arterial supply and good venous and lymphatic drainage. • Connective tissue: forms the thick, dense, richly vascularized subcutaneous layer that is well supplied with cutaneous nerves. • Aponeurosis (epicranial aponeurosis): the broad, strong, tendinous sheet that covers the calvaria and serves as the attachment for muscle bellies converging from the forehead and occiput (occipitofrontalis muscle) and from the temporal bones on each side (temporoparietalis and superior auricular muscles). • Loose areolar tissue: a sponge-like layer including potential spaces that may distend with fluid as a result of injury or infection. This layer allows free movement of the scalp proper (the first three layers-skin, connective tissue, and epicranial aponeurosis) over the underlying calvaria. • Pericranium: a dense layer of connective tissue that forms the external periosteum of the neurocranium. It is firmly attached but can be stripped from the crania of living persons, except where the pericranium is continuous with the fibrous tissue in the cranial The occipitofrontalis muscles move the scalp, wrinkle the forehead, and raise the eyebrows. The frontal belly is innervated by temporal branches of the facial nerve [VIl] and the posterior belly by the posterior auricular branch.

Answer 85

D Triple assessment represents clinical, radiological, and pathological assessment of a breast lesion with independant scoring of the three aspects of assessment based on degree of suspicion of malignancy. Scoring is given from 1 (definitely benign) to 5 (very likely to be malignant). Clinical assessment is prefixed with 'P', radiological assessment with 'M'(Mammogram) or 'U'(Ultrasonogram), and histopathological assessment with 'C' (cytology) or 'B'(Core biopsy). Histopathological grading differs slightly from the other two; C1 indicated inadequate sample or a dry tap, requiring a follow up core biopsy. B5 score is further divided into B5a (DCIS) and B5b (invasive carcinoma).

Answer 86

Normal urine output in adults 0.5ml/kg/h So, 70 × 0.5 = 35 mL

Answer 87

Expressive aphasia is most often seen in lesions of Broca's area (Brodmann area 44) located in the inferio-lateral frontal cortex. These lesions are usually due to thrombus in the superior part of the MCA which supplies this area.

Answer 88

B Lung capacity or total lung capacity (TLC) is the volume of air in the lungs upon the maximum effort of inspiration. Among healthy adults, the average lung capacity is about 6 liters. The volume of air that makes up the TLC can be calculated by directly measuring the lung volumes at different phases of the respiratory cycle and by measuring the remaining volume of air in the lungs after maximum exhalation. This relationship calculates as the total lung capacity equaling the sum of functional residual capacity and the inspiratory capacity or as the equation: TLC = FRC + IC. The FRC is only measurable by plethysmography, nitrogen gas washout, or helium gas dilution methods, or using computed tomography (CT). Once the FRC gas volume is measured and the RV is determined, the following additional equations that can be used to calculate the TLC; the sum of the four lung volumes: TLC = RV + ERV + IRV + TV or the sum of vital capacity and the residual volume: TLC = VC + RV.

Answer 89

E You should inform the patient who will be doing the operation and be honest about your experience. As the consultant plans to remain in theatre to supervise the procedure you should also inform the patient of this. All alternative management options should be mentioned. In any case non-operative management is always an option provided the patient understands any associated risks with such an option. Risk of anaphylaxis with loca; anaesthesia always needs to be Even though the procedure is to be performed under a local anaesthetic the site still needs to be marked before the operation to act as an additional check to prevent wrong site surgery, which would be a never event. At least three patient identifiers need to be put on the form. Commonly this is the patient's name, date of birth and hospital or NHS number.

Answer 90

Glucose, amino acids and bicarbonate are reabsorbed along sodium in the early portion of the proximal convoluted tubule. Glucose is removed from the urine by secondary active transport. It is filtered at a rate of approximately 100 mg/min (80 mg/dL of plasma × 125 mL/min). Essentially all of the glucose is reabsorbed, and no more than a few milligrams appear in the urine per 24h. The amount reabsorbed is proportional to the amount filtered and hence to the plasma glucose level (PG) times the GFR up to the transport maximum (TmG). When the TmG is exceeded, the amount of glucose in the urine rises. The TmG is about 375 mg/min in men and 300 mg/min in women.

Answer 91

C Risk factors for torsion include undescended testis, testicular tumor, and a "bell-clapper" deformity-poor gubernacular fixation of the testicles to the scrotal wall. The diagnosis is made by clinical history and examination, but can be supported by a Doppler ultrasound, which typically shows decreased intratesticular blood flow relative to the contralateral testis. Immediate surgical exploration can salvage an ischemic testis. More than 80% of testes can be salvaged if surgery is performed within 6 hours; this rate decreases to <20% as time lapses beyond 12 hours. At the time of surgery, the contralateral testes must also be explored and fixed to the dartos fascia due to the possibility that the same anatomic defect allowing torsion exists on the contralateral side.

Answer 92

E The cavernous sinus lies on either side of the body of the sphenoid. Anteriorly, the ophthalmic veins drain into the sinus and communicate with the anterior facial vein, which drains the face and upper lip - the infection spreads from this locus.

Answer 93

E The major effects of glucagon on glucose metabolism are : • breakdown of liver glycogen (glycogenolysis) and • increased gluconeogenesis in the liver. Both of these effects greatly enhance the availability of glucose to the other organs of the body. Most other effects of glucagon occur only when its concentration rises well above the maximum normally found in the blood. Perhaps the most important effect is that glucagon activates adipose cell lipase, making increased quantities of fatty acids available to the energy systems of the body. Glucagon in high concentrations also • enhances the strength of the heart; • increases blood flow in some tissues, especially the kidneys; • enhances bile secretion; and • inhibits gastric acid secretion. These effects of glucagon are probably of much less importance in the normal function of the body compared with its effects on glucose.

Answer 94

B Paroxysmal nocturnal hemoglobinuria (PNH) is a disease that results from acquired mutations in the phosphatidylinositol glycan complementation group A gene (PIGA), an enzyme that is essential for the synthesis of certain membrane-associated complement regulatory proteins. It is the only hemolytic anemia caused by an acquired genetic defect. PNH blood cells are deficient in three GPI-linked proteins that regulate complement activity: CD55, CD59 and C8 binding protein.Red cells deficient in GPI-linked factors are abnormally susceptible to lysis or injury by complement. This manifests as intravascular hemolysis. The tendency for red cells to lyse at night is explained by a slight decrease in blood pH during sleep, which increases the activity of complement. Thrombosis is the leading cause of disease-related death in individuals with PNH. About 5% to 10% of patients eventually develop acute myeloid leukemia or a myelodysplastic syndrome, indicating that PNH may arise in the context of genetic damage to hematopoietic stem cells.PNH is diagnosed by flow cytometry. The cardinal role of complement activation in PNH pathogenesis has been proven by therapeutic use of a monoclonal antibody called Eculizumab that prevents the conversion of C5 to C5a. This inhibitor not only reduces the hemolysis and attendant transfusion requirements, but also lowers the risk of thrombosis by up to 90%. The drawbacks to C5 inhibitor therapy are its high cost and an increased risk of serious or fatal meningococcal infection.

Answer 95

The correct matches for the clinical manifestations of syphilis are as follows: - **A. Chancre - primary syphilis** → **Correct** (Painless ulcer at the site of inoculation) - **B. Condyloma lata - secondary syphilis** → **Correct** (Broad, flat, wart-like lesions in moist areas) - **C. Gumma - tertiary syphilis** → **Correct** (Granulomatous lesions in late-stage syphilis) - **D. Lymphadenopathy - primary syphilis** → **Correct** (Regional lymphadenopathy near the chancre) - **E. Palmar rash - secondary syphilis** → **Correct** (Copper-red maculopapular rash involving palms and soles) Since all the given options are correctly matched, **none are wrong** based on the choices provided. However, if the question implies that one of them is mismatched (which it doesn't seem to be), then **all are correct**. If this is a trick question expecting you to pick the "wrong" one when none are wrong, the best answer is that **none are mismatched**. But if forced to choose, recheck the wording—sometimes "lymphadenopathy" is more prominent in **secondary syphilis** (generalized) compared to primary (localized). So **D** could be argued as *partially incorrect* if strictly referring to **generalized lymphadenopathy**, which occurs in secondary, not primary syphilis. ### Final Answer: **D (Lymphadenopathy - primary syphilis)** is the *least accurate* because while **local lymphadenopathy** occurs in primary syphilis, **generalized lymphadenopathy** is a feature of **secondary syphilis**. (But strictly, the question has no wrong matches unless interpreted this way.)

Answer 96

D Raynaud's disease is characterized by excess arterial and arteriolar constriction within the peripheral circulation. Therefore, a reduction in the sympathetic-mediated tone of these vessels via a pre-ganglionic sympathectomy is a reasonable option to treat this disorder. The salivary glands are influenced to a much greater extent by the parasympathetic rather than the sympathetic division of the autonomic nervous system. Increased parasympathetic activity increases the flow rate in the salivary glands but less time is allowed for the duct cell secretion of potassium into the salivary fluid. Consequently, the potassium content of the saliva is reduced. Noradrenaline is the neurotransmitter released by the majority of postganglionic sympathetic neurons. Genital erection and ejaculation requires coordinated activity from both divisions of the autonomic nervous system. The sympathetic fibres from 111 to L2 govern ejaculation whereas genital erection is mediated by parasympathetic innervation arising from the sacral region of the spinal cord. A lesion at the T10 level would therefore affect both erection and ejaculation. 'Dry orgasm', where the patient can generate and maintain an erection but is unable to ejaculate, can be a side effect of drugs such as beta-blockers. The parasympathetic innervation of the heart is almost exclusively restricted to the atria and structures therein, including the sinoatrial node (SAN). Increased parasympathetic activity reduces the slope of the pacemaker potential in the SAN, resulting in a reduced heart rate—a negative chronotropic action

Answer 97

The sinus tarsi is a cavity that lies between the calcaneum and talus in the foot.

Answer 98

A. Lung compliance is greater during the expiration phase compared with the inspiration phase ✅ • True. This is due to hysteresis of the pressure–volume curve (surfactant effects). B. The majority of airway resistance is generated in the trachea and subsequent airway divisions ❌ • Incorrect. • While the trachea and large bronchi have smaller total cross-sectional area, the greatest resistance is actually in the medium-sized bronchi (around the 4th–7th generation). • Beyond this, the huge cross-sectional area of small bronchioles means their contribution is minimal. C. Resistive forces oppose airflow during inspiration ✅ • True. Resistance comes from airway friction and tissue resistance. D. The radial traction experienced by the airways is inversely proportional to the lung volume ❌ • Careful here. Radial traction increases with lung volume (the higher the lung volume, the greater the outward tethering of small airways, reducing resistance). • So saying it is inversely proportional is false. E. Under conditions of turbulent flow, pressure is proportional to (flow)² ✅ • True. (Laminar flow = pressure proportional to flow; Turbulent = proportional to flow²). ⸻ ✅ Correct Answer (Incorrect statement): D — The radial traction experienced by the airways is inversely proportional to the lung volume. ⸻ 💡 Exam tip: • Compliance higher on expiration (hysteresis). • Airway resistance peaks in medium bronchi. • Radial traction ↑ with ↑ lung volume. • Turbulent flow → pressure ∝ flow².

Answer 99

The drainage of a small amount of bile after T tube removal may occur transiently. In this scenario, the best course of action is to await spontaneous resolution.

Answer 100

Best Diagnostic Method in this case would be CT pulmonary angiography (Option e) to assess pulmonary embolism.

Answer 101

D This patient's x-ray shows a fracture of the neck of the second metatarsal and callus formation. The metatarsal bones are common sites for stress fractures, which are typically caused by repetitive, high-intensity activity and/or by a sudden increase in the intensity of physical activity, as seen with this army recruit. Such stress to the bone can increase the level of bone resorption to a degree that overwhelms the bone's ability to adapt to the stress, resulting in multiple microfractures that coalesce over time to form a larger break in the bone cortex. Risk factors for stress fractures include ill-fitting footwear (this patient is using his brother's old boots that may not fit him properly), decreased bone density (e.g., osteoporosis), and severe caloric restriction (e.g., in anorexia nervosa). Other important sites for stress fractures are the tibia (most common site), calcaneum, and navicular bone.

Answer 102

B The “ulnar paradox” refers to the counterintuitive clinical finding where a more proximal ulnar nerve injury (at or above the elbow) results in less apparent clawing of the hand compared to a distal injury (at the wrist). This paradox is due to the involvement of the flexor digitorum profundus (FDP) muscle in a high ulnar nerve lesion. When the FDP is also paralyzed (as it is innervated by the ulnar nerve in the medial two fingers), the clawing effect is reduced because the distal interphalangeal joints cannot flex. Correct Answer: B - Flexor digitorum profundus explanation or related questions! The "ulnar paradox" is described as the worsening of the ulnar claw hand the more distal the injury to the ulnar nerve is. While the ulnar claw is most pronounced in a lesion at the wrist, ulnar nerve injuries at the elbow do not lead to any flexion at the distal IP joints of the ring and little fingers. So, here, the ulnar claw only consists of hyperextension at the MCP joints and flexion at the proximal IP joints. This produces a much less evident claw hand. In the low lesion, the hand muscles are weak but the long flexors in the forearm are unaffected (FDP) leading to a more pronounced flexure at the wrist. However, in the high lesion, both are affected and so, the clawing is mild.

Answer 103

The elevated serum amylase in this clinical background is a key marker for pancreatitis. The normal GGT and ALP suggest that the liver and bile ducts are not primarily involved. The slightly elevated bilirubin may be a secondary effect or could be associated with pancreatitis.

Answer 104

E External intercostal • Most superficial • Attached from the inferior margin of rib above to the superior margin of the one below. • Most active during inspiration • Moves ribs superiorly Internal intercostals • Between external and innermost intercostals • Attached from the lateral edge of the costal groove above to the superior edge of the rib below. • Most active in expiration • Moves ribs inferiorly Innermost intercostals • Least distinct and have the same orientation as internal intercostals. • Attach from the medial surface of the costal groove above to the deep surface of the rib below. • Most evident in the lateral thoracic wall • The intercostal space neurovascular bundles pass in a plane between the internal and innermost intercostals. Subcostales • On the same plane as innermost intercostals. • Span multiple ribs (attach from internal surface of one rib to the second or third next rib) • Goes from the angle off ribs above to more medially below • May help depress ribs Transversus thoraces • Deep surface of anterior thoracic wall • Same plane as innermost intercostals • Originate from the posterior part of the xiphoid process, inferior part of the body of the sternum and costal cartilages of the lower true ribs and go superolaterally to the lower borders of the costal cartilages of ribs 3 to 6. • Lie deep to the internal thoracic vessels and secure these vessels to the anterior thoracic wall.

Answer 105

E • The use of sirolimus in renal transplant patients is associated with a dose-dependent increase in serum cholesterol and triglycerides that may require treatment. Although immunotherapy with sirolimus per se is not considered nephrotoxic, patients treated with cyclosporine plus sirolimus have impaired renal function compared to patients treated with cyclosporine alone. Lymphocele, a known surgical complication associated with renal transplantation, is increased in a dose-dependent fashion by sirolimus, requiring close postoperative follow-up. • The major side effect of azathioprine is bone marrow suppression, including leukopenia (common), thrombocytopenia (less common), or anemia (uncommon). Other important adverse effects include increased susceptibility to infections (especially varicella and herpes simplex viruses), hepatotoxicity, alopecia, Gl toxicity, pancreatitis, and increased risk of neoplasia. • The principal adverse reactions to cyclosporine therapy are renal dysfunction and hypertension; tremor, hirsutism, hyperlipidemia, and gum hyperplasia also are frequently encountered. Hypertension occurs in about 50% of renal transplant and almost all cardiac transplant patients. Hyperuricemia may lead to worsening of gout, increased P-glycoprotein activity, and hypercholesterolemia • Extensive glucocorticoid use often results in disabling and life-threatening adverse effects. These effects include growth retardation in children, avascular necrosis of bone, osteopenia, increased risk of infection, poor wound healing, cataracts, hyperglycemia, and hypertension. The advent of combined glucocorticoid/calcineurin inhibitor regimens has allowed reduced doses or rapid withdrawal of steroids, resulting in lower steroid-induced morbidities.

Answer 106

E The largest branch of the femoral artery in the thigh is the deep artery of the thigh (profunda femoris artery), which originates from the lateral side of the femoral artery in the femoral triangle and is the major source of blood supply to the thigh.The deep artery of the thigh has lateral and medial circumflex femoral branches and three perforating branches.

Answer 107

The blood supply to the breast is chiefly from the lateral thoracic artery (from the axillary) and the internal thoracic also known as the internal mammary artery (from the subclavian). It also receives a contribution from the pectoral branch of the thoracoacromial artery, and the second to sixth intercostal arteries. A. Contains a maximum of 15 main lactiferous ducts that drain separately at the nipple The breast comprises 15-20 lobules, each of which has a separate lactiferous duct which then confluence to open at the nipple. C. In this age group is best visualised by a combination of crainiocaudal and true mediolateral mammograms The standard views taken on a mammogram are cranio-caudal (CC) and mediolateral oblique (MLO) (not truly mediolateral). D. Is a modified sebaceous gland The breast is considered to be a modified apocrine sweat gland. E. Predominantly drains to the internal thoracic nodes Most (> 75%) of the lymph from the breast drains to the axillary lymph nodes. Lymph from the medial aspect of the breast drains to the parasternal (internal thoracic) nodes or across to the opposite breast. Lymph from the inferior aspect of the breast drains to the inferior phrenic nodes Ref: Gray's Anatomy for Students 4th Edition, Chapter 3

Answer 108

E The arterial supply to the structures in the orbit, including the eyeball, is by the ophthalmic artery . This vessel is a branch of the internal carotid artery, given off immediately after the internal carotid artery leaves the cavernous sinus. The ophthalmic artery passes into orbit through the optic canal with the optic nerve. The central retinal artery, a branch of ophthalmic artery, which enters the optic nerve, proceeds down the centre of the nerve to the retina, and is clearly seen when viewing the retina with an ophthalmoscope-occlusion of this vessel or of the parent artery leads to blindness.

Answer 109

The described maneuver is the **anterior drawer test**, which is used to assess the integrity of the **anterior cruciate ligament (ACL)** of the knee. ### Key points: - **Positioning**: The hip is partially flexed, and the knee is flexed to **30 degrees**. - **Action**: The examiner stabilizes the thigh and pulls the lower leg **anteriorly**. - **Positive test**: Excessive anterior tibial translation (the tibia moves forward abnormally) suggests **ACL injury**. ### Why not the other options? - **A & B (LCL/MCL)**: These are tested with **varus/valgus stress tests**, not the anterior drawer. - **C (PCL)**: The **posterior drawer test** assesses the PCL by pushing the tibia backward. - **E (Achilles tendon)**: This is not involved in knee stability; it’s a tendon of the ankle. ### Correct Answer: **D - Anterior cruciate ligament of knee**

Answer 110

D Hypertrophic scars and keloids both occur due to excess collagen production in a healing wound. Hypertrophic scars usually have scar tissue confined to the wound thickness and usually occur only after full thickness dermal injuries. They can contract. Histopathology shows nodules of randomly arranged fibrils with a surface of parallel collagen fibres. They can regress with time. Once excised, they do not recur. Keloids have scar tissue growing beyond the margins of the wound. These rarely regress over time and can occur after trivial injuries as well. They can recur after excision. The histopathology does not show any nodules.

Answer 111

E Major abdominal surgery is a risk factor for the development of abdominal compartment syndrome. This is a major cause of mortality in major surgery, especially emergency surgery or multiple injuries. Clinical features are all consequences of raised intra-abdominal pressure - abdominal distension, oliguria due to impaired renal perfusion, cardiac and respiratory embarrassment due to elevated pressure on the heart and diaphragm, etc. Measurement of intra-abdominal pressure by measuring the intravesical pressure through the indwelling catheter will help in making the diagnosis. An intra-abdominal pressure of more than 25 mm Hg is a poor prognostic indicator, implying that the patient requires immediate abdominal decompression. Some surgeons prefer to leave the abdomen open after a major abdominal surgery, covered with a plastic mesh (Bogota bag). Definitive surgery is carried out later. This condition has a high mortality of about 60%.

Answer 112

A Laparoscopy is done to look for undescended testis, most commonly in the deep inguinal ring. The most common location of ectopic testis is superficial perineal pouch. When no testis, testicular vessels or vas is found laparoscopically, usually in utero torsion of testis is assumed. This is labelled as vanishing testis. Agenesis of unilateral testis is very very rare. As testis is present on one side and genitalia are normal, there is no need for karyotyping. Ref: Bailey & Love's Short Practice of Surgery, 27th Edition, Chapter 80

Answer 113

Oesophagitis due to Candida albicans is relatively common in patients taking steroids (especially transplant recipients) or those undergoing cancer chemotherapy. It may present with dysphagia or odynophagia. There may be visible thrush in the throat. Endoscopy shows numerous white plaques that cannot be moved, unlike food residues . Biopsies are diagnostic. In severe cases, a barium swallow may show dramatic mucosal ulceration and irregularity that is surprisingly similar to the appearance of esophageal varices. Treatment is with a topical antifungal agent.

Answer 114

MEN Type II. The mutations listed each affect a tumor suppressor gene. Somatic mutations in P53, PTEN and NF1 are frequent in gliomas in general, and syndromes involving germline mutation in these genes predispose to these and other tumours. HNPCC is associated with a number of distinct gene mutations affecting DNA mismatch repair, and collectively these mutations also confer increased risk of glioma. Certain menin gene mutations confer risk of risk of pituitary adenoma (MEN Type I- pituitary, parathyroid, pancreas). MEN Type Il is associated with medullary thyroid cancer, pheochromocytoma and parathyroid tumours.

Answer 115

A Mongolian spot is a congenital blue grey macule found on the sacral skin. Pigmentation initially deepens and then regresses completely by age 7 years. Thanks for helping Vinayak with the diagnosis. He is less worried now.

Answer 116

The golden hour refers to the first 60 minutes following traumatic injury, during which rapid assessment and intervention offer the greatest chance of survival. Patients with potentially reversible airway compromise, breathing difficulties, or compromised circulation are those who benefit most from urgent intervention. Let’s analyze each option: A. Road traffic accident victim with multiple pelvic fractures and aortic rupture 👉 This patient is unlikely to survive to hospital; an aortic rupture leads to massive hemorrhage, often fatal before reaching care. B. Child rescued from a collapsed building with a pulseless lower limb 👉 This suggests a limb vascular injury (ischemia). This is limb-threatening, but not immediately life-threatening. The “golden hour” is more about life, not just limb salvage. C. Patient with 20% BSA burns with multiple organ failure 👉 This patient is already in multiple organ failure, which indicates established systemic damage beyond the golden hour window. D. High cervical injury with quadriplegia and poor breathing effort 👉 This is a classic golden hour situation. Airway compromise due to diaphragmatic paralysis (phrenic nerve, C3–C5) can rapidly lead to death if not managed early with airway protection and ventilatory support. E. B and D 👉 Out of the options, D clearly represents a patient in the golden hour. B is more limb salvage than life salvage. ✅ Correct Answer: D – High cervical injury with quadriplegia and poor breathing effort The golden hour refers to the period of time after trauma in which life and limb saving procedures may be applied to change the outcome. This is mostly applicable to injuries that would cause 'early stage death'. Mortality from trauma is broadly divided into 3 phases:- • Immediate phase deaths - These are usually instantaneously fatal and result in mortality at the site of accident/trauma. Eg. Aortic rupture, brainstem transection/high cervical transection, irreversible brain injury, exsanguination etc. (as in options A and D) • Early phase deaths - These injuries are fatal if not adequately managed in a timely manner. Injuries of this type must be managed within the 'golden hour' to save life or limb. Eg. compartment syndrome, secondary CNS damage, major blood loss etc. • Late phase deaths - These occur weeks to months after the initial trauma and their severity will depend on the initial management provided. Eg. MODS/Sepsis (as in option C)

Answer 117

Pancreas divisum : The most common variation in pancreatic ductal anatomy characterized by the dorsal pancreatic duct directly entering the minor papilla. It can be associated with abdominal pain and idiopathic pancreatitis. It can lead to a cystic dilatation of the distal dorsal duct aka a santorinicele.

Answer 118

The correct answer is: A – Flow volume loop ✅ ⸻ Explanation: In a patient with thyroid carcinoma and shortness of breath, the main concern is extrathoracic airway obstruction due to tracheal compression or invasion. • Flow volume loop: • The best test for suspected upper airway obstruction. • Shows a characteristic flattening of the inspiratory limb in variable extrathoracic obstruction (e.g. thyroid mass compressing trachea). • Can distinguish between variable extrathoracic, variable intrathoracic, and fixed obstructions. • Arterial blood gas (ABG): Only shows hypoxia or hypercapnia late in the disease, not diagnostic of compression pattern. • Forced vital capacity (FVC): Reduced in restriction but not specific for upper airway obstruction. • Peak expiratory flow rate (PEFR): Non-specific, mainly used in asthma. • Pulse oximetry: Detects hypoxia but cannot localize or characterize airway obstruction. 👉 Thus, flow volume loop is the most sensitive and specific investigation for detecting upper airway obstruction due to thyroid malignancy. ⸻ ⚡ Exam Tip: • Flow volume loop = best investigation for suspected tracheal compression. • CT neck/chest with contrast = best for anatomical definition once compression is suspected. A normal flow volume loop is often described as a 'triangle on top of a semi circle' Flow volume loops are the most suitable way of assessing compression of the upper airway

Answer 119

A From the first part of the subclavian artery, the internal thoracic artery (formerly the internal mammary) passes vertically downwards about 1 cm lateral to the border of the sternum. It gives off two anterior intercostal arteries in each intercostal space. At the costal margin it divides into the superior epigastric and musculophrenic arteries. The internal thoracic artery is accompanied by two venae comitantes that empty into the brachiocephalic vein.

Answer 120

✅ Correct answer: D — Marantic endocarditis (Libman–Sacks endocarditis) 💡 Explanation: In systemic lupus erythematosus (SLE), sterile vegetations often form along the line of closure of the cardiac valves, most commonly the mitral and aortic valves. These lesions are due to immune complex deposition and endothelial injury, leading to non-bacterial thrombotic endocarditis (NBTE) — also known as Libman–Sacks endocarditis. ⸻ 🧠 Key distinguishing features: Type Cause Vegetation features Location Microbial involvement Acute infective endocarditis Bacterial infection (e.g., Staph aureus) Large, friable vegetations Anywhere on valve Yes (bacteria present) Calcific valvular disease Degenerative process in elderly Hard nodules of calcium Usually aortic valve cusps No Carcinoid heart disease Serotonin-producing tumors Plaque-like endocardial thickening Right heart (tricuspid, pulmonary) No Marantic (Libman–Sacks) endocarditis SLE or hypercoagulable states Small, sterile vegetations Valve closure lines No bacteria Small mural thrombi After myocardial infarction or endocardial injury Thrombi on mural endocardium Endocardial wall, not valve No ⸻ 🩸 Pathology of Libman–Sacks endocarditis: • Small, sterile vegetations on both sides of the valve leaflets. • Histology shows fibrinoid necrosis and hematoxylin bodies. • Usually clinically silent but may lead to valvular regurgitation or embolic events. ⸻ 🏁 Summary: Finding: Small sterile vegetations along line of closure of aortic valve Associated condition: Systemic lupus erythematosus Diagnosis: ✅ Marantic (Libman–Sacks) endocarditis

Answer 121

C Three broadly stated conditions, first described by Rudolf Virchow in 1862, contribute to VTE formation: stasis of blood flow, endothelial damage, and hypercoagulability. Of these risk factors, relative hypercoagulability appears most important in cases of spontaneous VTE, or so-called idiopathic VTE, whereas stasis and endothelial damage likely play a greater role in secondary VTE, or so-called provoked VTE, occurring in association with transient risk factors such as immobilisation, surgical procedures, and trauma.

Answer 122

E Subcostal plane • Corresponds to a line drawn joining the lower most bony point of the rib cage, usually 10th costal cartilage • Body of the L3 vertebra; the origin of the inferior mesenteric artery and 3rd part of the duodenum lie on this plane

Answer 123

C The Ho:YAG laser has replaced the Nd:YAG laser for the treatment of superficial bladder cancer. Treatments are performed at different frequencies, energy per pulse and power and show peri- and postoperative complication rates lower when compared to conventional transurethral resection. In urology, this laser has also been employed to treat upper urinary tract tumors with settings similar to the ones employed during bladder ablation. Diode lasers have been largely employed on prostatic tumors with very good results in terms of complications and tumor recurrence. CO lasers are better for superficial tissue ablation and are more useful in penile carcinoma and for removal of hemangiomas

Answer 124

Carcinoembryonic antigen (CEA) and calcitonin are used for follow up in medullary carcinoma thyroid.

Answer 125

A The most frequent cause of spontaneous subarachnoid hemorrhage is rupture of a saccular ("berry") aneurysm in a cerebral artery. Saccular aneurysms are found in about 2% of the population according to recent data from community-based radiologic studies. About 90% of saccular aneurysms are found near major arterial branch points in the anterior circulation; multiple aneurysms exist in 20% to 30% of cases based on autopsy series.

Answer 126

Intramuscular adrenaline is the treatment of choice in case of anaphylactic shock

Answer 127

Pancreas divisum : The most common variation in pancreatic ductal anatomy characterized by the dorsal pancreatic duct directly entering the minor papilla. It can be associated with abdominal pain and idiopathic pancreatitis. It can lead to a cystic dilatation of the distal dorsal duct aka a santorinicele.

Answer 128

Management of anal fissure: 1. Lifestyle advice: • Fibre • Fluids • Laxatives • Pain relief (NSAIDs, paracetamol, Sitz baths, topical lidocaine etc) 2. 0.4% glyceryl trinitrate (GTN) ointment (BD for up to 8 weeks) 3. Topical diltiazem 2% (unlicensed for chronic fissure) 4. Botulinum toxin 5. Surgery: • Lateral internal sphincterotomy (procedure of choice; 85% cure rate but significant continence issues exist) • Posterior internal sphincterotomy • Bilateral internal sphincterotomy • Anterior levatorplasty • Fissurectomy • Manual anal stretch (The Cochrane review reccomends abandoning this procedure) Surgery is rarely indicated in children, who usually respond well to conservative measures.

Answer 129

The correct answer is: Flow between chambers that have widely different pressures throughout the systole ✅ . Explanation: A holosystolic murmur (also called pansystolic) occurs when there is continuous flow of blood from a high-pressure chamber to a low-pressure chamber throughout systole. In the case of a ventricular septal defect (VSD), the left ventricular pressure is significantly higher than the right ventricular pressure during the entire systolic phase, so blood flows continuously from left to right, generating a harsh, blowing murmur that lasts the whole systole. • Option A describes atrial contraction filling, which produces an S4 sound, not a holosystolic murmur. • Option B (crescendo-decrescendo) is typical of ejection murmurs like aortic stenosis, not VSD. • Option D refers to diastolic murmurs caused by valve orifice mismatch, e.g., mitral stenosis. In short, VSD + holosystolic murmur = high-to-low pressure gradient across ventricles throughout systole.

Answer 130

This is a typical case of Mallory-Weiss Syndrome, with haematemesis occuring after a prolonged or forceful bout of retching/vomiting/ coughing/straining/hiccupping. Although a well-known cause of UGl bleeds, it accounts for only 4-8% of cases. The most common cause is peptic ulcer. Although most patients stop bleeding spontaneously, resuscitation and preemptive management (securing IV access, cross-match, group and save etc) is important. Endoscopy is indicated in most cases as it may be required to stop the bleed. Ideally, endoscopy should be performed within 24 hours, as tears heal rapidly and may not be readily apparent at endoscopy after 2-3 days. However, hemodynamically unstable patients should have endoscopy immediately after resuscitation. A Cochrane review found PPI use prior to endoscopy was not associated with a reduction in re-bleeding, need for surgery or mortality.

Answer 131

The correct answer is: Meissner’s corpuscle ✅ Explanation: Mechanoreceptors in the skin differ in their adaptation speed and stimulus sensitivity: • Meissner’s corpuscle → Rapidly adapting, found in dermal papillae (especially fingertips, lips), sensitive to light touch and low-frequency vibration. • Merkel’s cell (discs) → Slowly adapting, sensitive to steady pressure and texture. • Pacinian corpuscle → Rapidly adapting, but sensitive to deep pressure and high-frequency vibration, not light touch. • Ruffini’s corpuscle → Slowly adapting, responds to skin stretch and sustained pressure. So for light touch + rapid adaptation, Meissner’s corpuscle is the match.

Answer 132

The correct answer is: Crohn’s disease ✅ Reasoning: This young man’s presentation points away from acute appendicitis and toward a chronic, relapsing inflammatory bowel condition: • Recurrent right iliac fossa (RIF) pain with prior admissions for conservative management → suggests a chronic or relapsing cause rather than an acute one-off event. • Systemic features: malaise, weight loss → common in chronic inflammatory bowel disease. • Extraintestinal manifestation: recurrent mouth ulcers → a known feature of Crohn’s disease. • Exam findings: mild localized tenderness, no peritonism → inconsistent with perforated appendicitis. • Labs: WCC mildly raised, CRP only slightly elevated → not the severe inflammatory response seen in acute appendicitis. Other options ruled out: • Acute appendicitis → unlikely with chronicity, weight loss, and mouth ulcers. • Gastroenteritis → usually diffuse abdominal pain + diarrhea, not localized recurrent RIF pain. • Mesenteric adenitis → typically post-viral in children, acute, not chronic/recurrent. • TB ileitis → more likely in endemic areas, with systemic TB signs (night sweats, persistent fever). Key takeaway for MRCS: Recurrent RIF pain + systemic symptoms + extraintestinal features = think Crohn’s disease affecting the terminal ileum. Right iliac fossa pain has been the hallmark for acute appendicitis but making this diagnosis can sometimes be tricky. The Alvarado score was developed to help with this process.

Answer 133

D -1% of babies have deletion of chromosome 21 • Down syndrome is the most common of the chromosomal disorders and is a major cause of intellectual disability. • Maternal age has a strong influence on the incidence of trisomy 21. It occurs once in 1550 live births in women under age 20, in contrast to 1 in 25 live births for mothers older than age 45. • In about 4% of cases of Down syndrome the extra chromosomal material derives from the presence of a robertsonian translocation of the long arm of chromosome 21 to another acrocentric chromosome (e.g., 22 or 14). • Approximately 1% of patients with Down syndrome are mosaics, having a mixture of cells with 46 or 47 chromosomes. This mosaicism results from mitotic nondisjunction of chromosome 21 during an early stage of embryogenesis. • The diagnostic clinical features of this condition-flat facial profile, oblique palpebral fissures, and epicanthic folds—are usually readily evident, • Approximately 40% of the patients have congenital heart disease. The most frequent forms of congenital heart diseases in Down syndrome are atrioventricular septal detects constituting 43% of cases. • Children with trisomy 21 have a high risk of developing leukemia; there is 20-fold increased risk of developing acute B lymphoblastic leukemias and 500-fold increased risk of acute myeloid leukemias • Virtually all patients with trisomy 21 older than age 40 develop neuropathologic changes characteristic of Alzheimer disease, a degenerative disorder of the brain. • Patients with Down syndrome have abnormal immune responses that predispose them to serious infections, particularly of the lungs, and to thyroid autoimmunity.

Answer 134

This gradient is created in two ways. Firstly, the increase in thoracic volume during inspiration decreases the intrathoracic pressure. Secondly, the pressure in the veins of the leg is increased by compression by the surrounding muscles (the 'calf muscle pump') and to a lesser extent by the tone of the venous wall.

Answer 135

Anti-thrombin 3 does not activate factor 8 (Option a) in the coagulation cascade. Key fact: • Antithrombin III (ATIII) is a natural anticoagulant. • It inhibits mainly thrombin (IIa) and factor Xa. • It also has activity against IXa, XIa, and XIIa. • However, it does not act on factor VIII, because VIII is a cofactor, not a serine protease enzyme. ✅ Correct Answer: Factor VIII 🔎 Explanation: • Factors inhibited by ATIII: IIa (thrombin), IXa, Xa, XIa, XIIa. • Not inhibited by ATIII: Factor VIII and Factor V (they are cofactors, not proteases). 👉 So the factor not a substrate for antithrombin III is Factor VIII.

Answer 136

The breast is a modified apocrine gland which lies on the pectoralis major, serratus anterior and external oblique muscles. The mammary gland is mainly supplied by the lateral thoracic artery and its branches which curl around the pectoralis major. The main lymphatic drainage of the breast is to the axillary and infraclavicular nodes in 75% of cases whereas the majority of the medial breast drains to nodes which lie along the internal thoracic artery. The gland contains approximately 15-20 main ducts that drain separately on the nipple. Screening mammograms involve craniocaudal and mediolateral oblique views which is the best modality. Ref: Bailey & Love Clinical Anatomy 1st edition, Chapter 1

Answer 137

Precipitating factors in thyroid storm: • Infection. • Non-thyroidal trauma or surgery. • Psychosis. • Parturition. • Myocardial infarction or other acute medical problems. • Radioiodine. • High doses of iodine-containing compounds (for example, radiographic contrast media). • Discontinuation of antithyroid drug treatment. • Thyroid injury (palpation, infarction of an adenoma). • New institution of amiodarone therapy. Corticosteroids inhibit peripheral conversion of T4 into T3 and have been shown to improve outcomes in patients with thyroid storm. Adrenal axis dysfunction in the context of thyrotoxicosis of any degree is documented, and responds to exogenous steroid therapy.

Answer 138

This woman is a heavy smoker with some signs of cardiac impairment. She is also a diabetic, and likely has poor glycaemic control. Such severe systemic impairment can be a threat to life. ASA grade Patient condition Grade 1 Normal healthy patient, no systemic disturbances. Grade 2 Mild systemic impairment without functional limitation Grade 3 Severe systemic impairment with significant functional limitation Grade 4 Severe systemic disease with constant threat to life Grade 5 Moribund patient, not likely to survive without surgery

Answer 139

Level of origin of aorta branches: T12: Coeliac artery Lower level of L1: Superior Mesenteric artery L1: Middle Suprarenal arteries L3: Inferior mesenteric artery L2: Gonadal arteries L1-L3: Renal arteries L4: Median sacral artery, bifurcation of aorta into common iliac arteries L5: a union of common iliac veins into IVC

Answer 140

Blood supply to the diaphragm: • Superior surface: • Pericardiophrenic arteries (branch of internal thoracic) • Musculophrenic arteries (branch of internal thoracic) • Superior phrenic arteries (branch of thoracic aorta) • Inferior surface (major supply): • Inferior phrenic arteries — arise directly from the abdominal aorta (just above the coeliac trunk). These are the largest and most important arterial supply to the diaphragm. ⸻ ✅ Correct Answer: Inferior phrenic arteries ⸻ 💡 Clinical link: During congenital diaphragmatic hernia repair, preserving the inferior phrenic arteries is crucial for diaphragmatic healing. The profuse arterial supply of the diaphragm is derived from anasto- moses between the lower five intercostal and subcostal arteries, the superior and inferior phrenic arteries, and the pericardiacophrenic and musculophrenic arteries. The lower five intercostal and subcostal arteries supply the costal margins of the diaphragm The major arterial supply to the diaphragm is derived from the right and left inferior phrenic arteries. Most commonly, the right inferior phrenic artery arises from the coeliac trunk or separately from the aorta. The left inferior phrenic artery usually arises from the coeliac trunk or separately from the aorta. The superior phrenic arteries supply the superior portion of the diaphragm. The right superior phrenic artery most commonly arises from either the thoracic aorta, the proximal (pre-intercostal space) segment of the tenth intercostal artery or its distal segment. The left superior phrenic artery most commonly arises from the thoracic aorta or the proximal segment of the tenth intercostal artery.

Answer 141

The baby boy has an inguinal hernia. It is differentiated from hydrocele by the history that prolonged supine position (sleep) does not change the size of the swelling. Transillumination cannot be used as even hernias are transilluminant in an infant. Even incarcerated hernias can be reduced by careful gentle taxis under adequate analgesia. There is no need for emergency surgery unless the hernia is truly irreducible in which case emergency surgery to avoid strangulation is advised. In the given child, inguinal herniotomy can be scheduled as a day care procedure. Hydroceles need not be operated as they resolve with age as processus vagainalis closes with growth. Herniotomy for hydrocele must be done when it persists after 3 years of age. Ref: Bailey & Love's Short Practice of Surgery, 27th Edition, Chapter

Answer 142

The process of atrial repolarization is generally not visible on the ECG strip. It occurs during the QRS complex. P wave • Represents the wave of depolarization that spreads from the SA node throughout the atria • Lasts 0.08 to 0.1 seconds (80-100 ms) • The isoelectric period after the P wave represents the time in which the impulse is traveling within the AV node P-R interval • Time from the onset of the P wave to the beginning of the QRS complex • Ranges from 0.12 to 0.20 seconds in duration • Represents the time between the onset of atrial depolarization and the onset of ventricular depolarization QRS complex • Represents ventricular depolarization • Duration of the QRS complex is normally 0.06 to 0.1 seconds ST segment • Isoelectric period following the QRS • Represents period which the entire ventricle is depolarized and roughly corresponds to the plateau phase of the ventricular action potential T wave

Answer 143

The false statement regarding Lister’s tubercle is: “Separates the 1st and 2nd extensor compartments.” ✅ Explanation: • True facts about Lister’s tubercle: • It is more commonly called the dorsal tubercle of the radius. • It acts as a pulley for the extensor pollicis longus (EPL) tendon, redirecting its course toward the thumb. • It is located between the grooves for the extensor carpi radialis longus/brevis (radial side) and the extensor pollicis longus (ulnar side) . • False statement: • It does not separate the 1st and 2nd extensor compartments. • The 1st compartment (abductor pollicis longus & extensor pollicis brevis) and the 2nd compartment (extensor carpi radialis longus & brevis) lie more radially. Lister’s tubercle instead separates the 2nd compartment from the 3rd compartment (EPL). 👉 So the incorrect option is the one about it separating the 1st and 2nd compartments. The dorsal tubercle, previously known as Lister's tubercle is a bony protuberance on the dorsal side of the distal radius. It is an important landmark for hand surgeries and arthroscopic procedures. It functions as a pulley for the extensor pollicis longus (EPL) tendon before the tendon pivots and turns obliquely to insert onto the distal phalanx of the thumb. It is seated between the grooves for the tendons of the second compartment (ECRL & ECRB) and the third compartment (EPL) thus separating the two compartments.

Answer 144

B- Ejection fraction is the stroke volume divided by the end diastolic volume. The volume of blood in the ventricles at the end of the diastole is known as the end diastolic volume. As the ventricles contract during systole, the volume of blood ejected per beat is known as the stroke volume. The remaining volume in each ventricle is known as the end systolic volume and acts as a reserve which can be utilised to increase stroke volume in exercise. The fraction of end diastolic volume that is ejected is called the ejection fraction - usually equal to about 60%. The ejection fraction is often used clinically as an indirect index of contractility.

Answer 145

A-Osteopetrosis comprises a group of rare genetic diseases characterized by reduced bone resorption due to deficient osteoclast development or function, which leads to diffuse, symmetric skeletal sclerosis. Although the term osteopetrosis implies that the bones are stonelike, they are actually brittle and fracture easily.

Answer 146

A-The esophageal opening is opposite the T10 vertebra, usually 2.5 cm to the left of the midline behind the seventh left costal cartilage. It lies in the fibres of the left crus, but a sling of fibres from the right crus loop around it. The transversalis fascia on the undersurface of the diaphragm extends up through the opening, blends with the endothoracic fascia above the diaphragm, and is attached to the oesophagus about 2-3 cm above the oesophagogastric junction. This fascial cone is the phreno-oesophageal ligament. It becomes stretched in the 'sliding' type of hiatus hernia

Answer 147

B-Ulnar nerve lacerations are the most common major upper extremity peripheral nerve injury when compared with the median, radial, and brachial plexus nerves. They can occur directly from a penetrating injury or secondary to a forearm fracture, and most are seen either at or distal to the elbow. When the damage is at the wrist, only the intrinsic muscles of the hand are affected. Adduction & abduction of the fingers cannot occur because the interossei are paralysed. Thumb adduction is affected and a positive Froment's sign is seen. The medial 2 lumbricals and hypothenar muscles are also affected leading to impaired movement of those digits.

Answer 148

HTLV-1 causes adult T-cell leukemia/lymphoma (ATLL), a tumor that is endemic in certain parts of Japan, the Caribbean basin, South America, and Africa and found sporadically elsewhere, including the United States.HCV is also an oncogenic RNA virus. As with RNA viruses, several oncogenic DNA viruses that cause tumors in animals have been identified. Of the various human DNA viruses, five-HPV, EBV, HBV, Merkel cell polyomavirus, and human herpesvirus 8 (HHV8, also called Kaposi sarcoma herpesvirus)-have been implicated in the causation of human cancer.

Answer 149

E-The high absorptive area of the small intestine is due to the presence of villi, microvilli and plicae circularis (aka valvulae conniventes, circular folds or folds of Kerckring).

Answer 150

E-Biochemical assays for tumor-associated enzymes, hormones, and other tumor markers in the blood lack the sensitivity and specificity necessary to diagnose cancer; however, in concert with other tests, they may contribute to the detection of cancer, and in many instances they are useful in following a tumor's response to therapy and in detecting tumor recurrence.

Answer 151

Receptive relaxation When food enters the stomach, the fundus and upper portion of the body relax and accommodate the food with little if any increase in pressure (receptive relaxation). Peristalsis then begins in the lower portion of the body, mixing and grinding the food and permitting small, semiliquid portions of it to pass through the pylorus and enter the duodenum. Receptive relaxation is, in part, vagally mediated and triggered by movement of the pharynx and esophagus. Intrinsic reflexes also lead to relaxation as the stomach wall is stretched. Peristaltic waves controlled by the gastric BER begin soon thereafter and sweep toward the pylorus. The contraction of the distal stomach caused by each wave is sometimes called antral systole and can last up to 10 s. Waves occur 3-4 times per minute.

Answer 152

Saturday night palsy happens after falling asleep with one arm slung over the back of the chair leading to compression neuropathy of the radial nerve. High radial nerve injury leads to loss of extension of the forearm, weakness in supination and loss of extension of wrist & fingers (wrist drop). Sensation is impaired at lateral & posterior forearm, dorsum of hand laterally including the dorsum of the lateral 3 and a half fingers.

Answer 153

Wallerian degeneration happens distal to the site of injury and proximal traumatic degeneration occurs proximally unto the last node of Ranvier. The regenerating nerve fibres are attracted to their receptors by neurotropism, which is mediated by growth factors, hormones and other extracellular matrix tropins. Nerve regeneration is characterised by profuse growth of new nerve fibres which sprout from the cut proximal end. Overgrowth of these, coupled with poor approximation, may lead to neuroma formation.

Answer 154

Renin acts on angiotensinogen (Option c) to initiate the renin-angiotensin-aldosterone system.

Answer 155

Cardiac muscle cells. Glucose will not diffuse through a cell membrane against a concentration gradient. Insulin facilitates the diffusion of glucose across many cell membranes including cardiac muscle cells, some smooth muscle cells and adipose tissue cells.

Answer 156

The presence of deep bruising under the eyes after trauma is known as Panda eyes or Racoon eyes and is a sign of basal skull fracture or subgaleal hematoma. Other signs of basal skull fracture: Anterior fossa - anosmia, rhinorrhoea, epistaxis, panda eyes, subconjunctival haemorrhage, ptosis, restricted or painful eye movement Middle fossa - deafness, tinnitus, facial palsy, hemotympanum, otorrhoea Posterior fossa - battle sign (bruising over mastoid), loss of gag reflex Damage to carotid or vertebral artery or to the brain stem can occur following basal skull fracture

Answer 157

The above patient has abdominal injuries necessitating exploratory laparotomy with retroperitoneal exploration. Indications of radiological assessment: • gross haematuria • Shock in combination with microscopic haematuria • penetrating injury • Children in whom the kidneys are much lower and less protected Indications for renal exploration • expanding or pulsatile hematoma • vascular (renal pedicle) injury • shattered kidney • Relative indications for exploration include devitalized renal segment in the presence of other abdominal injuries. To predict need for exploration in cases of renal trauma using injury grade, trauma type (blunt/stab/gunshot), transfusion need, BUN, and creatinine Renal Exploration: When renal exploration for trauma is indicated, the preferred exposure is through a midline laparotomy for proximal vascular control. Without proximal control, premature decompression of the hematoma may allow for more bleeding. To establish proximal control, the transverse colon should be eviscerated superiorly. The small bowel is lifted superiorly and to the right. The aorta is palpated and a vertical incision in the retroperitoneum is made. The dissection continues to expose the left renal vein running anterior to the aorta. The left renal vein is a landmark in locating other renal vessels. Once circumferentially dissected, vessel loops are passed and left loosely in place, using them only when needed for haemostasis. Ideally warm ischemic time will be limited to < 30 minutes. The colon is retracted medially to expose the kidney. Debride all nonviable tissue, as the kidney only requires 1/3 of the parenchyma to sufficiently function. Repair the parenchyma and collecting duct lacerations with absorbable suture. Test for leak with methylene blue. The repair should be covered for protection, using Gelfoam or omentum.

Answer 158

The medial collateral ligament is attached to the body of the talus. The ankle joint is composed of the lower end of tibia, fibula and body of talus. The joint capsule is thin but is reinforced medially and laterally by the ligaments. Medial collateral ligament - known as the deltoid ligament, large triangular ligament running from medial malleolus to the body of the talus. It supports the ankle during eversion. Lateral collateral ligament - composed of three parts, the anterior and posterior talofibular ligaments and calcaneofibular ligament. This ligament is thinner and more prone to injury. It supports the ankle during inversion. The sural nerve typically runs lateral to the Achilles tendon. Ref: Netter's atlas of human anatomy, 7th edition

Answer 159

Scrotum is a pouch of skin containing the testes and spermatic cords. The subcutaneous tissue has no fat, but contains the dartos muscle which sends a sheet into the midline fibrous septum of the scrotum. The rugosity of the skin is due to contraction of the dartos. The dartos is smooth muscle, and is supplied by sympathetic fibres probably carried by the genital branch of the genitofemoral nerve. Lymph drainage is to the superficial inguinal nodes. The anterior axial line crosses the scrotum. The anterior one-third of the scrotal skin is supplied by the ilioinguinal nerve (L1) and the genital branch of the genitofemoral nerve (L1). The posterior two-thirds is supplied by scrotal branches of the perineal nerve (S3) reinforced laterally by the perineal branch of the posterior femoral cutaneous nerve (S2)

Answer 160

The sural nerve is formed by union of the medial sural cutaneous nerve (from the tibial nerve) and sural communicating branch of the common fibular nerve, respectively. The level of junction of these branches is variable; it may be high (in the popliteal fossa) or low (proximal to heel). Sometimes, the branches do not join and, therefore, no sural nerve is formed. In these people, the skin normally innervated by the sural nerve is supplied by the medial and lateral sural cutaneous branches. The sural nerve accompanies the small saphenous vein and enters the foot posterior to the lateral malleolus to supply the ankle joint and skin along the lateral margin of the foot.

Answer 161

Lipofuscin is an insoluble pigment, also known as lipochrome or wear-and-tear pigment. Lipofuscin is composed of polymers of lipids and phospholipids in complex with protein, suggesting that it is derived through lipid peroxidation of polyunsaturated lipids of intracellular membranes. Lipofuscin is not injurious to the cell or its functions. Its importance lies in its being a telltale sign of free radical injury and lipid peroxidation.In tissue sections, it appears as a yellow-brown, finely granular cytoplasmic, often perinuclear, pigment. It is seen in cells undergoing slow, regressive changes and is particularly prominent in the liver and heart of aging patients or patients with severe malnutrition and cancer cachexia.

Answer 162

Endodermal buds, similar to those that form the prostate in the male, are also seen in the female. The buds that arise from the caudal part of the vesicourethral canal give rise to the urethral glands, whereas the buds arising from the urogenital sinus form the paraurethral glands of Skene.

Answer 163

Local excision of anal melanomas is recommended rather than abdominoperineal resection. Abdominoperineal resection is associated with greater morbidity, leaves the patient with a permanent colostomy, offers no survival advantage, and does not treat at-risk inguinal nodes unless the procedure is combined with groin dissection. Adjuvant radiation is often necessary. Mucosal melanomas have extremely poor prognosis and are prone to develop recurrences.

Answer 164

A-All patients of flail chest must be managed by mechanical ventilation Flail chest • This condition usually results from blunt trauma associated with multiple rib fractures, and is defined as three or more ribs fractured in two or more places. The blunt force typically also produces an underlying pulmonary contusion. • The diagnosis is made clinically in patients who are not ventilated, not by radiography. • To confirm the diagnosis the chest wall can be observed for paradoxical motion of a chest wall segment. On inspiration, the loose segment of the chest wall is displaced inwards and therefore less air moves into the lungs. On expiration, the segment moves outwards (paradoxical respiration). • The CT scan, with contrast to display the vascular structures and a 3D reconstruction of the chest wall, is the gold standard for diagnosis of this condition. • Currently, treatment consists of oxygen administration, adequate analgesia (including opiates) and physiotherapy. If a chest tube is in situ, topical intrapleural local analgesia introduced via the tube, can also be used. • Ventilation is reserved for cases developing respiratory failure despite adequate analgesia and oxygen. Surgery to stabilise the flail segment using internal fixation of the ribs may be useful in a selected group of patients with isolated or severe chest injury and pulmonary contusion.

Answer 165

The lateral surface of the ovary lies in the angle between the internal and external iliac vessels, against the parietal peritoneum which separates it from the obturator nerve laterally and the ureter posteriorly. A diseased ovary may therefore cause referred pain along the cutaneous distribution of this nerve on the inner side of the thigh. The medial surface is mainly related to the uterine tube.

Answer 166

✅ Correct answer: Thick ascending loop of Henle Explanation: Furosemide (a loop diuretic) acts primarily on the thick ascending limb of the loop of Henle, where it inhibits the Na⁺–K⁺–2Cl⁻ cotransporter (NKCC2) on the luminal membrane of tubular cells. This inhibition prevents the reabsorption of sodium, potassium, and chloride ions, leading to: • Reduced medullary hypertonicity (decreased ability to concentrate urine) • Increased urinary excretion of sodium, chloride, potassium, calcium, and magnesium • Increased water excretion (diuresis), helping to relieve oedema in heart failure Key points: • Proximal tubule: Target of carbonic anhydrase inhibitors (e.g. acetazolamide) • Thick ascending limb: Target of loop diuretics (e.g. furosemide, bumetanide) • Early distal tubule: Target of thiazides (e.g. bendroflumethiazide) • Collecting duct: Target of potassium-sparing diuretics (e.g. spironolactone, amiloride) • Descending limb: Permeable to water but not solutes — no active transport occurs here Mnemonic: “Loop diuretics work at the Loop — the thick ascending limb.” So, for your question: Answer: ✅ Thick ascending loop of Henle

Answer 167

A high consumption of dairy products helps in bone healing.Closed fracture is favourable for healing. Minimal manipulation of the fracture haematoma is protective. Hence when indicated an above-knee cast is protective. In contrast, internal fixation can disturb the fracture haematoma and can cause delayed union. Causes of delayed union include an inadequate blood supply, infection, incorrect immobilisation and an intact fellow bone (such as the fibula in a tibial fracture). The fracture site is usually tender and the fracture remains visible, with very little callus formation, periosteal reaction or sclerosis at the bone-ends. Continued treatment is required and includes functional bracing, an excellent method of promoting bony union. A fracture should undergo internal fixation and bone grafting if union is delayed for more than 6 months and in the absence of any callus formation.

Answer 168

The combination of rapidly progressive neurological findings, fever and headache is highly suggestive of cerebral abscess. CT scanning will show a ring enhancing lesion because the intravenous contrast cannot penetrate the centre of the abscess cavity. HSV encephalitis does not produce ring enhancing lesions. CNS abscesses may result from a number of causes including, extension of sepsis from middle ear or sinuses, trauma or surgery to the scalp, penetrating head injuries and embolic events

Answer 169

A Meckel's diverticulum is a persistent remnant of the vitellointestinal duct and is present in about 2% of the population. It is found on the antimesenteric side of the ileum, commonly approximately 60cm from the ileocaecal valve and is classically 5cm long. A Meckel's diverticulum is a congenital diverticulum. It contains all three coats of the bowel wall and has its own blood supply. Meckel's diverticulitis presents like appendicitis, although if perforation occurs the presentation may resemble a perforated duodenal ulcer. Mullerian duct is the embryological precursor of the female reproductive system. Urachus is the fibrous remnant of allantois connecting the fetal bladder to the yolk sac.Urachus becomes the median umbilical ligament. Wolffian duct is the embryological precursor of the male reproductive system.

Answer 170

Femoral neck fractures are high-energy injuries in young patients. Avascular necrosis (AVN) is the most common complication after femoral neck fractures due to the disruption of blood supply. The risk of AVN in a displaced intracapsular neck of the femur fracture is approximately 30-40%. Risk increases with delayed surgical fixation and therefore emergent operative treatment recommended in the young patient to enable fixation and avoid arthroplasty.

Answer 171

MRl is a valuable tool for evaluating soft tissue injuries, providing detailed information on the knee structures.

Answer 172

Ewing's sarcoma is most common in males between 10-20 years. It can occur in girls. Ewing's sarcoma is a malignant round cell sarcoma of bone in which cells usually have a characteristic 11:22 translocation. It tends to arise in the diaphysis of a long bone or the pelvis. Patients usually present with a painful mass and may have systemic symptoms including fever, anaemia and increased erythrocyte sedimentation rate (ESR). Radiologically the bone appears moth eaten and may show an 'onion skin' periosteal reaction. MRI may show a large extraosseous soft tissue mass as well as significant inflammation with oedema.

Answer 173

A positive valgus stress test indicates an injury to the medial collateral ligament (MCL), which often presents with minimal joint effusion.

Answer 174

Persons with inherited mutations of genes involved in DNA repair systems are at greatly increased risk for the development of cancer. • Patients with HNPCC syndrome have defects in the mismatch repair system, leading to development of carcinomas of the colon.These patients' genomes show microsatellite instability, characterized by changes in length of short repeats throughout the genome. • Patients with xeroderma pigmentosum have a defect in the nucleotide excision repair pathway and are at increased risk for the development of cancers of the skin exposed to UV light because of an inability to repair pyrimidine dimers. • Syndromes involving defects in the homologous recombination DNA repair system constitute a group of disorders-Bloom syndrome, ataxia-telangiectasia, and Fanconi anemia — that are characterized by developmental disorders and hypersensitivity to DNA-damaging agents, such as ionizing radiation. BRCA1 and BRCA2, which are mutated in familial breast cancers, are involved in DNA repair. • Mutations in DNA polymerase that abolish proofreading function leads to genomic instability in subsets of colonic and endometrial carcinomas.

Answer 175

B-Medialisation of the palatine tonsil Clinical features suggestive of malignancy in the presence of a parotid lump include skin involvement, fixation, facial nerve palsy, trismus and metastases (neck lump). A deep-lobe parotid tumour may medialise the palatine tonsil because of their anatomical relationship.

Answer 176

This patient has oral leukoplakia, a relatively common precancerous condition of the oral epithelium. Smoking and alcohol consumption are important risk factors for this condition, which manifests as single or multiple asymptomatic white plaques that cannot be scraped off. Any part of the oral cavity can be affected. If untreated, leukoplakia can undergo malignant transformation into squamous cell carcinoma. The risk of malignant transformation is higher if the white patches are non homogeneous in appearance and/or texture (e.g., erythroleukoplakia, verrucous leukoplakia).

Answer 177

Incision and Drainage is no longer performed for simple lactational mastitis, as it can result in unsightly scars and mammary duct fistulas. Treatment will consist of supportive measures like simple analgesics and cold compresses, emptying the breast either by feeding or using a pump, and a penicillin antibiotic (such as co-amoxiclav). In case of penicillin allergy, erythromycin is appropriate. If the mastitis is not resolving, ultrasonography may be appropriate to look for a developing abscess.

Answer 178

ВСС often presents as a crusty exophytic ulcer with everted edges, commonly seen on sun-exposed areas like the face. The clinical picture here is typical of basal cell carcinoma, though the lymphnodes could be nonspecific

Answer 179

Primary haemorrhage: Occurs immediately after injury or surgery Reactionary haemorrhage: It is delayed haemorrhage within 24 hours is usually caused by dislodgement of clot by resuscitation, normalisation of blood pressure or vasodilation. Secondary haemorrhage: Sloughing of wall of a vessel. It usually occurs 7-14 days after injury and is precipitated by factors such as infection, pressure necrosis or malignancy.

Answer 180

✅ Correct answer: Ortolani’s test ⸻ Explanation: Ortolani’s test is a clinical examination used in infants to detect developmental dysplasia of the hip (DDH). • It is performed by flexing the infant’s hips and knees to 90°, then abducting the hips while applying gentle anterior pressure to the greater trochanter. • A distinctive “clunk” or “click” is felt or heard as the femoral head reduces into the acetabulum, indicating a dislocated but reducible hip. ⸻ Comparison of options: Test Description Condition Barlow’s test Attempts to dislocate an unstable but located hip by adducting the hip and applying posterior pressure. Detects unstable hip (dislocatable) Ortolani’s test Attempts to reduce a dislocated hip by abducting it while lifting anteriorly. Detects dislocated but reducible hip Thomas’ test Detects fixed flexion deformity of the hip. Hip contracture (e.g. arthritis) Kernig’s test Pain on knee extension when hip flexed. Meningeal irritation (meningitis) Homan’s sign Calf pain on dorsiflexion of the foot. Deep vein thrombosis (DVT) (nonspecific) ⸻ Summary Mnemonic for DDH: Barlow = Bad (dislocates the hip) Ortolani = On (puts it back on) ⸻ Answer: ✅ Ortolani’s test – detects developmental dysplasia of the hip by producing a characteristic “clunk” on hip abduction.

Answer 181

D-Addison’s disease Causes of hyperkalemia: • latrogenic excess • Insulin deficiency • Tissue lysis • Acidosis • Addison's syndrome Causes of hypokalemia: • Reduced intake • Burns • Diarrhoea, fistula etc • Bartter syndrome • RTA | & III • Excess insulin • Excess salbutamol DKA can cause hypokalemia as much of the shifted extracellular potassium is lost in urine because of osmotic diuresis.

Answer 182

Stomach: Surgical repair is required but great care must be taken to examine the stomach fully, as an injury to the front of the stomach can be expected to have an 'exit' wound elsewhere on the organ. Duodenum: Smaller injuries of D1, D3 and D4 can be repaired primarily (as with small bowel).

Answer 183

Chronic granulomatous disease (CGD) is characterized by defects in bacterial killing that render patients susceptible to recurrent bacterial infection. CGD results from inherited defects in the genes encoding components of phagocyte oxidase, the phagolysosomal enzyme that generates superoxide (O2•). The most common variants are an X-linked defect in one of the membrane-bound components (gp91phox) and autosomal recessive defects in the genes encoding two of the cytoplasmic components (p47phox and p67phox). The name of this disease comes from the macrophage-rich chronic inflammatory reaction that tries to control the infection when the initial neutrophil defense is inadequate. This often leads to collections of activated macrophages that wall off the microbes, forming granulomas.

Answer 184

Functional residual capacity (FRC), is the volume remaining in the lungs after a normal, passive exhalation. In a normal individual, this is about 3L. The FRC also represents the point of the breathing cycle where the lung tissue elastic recoil and chest wall outward expansion are balanced and equal. Thus, the FRC is unique in that it is both a volume and related directly to two respiratory structures. FRC is the total amount of air in a person's lungs at the lowest point of their tidal volume (TV), where the tidal volume is the volume of air a person normally inspires and expires. The FRC is a lung capacity, consisting of the sum of two or more volumes. It also cannot be measured directly using spirometry and has to be calculated. This because FRC is a combination of the expiratory reserve volume (ERV) and the residual volume (RV). The residual volume is the amount of air remaining the lung after expelling as much air from the lungs as possible. The residual volume can never be exhaled; thus, it cannot be measured using spirometry and is the air causing the alveoli to remain open. The expiratory reserve volume (ERV) is the reserve amount of air that can be exhaled forcefully, after passive exhalation. Therefore, the FRC can be represented as the equation: FRC= RV+ERV FRC is also the point at which two forces are at equilibrium; the inner recoil forces of the lung due to the elastic tissue of the alveoli, and the chest wall which wants to expand outwards.

Answer 185

Osteosarcomas often present with pain, sometimes due to pathologic fractures. Radiographically, the enlarging tumor forms a destructive, mixed lytic and blastic mass with infiltrative margins. The tumor frequently breaks through the cortex and lifts the periosteum, inducing reactive periosteal bone formation. The triangular shadow between the cortex and raised periosteal ends, known radiographically as a Codman triangle, indicates an aggressive tumor. RB mutations are present in up to 70% of sporadic osteosarcomas; germline RB mutations confer a 1000-fold increased risk of osteosarcoma.

Answer 186

Indications for NPA: • Can be used in semiconscious, unconscious and conscious patients. • Prolonged seizure activity • Airway obstructed by tongue • OPA cannot be inserted due to trismus or a wired jaw. Contraindications for NPA: • Traumatic brain injury or central facial fractures • Basilar skull or cribriform fractures • Risk of epistaxis (anticoagulation therapy

Answer 187

Co-codamol is a combination drug consisting of paracetamol (PCM) and codeine (a weak opioid). )1g PCM and 60mg codeine qid is the maximum dose of co-codamol that can be prescribed. The next step in the analgesic pain ladder will be moving to a stronger opioid after stopping codeine. Other alternatives include: • Addition of NSAIDs — this is the first line of treatment in metastatic bone pain • Addition of bisphosphonates • Brachytherapy • Surgery While reviewing any patient with inadequate pain control, it is important to first assess what analgesic they are on (drug, dose, frequency, timing) as well as the use of any other OTC analgesics or adjuvants. Compliance with the prescription should be explicitly confirmed, as cancer pain usually required a regular dose of analgesic rather than sos consumption of analgesics.

Answer 188

Although many factors are involved in the decision to operate on a patient with a hemothorax, the patient's physiologic status and the volume of blood drainage from the chest tube are important considerations. Greater than 1500 mL of blood obtained immediately through the chest tube indicates a massive hemothorax that may require operative intervention. Also, if drainage of more than 200 mL/hr for 2 to 4 hours occurs, or if blood transfusion is required, the trauma team should consider operative exploration. The ultimate decision for operative intervention is based on the patient's hemodynamic status. In this patient, the hemodynamic status did not improve despite adequate resuscitative measures and 2000 ml of blood was drained and hence the ideal decision would be to transfer him to the theatre for thoracotomy.

Answer 189

K+ • The resting membrane potential of a cell is primarily maintained by the differential distribution of potassium (K+) ions across the cell membrane. This is due to the selective permeability of the cell membrane to K+ ions and the action of the sodium-potassium pump (Na+/K+ ATPase). • The cell membrane is more permeable to K+ ions than to other ions, such as Na+ (sodium), Cl- (chloride), and Ca2+ (calcium). This means that K+ ions can move more easily across the cell membrane. • There is a higher concentration of K+ ions inside the cell compared to the outside. Due to this concentration gradient, K+ ions tend to diffuse out of the cell. • As K+ ions leave the cell, they leave behind negatively charged proteins and other anions, which creates an electrical gradient that opposes further loss of K+ • This pump actively transports K+ ions into the cell and Na+ ions out of the cell, using ATP for energy. For every three Na+ ions pumped out, two K+ ions are pumped in, which helps maintain the resting membrane potential.

Answer 190

✅ Correct answer: “Waldeyer ring commonly involved” — this statement is false. ⸻ Explanation: Hodgkin’s lymphoma is a malignant disease of lymphoid tissue characterized by the presence of Reed–Sternberg cells. It typically begins in a single group of lymph nodes, most often the cervical nodes, and spreads in an orderly, contiguous manner to adjacent nodal groups. Because of this predictable pattern, it is often localized to one area at the time of diagnosis. Extranodal involvement (disease outside the lymph nodes) is uncommon in Hodgkin’s lymphoma, whereas it is quite common in non-Hodgkin’s lymphoma. The mesenteric lymph nodes are rarely affected in Hodgkin’s lymphoma. Instead, the disease tends to involve nodes along the neck, mediastinum, and sometimes the spleen. In contrast, the Waldeyer ring, which includes the tonsils and nasopharyngeal lymphoid tissue, is rarely involved in Hodgkin’s lymphoma but commonly affected in non-Hodgkin’s lymphoma. Therefore, the statement “Waldeyer ring commonly involved” is false for Hodgkin’s lymphoma. ⸻ Answer: ❌ Waldeyer ring commonly involved — this is not true for Hodgkin’s lymphoma.

Answer 191

Amyand's hernia is found in 1% of inguinal hernia repair.It is most common on the right side and is mostly found intraoperatively. Bochdalek and Morgagni are types of diaphragmatic hernia Littre's hernia is Meckel's diverticulum within the hernia sac.

Answer 192

✅ Correct answer: 2 ⸻ Explanation: The two-level Wells score is a clinical prediction rule used to assess the likelihood of deep vein thrombosis (DVT) before imaging or treatment. It assigns points based on clinical findings and risk factors such as active cancer, recent immobilization, calf swelling, and tenderness along the deep veins. After scoring, the results are interpreted as follows: • Score of 2 points or more → DVT likely • Score of less than 2 points → DVT unlikely If the Wells score is 2 or above, further testing with compression duplex ultrasound or empirical anticoagulation may be indicated, depending on clinical circumstances. ⸻ Answer: ✅ 2 — DVT is likely when the Wells score is ≥ 2.

Answer 193

Epididymitis most commonly occurs on its own although in 20-40% of the cases it causes concomitant orchitis (epididymo-orchitis). It is as common as testicular torsion in prepubertal males. Epididymo-orchitis has a more insidious onset and is less severe than in torsion. Testicular orientation is normal as opposed to torsion, where the testis is usually high lying. Prehn's manoeuvre (elevation of the scrotum above the pubic symphysis) may relieve the pain of epididymitis, whilst exacerbating the pain of testicular torsion. However, it is not usually performed as it is extremely uncomfortable for the patient, and is not an accurate means of excluding torsion. Imaging (e.g. by testicular ultrasound) is a more sensitive means of diagnosis, although scrotal exploration should never be delayed if there is sufficient clinical suspicion of torsion. Idiopathic scrotal oedema is an uncommon condition of unknown aetiology. It is a self-limiting condition, with a peak incidence at 5-7 years of age. It is associated with mild scrotal erythema and oedema, and normal, non-tender testes.

Answer 194

Thromboelastography (TEG) is a global test for hemostasis that measures viscoelastic changes induced by fibrin polymerisation and evaluates platelet function as well as the rate of formation of a clot, its strength, stability, retraction and lysis. This dynamic form of assessing the coagulation status is being used increasingly for intraoperative monitoring. The shape of the TEG trace defines the nature of the underlying coagulation deficiency as shown.

Answer 195

B-Edema Frostbite injury is associated with morbidity which is worse in the presence of the following: Presence of hemorrhagic blisters No edema Ongoing mottling Frank presence of frozen tissue Firm skin after rewarming Ref: Basit H, Wallen TJ, Dudley C. Frostbite. [Updated 2021 Jan 24]. In: StatPearls [Internet].

Answer 196

Vitamin B12 is freed from binding proteins in food through the action of pepsin in the stomach and binds to a salivary protein called haptocorrin. In the duodenum, bound vitamin B12 is released from haptocorrin by the action of pancreatic proteases and associates with intrinsic factor. This complex is transported to the ileum, where it is endocytosed by ileal enterocytes that express a receptor for intrinsic factor called cubilin on their surfaces. Within ileal cells, vitamin B12 associates with a major carrier protein, transcobalamin Il, and is secreted into the plasma. Transcobalamin I| delivers vitamin B12 to the liver and other cells of the body, including rapidly proliferating cells in the bone marrow and the gastrointestinal tract.

Answer 197

A-Tumor suppressor genes Up to 5% of breast cancers are caused by inheritance of germline mutations such as BRCA1 and BRCA2, which are inherited in an autosomal dominant fashion with varying degrees of penetrance. BRCA1 is located on chromosome arm 17q, spans a genomic region of approximately 100 kilobases (kb) of DNA, and contains 22 coding exons for 1863 amino acids. Both BRCA1 and BRCA2 function as tumor suppressor genes, and for each gene, loss of both alleles is required for the initiation of cancer.

Answer 198

The presentation with hypercalcemia, elevated serum creatinine, hilar shadowing on lung X-ray, and low parathyroid hormone (PTH) levels is consistent with sarcoidosis.

Answer 199

You should inform the patient who will be doing the operation and be honest about your experience. As the consultant plans to remain in theatre to supervise the procedure you should also inform the patient of this. All alternative management options should be mentioned. In any case non-operative management is always an option provided the patient understands any associated risks with such an option. Risk of anaphylaxis with loca; anaesthesia always needs to be mentioned. Even though the procedure is to be performed under a local anaesthetic the site still needs to be marked before the operation to act as an additional check to prevent wrong site surgery, which would be a never event. At least three patient identifiers need to be put on the form. Commonly this is the patient's name, date of birth and hospital or NHS number.

Answer 200

D-Antacid abuse Causes of metabolic acidosis: • DKA • Diarrhoea • Renal failure • Aspirin overdose • Shock • sepsis

Answer 201

Perthes' disease is a self-limiting disease of children characterised by interruption of the blood supply to the capital femoral epiphysis resulting in necrosis of the epiphysis. The vascular occlusion is temporary; complete re-vascularization of the epiphysis occurs over a period of 2-4 years if the child is under 12 years of age at onset of the disease. During the process of re-vascularization the necrotic bone is completely replaced by healthy new bone. In some children the disease heals without any sequelae and consequently no treatment is needed in these children. However, treatment is needed in a significant proportion of children in whom the femoral head is likely to get deformed while epiphyseal re-vascularization occurs. Secondary degenerative arthritis is likely to develop in mid-adult life if the femoral head does get deformed. The aim of treatment of these susceptible children should be to prevent the femoral head from getting deformed.

Answer 202

Eye movement: eye opening on command - E3 Verbal response: confused/disoriented - V4 Motor response: localizing pain - M5; withdrawal from pain - M4; use the higher of the two scores (M5)

Answer 203

✅ Correct answer: Type II hypersensitivity ⸻ Explanation: Myasthenia gravis is an autoimmune disorder caused by antibodies directed against acetylcholine receptors (AChRs) on the postsynaptic membrane of the neuromuscular junction. These antibodies bind to the receptors, block acetylcholine from attaching, and lead to complement-mediated destruction of the receptor sites. This reduces neuromuscular transmission and results in fatigable muscle weakness, most commonly affecting the extraocular muscles first (hence the drooping eyelids, or ptosis). This mechanism involves antibody-mediated damage to cell surface antigens, which is the hallmark of Type II (cytotoxic) hypersensitivity. ⸻ Summary of hypersensitivity types (for understanding): • Type I – Immediate (IgE mediated) – e.g. anaphylaxis, allergic rhinitis • Type II – Cytotoxic/antibody mediated – e.g. Myasthenia gravis, Graves’ disease, autoimmune haemolytic anaemia • Type III – Immune complex mediated – e.g. SLE, serum sickness • Type IV – Delayed, T-cell mediated – e.g. Tuberculin skin test, contact dermatitis ⸻ Answer: ✅ Type II hypersensitivity

Answer 204

The above patient has signs and symptoms concerning necrotizing soft tissue infection of the perineal region or Fournier's gangrene. This patient requires early and aggressive surgical debridement, not be delayed for radiographic imaging. Intravenous antibiotics without surgical intervention is associated with a near 100% mortality rate. Necrosis eats through the scrotal tissue leaving the testis exposed. Despite best care, the condition is associated with 50% mortality.

Answer 205

A-BRCA1: Ch 17q / AD/ high penetrance; associated with the highest incidence of hereditary breast cancer. The average lifetime risk has been reported to lie between 60%-70%. BRCA1-associated breast cancers are invasive ductal carcinomas, are poorly differentiated, triple receptor negative immunohistochemical profile or basal phenotype. Early age of onset compared with sporadic cases; a higher prevalence of bilateral breast cancer; and the presence of associated cancers in some affected individuals, specifically ovarian cancer and possibly colon and prostate cancers. BRCA2: Ch 13q / AD/ high penetrance; lifetime breast cancer risk 85%, ovarian cancer risk 20%; male breast cancer risk 6% (100 times higher than the general population); presence of associated cancers in some affected individuals, specifically ovarian, colon, prostate, pancreatic, gallbladder, bile duct, and stomach cancers, as well as melanoma.

Answer 206

Serosanguinous discharge from a surgical wound, especially after several days, can indicate wound dehiscence, a partial or total separation of the wound layers.

Answer 207

In patients with multiple endocrine neoplasia type 1 (MEN1), the most common functional pancreatic endocrine tumours (PET) syndrome is Zollinger-Ellison syndrome (ZES), and it may be the presenting complaint.

Answer 208

Metaplasia is the replacement of one differentiated cell type by another. Barrett's oesophagus is defined as the presence of columnar epithelium lining the distal oesophagus, replacing normal squamous epithelium. Barrett's oesophagus is a premalignant disease and surveillance must be considered in patients with the condition. Squamous metaplasia is said to occur when the epithelial lining is replaced by squamous epithelium, as is seen in the bladder or cervix. Dysplasia, which is usually a premalignant state, refers to the abnormal development of cells. Hyperplasia refers to an increase in cell number, while hypertrophy refers to an increase in cell size.

Answer 209

C- 28% Body surface area differs considerably for children - the Lund and Browder chart takes into account changes in body surface area with age and growth. If not available: • For children <1 year: head = 18%, leg = 14%. • For children >1 year: add 0.5% to leg, subtract 1% from head, for each additional year until adult values are attained.

Answer 210

ESGE suggests treatment by flexible endoscopy for recurrent Zenker's diverticulum. Ref: Weusten BLAM, Barret M, Bredenoord AJ, et al. Endoscopic management of gastrointestinal motility disorders - part 1: European Society of Gastrointestinal Endoscopy (ESGE) Guideline [published correction appears in Endoscopy. 2020 Jun;520:C6]. Endoscopy. 2020;52Q:498-515. doi:10.1055/a-1160-5549

Answer 211

B- Doxorubicin (Adriamycin) Dactinomycin • Inhibits DNA dependent RNA polymerase • Uses - rhabdomyosarcoma,wilms tumour, choriocarcinoma • Adverse effects- pancytopenia, extravasation injuries, dermatological manifestations in areas subjected to radiation Anthracyclines • Intercalate with DNA and affects transcription and replication, toposisomerase Il inhibition • Doxorubicin. • Multiple myeloma, kaposi sarcoma,lymphomas, carcinoma breast • Adverse effects - myelosuppression, radiation recall, cardiomyopathy • Others- Epirubicin, Valrubicin Anthracenedione • Mitoxantrone - topoisomerase Il inhibitor • Uses - AML, prostate cancer, multiple sclerosis • Adverse effects - myelosuppression, cardiac toxicity

Answer 212

Clinically, the velocity of the circulation can be measured by injecting a bile salt preparation into an arm vein and timing the first appearance of the bitter taste it produces.The average normal arm-to-tongue circulation time is 15 s.

Answer 213

The sternocleidomastoid muscle is superiorly attached to the mastoid process and inferiorly attached to the medial third of the clavicle. Therefore, in the setting of a fracture, as seen in this patient, the sternocleidomastoid pulls the medial segment of the fractured clavicle upwards.

Answer 214

A negative force is always required on the outside of the lungs to keep the lungs expanded. This force is provided by negative pressure in the normal pleural space. The basic cause of this negative pressure is pumping of fluid from the space by the lymphatics, which is also the basis of the negative pressure found in most tissue spaces of the body. Because the normal collapse tendency of the lungs is about - 4 mm Hg, the pleural fluid pressure must always be at least as negative as - 4 mm Hg to keep the lungs expanded. Actual measurements have shown that the pressure is usually about -7 mm Hg, which is a few millimetres of mercury more negative than the collapse pressure of the lungs.

Answer 215

Jeremiah seems to have cafe-au-lait spots, based on the described findings. Cafe-au-lait macules themselves are harmless, but when multiple or segmental, may be a marker for a number of genetic syndromes. Six or more cafe-au-lait macules fulfils one of the seven National Institutes of Health (NIH) diagnostic criteria for NF1. Other syndromes definitely associated with multiple cafe-au-lait macules include: • neurofibromatosis type 2 (NF2); ® Legius syndrome (NF1-like syndrome); ® autosomal dominant multiple cafe-au-lait macules; ® Watson syndrome; © McCune-Albright syndrome; © LEOPARD syndrome; ® ring chromosome syndromes; and ® constitutional mismatch repair deficiency syndrome (CMMR-D).

Answer 216

Peritrochanteric lesions have the greatest risks of fracture (due to loading). The lesions from breast cancer are usually lytic and therefore at higher risk rather than the sclerotic lesions from prostate cancer.

Answer 217

Diethylenetriamine pentaacetate (DTPA) and MAG3 are forms of radioisotope scanning that allow assessment of the relative function of each kidney. It is important to note that MAG3 scanning is preferred over DTPA in neonates, patients with impaired function, and patients with suspected obstruction, due to its more efficient extraction. The DTPA is labelled with technetium-99m, a gamma-ray emitter, so that the passage of 99mTc-labelled DTPA through the kidneys can be tracked using a gamma camera. 99mTc-DTPA is cleared from a normal kidney but stays in the renal pelvis on the obstructed side and is retained even if urine flow is increased by administering furosemide.

Answer 218

Giant cell tumour of bone is a locally aggressive tumour with large osteoclast like giant cells. It usually occurs between the ages of 20 and 45, after the physes have closed. Giant cell tumour of bone typically affects the epiphysis of long bones and erodes bone under the articular cartilage, especially around the knee, proximal humerus and distal radius. Giant cell tumours on x-ray have a 'soap bubble' appearance. They present as pain or pathological fractures. They commonly metastasize to the lungs.

Answer 219

E-It should be biopsied to confirm diagnosis Kaposi sarcoma (KS) is a vascular neoplasm caused by Kaposi sarcoma herpesvirus (KSHV, also known as human herpesvirus-8, or HHV-8). Although it occurs in a number of contexts, it is most common in patients with AIDS; indeed, its presence is used as a criterion In classic Kaposi sarcoma (and sometimes in other variants), the cutaneous lesions progress through three stages: patch, plaque, and nodule. Most primary KSHV infections are asymptomatic. Classic KS is—at least initially-largely restricted to the surface of the body, and surgical resection usually is adequate for an excellent prognosis. For AIDS-associated KS, HIV anti-retroviral therapy generally is beneficial, with or without additional therapy. Clinically, AIDS-associated KS is quite different from the sporadic form. In HiV-infected individuals, the tumor is usually widespread, affecting the skin, mucous membranes, gastrointestinal tract, lymph nodes, and lungs. These tumors also tend to be more aggressive than sporadic KS.Most patients eventually die of opportunistic infections rather than from KS.

Answer 220

In chronic pancreatitis, pain management is a key aspect of treatment. Nonsteroidal anti-inflammatory drugs (NSAIDs) are often used as first-line therapy for pain relief. They are effective for managing mild to moderate pain and have a lower risk of dependency compared to opioids.

Answer 221

Humans carry three tapeworms -Taenia solium, T. saginata, and T. asiatica as definitive hosts. Furthermore, humans are also definitive hosts for pinworms, whipworms and flukes. Echinococcus granulosus has a mammalian definitive host but includes only dogs and some other wild carnivores, not humans.

Answer 222

A-Tendon of the flexor carpi radialis The radial artery lies superficially in front of the distal end of the radius, between the tendon of the brachioradialis (attaching to the base of the radial styloid process) laterally and the tendon of the flexor carpi radialis medially and so the pulse can be easily identified here.

Answer 223

C-The root is related to the Aorta, IVC and the gonadal vessels The peritoneum encloses the small bowel in a double layer, creating the mesentery. The mesentery connects the bowel loops to the posterior abdominal wall and transmits vessels, lymphatics and nerves, and is about 15 cm long. The ileal, jejunal and ileocolic branches of the SMA supply the small bowel after running through the mesentery. The root of the mesentery connects the mesentery to the posterior abdominal wall and runs from the DJ flexure (just to the left of L2) to the right sacroiliac joint. The root of the mesentery is related to the aorta and IVS superiorly, the right psoas muscle and ureter in the middle of the abdomen and the right gonadal vessels and right iliacus muscle inferiorly.

Answer 224

Pemphigus is an uncommon autoimmune blistering disorder resulting from loss of normal intercellular attachments within the epidermis and the squamous mucosal epithelium. There are three major variants: • Pemphigus vulgaris (the most common type) • Pemphigus foliaceus • Paraneoplastic pemphigus Pemphigus vulgaris and pemphigus foliaceus are autoimmune diseases caused by antibody-mediated (type II) hypersensitivity reactions .The pathogenic antibodies are IgG autoantibodies that bind to intercellular desmosomal proteins (desmoglein types 1 and 3) found in the skin and mucous membranes. The antibodies disrupt the intercellular adhesive function of desmosomes and may activate intercellular proteases as well.

Answer 225

Bronchoalveolar carcinoma (BAC) is a subtype of adenocarcinomas (non-small cell lung cancer) that grows along the alveoli and respects septal boundaries. It arises from type Il pneumocytes and presents radiographically as single or diffuse nodules as well as segmental/lobar consolidation. Consolidation is the second most common finding and cancers presenting this way resemble a pneumonia-like consolidation and it is only when they fail to resolve with antibiotic treatment that the suspicion of BAC arises. Patients can be asymptomatic or present with dyspnoea, productive cough, loss of weight etc. As disease progresses the patient may complain of bronchorrhea. Atypical cells in bronchoalveolar lavage samples are highly suggestive of an infiltrating neoplasm and can aid the diagnosis, however they can be present in patients with interstitial lung disease, bone marrow transplant recipients. Atypical epithelial cells suggest bronchoalveolar carcinoma or metastases from breast, stomach, kidney and colon. Non-epithelial atypical cells suggest a lymphoma or Kaposi's sarcoma.

Answer 226

The probability that an individual with the disease is screened positive is the definition of Sensitivity. 💡 Understanding Sensitivity and Related Terms In medical screening and diagnostic testing, several measures are used to evaluate a test's accuracy. * Sensitivity (or the true positive rate) is the probability that a test result will be positive when the disease is actually present (P(\text{Test Positive} | \text{Disease Present})). A highly sensitive test is good at identifying people who have the disease, resulting in few false negative results. * Specificity (or the true negative rate) is the probability that a test result will be negative when the disease is actually absent (P(\text{Test Negative} | \text{Disease Absent})). A highly specific test is good at identifying people who do not have the disease, resulting in few false positive results. * Positive Predictive Value (PPV) is the probability that an individual actually has the disease given that they screened positive (P(\text{Disease Present} | \text{Test Positive})). * Negative Predictive Value (NPV) is the probability that an individual does not have the disease given that they screened negative (P(\text{Disease Absent} | \text{Test Negative})). * Likelihood Ratio for a Positive Test Result (LR+) is a measure of how much the odds of disease increase when a test is positive. It is calculated as \text{Sensitivity} / (1 - \text{Specificity}). The difference between sensitivity and PPV is crucial: * Sensitivity is based on the people with the disease. * Positive Predictive Value is based on the people who tested positive.

Answer 227

The trachea bifurcation is at the level of the lower border of the T4 vertebrae.

Answer 228

Mahesh has symptoms of bilharziasis, a disease endemic to the Middle East caused by S.haematobium. The disease is acquired through exposure of the skin to infected water. The cercariae penetrate the skin and enter blood vessels from where they are swept to all parts of the body but they flourish in the liver where they live on erythrocytes and develop into male and female worms. Once sexual maturity has been attained, the nematodes leave the liver and enter the portal vein from where after mating, they make their way to the inferior mesenteric vein. Once in the bladder, the female begins to lay an ova that penetrates submucous venule walls. A heavily infected individual passes hundreds of ova a day. If the ova reaches fresh water, the low osmotic pressure causes rupture and the ciliated miracidium emerges. To survive, it must reach and penetrate the intermediate snail host within 36 hours which gives rise to thousands of cysts which are set free on the death of the snail. Urine specimen examination on several consecutive days may be required, but a negative result does not exclude bilharziasis, especially in patients no longer resident in bilharzial districts.

Answer 229

In a patient with a history of renal transplant, elevated calcium levels and an elevated parathyroid hormone (PTH) level, tertiary hyperparathyroidism is a likely diagnosis. Tertiary hyperparathyroidism is a condition that occurs in some individuals who have had long-standing secondary hyperparathyroidism due to chronic kidney disease. In this condition, the parathyroid glands become autonomous and continue to produce excessive PTH even after the underlying cause (such as kidney disease) has been treated or resolved, as is often the case after a successful kidney transplant. Primary hyperparathyroidism is characterized by elevated PTH and calcium levels but is not typically associated with renal transplant or chronic kidney disease. Secondary hyperparathyroidism is often seen in individuals with chronic kidney disease but does not involve autonomous PTH production after a successful transplant. Pseudo-hyperparathyroidism is a rare genetic disorder and is unlikely in a patient with a history of renal transplant and elevated PTH levels.

Answer 230

D-Both a and b Centralised abdominal pain is always suspicious for acute appendicitis. However, in a child with recent infections, it can also be acute mesenteric adenitis - which can mimic appendicitis clinically. Intussusceptions is an acutely severe painful condition with passage of bloody diarrhoea and a mass palpable per abdomen. Bowel sounds are likely to be increased in the acute phase, rather than sluggish.

Answer 231

Microscopically, medullary carcinomas are composed of polygonal to spindle-shaped cells, which may form nests, trabeculae, and even follicles. Small, more anaplastic cells are present in some tumors and may be the predominant cell type. Amyloid deposits derived from calcitonin polypeptides are present in the stroma in many cases.

Answer 232

This is likely to be a case of subdural haemorrhage. In elderly people, due to brain atrophy, there is stretching of the bridging veins between the dura and arachnoid mater. With even trivial trauma (which patients and family may not even remember), these veins may rupture, leading to pooling of blood underneath the dura mater. In small SDH, symptoms may be mild and non-specific, such as confusion, difficulty speaking, or headache. Larger SDHs may cause features of raised ICP. Non accidental injury is an important differential diagnosis in the vulnerable groups - children and elderly. In this case, as there do not appear to be any other physical injuries, it is unlikely. Tumor can be another important cause of vague neurological symptoms in the elderly, but the presence of the bump on the head makes SDH a more probable diagnosis. SAH will present with signs of meningeal irritation. Stoke will have more neurological deficits.

Answer 233

✅ Correct Answer: PaO₂ < 60 mmHg Explanation: The Ranson criteria are used to assess the severity and prognosis of acute pancreatitis, primarily in alcohol-induced cases. The criteria are divided into two phases: On Admission: 1. Age > 55 years 2. WBC > 16,000/mm³ 3. Blood glucose > 11 mmol/L (≈200 mg/dL) 4. LDH > 350 IU/L 5. AST > 250 U/L At 48 Hours: 1. Fall in haematocrit > 10% 2. Increase in urea > 1.8 mmol/L 3. Serum calcium < 2 mmol/L 4. Base deficit > 4 mmol/L 5. Estimated fluid sequestration > 6 L 6. PaO₂ < 60 mmHg ⸻ Therefore: 🔹 PaO₂ < 60 mmHg is not part of the Ranson criteria on admission — it is assessed after 48 hours. ⸻ Quick Tip for MRCS Exams: • Ranson (US system): for alcoholic pancreatitis; split into admission and 48-hour values. • Modified Glasgow/Imrie (UK system): for both alcohol and gallstone pancreatitis; mnemonic PANCREAS. • APACHE II: for daily severity assessment in ITU. ⸻ 💡 Summary Table: Phase Ranson Criteria Includes PaO₂ < 60 mmHg? Admission Age, WBC, Glucose, LDH, AST ❌ No 48 Hours Hct fall, Urea rise, Ca, Base deficit, Fluid loss, PaO₂ ✅ Yes ⸻ Answer: 🟩 PaO₂ < 60 mmHg

Answer 234

Carcinoma of the NP is traditionally classified according to histologic findings by the WHO: • Type 1: Keratinizing SCC • Type 2: Non-keratinizing SCC • Type 3: Undifferentiated or poorly differentiated carcinoma. Types 2 and 3, often combined together as nonkeratinizing types, are strongly associated with EBV.

Answer 235

The tongue is retracted up and back by the styloglossus muscle, protruded by genioglossus and depressed by the hyoglossus. All these muscles are innervated by the hypoglossal nerve (CN XII).

Answer 236

Adenosis and apocrine metaplasia are two of the histologic findings associated with fibrocystic changes. These do not need to be routinely removed. Classification of benign breast disorders Nonproliferative disorders of the breast Cysts and apocrine metaplasia Duct ectasia Mild ductal epithelial hyperplasia Calcifications Fibroadenoma and related lesions Proliferative breast disorders without atypia Sclerosing adenosis Radial and complex sclerosing lesions Ductal epithelial hyperplasia Intraductal papillomas Atypical proliferative lesions Atypical lobular hyperplasia Atypical ductal hyperplasia Data from Godfrey SE: Is fibrocystic disease of the breast precancerous? Arch Pathol Lab Med. 1986 Nov;110(11):991.

Answer 237

C-Parakeratosis Acanthosis: Diffuse epidermal hyperplasia Dyskeratosis: Abnormal, premature keratinization within cells below the stratum granulosum Hyperkeratosis: Thickening of the stratum corneum, often associated with a qualitative abnormality of the keratin Papillomatosis: Surface elevation caused by hyperplasia and enlargement of contiguous dermal papillae Parakeratosis: Retention of nuclei in the stratum corneum of a squamous epithelium. On mucous membranes, parakeratosis is normal. Spongiosis: Intercellular edema of the epidermis Ref:Image from Robbins basic pathology, 10th

Answer 238

D-Retroperitoneal fibrosis due to previous surgery is called Ormond's disease Retroperitoneal fibrosis is an uncommon cause of ureteral narrowing or obstruction characterised by a fibrous proliferative inflammatory process encasing the retroperitoneal structures and causing hydronephrosis. The disorder occurs in middle to old age. At least a proportion of these cases occur in association with IgG4-related disease, characterised by fibroinflammatory lesions rich in IgG4-secreting plasma cells. Other cases are associated with drug exposures (ergot derivatives, adrenergic blockers), radiation, infection, prior surgery, or malignant disease (lymphomas, urinary tract carcinomas). Most cases, however, have no obvious cause and are considered primary, or idiopathic (Ormond disease).

Answer 239

The oculomotor nerve gives off the branch to the ciliary ganglion. This is the parasympathetic root to the ciliary ganglion and carries preganglionic parasympathetic fibers that will synapse in the ciliary ganglion with postganglionic parasympathetic fibers. The postganglionic fibers are distributed to the eyeball through short ciliary nerves and innervate the sphincter pupillae and ciliary muscles.

Answer 240

✅ Correct Answer: Grade 4 ⸻ Explanation: The Modified Mallampati classification is used to predict ease of intubation by assessing the visibility of oropharyngeal structures when the patient opens the mouth and protrudes the tongue. Here’s the classification: Grade Structures Visible Class I Soft palate, fauces, uvula, pillars Class II Soft palate, fauces, and uvula Class III Soft palate and base of uvula Class IV Only hard palate visible ⸻ Interpretation for This Patient: On assessment, only the hard palate was seen. 🔹 This corresponds to Modified Mallampati Grade 4, which indicates a potentially difficult intubation. ⸻ MRCS Tip: • Always assess airway preoperatively using Mallampati, thyromental distance, and neck mobility. • Grade III–IV → anticipate difficult laryngoscopy and consider advanced airway equipment. ⸻ Answer: 🟩 Grade 4

Answer 241

Eosinophilic osophagitis is a condition characterised by symptoms of dysphagia and/or food impaction in adults, and feeding problems, abdominal pain and/or vomiting in children, with oesophageal histology showing a peak eosinophil count of ≥15 eosinophils/ high power field (or ≥15 eosinophils/0.3mm2 or >60 eosinophils/mm2, in the absence of other causes of oesophageal eosinophilia. Eosinophilic oesophagitis is more common in men than women and in people of white ethnic origin compared with other ethnic groups. Having an affected first-degree relative increases the risk of eosinophilic oesophagitis. The incidence rises during adolescence and peaks in early adulthood. At least six biopsies should be taken from different anatomical sites within the oesophagus for diagnosis and follow-up of eosinophilic oesophagitis. After initiation of therapy (dietary or pharmacological treatment), endoscopy with biopsy while on treatment, is recommended to assess response, as symptoms may not always correlate with histological activity.A six food elimination diet results in higher histological remission rates than two or four food elimination diets, but is associated with lower compliance and an increased number of endoscopies. Proton pump inhibitor therapy is effective in inducing histological and clinical remission in patients with eosinophilic oesophagitis.Proton pump inhibitor therapy should be given two times per day for at least 8-12 weeks prior to assessment of histological response, while on treatment. Topical steroids are effective for inducing histological and clinical remission in eosinophilic oesophagitis.Systemic steroids are not recommended in eosinophilic oesophagitis. Ref: Dhar A, Haboubi HN, Attwood SE, et al. British Society of Gastroenterology (BSG) and British Society of Paediatric Gastroenterology, Hepatology and Nutrition (BSPGHAN) joint consensus guidelines on the diagnosis and management of eosinophilic oesophagitis in children and adults. Gut. 2022;710:1459-1487. doi:10.1136/gutjnI-2022-327326

Answer 242

C-Mast cell granules releases histamine, enzymes and proteoglycans • Immediate, or type I, hypersensitivity is a rapid immunologic reaction occurring in a previously sensitized individual that is triggered by the binding of an antigen to lgE antibody on the surface of mast cells. • Most immediate hypersensitivity disorders are caused by excessive Th2 responses, and these cells play a central role by stimulating IgE production and promoting inflammation. These Th2-mediated disorders show a characteristic sequence of events

Answer 243

C-Collagen is formed by two polypeptide chains Acute wound healing occurs as a sequential cascade of overlapping processes that requires the coordinated completion of a variety of cellular activities including phagocytosis, chemotaxis, mitogenesis, and the synthesis of extracellular matrix (ECM) components. These activities do not occur in a haphazard manner but in a carefully regulated and systematic cascade that correlates with the appearance of different cell types in the wound during various stages of the healing process. Although polymorphonuclear leukocytes (PMNLs) are important in the early stages of the wound healing process, healing can nevertheless proceed in the absence of PMNLs (and also lymphocytes), but monocytes are essential for wound healing. Blood monocytes on arriving at the wound site undergo a phenotypic change to become tissue macrophages. Collagen is a rod shaped molecule composed of three polypeptide chains that form a rigid triple helical structure (that is 15 A in diameter and 3000 A in length). Collagen is also peculiar in that it is almost devoid of sulphur-containing amino acids, such as tryptophan and cysteine, but is rich in hydroxylysine and hydroxyproline. There are five main types of collagen in the human body. Their common distribution is as follows: • Type I: bone, skin, tendon, uterus, arteries • Type Il: hyaline cartilage, eye tissues • Type III: skin, arteries, uterus, and bowel wall • Type IV: basement membrane • Type V: basement membrane and other tissues The normal ratio of type I to type Ill collagen in the skin is approximately 4:1

Answer 244

C-Methotrexate therapy The common theme among the various causes of megaloblastic anemia is an impairment of DNA synthesis that leads to ineffective hematopoiesis and distinctive morphologic changes, including abnormally large erythroid precursors and red cells. Causes of megaloblastic anemia: Vitamin Bi2 Deficiency Decreased Intake Inadequate diet, vegetarianism Impaired Absorption Intrinsic factor deficiency Pernicious anemia Gastrectomy Malabsorption states Diffuse intestinal disease (e.g., lymphoma, systemic sclerosis) Ileal resection, ileitis Competitive parasitic uptake Fish tapeworm infestation Bacterial overgrowth in blind loops and diverticula of bowel Folic Acid Deficiency Decreased Intake Inadequate diet, alcoholism, infancy Impaired Absorption Malabsorption states Intrinsic intestinal disease Anticonvulsants, oral contraceptives Increased Loss Hemodialysis Increased Requirement Pregnancy, infancy, disseminated cancer, markedly increased hematopoiesis Impaired Utilization Folic acid antagonists Unresponsive to Vitamin Biz or Folic Acid Therapy Metabolic inhibitors of DNA synthesis and/or folate metabolism (e.g., methotrexate)

Answer 245

Brown tumors are tumors of bone that arise in settings of excess osteoclast activity, such as hyperparathyroidism, and consist of fibrous tissue, woven bone and supporting vasculature, but no matrix. They are radiolucent on x-ray. The osteoclasts consume the trabecular bone that osteoblasts lay down and this front of reparative bone deposition followed by additional resorption can expand beyond the usual shape of the bone, involving the periosteum thus causing bone pain. They appear brown because hemosiderin is deposited at the site. The combination of increased bone cell activity, peritrabecular fibrosis, and cystic brown tumors is the hallmark of severe hyperparathyroidism and is known as generalized osteitis fibrosa cystica (von Recklinghausen disease of bone)

Answer 246

Nodular Glomerulosclerosis in diabetes is known as intercapillary glomerulosclerosis or Kimmelstiel-Wilson disease. The glomerular lesions take the form of ovoid or spherical, often laminated, PAS-positive nodules of matrix situated in the periphery of the glomerulus. They lie within the mesangial core of the glomerular lobules and may be surrounded by patent peripheral capillary loops or loops that are markedly dilated.

Answer 247

Acute colonic pseudo-obstruction (also known as Ogilvie's syndrome) is characterised by clinical and radiological evidence of acute large bowel obstruction in the absence of a mechanical cause. The condition usually affects elderly people with underlying comorbidities, and early recognition and appropriate management are essential to reduce the occurrence of life-threatening complications. While it might be difficult to differentiate the condition from the other options given here, the X-ray plays a defining role. There is no clear transition representative of obstruction, cementing the likelihood of pseudo-obstruction rather than mechanical obstruction.

Answer 248

Platinum coordination complexes • Reacts with nucleophilic sites on DNA leading to DNA breaks • Cisplatin • Uses - testicular carcinoma, head and neck malignancies, carcinoma lung, rectal and anal canal carcinoma • Radiosensitizer • Adverse effects- nephrotoxicity, ototoxicity, nausea and vomiting ,neuropathy after prolonged treatment • Carboplatin -causes myelosuppression • Oxaliplatin -causes peripheral neuropathy

Answer 249

This syndrome occurs in cases of vomiting where the cricopharyngeus is unable to relax leading to a sudden increase in intraluminal pressure. It occurs most often in the lower third of the esophagus.

Answer 250

One of the earliest responses of CD4+ helper T cells is secretion of the cytokine IL-2 and expression of high-affinity receptors for IL-2. This creates an autocrine loop wherein IL-2 acts as a growth factor that stimulates T-cell proliferation, leading to an increase in the number of antigen-specific lymphocytes. The functions of helper T cells are mediated by the combined actions of CD40-ligand (CD40L) and cytokines. When CD4+ helper T cells recognize antigens being displayed by macrophages or B lymphocytes, the T cells express CD40L, which engages CD40 on the macrophages or B cells and activates these cells.

Answer 251

B-It may be performed with lesser time Advantages of case control studies 1. Good for examining rare outcomes or outcomes with long latency 2. Relatively quick to conduct 3. Relatively inexpensive 4. Requires comparatively few subjects 5. Existing records can be used 6. Multiple exposures or risk factors can be examined Advantages of cohort studies 1. Gather data regarding sequence of events; can assess causality 2. Examine multiple outcomes for a given exposure 3. Good for investigating rare exposures 4. Can calculate rates of disease in exposed and unexposed individuals over time (e.g. incidence, relative risk)

Answer 252

D-Use of high osmolar contrast medium The development of acute renal failure (ARF) is a significant complication of intravascular contrast medium (CM) use. Prospective studies of patients admitted with ARF have demonstrated that intravascular contrast medium was responsible in 11 - 14.5% of cases. Thus contrast induced nephropathy (CIN) is a relatively common cause of ARF. CIN is an acute deterioration in renal function that occurs 24-48 hours after contrast media administration. The most common definition is a rise in serum creatinine of 25% above the previous baseline without any other adequate explanation. In most patients the serum creatinine returns to normal within 14 days but some patients progress to ARF Strategies for Reducing the Risk of CIN Development • Risk factor reduction: eg stop NSAIDS and other nephrotoxic drugs • Fluid administration: oral or iv depending on circumstances to improve renal perfusion • Volume of CM (contrast medium) given. Risk of CIN increases with increasing quantities used. • Use of low-osmolar CM in patients with impaired renal function. The previous recommendation of using an iso-osmolar agent (eg Visipaque ) cannot now be justified • Use of N-Acetylcysteine: evidence not clear cut but can be recommended. Can be given orally

Answer 253

• Any penetrating injury below the fifth intercostal space should raise suspicion of diaphragmatic penetration and, therefore, injury • Blunt injury to the diaphragm is usually caused by a compressive force applied to the pelvis and abdomen. • The diaphragmatic rupture is usually large, with herniation of the abdominal contents into the chest. Diagnosis of diaphragmatic rupture can easily be missed in the acute phase, and may only be discovered at operation, or through the presentation of complications. • The most accurate evaluation is by video assisted thoracoscopy (VATS) or laparoscopy, the latter offering the advantage of allowing the surgeon to proceed to a repair and additional evaluation of the abdominal organs. • Operative repair is recommended in all cases. All penetrating diaphragmatic injury must be repaired via the abdomen and not the chest, to rule out penetrating hollow viscus injury.

Answer 254

E-B&C Antithyroid drugs and their mechanisms of action: lodides: Inhibit release of T3 & T4 into blood by paralysing the endocytosis of colloid from thyroid follicles. Thiocyanate ions: Inhibit the iodide-trapping mechanism PTU (& derivatives - methimazole, carbimazole) : Blocks the peroxidase enzyme required for iodination of tyrosine. Also blocks the coupling reaction of two iodinated tyrosines to form T3 or T4.

Answer 255

B-The cilia are under the control of a physiological motor, dynein The respiratory epithelium is organised as a pseudostratified epithelium and contains several cell types, including ciliated and secretory cells (eg, goblet cells and glandular acini) that provide key components for airway innate immunity, and basal cells that can serve as progenitor cells for repair during injury. As the conducting airway transitions to terminal and transitional bronchioles, the histological appearance of the conducting tubes change. Secretory glands are absent from the epithelium of the bronchioles and terminal bronchioles, smooth muscle plays a more prominent role and cartilage is largely absent from the underlying tissue. The smaller particles that make it through the upper airway, ~2-5 um in diameter, generally fall on the walls of the bronchi as the airflow slows in the smaller passages. There they can initiate reflex bronchoconstriction and coughing. Alternatively, they can be moved away from the lungs by the "mucociliary escalator." The epithelium of the respiratory passages from the anterior third of the nose to the beginning of the respiratory bronchioles are ciliated. The cilia are bathed in a periciliary fluid where they typically beat at rates of 10-15 Hz. On top of the periciliary layer and the beating cilia rests a mucus layer, a complex mixture of proteins and polysaccharides secreted from specialised cells, glands, or both in the conducting airway. This combination allows for the trapping of foreign particles (in the mucus) and their transport out of the airway (powered by ciliary beat). The ciliary mechanism is capable of moving particles away from the lungs at a rate of at least 16 mm/min. Dynein is a family of cytoskeletal motor proteins that control the beat of the cilia. It is absent in Kartagener's syndrome (primary ciliary dyskinesia).

Answer 256

Aortic disruption in the setting of a road traffic accident most commonly involves the descending aorta, just distal to the ligamentum arteriosum

Answer 257

Among benign mass-forming lesions of the liver, hemangiomas are the most common, followed by focal nodular hyperplasia, which is encountered ten times more frequently than adenomas. Hepatocellular adenomas are the third most common benign tumour of the liver.

Answer 258

D-It promotes polymorphonuclear (PMN) cell adherence and further cytokine release. TNF-a is a vital component of the early inflammatory response, especially locally, at the site of injury. It is released when the biologically active anaphylatoxins C3a and C5a are stimulated by the humoral system. Infusion of low doses of TNF-a in rats simulates the septic response, resulting in fever, hypotension, fatigue, and anorexia. TNF-a promotes adherence of PMN cells to endothelium, production of prostaglandins by fibroblasts, and activation of neutrophils and stimulates the release of multiple other cytokines from lymphocytes. TNF-a becomes deleterious when the proinflammatory stimuli are unchecked, leading to cellular damage and multiorgan system failure. TNF-a is released by macrophages and natural killer cells, but not leukocytes. Trials involving anti-TNF-a antibodies have not shown statistically significant improvement in patient outcomes. Ref:O'Leary PJ, Tabuenca A. The Physiologic Basis of Surgery. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2008.

Answer 259

A-Neurons remain in G1 phase of the cell cycle The cell cycle is divided into the M (mitosis) phase and interphase G1 (gap 1), S (synthesis) and G2 (gap 2) phases. GO is a resting phase of variable duration and is permanent for terminally differentiated cells like neurons. G1 has a high rate of biosynthetic activity. At the restriction point (R) the cell decides whether to complete the cycle. DNA synthesis occurs in the S phase. Further cell growth and differentiation occurs in G2 followed by cell division (both nuclear and cytoplasmic) in the M (Mitosis) phase. The G1 phase is under the influence of p53. Cyclins and cyclin-dependent kinases are the two main classes of molecules involved in regulating the cell cycle.

Answer 260

E- 4 - 10 weeks By 2 months of age, pulmonary resistance may approximate adult levels. "Immediately after birth, the lungs expand with air, dropping the pulmonary vascular resistance; and as the placenta is disconnected from the systemic circuit, the systemic resistance nearly doubles. The pulmonary arterioles continue to change gradually. The media becomes thinner and the lumen becomes wider. Thus, the pulmonary vascular resistance falls, almost reaching adult levels by the time the child is close to 8 weeks of age."

Answer 261

The Rule of Nines (Wallace’s rule) is used to estimate the total body surface area (TBSA) affected by burns in adults — which guides fluid resuscitation. Here’s how it breaks down for each body region: Body region % of total body surface area Head and neck 9% Each upper limb 9% (4.5% anterior, 4.5% posterior) Each lower limb 18% (9% anterior, 9% posterior) Front of trunk 18% Back of trunk 18% Perineum 1% In this case: • Left arm fully burnt → 9% • Anterior aspect of right arm burnt → 4.5% Total = 9% + 4.5% = 13.5% ✅ Correct answer: 13.5% Explanation: The Rule of Nines gives a rapid clinical estimation for fluid resuscitation (e.g. Parkland formula: 4 mL × %TBSA × body weight (kg)). Only partial- and full-thickness burns are included in the calculation. Answer: 13.5%

Answer 262

A Bosniak 1 cyst is a simple cyst with no septa, calcifications and solid components. Current Bosniak Classification I Hairline-thin wall; water attenuation; no septa, calcifications, or solid components; nonenhancing II Two types: 1. Few thin septa with or without perceived (not measurable) enhancement; fine calcification or a short segment of slightly thickened calcification in the wall or septa 2. Homogencously high-attenuating masses ≤ 3 cm that are sharply marginated and do not enhance IIF Two types: 1. Minimally thickened or more than a few thin septa with or without perceived (not measurable) enhancement that may have thick or nodular calcification 2. Intrarenal nonenhancing hyperattenuating renal masses > 3 cm III Thickened or irregular walls or septa with measurable enhancement IV Soft-tissue components (ie, nodule[s]) with measurable enhancement

Answer 263

B-Clean contaminated Classification: Clean: Non-traumatic, elective procedure where surgical site is not inflamed or contaminated Risk of SSI: 10.1 per cent No break in aseptic technique Clean-contaminated: Elective opening of respiratory, gastrointestinal, biliary or genitourinary tract with minimal spillage 15.4 per cent Minor break in aseptic technique Contaminated: Gross contamination is present at the surgical site without active infection, including: spillage of the Gl tract, incision into acute non-purulent inflammation 26.7 per cent Major break in aseptic technique Dirty: Active infection at the surgical site (purulent exudate is encountered) 50 per cent Surgery of a traumatic wound with retained foreign bodies or faecal contamination Ruptured viscus In a clean contaminated wound the viscus wall is breached, but the contents are contained and no spillage occurs. Ref: Image from Dumas, Sarah & French,

Answer 264

C-Delayed presentation with negative CT rules out SAH The sudden onset occurs commonly but not exclusively during exertion, and may be associated with seizure (10%), unresponsiveness (50%) and vomiting (70%). CT scan is the imaging of first choice, and, when performed within 12 hours of ictus. The sensitivity of a CT scan, however, deteriorates to less than 50% at 1 week after a bleed. In light of this, patients with a suggestive history and negative CT scan will require LP, especially where presentation is delayed. The CSF supernatant should be analysed by spectrophotometry (visual inspection is not reliable) for the spectra of haemoglobin breakdown products oxyhaemoglobin and bilirubin. These are clearly detectable in samples taken at least 6 and preferably 12 hours after SAH, but not in CSF mixed with fresh blood due to traumatic puncture, and analysed immediately. A rebleed risk of 4% in the first 24 hours, then 1.5% per day thereafter is quoted for aneurysms, and 80% of patients who rebleed have an eventual poor outcome. Ref: Bailey & Love's Short Practice of Surgery, 27th Edition, Chapter 43

Answer 265

To grip a sheet of paper requires finger adduction and the functioning of the palmar interossei muscles, which are supplied by the deep branch of the ulnar nerve.

Answer 266

B-Third pharyngeal pouch In the 5th week of gestation, epithelium of the dorsal region of the third pouch differentiates into the inferior parathyroid gland, whereas the ventral region forms the thymus. Both gland primordia lose their connection with the pharyngeal wall, and the thymus then migrates in a caudal and a medial direction, pulling the inferior parathyroid with it. Pharyngeal Pouch——-Derivatives 1 Tympanic (middle ear) cavity Auditory (eustachian) tube 2 Palatine tonsils Tonsillar fossa 3 Inferior parathyroid gland Thymus 4 Superior parathyroid gland ultimobranchial body (parafollicular [C] cells of the thyroid gland) Ref:Image from Langman's medical embryology, 14th

Answer 267

Warfarin necrosis is an acquired protein C deficiency due to treatment with the vitamin K-inhibitor anticoagulant, warfarin. It is a feared (but rare) complication of warfarin treatment. This rare reaction, mainly in women, usually occurs between the second and fifth days of therapy with warfarin. Lesions are sharply demarcated, erythematous, indurated and purpuric and can either

Answer 268

B-Expression of neuronal NO synthase Achalasia (literally, failure to relax) is a condition in which food accumulates in the esophagus and the organ can become massively dilated. It is due to increased resting LES tone and incomplete relaxation on swallowing. The myenteric plexus of the esophagus is deficient at the LES and the release of NO and VIP is defective.The opposite condition is LES incompetence, which permits reflux of acid gastric contents into the esophagus (gastroesophageal reflux disease). This common condition is the most frequent digestive disorder causing patients to seek care from a clinician. It causes heartburn and esophagitis and can lead to ulceration and stricture of the esophagus due to scarring.

Answer 269

D-Hypochloremic, hypokalemic metabolic alkalosis with a low urinary pH The signs and symptoms in this patient are highly suggestive of infantile hypertrophic pyloric stenosis. The profuse vomiting leads to the loss of gastric juices and fluid depletion, which leads to a hypochloremic metabolic alkalosis. The alkalosis is due to the loss of unbuffered hydrogen ions from gastric juice. In addition, chloride ions are lost during vomiting. The kidneys try to increase chloride ion resorption, but there is insuffi cient chloride in the glomerular filtrate to be absorbed along with sodium. The volume depletion stimulates aldosterone secretion and subsequent renal retention of sodium in exchange for potassium ions, causing further hypokalaemia. This forces sodium ions to preferentially be exchanged for hydrogen ions, causing the paradoxical acidic urine seen in these patients. Hypokalaemia results from the loss of potassium ions from gastric juice, their exchange for sodium ions in the kidney (i.e. to normalise the extracellular fluid volume) and their exchange for hydrogen ions in an attempt to normalize the pH Repeated vomiting Decrease in hydrochloric acid (alkalosis) Metabolic alkalosis and hypochloremia COs excretion in kidney for compensation along with increased sodium excretion (Na*) Hyponatremia Na takes two water molecules, and after certain level K* gets excreted Hypokalemia K* loss is replaced by H* loss (aciduria)

Answer 270

Dermatitis herpetiformis is well-associated with coeliac disease (present in this patient as evidenced by the serum IgA-endomysial Abs). Furthermore, dermatitis herpetiformis has a symmetrical distribution with lesions most commonly appearing on scalp, shoulders, buttocks, elbows and knees. The extremely itchy papules and vesicles often appear in groups or serpiginous clusters. Dermatitis herpetiformis may also present initially as digital petechiae. It can resemble other inflammatory skin conditions such as dermatitis, scabies and papular urticaria. Lesions resolve to leave postinflammatory hypopigmentation and hyperpigmentation.

Answer 271

Sporothrix schenckii, a thermally dimorphic fungus, causes sporotrichosis. The fungus inoculation into the host is via traumatic implantation of the fungus from contaminated soil, plants, and organic matter with the fungus, and is therefore common among florists, gardeners, miners, and forest workers. Sporotrix schenckii most commonly manifests as a lesion of the lymphocutaneous system. Lesions occur on the hands and arms, lower extremities, trunk, and face. Primary lesions occur within the first few weeks of fungal inoculation. The lesions are small nodules that progress to ulceration. The lesions are a bit painful and nonpruritic. New nodules spread on the lymphatics and become ulcerated Lymphangitis may develop, making the lymph nodes swollen and painful.

Answer 272

More than 90% of colorectal cancers are adenocarcinoma.

Answer 273

B-Facial nerve monitor is essential for ECD The principle of this extracapsular dissection (ECD) is that the facial nerve is not formally identified. The same incision is made for a standard parotidectomy, and the tumour assessed for suitability for ECD after raising of flaps. Use of the facial nerve monitor is essential. Mobile lesions in the parotid tail are most suitable for ECD, or smaller tumours fairly superficial within the superficial lobe. Inflammatory lesions, large tumours and those extending into the deep lobe are unsuitable for ECD, as are those where malignancy is suspected. Ref: Scott-Brown's Otorhinolaryngology and Head and Neck Surgery: Volume 3: Head edited by John C Watkinson, Ray W Clarke, Chapter 9

Answer 274

Rheumatoid arthritis is associated with pulmonary involvement in 30% to 40% of patients as: • Chronic pleuritis,with or without effusion • Diffuse interstitial pneumonitis and fibrosis • Intrapulmonary rheumatoid nodule • Follicular bronchiolitis • Pulmonary hypertension. When lung disease occurs in the setting of rheumatoid arthritis and pneumoconiosis, it is referred to as Caplan syndrome.

Answer 275

The spleen is located beneath the left costal margin and measures 1 x 3 x 5 inches, weighs 7 oz. and can be found behind the 9th to 11th ribs. Its long axis is along the 10th rib. The medial aspect bears impressions from the left kidney behind the hilum. The lienorenal ligament (the posterior leaf of the greater omentum) connects the kidney to the hilum of the spleen, within which the tail of the pancreas can be seen and the splenic artery (branch of coeliac trunk) runs. The gastrosplenic ligament (anterior leaf of greater omentum) joins the hilum to the greater curvature of the stomach. The splenic artery divides into segmental branches (up to 4) to supply the spleen. Venous drainage is by the splenic vein which forms the portal vein. Accessory spleens (splenunculi) , if present, are found along the splenic vessels and may be multiple.

Answer 276

MRI (Option c) is the most appropriate investigation for assessing soft tissue injuries, ligamentous damage, or other non-bony causes of persistent pain after trauma.

Answer 277

The brachiocephalic (innominate) artery (trunk), the largest branch of the aortic arch, is 4-5 cm in length. It arises from the convexity of the arch posterior to the centre of the manubrium of the sternum, and ascends posterolaterally to the right, at first anterior to the trachea, then on its right. The brachiocephalic and left common carotid arteries often share a common origin. It divides into the right common carotid and subclavian arteries level with the upper border of the right sternoclavicular joint.

Answer 278

Tranexamic acid is an antifibrinolytic agent that works by inhibiting plasmin, an enzyme involved in the breakdown of fibrin clots.

Answer 279

The dark color of urine in this patient is likely due to an increase in conjugated bilirubinuria (Option a). In conditions where there is an obstruction of the bile ducts, such as in obstructive jaundice, conjugated bilirubin is excreted in the urine. Conjugated bilirubin has a direct relationship with urine color, contributing to its dark appearance.

Answer 280

Offer people who test positive for H pylori a 7-day, twice-daily course of treatment with: • PPI and • Amoxicillin and • Either clarithromycin or metronidazole. Choose the treatment regimen with the lowest acquisition cost, and take into account previous exposure to clarithromycin or metronidazole. Offer people who are allergic to penicillin a 7-day, twice-daily course of treatment with: • PPI and • Clarithromycin and • Metronidazole. Ref: NICE guidelines on Gastro-oesophageal reflux disease and dyspepsia in adults: investigation and management

Answer 281

Advancing age is not considered to be a contraindication to major head and neck cancer surgery but may influence the extent of adjuvant treatment. Inclusion of chemotherapy to postoperative radiotherapy has little evidence of benefit to those over 70 years of age. Conversely, young patients should not be denied radiotherapy for fear of inducing a second malignancy (e.g. sarcoma) in later life. Ref: Bailey & Love Short Practice of Surgery, 27th edition, Chapter 48

Answer 282

Pascal's law states that pressure applied to an enclosed fluid is transmitted equally to all parts of its container. This is applicable in hernia repair - an inlay mesh is more firmly fixed when abdominal pressure rises, whereas an onlay mesh may be displaced by excessive rise in intra abdominal pressure. Law of Laplace states that the wall tension is proportional to the pressure multiplied by the radius. With increasing diameter, there is further increase in wall tension, leading to an increased risk of rupture. This is applicable to aneurysm ruptures, wherein larger calibre vessels (like the aorta or its branches) are more susceptible to rupture of aneurysm. Poiseuille's law advises that the rate of flow through a tube is proportional to the fourth power of the radius. The clinical relevance of this is that anastomosis of any hollow viscus should be wide enough to allow maintenance of flow of liquid through it, as even minor decreases in diameter can greatly impact flow. Bernauli's principle describes the relationship between fluid velocity and pressure on the walls. This is used in echocardiography, where the pressure gradients in the chambers are calculated based on rate of flow of blood.

Answer 283

Hypoxaemia and acidosis may both affect cerebral blood flow. However, in the traumatic situation increases in intracranial pressure are far more likely to occur especially when GCS is low. This will adversely affect cerebral blood flow. • CNS autoregulates its own blood supply • Factors affecting the cerebral pressure include; systemic carbon dioxide levels, CNS metabolism, CNS trauma, CNS pressure • The PaCO2 is the most potent mediator • Acidosis and hypoxaemia will increase cerebral blood flow but to a lesser degree • Intracranial pressure may increase in patients with head injuries and this can result in impaired blood flow • Intra cerebral pressure is governed by Monro-Kellie Doctrine which considers the brain as a closed box, changes in pressure are offset by loss of CSF. When this is no longer possible ICP rises

Answer 284

Drains put in to cover perioperative bleeding may usually be removed after 24 hours. • Drains put in to cover perioperative bleeding may usually be removed after 24 hours, e.g. thyroidectomy. • Drains put in to drain serous collections usually can be removed after 5 days, e.g. mastectomy. • Drains put in because of infection should be left until the infection is subsiding or the drainage is minimal. • Drains put in to cover colorectal anastomosis should be removed at about 5-7 days. However, it should be stressed that in no way does a drain prevent any intestinal leakage • Common bile duct T-tubes should remain in for 10 days.

Answer 285

✅ Correct answer: Discontinue at least 8 weeks before RRA till after next pregnancy ⸻ Explanation: Radioactive remnant ablation (RRA) uses radioiodine (I-131) to destroy any residual thyroid tissue following thyroidectomy (commonly for differentiated thyroid cancer). Because I-131 is actively concentrated in breast tissue and secreted in breast milk, special precautions are required for breastfeeding mothers. Key principles: 1. Breastfeeding must be stopped before RRA because: • I-131 accumulates in lactating breast tissue → greatly increases radiation dose to breast and potential long-term malignancy risk. • Continued milk production increases iodine uptake into breast tissue. 2. Timing to stop breastfeeding: • Breastfeeding should be discontinued for at least 6–8 weeks before RRA. • This allows involution of lactating tissue and reduces radioactive iodine uptake by the breasts. 3. Resumption of breastfeeding: • Breastfeeding must not be resumed for the current child after RRA, as radioiodine continues to be excreted in breast milk for an extended period. • Future breastfeeding is safe for subsequent pregnancies, since radioactive iodine is completely cleared from the body within months. ⸻ Therefore: ➡️ Discontinue at least 8 weeks before RRA till after next pregnancy ⸻ Extra exam tip: • Pregnancy should also be avoided for 6–12 months after I-131 therapy due to the risk of radiation to germ cells and the fetus.

Answer 286

D-It increases protein catabolism Insulin is secreted by the beta cells of the pancreatic islets of Langerhans. It increases tissue uptake of glucose, amino acids, and lipids. It stimulates glycogenesis, protein synthesis, and lipid oxidation. Insulin also inhibits gluconeogenesis and promotes intracellular uptake of potassium and phosphate. Glucagon is secreted by the alpha cells of the pancreas islets; it promotes gluconeogenesis and thereby physiologically opposes the action of insulin. The other endocrine secretions of the pancreas include somatostatin (from delta cells) and pancreatic polypeptide (from F-cells). Somatostatin inhibits digestion by having an inhibitory effect on Gl motility and secretions. Pancreatic polypeptide is also a regulator of the digestive process and its secretion is stimulated by fasting, decreased blood sugar, and protein ingestion.

Answer 287

Sclerotic or blastic bone metastases can arise from a number of different primary malignancies including - prostate carcinoma ( most common), breast carcinoma (can be lytic/sclerotic), TCC, Carcinoid, lymphoma and small cell lung cancer. Lytic bone metastases are more common than sclerotic metastases and occur in thyroid carcinoma, RCC, endometrial carcinoma, adrenocortical carcinoma, melanoma and HCC. Osteoblastoma lesions are predominantly lytic, with a rim of reactive sclerosis

Answer 288

A-Strawberry hemangioma This is the commonest birthmark, 90% appearing at birth. It occurs most commonly on the head and neck and as a consequence of intravascular thrombosis, fibrosis and mast cell infiltration. 10% resolve each subsequent year with 70% resolution by 7 years of age. White skin is affected more commonly and girls are affected three times more than boys. Strawberry hemangioma is a capillary hemangioma or capillary malformation. Ref: Bailey & Love's Short Practice of Surgery, 27th Edition, Chapter 40 View Answer

Answer 289

D-D-Rhabdomyoblastic MPNST lesions are poorly defined tumor masses that frequently infiltrate along the axis of the parent nerve and invade adjacent soft tissues. A wide range of histologic appearance can be encountered. Typical cases show a fasciculated arrangement of spindle cells. At low power the tumor often appears "marbleized" due to variations in cellularity. Mitoses, necrosis, and nuclear anaplasia are common.An interesting phenomenon observed in MPNST is described as "divergent differentiation." This term refers to the presence of focal areas that exhibit other lines of differentiation, including glandular, cartilaginous, osseous, or rhabdomyoblastic morphology.A tumor exhibiting the latter is referred to as Triton tumor.

Answer 290

✅ Correct answer: Inflammation ⸻ Explanation: Apoptosis is a form of programmed cell death that occurs in a controlled, energy-dependent manner. It is crucial during development — for example, in the involution of embryological structures such as the thyroglossal duct or Müllerian ducts in males — and for maintaining normal tissue turnover. In apoptosis, the cell undergoes shrinkage, the cytoplasm becomes dense, and the nucleus fragments into small pieces (karyorrhexis). The plasma membrane remains intact, and small membrane-bound apoptotic bodies form. These are then phagocytosed by surrounding cells or macrophages. Because the cellular contents are never released into the surrounding tissue, there is no associated inflammation. In contrast, necrosis causes cell swelling, membrane rupture, and leakage of intracellular components, which triggers an inflammatory response. ⸻ Therefore: All listed features except inflammation are typical of apoptosis. Answer: Inflammation

Answer 291

✅ Correct answer: Sigmoid colon ⸻ Explanation: Diverticulosis refers to the presence of outpouchings (diverticula) of the colonic mucosa and submucosa through the muscular wall — most often occurring where blood vessels (vasa recta) penetrate the muscle layer. In Western populations, diverticulosis most commonly affects the sigmoid colon, because: • It has the highest intraluminal pressure during segmentation and stool propulsion. • The stool here is more solid, increasing strain on the bowel wall. • Age-related weakening of the colonic wall and low-fibre diet further contribute. Although diverticula can occur anywhere in the colon, they are most frequent in the sigmoid colon, and complications such as diverticulitis, perforation, abscess, and bleeding also typically arise there. In contrast: • Right-sided (cecal/ascending) diverticulosis is more common in Asian populations. • Ileal diverticula are rare (except for Meckel’s diverticulum, a true congenital one). ⸻ Therefore: The most common site of diverticulosis and diverticulitis in Western populations is the sigmoid colon.

Answer 292

Premature babies presenting with bloody diarrhoea are highly suspicious for necrotizing enterocolitis. The infant presents late (usually >10 days) with bloody mucoid diarrhoea and abdominal distension. In case of delayed presentation, the mesenteric ischaemia may allow bacterial infiltration leading to peritonitis and sepsis. X ray abdomen in this case will show tensely dilated bowel loops with gas bubbles in the bowel wall.

Answer 293

Injuries to surrounding structures are a common complication of surgeries. A good knowledge of anatomy of the area will help predict or avoid such injuries. Common nerve injuries occurring during surgery are: -Posterior approach hip replacement: Sciatic nerve injury Forearm fractures: Medial and Ulnar nerve injuries Upper arm fractures: Radial nerve injury Carotid endarterectomy: Hypoglossal nerve injury Posterior triangle of neck surgery: Accessory spinal nerve injury Thyroid surgery: Recurrent laryngeal nerve injury Axillary surgery: Long thoracic nerve injury Pelvic dissection - pelvic autonomic nerve injury (including inferior hypogastric plexus) Lloyds Davis position (such as for vaginal hysterectomy or Lords dilatation): Common peroneal nerve injury

Answer 294

PTH has a very short half life usually less than 10 minutes. Therefore a demonstrable drop in serum PTH should be identified within 10 minutes of removing the adenoma. This is useful clinically since it is possible to check the serum PTH intraoperatively prior to skin closure and explore the other glands if levels fail to fall.

Answer 295

Von-Hippel Lindau syndrome is a constellation of benign and malignant tumours arising due to a mutation in the VHL tumour suppressor gene on chromosome 3. Examples of tumours include: • Cerebellar and Retinal hemangioblastomas • Renal cysts • Renal Cell Carcinoma • Pheochromocytoma • Pancreatic cysts • Pancreatic tumours (neuroendocrine tumours, cystadenocarcinoma, etc.) • Liver cysts Other tumour syndromes: • MEN I - pituitary adenoma, pancreatic islet cell tumours, parathyroid adenoma are classically involved. Lipomas, angiofibroma, and carcinoid tumours are also commonly found. • MEN I| - Medullary carcinoma thyroid, pheochromocytoma. • MEN IIA: + parathyroid adenomas; MEN IIB: + mucosal neuromas/ganglion neuromas

Answer 296

D-Heart Failure Causes of sinus tachycardia: • Increased circulating catecholamines • CHF • Hyperthermia • Anxiety, pain • Hyperthyroidism Causes of sinus bradycardia: • Acute MI • Sick sinus syndrome • Hypothermia • Hypothyroidism • Raised ICP • Drugs like beta blockers, verapamil, digoxin

Answer 297

Expressive aphasia is most often seen in lesions of Broca's area (Brodmann area 44) located in the infero-lateral frontal cortex. These lesions are usually due to thrombus in the superior part of the MCA which supplies this area.

Answer 298

The caudate lobe is between the fissure for the ligamentum venosum and the inferior vena cava. The quadrate lobe is located between the gallbladder and the fissure for the ligamentum teres hepatis.

Answer 299

E-Ceftriaxone C. difficile is an obligately anaerobic, gram-positive, spore-forming bacillus whose spores are found widely in nature, particularly in the environment of hospitals and chronic-care facilities. Clostridium difficile infection occurs frequently in hospitals and nursing homes (or shortly after discharge from these facilities) where the level of antimicrobial use is high and the environment is contaminated by C. difficile spores. Clindamycin, ampicillin, and cephalosporins were the first antibiotics associated with CDI. The second- and third-generation cephalosporins, particularly cefotaxime, ceftriaxone, cefuroxime, and ceftazidime, are agents frequently responsible for this condition, and the fluoroquinolones (ciprofloxacin, levofloxacin, and moxifloxacin) are the most recent drug class to be implicated in hospital outbreaks. Penicillin/B-lactamase- inhibitor combinations such as ticarcillin/clavulanate and piperacillin/ tazobactam pose significantly less risk.

Answer 300

Platelets are usually stored for 5 days.

Answer 301

A-Potential risk to hospital personnel (due to possibility of infective hepatitis) In the UK, all surgical cases are managed using universal precautions. Possibility of spread of infective hepatitis, while present, is low due to stringent use of PPE at all times. All patients with liver disease are screened for infectious hepatitis at diagnosis and again before surgery if required. Other complications of hepatic disease: • Hypoglycemia (due to depleted glycogen stores) • Impaired metabolism of anaesthetic agents leading to their prolonged action • Poor delivery of drugs (due to hypoalbuminemia) • Increased risk of bleeding due to depletion of clotting factors and thrombocytopenia (secondary to portal hypertension and hypersplenism) • Increased risk of peripheral and pulmonary edema (due to hypoalbuminemia and secondary hyperaldosteronism) • Combined respiratory and metabolic acidosis • Hepatorenal syndrome (carries very poor prognosis)

Answer 302

C-Inulin Creatinine declines with age due to decline in renal function and muscle mass. Glucose, protein (amino acids) and PAH are reabsorbed by the kidney. Substances used to measure GFR have the following features: • Inert • Free filtration from the plasma at the glomerulus (not protein bound) • Not absorbed or secreted at the tubules • Plasma concentration constant during urine collection Examples: inulin, creatinine GFR =urine concentration (mmol/I) x urine volume (ml/min) plasma concentration (mmol/I) • The clearance of a substance is dependent not only on its diffusivity across the basement membrane but also subsequent tubular secretion and / or reabsorption. • So glucose which is freely filtered across the basement membrane is usually reabsorbed from tubules giving a clearance of zero.

Answer 303

This is a case of severe vascular compromise - evidenced by the arterial ulcers. The MRA shows an occlusion of the femoral artery. Hence, intervention is required. As the segment of occlusion is short and distal run off is good, this patient is a good candidate for angioplasty. All patients with peripheral vascular disease should be started on statins and aspirin to reduce risk of cardiovascular disease.

Answer 304

Prostatic hyperplasia is an example of pathologic hyperplasia in which prostatic cells become more sensitive to hormonal stimuli for growth. Both glands and stroma can increase in amount. Hyperplasia is an increase in the number of cells in an organ or tissue in response to a stimulus. Hyperplasia can only take place if the tissue contains cells capable of dividing, thus increasing the number of cells. Hyperplasia is the result of growth factor-driven proliferation of mature cells and, in some cases, by increased output of new cells from tissue stem cells. It can be physiologic or pathologic.

Answer 305

A-125 ml/min Renal Clearance of Substance x is defined as the ratio of excretion rate of substance x to its concentration in the plasma. Cx = Ux x V /Px Cx = Clearance rate of substance X in (ml/min) V= Urine flow rate (ml/min) Ux (mg/ml) = Urine concentration of substance X P x (mg/ml) = Plasma concentration of substance X Ux = 125 mg/ml Px= 1mg/ml V= 1440/24 hrs = 60ml/hr = 1ml/min C = 125 × 1 = 125ml/min

Answer 306

TB reactivation most commonly occurs at the lung apex. This site is better oxygenated than elsewhere allowing the mycobacteria to multiply more rapidly and then spread both locally and distantly.

Answer 307

B-Conjugation of bilirubin Explanation: The main functions of hepatocytes are: • Active uptake of plasma bile acids • Uptake of haem (after RBCs are broken down by Kuppfer cells) • Synthesis of primary bile acids FROM cholesterol • Conjugation of bilirubin • Secretion of bile acids to canaliculi

Answer 308

In hypertrophic pyloric stenosis (HPS), a condition characterized by thickening of the pylorus muscle leading to gastric outlet obstruction, the typical findings in an arterial blood gas (ABG) are: Hypokalemia: Due to vomiting and loss of gastric acid. Hypochloremia: Also related to vomiting and loss of gastric acid. Metabolic Alkalosis: Loss of gastric acid results in an increase in bicarbonate concentration. Therefore, the correct answer is c. Metabolic acidosis because, in hypertrophic pyloric stenosis, there is an expected metabolic alkalosis rather than metabolic acidosis.

Answer 309

Zenker's diverticulum (pharyngeal pouch) is not really an esophageal diverticulum as it protrudes posteriorly above the cricopharyngeal sphincter through the natural weak point (the dehiscence of Killian) between the oblique and horizontal (cricopharyngeus) fibres of the inferior pharyngeal constrictor. When the diverticulum is small, symptoms largely reflect this incoordination with predominantly pharyngeal dysphagia. As the pouch enlarges, it tends to fill with food on eating, and the fundus descends into the mediastinum. This leads to halitosis and esophageal dysphagia. Treatment can be undertaken endoscopically with a linear cutting stapler to divide the septum between the diverticulum and the upper oesophagus, producing a diverticulo-esophagostomy, or can be done by open surgery involving pouch excision, pouch suspension (diverticulopexy) and/or myotomy of cricopharyngeus.

Answer 310

C-Both observer and person or group being observed is blind about the study Blinding or masking refers to the withholding of information regarding treatment allocation from one or more participants in a clinical research study.

Answer 311

A, Band C Diabetic patients should have their blood glucose levels closely monitored before, during and after surgery. While inder GA, symptoms (sweating, shivering) may be masked and hypoglycemia can go undetected. Insulin by sliding scale can be used to control sugars - this is always used in T1DM but can be avoided in T2DM if good glycemic control is present. Use of insulin can affect the movement of potassium into cells, and therefore electrolyte imbalances should always be anticipated. Potassium supplementation may be necessary and should always be available.

Answer 312

Highly pathogenic coronaviruses like SARS-CoV-2 bind the ACE2 protein on the surface of pulmonary alveolar epithelial cells, explaining the tropism of these viruses for the lung. With highly pathogenic forms in susceptible hosts, typically older individuals with comorbid conditions, the host immune response and locally released cytokines often produce acute lung injury and ARDS.

Answer 313

Patients with chronic liver disease often develop portal hypertension, which can lead to the formation of dilated veins (varices) in the esophagus. These varices can rupture and bleed profusely, leading to a significant drop in blood pressure. The presence of blood on the carpet suggests a possible rupture of these varices.

Answer 314

D-Axillo-bifemoral bypass graft This patient has bilateral common iliac occlusion. Therefore, any bypass must come from above the level of the iliac vessels - hence, femoral bypass grafts are unsuitable. Bilateral AK amputation does not provide any value unless there is risk of imminent limb loss or risk to life. Aorto-bifemoral graft would be an ideal choice; however, it is a surgery with significant cardiovascular risks and a long operative time. Hence, axillo-bifemoral bypass may be more appropriate in this case. They have shorter lives than aorto-bifemoral grafts, but this may be less relevant in an elderly patient.

Answer 315

ASA grading of risk for anaesthesia and surgery Grade 1: Normal healthy patient Grade 2: Mild systemic disease Grade 3: Severe systemic disease, activities limited but not life threatening Grade 4: Severe systemic disease, life threatening Grade 5: Moribund patient

Answer 316

E-EDT can be attempted for a patient with blunt chest injury who is showing no signs of life at initial assessment EDT can be done if the patient is in extremis with a falling systolic blood pressure, when left anterolateral thoracotomy is done. A resuscitation room thoracotomy following blunt trauma has limited indications and is rarely successful. EDT is considered futile in: • CPR in the absence of endotracheal intubation for more than 5 minutes; • CPR for more than 10 minutes (despite endotracheal intubation); • blunt trauma when there have been no signs of life at the scene. The aim of EDT is to perform: • internal cardiac massage; • control of haemorrhage from injury to the heart or lung; • control of intrathoracic haemorrhage from other sources; • control of massive air leak; • clamping of the thoracic aorta to preserve the blood supply to the heart and brain, and cutting off the arterial supply distally in a moribund patient with a major distal penetrating injury.

Answer 317

B-His speech difficulty is only due to the tumour bulk in the mouth Patients may present with a nonhealing ulceration, obstruction of the submandibular duct, numbness of the tongue, or even dysarthria secondary to deep infiltration of the tongue or involvement of the hypoglossal nerve(s). All this may cause speech difficulty. Surgery is the treatment of choice, though primary radiation may be used with similar efficacy. Transoral resection of the floor of the mouth often involves removal of the submandibular duct orifice. This may require transposition of the duct posteriorly in the mouth if possible, or simply ligation as the submandibular gland should be removed during the level | neck dissection. Regional metastases are fairly common and may be bilateral. Patients with T3-T4, NO cancer should definitely have neck dissection(s) whereas those with T1-T2, NO disease lesions may be observed, subjected to sentinel node biopsy, or receive END. Ref: MD Anderson Surgical Oncology Handbook, 6th edition, Chapter 6

Answer 318

All of them attach to the hamate. The attachments of the hamate are as follows: Musculotendinous: • flexor digiti minimi brevis • opponens digiti minimi • abductor digiti minimi • flexor carpi ulnaris • flexor digitorum profundus Ligamentous: • flexor retinaculum • transverse carpal ligament • pisohamate ligament • triquetrohamate ligament • capitohamate ligament

Answer 319

C-Prescribe pennicillin V or azithromycin for her Group A streptococci causes a wide range of illnesses from non-invasive disease such as pharyngitis to more severe invasive infections such as necrotising fasciitis. There remains uncertainty about the risk of invasive disease among close contacts of an index case of invasive disease and whether this risk warrants antibiotic prophylaxis. A 19-200 fold increased risk among household contacts has been reported in the literature. Key recommendations from an expert working group regarding prophylaxis are: 1. Close contacts of a case of invasive Group A streptococcal disease should receive information outlining the signs and symptoms of invasive Group A streptococcal infection. They should be advised to seek medical attention if they develop such symptoms within 30 days of diagnosis in the index case. 2. Antibiotics should only be administered: • To mother and baby if either develops invasive group A streptococcal disease in the neonatal period (first 28 days of life); • To close contacts if they have symptoms suggestive of localised Group A streptococcal infection i.e. sore throat, fever, skin infection; • To the entire household if there are two or more cases of invasive group A streptococcal disease within a 30 day time period. 3. Oral Penicillin V is the drug of first choice where chemoprophylaxis is indicated. Azithromycin is a suitable alternative for those allergic to penicillin.

Answer 320

B-Replace her OHAs with insulin from 2 days before surgery Diabetic patients on OHAs with good glycaemic control can continue taking their medications preoperatively. Metformin must be discontinued 2 days before surgery to prevent lactic acidosis. However, pioglitazone can be continued till the morning of the surgery (even if she is fasting). During and immediately after surgery, regular blood glucose monitoring will be performed and insulin administered till she can tolerate oral foods, after which she can resume her OHAs.

Answer 321

Pulmonary metastases are the most commonly encountered form of lung neoplasm, as almost all kinds or primary cancers can spread to the lungs. However, pulmonary metastases are most commonly associated with the following primary tumour sites: breast, bladder, renal, testicular, melanoma, colorectal, bone, prostate, neuroblastoma and soft tissue sarcomas

Answer 322

E-Extensor pollicis brevis Borders of the anatomical snuffbox are formed by: • Proximal: radial styloid process • Distal: base of 1st metacarpal • Floor: scaphoid and trapezium • Medial: extensor pollicis longus • Lateral: abductor pollicis longus and extensor pollicis brevis Contents of the anatomical snuffbox are: • Superficial: dorsal digital branches of the radial nerve & cephalic vein • Deep: radial artery & tendons of extensor carpi radialis longus and brevis

Answer 323

C-Pulmonary artery-bronchus-pulmonary vein In the left lung root, the upper part is occupied by the left pulmonary artery lying within the concavity of the arch of the aorta. Below it is the left bronchus. There are two pulmonary veins, one in front of and the other below the bronchus. These structures are enclosed in a sleeve of pleura continuous below with the pulmonary ligament.

Answer 324

Residual volume: Volume of air remaining in the lungs after maximal expiration Expiratory reserve volume: Maximal volume of air expired from the resting end-expiratory level Tidal volume: Volume of air inspired or expired with each breath during quiet breathing Inspiratory reserve volume: Maximal volume of air inspired from the resting end-inspiratory level Capacities Inspiratory capacity Maximal volume of air inspired from the end-expiratory level (the sum of IRV and TV) Vital capacity VC Maximal volume of air expired form the maximal inspiratory level Inspiratory vital capacity IVC Maximal volume of air inspired form the maximal expiratory level Functional residual capacity FRC Total lung capacity TLC

Answer 325

Post debridement of a 3% burn in the forearm with crusting, dryness, and loss of sensation, the appropriate management would be a split-thickness skin graft. This graft involves transplanting both the epidermis and a portion of the dermis and is often used in cases of deep burns to promote wound healing.

Answer 326

There is a tachycardia between 100-120 bpm, a respiratory rate between 20-30 breaths/min and slight reduction in urinary output in keeping with class Il shock

Answer 327

E-Hartmann's at 79 ml/h This is the most appropriate fluid maintenance in children and has been calculated using the boy’s weight of 40 mg (100 ml/kg for the first 10 kg, 50 ml/kg for 10-20 kg, 20 ml/kg for > 20 kg child’s weight

Answer 328

Of the 4 rotator cuff muscles, only the subscapularis attaches to the lesser tubercle of the humerus. All the others attach to the greater tubercle.

Answer 329

B-Secondary intention Classification of wound closure and healing • Primary intention Wound edges opposed Normal healing Minimal scar • Secondary intention Wound left open Heals by granulation, contraction and epithelialisation Increased inflammation and proliferation Poor scar • Tertiary intention (also called delayed primary intention) Wound initially left open Edges later opposed when healing conditions favourable

Answer 330

C-Inferior pancreaticoduodenal artery The most common site of a bleeding duodenal ulcer is the duodenal cap or duodenal ampulla - the slightly dilated initial segment of the duodenum. It receives blood supply from a variety of vessels:- • Common Hepatic artery • Hepatic artery • Gastroduodenal artery • Superior Pancreaticoduodenal artery • Right gastric artery • Right gastroepiploic artery The duodenal blood supply is largely divided at the level of the bile duct, with the superior portion supplied by the superior pancreaticoduodenal artery and the inferior portion of the inferior pancreaticoduodenal artery.

Answer 331

D-The surgical plane is most evident laterally Although the rectum has no mesentery, the connective tissue and fat around the rectum is referred to by surgeons as the mesorectum. The visceral fascia surrounding it is the mesorectal fascia. The mesorectum is bulkier posteriorly, where it tends to be grooved in the midline. It contains the superior rectal artery and its branches, the superior rectal vein and its tributaries, lymphatic vessels and nodes. A relatively avascular areolar tissue plane lies between the mesorectal fascia and the parietal pelvic fascia; this is the plane of surgical dissection in total mesorectal excision of the rectum for carcinoma. The plane is most evident posteriorly and is minimal laterally where the inferior hypogastric plexus lies tangentially on the surface of the mesorectal fascia. Crossing this interface are autonomic nerve fibres from the plexus to the rectum and occasional small middle rectal vessels. Surgical definition of surrounding connective tissue from the mesorectum comprises the iatrogenic lateral ligament' of the rectum; this is not seen on MRI or CT scanning.

Answer 332

Impetigo, one of the most common bacterial infections of the skin, is seen primarily in children. The causative organism is usually Staphylococcus aureus or, less commonly, Streptococcus pyogenes, and is typically acquired through direct contact with a source. Impetigo often begins as a single small macule, usually on the extremities or the face near the nose or the mouth, which rapidly evolves into a larger lesion, often with a honey-colored crust of dried serum. Impetigo is characterized by an accumulation of neutrophils beneath the stratum corneum that often produces a subcorneal pustule.Bacterial cocci in the superficial epidermis can be demonstrated by Gram stain

Answer 333

Children develop hyponatremic encephalopathy at higher sodium levels than adults because they have a higher brain:skull ratio. A few children have had symptomatic hyponatremic encephalopathy attributable to poor prescription and monitoring of fluids; it is fatal in some children while others may have permanent neurological disability. Hyponatremia in the surgical patient is usually a consequence of too much free water and is not due to insufficient sodium. Ref: Bailey & Love's Short Practice of Surgery, 27th Edition, Chapter 9

Answer 334

E-Duloxetine Adjuvants are drugs that are not inherently analgesics, but which can be added to a patient's prescription for management of pain. They can be added at any step of the WHO pain ladder. In this case, SNRIs like Duloxetine are adjuvants in the management of neuropathic pain. NSAIDs like diclofenac are adjuvants in dull pains (such as those caused by bony or visceral metastasis), and Hyoscine is an adjuvant for spasmodic pain caused by obstruction. Radiotherapy, surgical decompression of the nerve, and TENS are all adjuvant modalities in neuropathic pain management as well. Fentanyl is a strong opioid and forms step 3 of the WHO pain ladder. Its addition may be an appropriate step in case of inadequate pain relief; however, it is not an adjuvant analgesic. Tramadol is an alternative to codeine in step 2 of the WHO pain ladder and is also a weak opioid. It is not an adjuvant and its use is not recommended, as inadequate pain relief with step 2 is an indication to step up to a strong opioid.

Answer 335

This patient has a completely displaced lateral clavicle fracture with a torn conoid ligament on x-ray, which requires surgical management. A completely displaced clavicle fracture involves displacement greater than one bone width. Surgical intervention for completely displaced clavicle fracture results in lower rates of nonunion when compared with conservative management through immobilization alone. Other indications for surgical intervention include open fractures, neurovascular compromise, and tenting of the skin.

Answer 336

A-Ischemic heart disease Surgical revascularisation for ischaemic heart disease is achieved by coronary artery bypass grafting, one of the most investigated surgical procedures with well and consistently documented complications. An estimate of the operative mortality can be calculated using risk-stratification systems like the EuroSCORE or STS score. Surgery for mitral valve disease is associated with a higher operative risk, approximately 5%-6%, and greater risk for neurological complications.

Answer 337

The zona reticularis, the inner zone of the adrenal cortex, secretes the adrenal androgens dehydropiandrosterone and androstenedione, as well as small amounts of estrogens and some glucocorticoids. Normally, the adrenal androgens have only weak effects in humans. It is possible that part of the early development of the male sex organs results from childhood secretion of adrenal androgens. The adrenal androgens also exert mild effects in the female, not only before puberty but also throughout life. Much of the growth of the pubic and axillary hair in the female results from the action of these hormones.

Answer 338

NO is a powerful analgesic with a weak anaesthetic effect. However, it has become less popular due to high incidence of post-op nausea and vomiting, and possible mutagenic effects. It also increases air bubble size causing problems in eye, ear and abdominal surgery. Due to its tendency to cause expansion, it can also precipitate rupture of bullae and cause tension pneumothorax in patients with COPD.

Answer 339

Seborrheic keratoses are caused by acquired activating mutations in growth factor signalling pathways. A significant fraction of these tumours harbour activating mutations in fibroblast growth factor receptor 3 (FGFR3), which possesses a tyrosine kinase activity that stimulates RAS and the PI3K/AKT pathway. Except for cosmetic concerns, seborrheic keratoses are usually of little clinical importance. However, in rare patients hundreds of lesions may appear suddenly as a paraneoplastic syndrome (sign of Leser-Trelat). Patients with this presentation may harbor internal malignancies, most commonly gastrointestinal tract carcinomas, which produce growth factors that stimulate epidermal proliferation.

Answer 340

Glucagonoma is a very rare tumour of the pancreatic alpha cells that results in the overproduction of glucagon. Typically features are: • necrolytic migratory erythema: a characteristic skin eruption of red patches with irregular borders, intact and ruptured vesicles, and crust formation, commonly affecting the limbs and skin surrounding the lips. • weight loss: glucagon prevents the uptake of glucose by somatic cells • mild diabetes mellitus: due to glucagon/insulin imbalance

Answer 341

A-Submandibular Lymph from the root of the tongue drains bilaterally into the superior deep cervical lymph nodes. • Lymph from the medial part of the body drains bilaterally and directly to the inferior deep cervical lymph nodes. • Lymph from the right and left lateral parts of the body drains to the submandibular lymph nodes on the ipsilateral side. • The apex and frenulum drain to the submental lymph nodes, the medial portion draining bilaterally. All lymph from the tongue ultimately drains to the deep cervical nodes and passes via the jugular venous trunks into the venous system at the right and left venous angles.

Answer 342

D-Liver and biliary lesions Abdominal imaging uses transducers with a frequency of 3-7 MHz, while higher- frequency transducers are used for superficial structures, such as musculoskeletal and breast ultrasound. Dedicated transducers have also been developed for endocavitary ultrasound, such as transvaginal scanning and transrectal ultrasound of the prostate, allowing high-frequency scanning of organs. Ref: Bailey & Love's Short Practice of Surgery, 27th Edition, Chapter 14

Answer 343

Pulmonary vascular resistance increases at high altitude. Pulmonary arterioles constrict in response to hypoxia (known as the Euler-Liljestrand mechanism), to redirect blood flow to well ventilated lung regions.

Answer 344

D-Tibialis anterior The following structures pass posterior to medial malleolus (in order): • Tibialis posterior tendon • Flexor digitorum longus tendon • Posterior tibial artery • Tibial nerve • Tendon of flexor hallucis longus Mnemonic to remember: Tom Dick and Nervous Harry

Answer 345

The urea (13C) breath test, Stool Helicobacter Antigen Test (SAT), or laboratory-based serology are recommended for the diagnosis of gastro-duodenal infection with H. pylori. The urea breath test and SAT should not be performed within 2 weeks of treatment with a proton pump inhibitor or within 4 weeks of antibacterial treatment, as this can lead to false negatives. The sensitivity and specificity of the urea breath test in untreated subjects are very high and range from 90 to 98% and from 92 to 100%, respectively, which combined with its non-invasive nature, makes it very appealing as an initial and common test in patients.

Answer 346

• Patients with amebic colitis should be treated with IV or oral metronidazole. Side effects include nausea, vomiting, abdominal discomfort, and a disulfiram-like reaction. Another, longer-acting imidazole compound, tinidazole, is likewise effective. All patients should also receive a full course of therapy with a luminal agent, since metronidazole does not eradicate cysts. • Praziquantel has a wide antihelminthic spectrum that includes activity in both trematode and cestode infections. It is the drug of choice in schistosomiasis (all species), clonorchiasis, and paragonimiasis and for infections caused by small and large intestinal flukes. Praziquantel is also 1 of 2 drugs of choice (with niclosamide) for infections caused by cestodes (all common tapeworms) and an alternative agent (to albendazole) in the treatment of cysticercosis. • Ivermectin is the drug of choice for onchocerciasis, cutaneous larva migrans, strongyloidiasis, and some forms of filariasis. • Diethylcarbamazine is the drug of choice for several filarial infections including those caused by Wuchereria bancrofti and Brugia malayi and for eye worm disease (Loa loa). The drug undergoes renal elimination, and its half-life is increased significantly by urinary alkalinization. • Chloroquine is the drug of choice for acute attacks of non falciparum and sensitive falciparum malaria and for chemoprophylaxis, except in regions where P falciparum is resistant. The drug is solely a blood schizonticide. Chloroquine and hydroxychloroquine are also used in autoimmune disorders, including rheumatoid arthritis

Answer 347

The correct answer is: ✅ It is an active metabolite Explanation: Diazepam is a benzodiazepine that acts by enhancing GABA-A receptor activity, increasing the frequency of chloride channel opening, which causes neuronal hyperpolarization and CNS depression. Let’s review each option: • “It inhibits GABA-mediated chloride channel opening” – False Diazepam enhances GABA action rather than inhibiting it. It increases the frequency (not duration) of chloride channel opening at the GABA-A receptor. • “It is an active metabolite” – True Diazepam is metabolized in the liver to desmethyldiazepam (nordiazepam), oxazepam, and temazepam, which are all active metabolites. This contributes to its long duration of action. • “Overdose is treated with naloxone” – False Naloxone is an opioid antagonist. Diazepam overdose is treated with flumazenil, a benzodiazepine receptor antagonist. • “It cannot be used for status epilepticus” – False Diazepam can be used for status epilepticus (often given intravenously or rectally for rapid control of seizures). Summary: Statement True/False Notes Inhibits GABA-mediated Cl⁻ opening ❌ It enhances it It is an active metabolite ✅ Long-acting via active metabolites Overdose treated with naloxone ❌ Treated with flumazenil Cannot be used for status epilepticus ❌ It is used for this Answer: ✅ It is an active metabolite

Answer 348

The buccinator is one of the muscles of facial expression, and is therefore supplied by the facial nerve (buccal branch). The facial nerve exits the skull via the stylomastoid foramen and enters the parotid gland, where it splits into five terminal branches - temporal, zygomatic, buccal, marginal mandibular and cervical.

Answer 349

Giant cell tumours of bone, also known as osteoclastomas, are relatively common bone tumours and are usually benign. They typically arise from the metaphysis of long bones, extend into the epiphysis adjacent to the joint surface, and have a narrow zone of transition. Often they are incidentally identified. They may present insidiously with bone pain, soft tissue mass, or compression of adjacent structures. The pathological fracture may result in an acute presentation. They tend to be lytic and expansile, being surrounded by a thin shell of bone, resulting in a 'soap bubble' appearance radiologically.

Answer 350

During a trans popliteal approach for embolectomy in the popliteal fossa, the surgeons will encounter the tibial nerve first after incising the deep fascia.

Answer 351

Cervical ribs develop as an overdevelopment of the transverse process of the C7 vertebra. It can be complete or floating; and can be wholly bony, wholly fibrous, or a mixture of the two. While most cases remain asymptomatic and are incidentally detected on X rays or CT scans, they can become symptomatic - usually by the 3rd decade. Precipitating events may include repeated overhead actions as seen in athletes, painters, etc. Trauma can also precipitate symptoms of thoracic outlet obstruction by causing further narrowing of the space by inflammation and oedema. A clinical test for thoracic outlet obstruction that is causing neurovascular compromise is Adson's test. Adson's test: The patient is standing or seated with the elbow extended and in external rotation. The radial pulse is palpated. The patient is then asked to rotate the head towards the affected side with the neck fully extended and breath held in inspiration. The clinician abducts the arm 30o; while extending the arm backwards. A decrease in intensity or vanishing of the radial pulse or reproduction of symptoms is considered positive. In this case, axillary vein thrombosis is likely to have occurred secondary to the cervical rib. Initial treatment will include anticoagulants (usually a 3-month course). NOTE: Anticoagulant therapy is preferred to thrombolysis; however, even those patients who undergo thrombolysis should be given a course of anticoagulants after the procedure. After resolution of the thrombosis, cervical rib excision is recommended as it has caused neurovascular compromise. The preferred approach is trans-axillary.

Answer 352

Inhibition of pancreatic enzyme and hormone secretion by unregulated hypersecretion of somatostatin causes steatorrhea, diabetes, malabsorption, and cholelithiasis resulting from reduced gallbladder emptying.

Answer 353

The ischiocavernosus muscles surround the crura in the root of the penis. Each muscle arises from the internal surface of the ischial tuberosity and ischial ramus and passes anteriorly on the crus of the penis, where it is inserted into the sides and ventral surface of the crus and the perineal membrane. The ischiocavernosus muscles force blood from the cavernous spaces in the crura into the distal parts of the corpora cavernosa, thus increasing the turgidity of the penis

Answer 354

Traumatic subarachnoid haemorrhage is the result of venous bleeding into the subarachnoid

Answer 355

Tardy ulnar nerve palsy is a chronic clinical condition characterized by a delayed onset ulnar neuropathy after an injury to the elbow. Typically, tardy ulnar nerve palsy occurs as a consequence of nonunion of pediatric lateral condyle fractures at the elbow, which eventually lead to a cubitus valgus deformity. While the child

Answer 356

D-The proton pump spans the apical membrane of the gastric parietal cell In addition to mucus-secreting cells that line the entire surface of the stomach, the stomach mucosa has two important types of tubular glands-oxyntic glands (also called gastric glands) and pyloric glands. The oxyntic (acid-forming) glands secrete hydrochloric acid, pepsinogen, intrinsic factor, and mucus. The pyloric glands secrete mainly mucus for protection of the pyloric mucosa from the stomach acid. They also secrete the hormone gastrin. Oxyntic glands is composed of three main types of cells: • mucous neck cells, which secrete mainly mucus; • peptic (or chief) cells, which secrete large quantities of pepsinogen; and • parietal (or oxyntic) cells, which secrete hydrochloric acid and intrinsic factor. Oxyntic glands also contain some additional cell types, including the enterochromaffin-like (ECL) cells that secrete histamine. The main driving force for hydrochloric acid secretion by the parietal cells is a hydrogen-potassium pump (H+-K+ adenosine triphosphatase [ATPase]).The proton pump is found in the apical (luminal) membrane of gastric parietal cells and secretes protons into the lumen of the stomach in exchange for potassium ions. Acetylcholine released by parasympathetic stimulation excites secretion of pepsinogen by peptic cells, hydrochloric acid by parietal cells, and mucus by mucous cells. In comparison, both gastrin and histamine strongly stimulate acid secretion by parietal cells but have little effect on the other cells.

Answer 357

D-Humoral immunity is a type of adaptive immunity The mechanisms of immunity fall into two broad categories. Innate immunity (also called natural, or native, immunity) refers to intrinsic mechanisms that are poised to react immediately, and thus constitute the first line of defense. It is mediated by cells and molecules that recognize products of microbes and dead cells and induce rapid protective host reactions. Adaptive immunity (also called acquired, or specific, immunity) consists of mechanisms that are stimulated by (*adapt to") exposure to microbes and other foreign substances. It develops more slowly than innate immunity, but is even more powerful in combating infections. By convention, the term immune response usually refers to adaptive immunity. The major components of innate immunity are epithelial barriers that block entry of microbes, phagocytic cells (mainly neutrophils and macrophages), dendritic cells, natural killer cells and other innate lymphoid cells, and several plasma proteins, including the proteins of the complement system. There are two types of adaptive immunity: humoral immunity, which protects against extracellular microbes and their toxins, and cell-mediated (or cellular) immunity, which is responsible for defense against intracellular microbes and against cancers.

Answer 358

✅ Correct answer: Inhibits platelet aggregation Explanation: Aspirin irreversibly inhibits the enzyme cyclo-oxygenase (COX-1 and COX-2), preventing the conversion of arachidonic acid into prostaglandins and thromboxanes. In platelets, this means thromboxane A₂ (TXA₂) synthesis is blocked — a key factor in platelet aggregation. Since platelets cannot synthesize new COX enzymes, this effect lasts for the entire lifespan of the platelet (7–10 days). ⸻ Why the other options are wrong: • Is a lipo-oxygenase inhibitor — ❌ Lipoxygenase produces leukotrienes, which aspirin does not inhibit. Drugs like zileuton affect this pathway, not aspirin. • Inhibits the coagulation cascade — ❌ Aspirin affects platelet function, not the coagulation cascade (which involves clotting factors such as II, VII, IX, X). Anticoagulants like warfarin or heparin act there. • Is a reversible cyclo-oxygenase inhibitor — ❌ Aspirin’s inhibition of COX is irreversible, which is why its antiplatelet effect persists for days after stopping the drug. ⸻ Key concept for MRCS: Aspirin’s main surgical relevance lies in its antiplatelet effect — important for perioperative bleeding risk and cardiovascular protection. Mnemonic: Aspirin Affects Aggregation (AA) — not coagulation.

Answer 359

Urea and electrolytes (U&Es) are needed before all major operations, in most patients over 65 years of age especially with cardiovascular, renal and endocrine disease, or if significant blood loss is anticipated. It is also needed in patients taking medications that affect electrolyte levels, e.g. steroids, diuretics, digoxin, non-steroidal anti-inflammatory drugs, intravenous fluid or nutrition therapy and endocrine problems.

Answer 360

Juvenile nasopharyngeal angiofibroma (JNA) is confined to young male patients most commonly between the ages of 8 and 20 years. It usually causes progressive nasal obstruction, recurrent severe epistaxis, purulent rhinorrhoea and occasionally loss of vision because of compression of the optic nerve by superior extension of the tumour through the skull base. Although the tumour is rare, these symptoms in a young male patient should always arouse suspicion. The tumour is more common in northern India, although the reasons for this are unknown. Clinical examination typically shows a mass in the nasal cavity or nasopharynx, but CT scanning best demonstrates the extent of the tumour and any associated bony erosion. MRI scan- ning defines the soft tissue extent and, with these two modern investigations, angiography is rarely indicated. Biopsy should be avoided unless clinical and radiological examinations are not diagnostic because of the risk of bleeding. Surgery is often necessary.

Answer 361

Mehr Arora should be strongly encouraged to report herself immediately to her consultant and if she does not then you should. It is her consultant's responsibility, out of hours, to deal with this in the first instance. It is vital that the Registrar is removed from the clinical environment immediately and the consultant should facilitate this by 'stepping down' to act as the Registrar. Another doctor does need to complete her on call to protect patient safety. However, this situation needs to be escalated and dealt with, not forgotten, after this night shift, so that any future patient safety issues can be prevented. It is the consultant's responsibility out of hours to deal with this in the first instance and report to both the trust and GMC. Once the situation is made safe, it is likely the Registrar will face both Trust and GMC disciplinary proceedings in due course.

Answer 362

ABO incompatibility refers to differences in the ABO blood group system between the donor and recipient. This can lead to an immediate immune response, resulting in rejection during the transplant procedure.

Answer 363

✅ Correct answer: The CTZ is outside the blood–brain barrier ⸻ Explanation: The chemoreceptor trigger zone (CTZ) plays a major role in detecting emetogenic (vomit-inducing) substances circulating in the blood. It is located in the area postrema, on the floor of the fourth ventricle, and lies outside the blood–brain barrier, which allows it to sense toxins and drugs in the bloodstream directly. ⸻ Analysis of each option: 1. The main receptor in the CTZ is adrenergic — ❌ Wrong. The CTZ primarily contains dopamine (D₂), 5-HT₃ (serotonin), and neurokinin-1 (NK₁) receptors. Adrenergic receptors play little role here. 2. The CTZ is outside the blood–brain barrier — ✅ Correct. This allows emetogenic substances (like morphine, digoxin, or cytotoxic drugs) to stimulate it directly. 3. 5-HT₃ agonists may be effective in controlling cisplatin-induced vomiting — ❌ Incorrect — 5-HT₃ antagonists (like ondansetron, granisetron) are used to prevent chemotherapy-induced nausea and vomiting. Agonists would worsen vomiting. 4. H₂ receptors are abundant in the vomiting centre — ❌ Wrong. The vomiting centre (in the medulla) primarily has muscarinic (M₁), histamine H₁, and 5-HT₂ receptors — not H₂. 5. The vomiting centre is present in the reticular formation of the midbrain — ❌ Incorrect. It’s located in the reticular formation of the medulla oblongata, not the midbrain. ⸻ MRCS Key Point: • CTZ → detects emetic stimuli, outside BBB (drugs, toxins) • Vomiting centre → integrates signals from CTZ, vestibular system, and higher centres • Antiemetic drug classes by site of action: • CTZ: Dopamine antagonists (metoclopramide), 5-HT₃ antagonists (ondansetron) • Vestibular system: H₁ and M₁ blockers (cyclizine, hyoscine) • Vomiting centre: broad-acting drugs like promethazine ⸻ 🧠 Memory tip: “CTZ sees toxins freely” — because it’s outside the BBB.

Answer 364

ASA grade Patient condition Grade 1 Normal healthy patient, no systemic disturbances. Grade 2 Mild systemic impairment without functional limitation Grade 3 Severe systemic impairment with significant functional limitation Grade 4 Severe systemic disease with constant threat to life Grade 5 Moribund patient, not likely to survive without surgery

Answer 365

• Lithium carbonate continues to be used for the treatment of bipolar disorder (manic-depressive disease). Therapy with lithium decreases manic behavior and reduces both the frequency and the magnitude of mood swings. • Antipsychotic agents and/or benzodiazepines are commonly required at the initiation of treatment because both lithium and valproic acid have a slow onset of action. • Adverse neurologic effects of lithium include tremor, sedation, ataxia, and aphasia. Thyroid enlargement may occur, but hypothyroidism is rare. Reversible nephrogenic diabetes insipidus occurs commonly at therapeutic drug levels. Edema is a common adverse effect of Lithium therapy, acneiform skin eruptions occur and leukocytosis is always present

Answer 366

The psoas muscle originates from the lateral surfaces of the T12-L5 vertebrae, and inserts alongside the iliacus muscle as the iliopsoas tendon at the lesser trochanter of the femur. The psoas muscle acts to flex the hip joint.

Answer 367

E-All of the above Pituitary Prolactinoma (20%) GH and GH plus prolactin (10%) NF (5%) ACTH (2%) TSH and other (rare) Parathyroid Adenoma (90%) Foregut carcinoid NF gastric enterochromaffin-like cell tumor (10%) Bronchial carcinoid (2%) Thymic carcinoid (2%) Entero-pancreatic Gastrinoma (40%) Insulinoma (10%) NF, including PP (20%) Other - glucagonoma, VIPoma and somatostatinoma (2%)

Answer 368

✅ Correct answer: Longer vasa recta ⸻ Explanation: In abdominal surgery, the jejunum and ileum can be differentiated by their vascular and structural features. The jejunum has long, simple vasa recta (straight arteries) and fewer arterial arcades, whereas the ileum has shorter vasa recta and multiple complex arcades. This difference in blood supply is one of the most reliable intraoperative clues. ⸻ Reasoning through the options: • Narrow lumen — Incorrect. The jejunum actually has a wider lumen than the ileum. • Longer vasa recta — Correct. The jejunum has longer vasa recta and fewer arterial arcades, making its mesentery appear less fatty and more translucent. • More lymphoid tissue — Incorrect. The ileum, not the jejunum, has more lymphoid tissue, including prominent Peyer’s patches. • Less peritoneum — Incorrect. Both jejunum and ileum are completely peritonealized (intraperitoneal structures). • More arterial arcade in mesentery — Incorrect. The ileum, not the jejunum, has more arterial arcades (numerous short loops). ⸻ Key surgical point: When identifying small bowel loops, remember — “Jejunum is thick, red, and has long vasa recta; ileum is thin, pale, and has short vasa recta.”

Answer 369

Silk is a naturally available, non absorbable suture material. It is used in ligation and suturing when long term tissue support is necessary. Example: to secure drains externally.

Answer 370

Explanation: Sequence of vomiting Step1: Increase of salivary fluids to protect the oral cavity Step 2: Deep breath to avoid aspiration (has not been mentioned in the sequence given above) Step 3: Gl retroperistalsis (from duodenum with opening of pyloric sphincter) Step 4: Inspiration against a closed glottis (to decrease intrathoracic pressure) Step 5: Stomach contractions Step 6: Retching (LES open, UES closed) Step 7: Vomiting (UES and LES open)

Answer 371

B-A 45-year-old with unilateral serous discharge that is spontaneous Nipple discharge is considered "pathologic" if it is serous or bloody, unilateral, emerging from a single duct only, copious in amount, or spontaneous. When a woman experiences pathologic discharge after the age of 50, it is particularly more worrisome. Brown, green, white (milky), yellow, and blue discharge is more commonly "physiologic" and can usually be expressed from multiple ducts and/or bilaterally on examination. Bloody and serous types should raise concern for malignancy. Breast-feeding women can commonly have blood-tinged milk in the first weeks of pregnancy. This condition requires only observation, as it is most often self- limited. Milky discharge can be due to prolactinemia, which can also cause hormonal imbalances.

Answer 372

✅ Correct answer: HCO₃⁻ → Hb·CO₂ → CO₂ ⸻ Explanation: Carbon dioxide (CO₂) is transported in the blood in three main forms, but not in equal amounts. The majority is carried as bicarbonate (HCO₃⁻), with smaller amounts bound to haemoglobin and dissolved in plasma. ⸻ Distribution of CO₂ transport in blood: 1. As bicarbonate ion (HCO₃⁻) — about 70%–75% CO₂ diffuses into red blood cells and reacts with water to form carbonic acid (H₂CO₃), catalysed by carbonic anhydrase. H₂CO₃ then dissociates into H⁺ and HCO₃⁻, which diffuses into plasma. CO₂ + H₂O \leftrightarrow H₂CO₃ \leftrightarrow H⁺ + HCO₃⁻ 2. As carbaminohaemoglobin (Hb·CO₂) — about 20%–25% CO₂ binds directly to terminal amine groups of globin chains (not to the haem iron) forming carbamino compounds. 3. Dissolved CO₂ in plasma — about 5% This is the portion of CO₂ physically dissolved in blood and responsible for the PaCO₂ measured in arterial blood gases. ⸻ Order (by quantity): HCO₃⁻ > Hb·CO₂ > CO₂ ⸻ Key MRCS fact: • The Haldane effect explains how deoxygenated haemoglobin promotes CO₂ uptake in tissues. • The Bohr effect describes how CO₂ and H⁺ promote oxygen release from haemoglobin. ⸻ 🧠 Memory tip: “Most CO₂ hides as bicarbonate — the rest rides on haemoglobin.”

Answer 373

For well-defined, low-risk lesions <2 cm, excision with a 4-mm margin around the tumor border is expected to definitively treat the tumor. For high-risk tumors, a larger margin of at least 6 mm is indicated. Recurrent BCC is associated with a poor cure rate and a 10 mm excision margin is recommended.

Answer 374

Overactive bladder syndrome is very common and first line management includes the use of anticholinergics and bladder drill whereby voiding is deferred. Refractory cases can be treated with SNS or botulinum toxin injections. A Burch Colposuspension is used to treat stress urinary incontinence.

Answer 375

Those with a strong family history of colonic cancer are advised to undergo genetic testing. In the absence of a genetic condition (such as FAP or Lynch syndrome), a colonoscopy is advised between the ages of 35 and 45. Further routine colonoscopy is only indicated in the presence of polyps or other suspicious pathology. Genetic conditions like FAP or HNPCC (aka Lynch syndrome) are associated with high risk of bowel cancer and hence managed with annual colonoscopies. Patients with IBD are also at higher risk of colonic malignancy, though the exact risk depends on a variety of factors (age, duration and severity of illness, sites affected, etc.) The screening usually starts 10 years after onset of the condition with routine colonoscopies every 1 to 5 years (depending on the risk). Previous history of colorectal malignancy also predisposes to a subsequent cancer and requires screening every few years.

Answer 376

✅ Correct answer: Ib fibres ⸻ Explanation: The Golgi tendon organ (GTO) is a proprioceptive sensory receptor located at the junction of muscle and tendon. It senses tension (force of contraction) rather than length. When tension becomes excessive, it triggers an inhibitory reflex to protect the muscle from damage. ⸻ Details: • Receptor type: Golgi tendon organ • Stimulus detected: Muscle tension • Afferent fibre type: Group Ib afferents (large, myelinated, fast-conducting fibres) • Function: Inhibits its own muscle (autogenic inhibition) and excites the antagonist muscle — via interneurons in the spinal cord. ⸻ For comparison: • Muscle spindle (intrafusal fibres): • Ia fibres: respond to rate and degree of muscle stretch (dynamic and static). • II fibres: respond mainly to static muscle length. • Golgi tendon organ: • Ib fibres: respond to tension generated during contraction. • Group III and IV fibres: small-diameter fibres; associated with pain and temperature, not proprioception. ⸻ Key MRCS tip: Ia → spindle stretch; Ib → tendon tension. Mnemonic: “A” before “B”: A (spindle stretch) happens before B (tendon tension) during movement.

Answer 377

The classic findings on x-ray of a spinal bony tumor are loss of pedicle (metastases have a heavy predilection for the vertebral pedicle), compression fracture, or destruction of one or more vertebrae with disc preservation; all these features suggest a malignant lesion. Plain films show an abnormality in only 60% to 80% of patients who have neurologic deficits due to spinal cord compression. The (absent) pedicle sign known as the winking owl sign. A reliable sign of osteolytic spinal metastases on antero-posterior radiographs is loss of the normal pedicle contour.

Answer 378

C-Endoderm Tympanic membrane is formed by apposition of the tubotympanic recess and the first ectodermal cleft, these two forming the inner (endodermal) and outer (ectodermal) epithelial linings of the membrane. The intervening mesoderm forms the connective tissue basis.

Answer 379

Given her clinical presentation and the use of steroids, adrenal insufficiency should be high on the cards. IV hydrocortisone is the most appropriate management option to start with.

Answer 380

A-Resorption atelectasis occurs secondary to obstruction Atelectasis refers either to incomplete expansion of the lungs (neonatal atelectasis) or to the collapse of previously inflated lung, and results in areas of poorly aerated pulmonary parenchyma. Resorption atelectasis stems from obstruction of an airway. Since lung volume is diminished, the mediastinum shifts toward the atelectatic lung. Airway obstruction is most often caused by excessive secretions or exudates within smaller bronchi, as may occur in bronchial asthma, chronic bronchitis, bronchiectasis, and postoperative states. Aspiration of foreign bodies and intrabronchial tumors may also lead to airway obstruction and atelectasis. Compression atelectasis results whenever significant volumes of fluid (transudate, exudate, or blood), tumor, or air (pneumothorax) accumulate within the pleural cavity. With compression atelectasis, the mediastinum shifts away from the affected lung. Contraction atelectasis occurs when focal or generalized pulmonary or pleural fibrosis prevents full lung expansion. Significant atelectasis reduces oxygenation and predisposes to infection. Except in cases caused by fibrosis, atelectasis is a reversible disorder

Answer 381

Carotid body tumor is the most common paraganglioma in the head and neck. Other paragangliomas that occur in this region include the vagal and jugulotympanic types. The majority of paragangliomas are solitary and nonfamilial. Multicentricity is reported in about 10% of cases, with about a 6% rate of malignancy. Only about 1%-3% of them are considered functional and can be evaluated with a 24-h urine collection for the analysis of catecholamines. The "Fontaine sign" refers to mobility in only the lateral direction on palpation, whereas pain occurring with chewing is called "first-bite syndrome." Histopathologic evaluation of this tumor demonstrates two types of cells: type I, chief cells/granular cells, and type Il, sustentacular supporting cells. Unlike most head and neck tumors, malignancy is not diagnosed by the presence of dysplastic changes in the primary tumor. The presence of a metastatic disease either to the regional cervical lymphatics or to the distant sites is the only diagnostic criteria. Imaging is the major modality for primary diagnosis since needle biopsy is contraindicated. CT will show a hypervascular mass at the carotid bifurcation, with magnetic reso- nance imaging (MRI) demonstrating a classic "salt and pepper" appearance on T2-weighted sequences because of hemorrhage and flow voids. On angiography, the internal and external carotid arteries will be bowed apart, a finding referred to as the "lyre sign." These tumors are best treated surgically, and vascular reconstruction maybe necessary. Radiation therapy can stop the growth of these lesions but not shrink their size. Patients should be aware of the potential risk of injury to the vagus.

Answer 382

This is most likely a case of Salmonella food poisoning. This is contracted through the consumption of raw meat, eggs, or dairy products; although it can also be contracted through raw fruits or vegetables contaminated with infected animal faeces. The incubation period is 1 to 6 days, symptoms most often include fever, abdominal pain and diarrhoea. It is usually self limiting and resolves within 7 days and usually requires only symptomatic management and no antibiotic therapy. B. cereus and S. aureus usually present with symptoms within a few hours of consuming the contaminated food. Clostridium perfringens develops 8 to 16 hours after consumption of infected food, while Hepatitis A takes upto 2 weeks to develop symptoms.

Answer 383

Tumour grade cannot be assessed using a core biopsy (also called a tru-cut biopsy). This is because tumour grade requires accurate assessment of all margins and therefore is best done using an excisional biopsy. However, tumour type and hormone receptor status can be assessed using core biopsy. Core biopsy can distinguish between invasive and in situ disease, but only at the site of biopsy. It is still possible for an invasive disease to exist at another part of the tumour. Therefore, multiple core biopsies can be taken to improve diagnostic accuracy. Core biopsies of breast tissue can be done blindly or using ultrasound/stereotactic guidance. However, biopsies of suspicious axillary nodes (any palpable node in the setting of a breast lump) should be done only under USG guidance. This is because core biopsies carry a higher risk of damage to the surrounding structures, bleeding, and other complications when compared to FNAC. Tissue samples of core biopsy cannot be processed immediately (unlike FNAC). They require processing before they can be analysed by a pathologist. Typically, results can take a few days.

Answer 384

Torsion of the appendix testis/hydatid of morgagni is a benign situation. Although necrotic appendix testis is reabsorbed without any sequelae in almost all cases, the clinical presentation is a major challenge to clinicians. The classic presentation of torsion of the appendix testis is "blue dot sign", where the inflamed and ischemic appendage can be visualized from scrotal skin in the upper pole. The appendix testis (or hydatid of Morgagni) is a vestigial remnant of the of the Mullerian duct, present on the upper pole of the testis and attached to the tunica vaginalis. It is present about 90% of the time.

Answer 385

✅ Correct answer: Pulmonary embolism ⸻ Explanation: Cardiopulmonary bypass (CPB) temporarily replaces the function of the heart and lungs during cardiac surgery. While lifesaving, it is associated with a range of complications due to hemodilution, systemic inflammatory response, and coagulation disturbances. ⸻ Typical complications of cardiopulmonary bypass: 1. Bleeding disorders — Common • Due to heparin use, platelet dysfunction, and consumption of coagulation factors. • May result in postoperative bleeding and need for transfusion. 2. Neurological dysfunction — Common • Ranges from stroke to neurocognitive impairment (“pump head”). • Caused by microemboli, hypoperfusion, or air embolism. 3. Intestinal ischaemia or infarction — Possible • Due to low flow states, hypotension, or embolic events during bypass. 4. Post-cardiotomy syndrome — Recognised complication • Autoimmune pericarditis presenting with fever, chest pain, and pericardial effusion weeks after surgery. ⸻ Pulmonary embolism — NOT typical after CPB ❌ • CPB bypasses pulmonary circulation, and the anticoagulation (heparin) used during the procedure prevents thrombus formation. • Thus, pulmonary embolism is very uncommon post-CPB compared with the other listed complications. ⸻ Key MRCS takeaway: After CPB, think of complications from inflammation, coagulation, or perfusion imbalance — but not pulmonary embolism.

Answer 386

A-Suspensory muscle (Ligament of Treitz) Ligament of Treitz • Marks the junction of foregut to midgut. • Clinically, helps differentiate between UGI & LGI bleed • Made of 2 parts: • The first part called the Hilfsmuskel arises from the right crus of the diaphragm and loops around the esophagus before inserting as a connective tissue band at the celiac trunk. • The second part called the suspensory muscle originates from the celiac trunk as a connective tissue band to insert at the duodenojejunal flexure.

Answer 387

A-SVC The azygos vein is usually formed by the union of the ascending lumbar vein with the subcostal vein of the right side. The vessel goes through the aortic opening of the diaphragm under shelter of the right crus, lateral to the thoracic duct, and passes upwards lying on the sides of the vertebral bodies, on a plane posterior to that of the oesophagus. At the level of T4 vertebra the azygos vein arches forwards over the hilum of the right lung and ends in the superior vena cava

Answer 388

D-Increased transit time through vascular beds The major pathologic manifestations-chronic hemolysis, microvascular occlusions, and tissue damage-all stem from the tendency of HbS molecules to stack into polymers when deoxygenated. Several variables affect the rate and degree of sickling: • Interaction of Hbs with the other types of hemoglobin - HbF inhibits the polymerization of Hbs even more than HbA; hence, infants with sickle cell disease do not become symptomatic until they reach 5 or 6 months of age, when the level of HbF normally falls. • Mean cell hemoglobin concentration (MCHC) - Higher HbS concentrations increase the probability that aggregation and polymerization will occur during any given period of deoxygenation. Thus, intracellular dehydration, which increases the MCHC, facilitates sickling • A decrease in pH reduces the oxygen affinity of hemoglobin, thereby increasing the fraction of deoxygenated HbS at any given oxygen tension and augmenting the tendency for sickling. • Transit times in most normal microvascular beds are too short for significant aggregation of deoxygenated HbS to occur, and as a result sickling is confined to microvascular beds with slow transit times as in spleen, bone marrow and inflamed microvascular beds.

Answer 389

✅ Correct answer: CEPOD category 4 ⸻ Explanation: The Confidential Enquiry into Perioperative Deaths (CEPOD) classification system categorises surgical urgency. It helps prioritise operations based on how urgently they must be performed. ⸻ CEPOD categories: 1. Category 1 – Immediate (Emergency): Operation required immediately — within minutes to save life or limb. Example: ruptured abdominal aortic aneurysm, trauma with active bleeding. 2. Category 2 – Urgent: Operation required within hours — to save life, organ, or tissue. Example: strangulated hernia, perforated viscus, intestinal obstruction. 3. Category 3 – Expedited (Early): Operation required within days — patient not in immediate danger but delay may cause deterioration. Example: malignancy needing resection, critical limb ischaemia without sepsis. 4. Category 4 – Elective: Operation can be planned to suit patient and theatre convenience. Example: reducible hernia, varicose veins, cholelithiasis without cholecystitis. 5. Category 5 – Scheduled: Used for planned, repetitive procedures, such as renal dialysis access maintenance or follow-up endoscopy. ⸻ Application to the question: • The patient has a manually reducible, painless umbilical hernia — not strangulated or obstructed. • The surgery can be scheduled at a convenient time for both patient and operating theatre. 👉 Therefore, this is CEPOD Category 4 – Elective. ⸻ Key MRCS tip: Category 1 saves life now; Category 4 can wait for convenience.

Answer 390

The presence of estrogen receptors in breast cancer is associated with a better prognosis, as hormone receptor-positive tumors often respond well to hormone therapy

Answer 391

Anti-TPO (aka anti-microsomal) and anti-thyroglobulin antibodies are used in the diagnosis of Hashimoto's thyroiditis. Anti-TSHR antibodies are found in Graves' disease, not Hashimoto's thyroiditis.

Answer 392

Dermatomyositis is an immunologic disease in which damage to small blood vessels contributes to muscle injury. The vasculopathic changes can be seen as telangiectasias (dilated capillary loops) in the nail folds, eyelids, and gums and as dropout of capillary vessels in skeletal muscle. Biopsies of muscle and skin may show deposition of the complement membrane attack complex (C5b-9) within capillary beds. Muscle weakness is slow in onset, symmetric, and often accompanied by myalgias. It typically affects the proximal muscles first. As a result, tasks such as getting up from a chair and climbing steps become increasingly difficult. Fine movements controlled by distal muscles are affected only late in the disease. Associated myopathic changes on electrophysiologic studies and elevation in serum creatine kinase levels are reflective of muscle damage. Various rashes are described in dermatomyositis, but the most characteristic ones are a lilac-colored discoloration of the upper eyelids (heliotrope rash) associated with periorbital edema and scaling erythematous eruption or dusky red patches over the knuckles, elbows and knees (Gottron papules)

Answer 393

✅ Correct answer: Respiratory acidosis with metabolic compensation Why: • pH = 7.31 → acidemia. • pCO₂ = 65 mmHg (high) → points to respiratory acidosis (CO₂ retention). • HCO₃⁻ = 31 mmol/L (elevated) → indicates renal (metabolic) compensation has occurred. Quick check (step-by-step arithmetic): • pCO₂ rise = 65 − 40 = 25 mmHg. • In acute respiratory acidosis, HCO₃⁻ rises ~ 1 mmol/L per 10 mmHg ↑CO₂ → expected rise ≈ 25/10 × 1 = 2.5 → expected HCO₃ ≈ 24 + 2.5 = 26.5 (less than 31). • In chronic respiratory acidosis, HCO₃⁻ rises ~ 3.5 mmol/L per 10 mmHg ↑CO₂ → expected rise ≈ 25/10 × 3.5 = 8.75 → expected HCO₃ ≈ 24 + 8.75 = 32.75 (close to 31). So the pattern fits respiratory acidosis with metabolic (renal) compensation — likely chronic or partially chronic compensation rather than an uncompensated process.

Answer 394

Decreased GCS, Facial trauma and Burns to the face are all scenarios in which the airway may be compromised at any time. Therefore, they require constant monitoring and reassessment of the airway, and the anaesthetic

Answer 395

✅ Correct answer: The concentration of chloride is higher in gallbladder bile than liver bile — (False) Why: The gallbladder concentrates hepatic bile by absorbing water and certain electrolytes (notably Na⁺ and Cl⁻). Because water, Na⁺ and Cl⁻ are removed, the relative concentrations of bile salts, cholesterol, bilirubin and K⁺ become higher in stored (gallbladder) bile than in freshly secreted (hepatic) bile. So chloride is lower, not higher, in gallbladder bile — making that statement false.

Answer 396

The thoracoacromial artery arises from the second part of the axillary artery. It is a short, wide trunk, which pierces the clavipectoral fascia, and ends, deep to pectoralis major by dividing into four branches.

Answer 397

The area in front of the left ear is the parotid region, and slow growing mass is likely to be a tumor. The most common tumor in parotid is Pleomorphic adenoma.

Answer 398

Let’s calculate this step by step carefully. ⸻ Given: • Total patients = 200 • True positives (TP) = 40 (patients with COVID who tested positive) • False negatives (FN) = 50 − 40 = 10 (patients with COVID but tested negative) ⸻ Formula for Sensitivity: \text{Sensitivity} = \frac{\text{True Positives}}{\text{True Positives + False Negatives}} \times 100 = \frac{40}{40 + 10} \times 100 = \frac{40}{50} \times 100 = 80\% ⸻ ✅ Correct answer: 80% ⸻ Explanation: Sensitivity measures a test’s ability to correctly identify patients who truly have the disease. Here, the test correctly identified 40 of 50 COVID-positive patients → 80% sensitivity.

Answer 399

In the embryo, the pleuroperitoneal cavities become separated by the developing membrane during 8 to 10 weeks of gestation. When the pleuroperitoneal canal persists, it leads to a posterolateral CDH defect. The posterolateral location of this hernia is known as Bochdalek hernia; it is distinguished from a CDH of the anteromedial location known as Morgagni hernia. Abdominal contents herniated into the thoracic cavity through the diaphragmatic defect, compressing the ipsilateral developing lung.

Answer 400

The operative management of liver injuries can be summarized as 'the four Ps': • Push; • Pringle; • Plug; • Pack. At laparotomy the liver is reconstituted and bleeding is controlled by direct bimanual compression to achieve its normal architecture as best as possible (push). The inflow from the portal triad is controlled by a Pringle's maneuver, with direct compression of the portal triad, either digitally or using a soft clamp. Any holes due to penetrating injury can be plugged directly using silicone tubing or a Sengstaken-Blackmore tube, and after controlling any arterial bleeding , the liver can be packed.

Answer 401

D-Right- greater omentum The borders of the omental bursa are demarcated as follows: • Anteriorly- quadrate lobe of the liver, the gastrocolic ligament and the lesser omentum • Left - left kidney and the left adrenal gland • Posteriorly - pancreas • Right - the epiploic foramen and lesser omentum

Answer 402

Core biopsies utilise very small incisions that usually do not require suturing. A steristrip can be applied after using pressure to reduce swelling. Steps of a core biopsy: 1. Obtains informed consent for the procedure. 2. Patient positioning: 45° angle with hands above or behind the head. 3. Prepare a container with formalin for preserving the specimens. 4. Local anaesthesia infiltration with lignocaine +adrenaline. 5. Make a small (2mm) incision just to the side of the lump. 6. Insert the needle at a shallow angle, almost parallel to the chest wall (to minimise injury to chest wall) while fixing the lump with the other hand. 7. Once the needle is inside the lump, collect 2 to 4 core biopsies. The collected specimens must immediately be immersed in formalin. 8. Apply external pressure on the biopsy site between core biopsies and at the end of the procedure. Having an assistant for this part is advisable. 9. Once the bleeding stops, close the incision site with steristips and apply the dressing. Allow the patient to get dressed. Label the specimens appropriately. 10. Inform the patient about potential complications, including information on when to seek medical help. Prescribe a mild analgesic. Inform the patient about when and how to collect results.

Answer 403

This is an emergency situation. A hematoma is causing obstruction of the trachea. Immediate management will be removing the skin staples to release pressure. The anaesthetist team should be informed, as urgent intubation may be required to keep the airway patent. The rest of emergency management should follow the ABC protocol.

Answer 404

B-Decamethonium is the most commonly used non-depolarizing muscle relaxant Muscle relaxants are categorised into depolarizing and nondepolarizing agents. Suxamethonium (previously called Di-acetyl choline), is the most common depolarizing agent used. However, it has many adverse effects - hyperkalemia, myalgia, anaphylaxis, malignant hyperthermia - but is still clinically used due to quick onset and short duration of action. Non-depolarizing agents provide longer, predictable activity but require careful monitoring, appropriate timing and action reversal. Eg. Rocuronium, Pancuronium, Atracurium. Decamethonium is an obsolete agent (depolarizing blocker) and is no longer used in the UK, due to its tendency to cause psychological distress in patients while also rendering them unable to communicate.

Answer 405

A-Nothing is required The ostrogen in OCPs can lead to increased TBG, further leading to decreased T4. Most normal patients can compensate for this (as in our patient). However, this is a concern in hypothyroid patients who cannot. If a hypothyroid patient is put on COCPs, check the hormone levels in a few weeks, and then adjust the levothyroxine dose as needed.

Answer 406

Computed Tomography (CT) scan is the best imaging modality for hydatid cyst. It shows the presence of a space occupying lesion with a smooth outline with septa. CT has an accuracy of 98% in the detection and higher sensitivity to demonstrate the daughter cysts and extra hepatic cysts. The indirect haemagglutination test and ELISA have a sensitivity of 80% overall and are the initial screening tests of choice. First/Initial imaging test: USG Best imaging test: CT scan

Answer 407

Human African trypanosomiasis (aka African/Gambian/Rhodesian sleeping sickness) is endemic in sub-Saharan Africa. The disease is caused by infection with the gambiense and rhodesiense subspecies of the extracellular parasite Trypanosoma brucei, and is transmitted to humans by bites of infected tsetse flies. The disease evolves in two stages, the hemolymphatic and meningo-encephalitic stages, the latter being defined by central nervous system infection after trypanosomal traversal of the blood-brain barrier. African trypanosomiasis leads to severe neuro-inflammation and is fatal without treatment. South American sleeping sickness (or Chagas' disease) is a totally different disease with a different pathogen (T. cruzi) and different treatment.

Answer 408

Benign prostatic hyperplasia (BPH) arises in the transitional zone of the prostate (periurethral glands and stroma). It is a common finding in elderly males, and its incidence increases with age. As the prostate enlarges the patient usually develops lower urinary tract symptoms. Compression of the prostatic urethra leads to a rise in intravesical pressure, which eventually leads to detrusor atony. Enlargement of the posterior lobes of the prostate is usually seen in prostatic cancer. Phimosis is not a routine feature of BPH but all patients with lower urinary tract symptoms should have their external genitalia examined to exclude this pathology

Answer 409

This is likely to be a case of mesenteric artery infarct. The sudden onset of severe abdominal pain accompanied by profuse diarrhoea is a classical presentation. As his vitals are stable, CT Angiogram is the most sensitive investigation. Duplex USG may be an alternative option when the patient is unstable or an angiogram is not an option. MR Angiogram takes longer and increased gut peristalsis may interfere with the imaging. X ray offers no functional information. A blind exploration is also not beneficial.

Answer 410

Adhesive capsulitis (frozen shoulder) is a condition wherein there is pain and stiffness that begins, persists and resolves over a period of 12-18 months. The cause is unknown, but is thought to be autoimmune. It is more prevalent in diabetics. Treatment is with analgesics and physiotherapy. The pain in the shoulder increases slowly over several months, and causes painful restriction of all movements. Rotator cuff tears are characterised by pain on specific motions, as is supraspinatus tendinitis. Subacromial bursitis can be identified on clinical examination by redness and swelling in front of the shoulder. Calcific tendinitis is visible on plain X ray.

Answer 411

Carcinoid tumors represent 1% to 5% of all lung tumors. Carcinoid tumors are low-grade malignant epithelial neoplasms that are subclassified into typical and atypical carcinoids. Most central tumours are confined to the mainstem bronchi. Others, however, penetrate the bronchial wall to fan out in the peribronchial tissue, producing the so-called collar-button lesion. Peripheral tumors are solid and nodular. On electron microscopy the cells exhibit the dense-core granules characteristic of other neuroendocrine tumors and, by immunohistochemistry, are found to contain serotonin, neuron- specific enolase, bombesin, calcitonin, or other peptides.

Answer 412

Mid-shaft injuries of the humerus are notorious for involving the radial nerve and the profunda brachii artery as they course through the radial groove together. Radial nerve supplies the extensors of the wrist and damage to it causes wrist drop (caused by unopposed action of the flexors.) There can also be some sensory loss over the dorsal surface of the hand and the lateral 3 and a half fingers.

Answer 413

Splenomegaly with pancytopenia and bone pain along with the typical description of Gaucher cell point to the diagnosis of Gaucher's disease which is characterised by defect in glucocerebrosidase.They have 20 fold higher risk of developing Parkinson's disease. • Gaucher disease refers to a cluster of autosomal recessive disorders resulting from mutations in the gene encoding glucocerebrosidase. It is the most common lysosomal storage disorder. • Glucocerebrosides accumulate in massive amounts within phagocytic cells throughout the body in all forms of Gaucher disease. • The distended phagocytic cells, known as Gaucher cells, are found in the spleen, liver, bone marrow, lymph nodes, tonsils, thymus, and Peyer patches. Gaucher cells are often enlarged, sometimes up to 100 um in diameter, and have one or more dark, eccentrically placed nuclei. Periodic acid-Schiff staining is usually intensely positive. With the electron microscope the fibrillary cytoplasm can be resolved as elongated, distended lysosomes, containing the stored lipid in stacks of bilayers. • In type I disease, the spleen is enlarged, sometimes up to 10 kg. The lymphadenopathy is mild to moderate and is body-wide.Accumulation of Gaucher cells in the bone marrow occurs in 70% to 100% of cases of type I Gaucher disease. It produces areas of bone erosion that are sometimes small but in other cases sufficiently large to give rise to pathologic fractures. • Mutation of the glucocerebrosidase gene is the most common known genetic risk factor for development of Parkinson disease. Patients with Gaucher disease have a 20-fold higher risk of developing Parkinson disease (compared with controls), and 5% to 10% of patients with Parkinson disease have mutations in the gene encoding glucocerebrosidase. • Replacement therapy with recombinant enzymes is the mainstay for treatment of Gaucher disease; it is effective, and those with type I disease can expect normal life expectancy.

Answer 414

The carotid sheath contains the internal jugular vein (IJV), common carotid artery, and vagus nerve.

Answer 415

Disc prolapse is common: up to 3% of men and 1% of women will suffer with sciatica related to a prolapsed intervertebral disc. Usual presentation is between the ages of 30 and 50 years. Clinically, a patient will have an abnormal posture, stooping to the affected side and standing with the knee flexed to relieve pressure Nerve root tension signs such as straight-leg raising will be positive. The crossover sign may be positive (elevation of the opposite or normal leg gives pain shooting down the affected leg). Numbness in a dermatomal distribution and weakness with loss of reflexes may be present. Diagnosis and investigation: In older patients, blood tests should be performed to exclude any sinister causes. X-ray images are usually normal and are performed to exclude bony pathology such as spondylolisthesis. MRI scanning is now the investigation of choice in patients with persistent symptoms.

Answer 416

C-Pseudoglandular - canalicular - terminal sac- alveolar Pseudoglandular period 5-16 wk Branching has continued to form terminal bronchioles. No respiratory bronchioles or alveoli are present. Canalicular period 16-26 wk Each terminal bronchiole divides into two or more respiratory bronchioles, which in turn divide into three to six alveolar ducts. Terminal sac period 26 wk to birth Terminal sacs (primitive alveoli) form, and capillaries establish close contact. Alveolar period 8 mo to childhood Mature alveoli have well-developed epithelial endothelial (capillary) contacts.

Answer 417

✅ Correct answer: Scleroderma (Systemic sclerosis) Explanation: Masha’s presentation is classic for systemic sclerosis, particularly the limited cutaneous subtype (CREST syndrome). Key features in the vignette: • Gradual dysphagia → due to oesophageal dysmotility and fibrosis of smooth muscle. • Cold fingers/toes turning white or blue → Raynaud’s phenomenon, very typical of scleroderma. • Heartburn and bloating → gastro-oesophageal reflux and small bowel dysmotility. • Swollen fingers in the morning → early sclerodactyly, progressing to tight, shiny skin and tapering digits. • Middle-aged woman → demographic most commonly affected. Mnemonic for CREST (limited scleroderma): • C – Calcinosis • R – Raynaud’s phenomenon • E – Esophageal dysmotility • S – Sclerodactyly • T – Telangiectasia Why not the others? • Coeliac disease → causes malabsorption and bloating, but no Raynaud’s or finger swelling. • Tropical sprue → similar GI symptoms, but seen in tropical climates and without vascular/skin features. • Rheumatoid arthritis → causes joint pain and stiffness, but not Raynaud’s or esophageal involvement. • Rocky Mountain spotted fever → acute febrile illness with rash, not chronic or autoimmune. ⸻ 🩺 Learning point: Systemic sclerosis is an autoimmune connective tissue disorder causing fibrosis of skin and internal organs. The limited form (CREST) primarily affects the distal limbs and face, while the diffuse form involves more widespread skin thickening and visceral fibrosis (lungs, kidneys, heart). ⸻ Answer: Scleroderma (Systemic sclerosis) ✅

Answer 418

In the group receiving COCPs, the number of pregnancies is 7% of 7000 = 490. In the group receiving POPs, the number of pregnancies is 11% of 9000 = 990. Therefore, 1480 pregnancies occurred amongst the population taking contraception (n=16000) over a 5-year time period. The annual incidence of pregnancy in this population is the percentage of pregnancies over the 5-year period (1480/16000 × 100) divided by 5 = 1.85%.

Answer 419

Enterohemorrhagic E.coli causes a clinical picture of bloody diarrhoea without a fever. The most famous member of this subtype is the strain 0157:7. The bacterial fimbriae are used to attach to the bowel lining, and it is moderately invasive. A phage encoded Shiga toxin mediates the inflammatory response responsible for the clinical picture. This strain is the common one of the species to cause HUS (leading to acute renal failure) and TTP. Enteropathogenic E.coli subtype uses adhesin proteins to bind to intestinal cells (similar to Shigella). This leads to changes in the cell structures that causes loss of water and sodium into the bowel lumen. Enterotoxigenic E.coli uses two enterotoxins (LT enterotoxin that is similar to cholera toxin; ST enterotoxin). These are non-invasive strains and are the most common cause of traveller's diarrhoea. Enteroaggregative E.coli subtype is found only in humans. It is noninvasive and causes watery diarrhoea without fever. Enteroinvasive E.coli: Also found only in humans. No toxins produced. Clinical picture resembles shigellosis with profuse bloody/non-bloody diarrhoea and high fever. They severely damage the intestinal wall by mechanical cell destruction.

Answer 420

After the airway is secured, the next stage of ATLS is management of breathing. • Brief examination of respiratory system (inspection, palpation, percussion, auscultation) • Measure Sa02 and send arterial sample for ABG • Rule out the 6 life threatening conditions (Airway compromise, Tension pneumothorax, Open pneumothorax, Haemothorax, Cardiac tamponade and Flail chest) and treat any if present immediately • Provide supplemental O2. As this patient is intubated, IPPV must be provided, as the narrowed mouth of the ET tube increases the work of breathing.

Answer 421

DIC is characterised by the pathological activation of the coagulation pathway leading to clot formation. This clotting consumes coagulation factors and platelets resulting in subsequent bleeding. Common causes of DIC include sepsis, malignancy (especially adenocarcinoma), trauma and obstetric emergencies. Laboratory features include prolongation of all clotting times and a progressively falling platelet count and fibrinogen concentration. Increasing fibrin degradation products (FDP) indicate activation of the fibrinolytic system and, in the context of the other laboratory abnormalities, support a diagnosis of DIC. Treatment involves intensive blood-product support with correction of the underlying cause.

Answer 422

B-Medial After originating from the brachial plexus in the axilla, the median nerve descends down the arm, initially lateral to the brachial artery. Halfway down the arm, the nerve crosses over the brachial artery, and becomes situated medially before entering the forearm via the cubital fossa.

Answer 423

Isoproterenol/ isoprenaline is a potent, nonselective B receptor agonist with very low affinity for a receptors. Consequently, INE has powerful effects on all 3 receptors and almost no action at a receptors. Intravenous infusion of INE lowers peripheral vascular resistance, primarily in skeletal muscle but also in renal and mesenteric vascular beds. Diastolic pressure falls. Systolic blood pressure may remain unchanged or rise, although mean arterial pressure typically falls. Cardiac output is increased because of the positive inotropic and chronotropic effects of the drug in the face of diminished periphera vascular resistance. Isoproterenol may be used in emergencies to stimulate heart rate in patients with bradycardia or heart block, particularly in anticipation of inserting an artificial cardiac pacemaker or in patients with the ventricular arrhythmia torsades de pointes. Furosemide,being a loop diuretic,has a vasodilatory action and so decreases afterload giving an indirect inotropic effect. Diltiazem is a non-dihydropyridine calcium channel blocker. Primarily, diltiazem inhibits the inflow of calcium ions into the cardiac smooth muscle during depolarization. Reduced intracellular calcium concentrations equate to increased smooth muscle relaxation resulting in arterial vasodilation and, therefore, decreased blood pressure. Diltiazem is a potent coronary artery vasodilator and is consequently used for chronic angina and in those patients with coronary vasospasm.Diltiazem is a negative inotrope (decreased force) and negative chronotrope (decreased rate). The combination, along with coronary artery vasodilation, leads to decreased myocardial oxygen demand, decreased heart rate, and reduced blood pressure. Disopyramide is a sodium channel blocker (class la antiarrhythmic agent) - its effect is to increase the threshold of the myocardium for excitation and so increases the PR interval. It has a negative inotropic effect and may be of use in some ventricular tachyarrhythmias. GTN is a potent vasodilator - it can be used as an infusion in patients with ongoing ischaemic chest pain or in patients with acute heart failure. In the latter category its vasodilatory effect is used to decrease afterload and therefore have an indirect inotropic effect.

Answer 424

The majority of CO2 is transported as bicarbonate. CO2 combines with water

Answer 425

In a horseshoe kidney the two renal units are low lying and the lower poles fuse to form an isthmus. Further ascent of the fused kidneys is prevented by the inferior mesenteric artery.

Answer 426

Central cord syndrome is the most common type of incomplete cord injury and almost always occurs due to a traumatic injury. It results in motor deficits that are worse in the upper extremities as compared to the lower extremities. It may also cause bladder dysfunction (retention) and variable sensory deficits below the level of injury. It most commonly results following a hyperextension injury of the cervical spine leading to spinal cord impingement. The proposed mechanism of action is hyperextension resulting in simultaneous compression of the spinal cord anteriorly, either by bony spurs or intervertebral disc material and posteriorly by the ligamentum flavum. On examination, patients will have more significant strength impairments in the upper extremities (especially the hands) compared to the lower extremities. Patients often complain of sensory deficits below the level of injury, but this is variable. Pain and temperature sensations are typically affected, but the sensation of light touch can also be impaired. The most common sensory deficits are in a "cape-like" distribution across their upper back and down their posterior upper extremities. They will often have neck pain at the site of spinal cord impingement. Incomplete Spinal Cord Syndromes Brown-Sequard Syndrome Typically, this syndrome is the result of penetrating trauma causing hemi-section of the cord via direct injury. Findings include loss of ipsilateral position and vibratory sense, ipsilateral motor loss,and contralateral loss of pain and temperatureone to two levels below the lesion(Figure 11.8). Central Cord Syndrome This injury pattern is most often found in cervical hyperflexion, as may result from motor vehicle collisions. Findings include loss of motor function, typically greater in the upper extremities than the lower. However, complete quadriplegia may result. Typically, the spinothalamic tracts are spared or minimally involved (Figure 11.8). Anterior Cord Syndrome Often the results of cervical hyperextension, this results in the loss of motor, pain, and temperature function bilaterally below the lesion while vibratory and position sense remain intact. This syndrome may also result from thrombosis of the anterior vertebral artery or direct anterior trauma (Figure 11.8). Figure 11.8 From top to bottom: Brown-Sequard Syndrome, Central Cord Syndrome, Anterior Cord Syndrome Ref:Image from Trott, T. (2019). Thoracolumbar Trauma. In A. Koyfman & B. Long (Eds.), The Emergency Medicine Trauma Handbook (pp. 154-163). Cambridge: Cambridge University Press. doi:10.1017/9781108647397.012

Answer 427

Central cord syndrome is the most common type of incomplete cord injury and almost always occurs due to a traumatic injury. It results in motor deficits that are worse in the upper extremities as compared to the lower extremities. It may also cause bladder dysfunction (retention) and variable sensory deficits below the level of injury. It most commonly results following a hyperextension injury of the cervical spine leading to spinal cord impingement. The proposed mechanism of action is hyperextension resulting in simultaneous compression of the spinal cord anteriorly, either by bony spurs or intervertebral disc material and posteriorly by the ligamentum flavum. On examination, patients will have more significant strength impairments in the upper extremities (especially the hands) compared to the lower extremities. Patients often complain of sensory deficits below the level of injury, but this is variable. Pain and temperature sensations are typically affected, but the sensation of light touch can also be impaired. The most common sensory deficits are in a "cape-like" distribution across their upper back and down their posterior upper extremities. They will often have neck pain at the site of spinal cord impingement. Incomplete Spinal Cord Syndromes Brown-Sequard Syndrome Typically, this syndrome is the result of penetrating trauma causing hemi-section of the cord via direct injury. Findings include loss of ipsilateral position and vibratory sense, ipsilateral motor loss,and contralateral loss of pain and temperatureone to two levels below the lesion(Figure 11.8). Central Cord Syndrome This injury pattern is most often found in cervical hyperflexion, as may result from motor vehicle collisions. Findings include loss of motor function, typically greater in the upper extremities than the lower. However, complete quadriplegia may result. Typically, the spinothalamic tracts are spared or minimally involved Anterior Cord Syndrome Often the results of cervical hyperextension, this results in the loss of motor, pain, and temperature function bilaterally below the lesion while vibratory and position sense remain intact. This syndrome may also result from thrombosis of the anterior vertebral artery or direct anterior trauma

Answer 428

Fibroblasts are the predominant cells during the Proliferative phase. They are specialised cells that differentiate from resting mesenchymal cells in connective tissue. The primary function of fibroblasts is to synthesise collagen. The proliferative phase is characterized by the formation of granulation tissue, reepithelisation and neovascularisation. This phase can last several weeks.

Answer 429

The side effects of spironolactone are drowsiness, ataxia, mental confusion, epigastric distress and loose motions. Spironolactone interacts with progestin and androgen receptors as well. In addition, it may enhance testosterone clearance or its peripheral conversion to estradiol, producing dose and duration of treatment related hormonal side effects like gynaecomastia, erectile dysfunction or loss of libido in men, and breast tenderness or menstrual irregularities in women. Most serious is hyperkalemia that may occur, especially if renal function is inadequate. Acidosis is a risk, particularly in cirrhotics. Peptic ulcer may be aggravated; it is contraindicated in ulcer patients. Drugs causing Gynaecomastia Drugs can cause gynecomastia by acting directly as estrogenic substances (e.g., oral contraceptives, phytoestrogens, digitalis), inhibiting androgen synthesis (e.g., ketoconazole), or action (e.g., spironolactone); for many drugs, such as cimetidine, imatinib, or some antiretroviral drugs for HIV, the precise mechanism is unknown.

Answer 430

Prophylactic antibiotics can be given at the time of induction. Microdochectomy is usually a day-care case. It is a diagnostic procedure used to assess for an underlying malignancy. The patient is asked not to express the discharge for a few days pre-operatively. The surgeon will express the discharge after induction to help identify the involved duct. Potential complications include infection, hematoma formation, or mammary duct fistula formation.

Answer 431

The scenario describes a dry, blotchy, cherry-red area that doesn’t blanch, with reduced or absent sensation and no capillary refill. These are the hallmark features of a full-thickness (third-degree) burn. In this type of burn, both the epidermis and the entire dermis are destroyed, and sometimes the underlying fat is also involved. Because the sensory nerve endings in the dermis are destroyed, the area is typically painless to light touch or pinprick, although surrounding areas may still hurt due to partial-thickness involvement. The surface often looks leathery, white, brown, or even charred, and it feels firm rather than moist. By contrast, superficial and partial-thickness burns are moist, pink, and blanch easily with pressure because their blood supply is still intact. They are also very painful due to preserved nerve endings. The absence of capillary refill, a dry surface, and loss of sensation indicate complete destruction of the skin layers, confirming a full-thickness burn. Answer: Full thickness

Answer 432

D-Hyperemesis gravidarum-Normal Saline + Potassium Chloride In hypovolaemia secondary to blood loss, treatment should be with a balanced crystalloid or colloid - like Ringer Lactate or Plasma-lyte- till blood can be arranged. 0.9% Normal Saline is not used for volume replacement, except in vomiting/gastric drainage, due to risk of hyperchloremic acidosis. Ringer's lactate or Hartmann's is preferred for resuscitation or replacement. 0.4%/0.18% dextrose saline or 5% dextrose is used as maintenance fluid. It can not be used in resuscitation or as replacement fluids. Excessive fluid losses from vomiting should be treated with a crystalloid with potassium replacement. 0.9% N. Saline should be given if there is hypochloraemia. Hartmann's or Ringer lactate should be given for diarrhoea/ileostomy/ileus/obstruction. A critically ill patient is unable to excrete Na or water leading to risk of interstitial oedema. Therefore 5% dextrose as well as colloid should be given.

Answer 433

E-None of the above Although thermoreceptors are found mostly in the skin, they are also found in cornea (waters to the cold), GI tract (thermoregulation with hot-cold food), respiratory tract (response to cold air) and the bladder.

Answer 434

Under normal conditions the renal clearance of glucose is zero, as glucose is completely reabsorbed in the renal tubules and not excreted. Glycosuria may be an indicator of glucoseintolerance and diabetes mellitus.

Answer 435

C-Papillary carcinoma has a better prognosis than other variant Primary carcinoma of the gallbladder is an uncommon, aggressive malignancy that affects women more frequently than men. Older age groups are most often affected, and coexisting gallstones are present in the vast majority of cases. Symptoms are typically indolent. Chronic abdominal pain, anorexia, or weight loss are common initial complaints. Because most patients present with advanced disease, the prognosis is poor, with a reported 5-year survival rate of less than 5% in most large series. Adenocarcinomas account for 90% of gallbladder carcinomas and are characterised by glands lined by cuboidal or columnar cells, which may contain mucin. They may be well, moderately, or poorly differentiated, depending on the degree of gland formation. There are several histologic variants of adenocarcinoma recognized: papillary, intestinal, mucinous, signet-ring cell, and clear cell. Many tumours contain more than one histologic variant. Papillary carcinomas tend to fill the lumen of the gallbladder before invading the gallbladder wall; therefore, they are associated with a better prognosis than other variants.

Answer 436

✅ Correct answer: 110 mg without adrenaline ⸻ Explanation You were originally asked to prepare 500 mg of prilocaine with adrenaline for a regional block. When substituting with bupivacaine, you must adjust the dose because bupivacaine is much more potent and toxic than prilocaine. ⸻ Maximum safe doses of local anaesthetics Local Anaesthetic Max dose (without adrenaline) Max dose (with adrenaline) Lidocaine 3 mg/kg 7 mg/kg Prilocaine 6 mg/kg (max 400–600 mg) 8 mg/kg (max 600 mg) Bupivacaine 2 mg/kg (max 150 mg) 3 mg/kg (max 150 mg) ⸻ Step-by-step reasoning 1. The consultant requested 500 mg prilocaine with adrenaline — this is near the upper safe limit for an adult (≈ 70–80 kg). 2. Bupivacaine is far more potent, so an equivalent volume or mg-for-mg substitution would be dangerous. 3. The maximum dose of bupivacaine (for a 70 kg adult): • Without adrenaline: 2 mg/kg × 70 = 140 mg • With adrenaline: 3 mg/kg × 70 = 210 mg, but 150 mg is usually the upper clinical limit. 4. Because bupivacaine is not normally mixed with adrenaline for regional blocks (due to risk of ischaemia and prolonged action), the safe preparation is without adrenaline, and the maximum practical dose is about 110 mg for safety. ⸻ Clinical point • Bupivacaine has a long duration (up to 8 hours) but higher cardiotoxicity, especially if given intravascularly. • Prilocaine is shorter-acting and safer in larger doses. • Always calculate dose per kg, and use the lowest effective concentration. ⸻ Summary Agent Requested dose Substitute Safe equivalent Prilocaine (with adrenaline) 500 mg Bupivacaine ≈ 110 mg without adrenaline ⸻ ✅ Final Answer: 110 mg without adrenaline

Answer 437

The T wave represents ventricular repolarization. The common sense approach to remembering this, is to acknowledge that ventricular repolarisation is the last phase of cardiac contraction and should therefore correspond the last part of ECG.

Answer 438

Facial nerve arises from the second pharyngeal arch. The correct answer is Facial nerve. Here’s the reasoning: Each pharyngeal (branchial) arch during embryological development is associated with a specific cranial nerve, which supplies the muscles derived from that arch. • First arch – supplied by the Trigeminal nerve (mandibular division, CN V3) → gives rise to the muscles of mastication. • Second arch – supplied by the Facial nerve (CN VII) → gives rise to the muscles of facial expression, stapedius, stylohyoid, and posterior belly of the digastric muscle. • Third arch – supplied by the Glossopharyngeal nerve (CN IX) → forms the stylopharyngeus muscle. • Fourth and sixth arches – supplied by branches of the Vagus nerve (CN X) → supply muscles of the pharynx and larynx. The optic nerve (CN II) is purely sensory and not associated with any pharyngeal arch. Therefore, the nerve of the second pharyngeal arch is the Facial nerve (CN VII).

Answer 439

The great saphenous vein ascends anterior to the medial malleolus, passes posterior to the medial condyle of the femur (about a hand's breadth posterior to the medial border of the patella), anastomoses freely with the small saphenous vein. traverses the saphenous opening in the fascia lata. empties into the femoral vein. The small saphenous vein originates from the lateral side of the dorsal venous arch, ascends up the posterior surface of the leg, and then penetrates deep fascia to join the popliteal vein posterior to the knee; proximal to the knee, the popliteal vein becomes the femoral vein.

Answer 440

This is a pretty classic presentation of infantile hypertrophic pyloric stenosis. This condition is caused by diffuse hypertrophy and hyperplasia of the smooth muscle of the antrum of the stomach and pylorus, leading to narrowing and obstruction of the pyloric canal. It usually occurs in infants aged 2-8 weeks. The typical symptoms are non-bilious vomiting that may be projectile. This usually happens a little bit after a feed. Subsequently, the baby will become irritable, hungry, and dehydrated. The hypertrophic pylorus may be palpated as an "olive" mass in the epigastric/RUQ region.

Answer 441

A, B& C The carpometacarpal (CMC) joints are stabilised by 3 sets of ligaments - the dorsal carpometacarpal ligaments, palmar carpometacarpal ligaments and interosseous ligaments. The CMC joints are innervated by the anterior interosseous nerve, posterior interosseous nerve (which are branches of the median and radial nerve respectively) & the deep and dorsal branches of ulnar nerve. Arterial supply is from the posterior carpal branches of the radial and ulnar arteries.

Answer 442

B-Originates from the medial aspect of the supraspinous fossa. The supraspinatus is a small triangular shaped muscle that originates from the medial aspect of the supraspinous fossa. It runs inferior to the acromion and eventually inserts onto the superior facet of the greater tubercle of the humerus after passing over the glenohumeral joint. It lies deep to the trapezius muscle.

Answer 443

Leukoplakia is a clinical term used to describe any white patch or plaque that cannot be rubbed off or characterised clinically or pathologically as another disease.It may be smooth or wrinkled, fissured and vary in white colouration depending on the thickness of the lesion.

Answer 444

E-All of the above If metformin is contra-indicated or not tolerated (as in this case because of her eGFR), consider initial drug treatment with a dipeptidyl peptidase-4 (DPP-4) inhibitor or pioglitazone or a sulfonylurea. Do not offer or continue pioglitazone if they have any of the following: • Heart failure or history of heart failure. • Hepatic impairment. • Diabetic ketoacidosis (DKA). • Current, or a history of, bladder cancer. • Uninvestigated macroscopic haematuria.

Answer 445

B-Foramen of luschka CSF leaves the 4th ventricle via the laterally placed foramen of Luschka and also via the midline foramen of Magendie. The CSF fills the space between the arachnoid mater and pia mater (covering surface of the brain). The total volume of CSF in the brain is approximately 150ml. Approximately 500 ml is produced by the ependymal cells in the choroid plexus (70%), or blood vessels (30%). It is reabsorbed via the arachnoid granulations which project into the venous sinuses. Circulation 1. Lateral ventricles (via foramen of Munro) 2. 3rd ventricle 3. Cerebral aqueduct (aqueduct of Sylvius) 4. 4th ventricle 5. Subarachnoid space (via foramina of Magendie and Luschka) 6. Reabsorbed into the venous system via arachnoid granulations into superior sagittal sinus Composition • Glucose: 50-80mg/dl • Protein: 15-40 mg/di • Red blood cells: Nil • White blood cells: 0-3 cells/ mm3

Answer 446

Smoking induces the production of certain cytochrome P450 enzymes, which are involved in the metabolism of various substances. This can affect the metabolism of drugs, often requiring smokers to need higher doses to achieve the same effect as non-smokers.

Answer 447

A-BP should be controlled to 140/90mmHg before taking her up for surgery Elective surgeries should be delayed or warrant discussion with the anaesthetist if a patient's BP is >180mmHg systolic and >110mmHg diastolic. The label of high BP should be given only after three independent measurements taken at least 1 hour apart (to exclude white coat hypertension). If the patient seems anxious or in pain, appropriate analgesics and rest in a quiet place should be offered before repeating measurements, as pain and anxiety can cause high BP recordings. Once a diagnosis of hypertension is made, it is necessary to establish the cause before proceeding with surgery. Reversible causes (pheochromocytoma, renal disease, coarctation of aorta) should be identified if present, and appropriately managed. These patients should also be given cardiac and renal function evaluation, to ensure that these organs are optimally functioning before surgery.

Answer 448

Hyponatraemia after a brain insult should prompt consideration of cerebral salt wasting and syndrome of inappropriate ADH (SIADH). Each involves inappropriate excretion of a concentrated urine due to failure of normal pituitary control. Cerebral salt wasting leads to volume depletion, requiring prompt replacement

Answer 449

In the posteromedial approach to Baker's cyst, the part of the neurovascular bundle that is most superficial and susceptible to damage is the saphenous vein. A Baker's cyst, also known as a popliteal cyst, is a fluid-filled swelling that develops in the popliteal space, which is the hollow at the back of the knee

Answer 450

B-Exploration of retroperitoneal rectum and bladder, closure of adjacent holes, interposition of omentum between the repaired holes, faecal diversion An isolated retroperitoneal rectal injury is treated with faecal diversion by a colostomy. Penetrating bladder injuries need to be explored with bladder exploration and closure of the holes. When there is a penetrating bladder injury in close proximity to a penetrating rectal injury, the posterior bladder hole and the rectal hole must be closed and healthy tissue such as omentum placed between them. This is true even if the rectal injury is below the peritoneal reflection. Failure to do so has a high rate of colovesical fistula formation. For an isolated retroperitoneal rectal injury, a diverting loop colostomy would be sufficient.

Answer 451

D-The prognosis is worse in chronic alcoholics Acute lung injury (ALI) is characterized by the abrupt onset of hypoxemia and bilateral pulmonary edema in the absence of cardiac failure (non-cardiogenic pulmonary edema). Acute respiratory distress syndrome (ARDS) is a manifestation of severe ALI. Endothelial activation is an important early event. In some instances, endothelial activation is secondary to pneumocyte injury, which is sensed by resident alveolar macrophages. In response, these immune sentinels secrete mediators such as tumor necrosis factor (TNF) that act on the neighboring endothelium. Neutrophils adhere to the activated endothelium and migrate into the interstitium and the alveoli, where they degranulate and release inflammatory mediators including proteases, reactive oxygen species, and cytokines. Endothelial activation and injury make pulmonary capillaries leaky, allowing interstitial and intra-alveolar edema fluid to form. Damage and necrosis of type Il alveolar pneumocytes lead to surfactant abnormalities, further compromising alveolar gas exchange. Ultimately the inspissated protein-rich edema fluid and debris from dead alveolar epithelial cells organize into hyaline membranes, a characteristic feature of ALI/ARDS. Resolution of injury is impeded in ALI/ARDS due to epithelial necrosis and inflammatory damage that impairs the ability of remaining cells to assist with edema resorption. Eventually, however, if the inflammatory stimulus lessens, macrophages remove intra-alveolar debris and release fibrogenic cytokines such as transforming growth factor B (TGF-B) and platelet-derived growth factor. These factors stimulate fibroblast growth and collagen deposition, leading to fibrosis of alveolar walls. Profound dyspnea and tachypnea herald ALI/ARDS, followed by increasing respiratory failure, hypoxemia, cyanosis, and the appearance of diffuse bilateral infiltrates on radio- graphic examination. Hypoxemia may be refractory to oxygen therapy due to Ventilation-perfusion mismatch, and respiratory acidosis can develop.

Answer 452

B-It should be managed with an airtight occlusive tape over all four sides Open pneumothorax ('sucking chest wound') This is due to a large open defect in the chest (>3cm), leading to immediate equilibration between intrathoracic and atmospheric pressure. If the opening in the chest wall exceeds about two thirds of the diameter of the trachea, then with each inspiratory cycle, air will be preferentially drawn through the defect, rather than through the trachea. Air accumulates in the hemithorax (rather than in the lung) with each inspiration, leading to profound hypoventilation on the affected side and hypoxia. If there is a valvular effect, increasing amounts of air in the pleura will result in a tension pneumothorax . Initial management consists of promptly closing the defect with a sterile occlusive plastic dressing (e.g. Opsite®), taped on three sides to act as a flutter type valve. A chest tube is inserted as soon as possible in a site remote from the injury site.

Answer 453

D-A& B The first metacarpal bone is the shortest and most mobile metacarpal. It proximally articulates with the trapezium & distally with the first proximal phalanx.

Answer 454

The lymphatics of the ovary drain to para-aortic nodes alongside the origin of the ovarian artery (L2), just above the level of the umbilicus. Clinical observation shows that it is also possible for lymph to reach inguinal nodes via the round ligament and the inguinal canal, and to reach the opposite ovary by passing across the fundus of the uterus.

Answer 455

Atrial septal defect results in a left-to-right shunt and volume overload of the chambers receiving excess blood flow, eventually causing right ventricular failure. As the blood in the left atrium is already oxygenated, mixing with venous blood within the right side of the heart merely decreases cardiac efficiency. In contrast, right-to-left shunts are more dangerous as they allow poorly oxygenated blood into the peripheral vascular system, causing cyanosis. Right ventricular tract outflow obstruction results in reduced pulmonary blood flow and cyanosis. However, these patients are not typically breathless, and their chest radiographs demonstrate oligaemic lung fields. Tetralogy of Fallot is characterised by four heart malformations which include pulmonary stenosis, overriding aorta, ventricular septal defect and right ventricular hypertrophy. Cyanosis in this pathology is also due to a right-to-left shunt. In infants with transposition of the great arteries, the pulmonary and systemic circuits occur in parallel rather than in series, resulting in the mixing of oxygenated and deoxygenated blood. Total anomalous pulmonary venous drainage is a rare cyanotic congenital defect in which all four pulmonary veins are malpositioned and make anomalous connections with the systemic venous circulation. Due to the lack of systemic blood flow resulting from this condition, these patients may survive only in the presence of a patent foramen ovale or atrial septal defect.

Answer 456

C-20% of bile is recycled by the terminal ileum Approximately 5 L of bile is produced by the liver every day. It consists of 97% water, 1.8% bicarbonate, 0.7% bile salts, 0.2% glucuronidated bilirubin, 0.3% cholesterol, fatty acids, and lecithin. The gallbladder concentrates this 5 L into 500 mL per day by gradually extracting the water into its mucosal lining. In the absence of a gallbladder to concentrate bile, large volumes of it will flow into the duodenum and may cause biliary reflux. Similarly, a bile leak as previously described may result in litres of bile being leaked daily. Production of bile salts is stimulated by secretin, cholecystokinin, and vagal innervation. It is suppressed by fasting and sympathetic alpha agonists. Ninety per cent of the bile is recycled in the terminal ileum.

Answer 457

Infants and small children have a wide abdomen, a broad costal margin and a shallow pelvis. They also have a low lying umbilicus. This unique anatomy means that transverse supraumbilical incisions often give better access

Answer 458

This is a case of EDH after trauma. Since the EDH is large and is causing compression of the 3rd nerve - dilated pupil, reduced consciousness level. This required urgent surgical correction, as the raised ICP may cause herniation of the brain. The management is either burr hole decompression or a parieto-occipital craniotomy (depending on the availability of resources in the centre). Craniotomy is superior to burr-hole in decompression and also may allow for evacuation of the collection.

Answer 459

The presence of both choking and vomiting is a sign of upper Gl pathology. Concomitant presence of polyhydramnios is suggestive of esophageal atresia. Malrotation usually presents with lower Gl obstruction. Pyloric stenosis presents with vomiting but not choking and is not preceded by history of polyhydramnios. Hirschsprung disease is characterised by delayed passage of meconium and progressive bowel dilatation and abdominal distension. Meconium ileus presents with vomiting and progressive abdominal distension. There is no preceding polyhydramnios.

Answer 460

A-Extradural hematoma An epidural hematoma (EDH) is an extra-axial collection of blood within the potential space between the outer layer of the dura mater and the inner table of the skull. It is confined by the lateral sutures (especially the coronal sutures) where the dura inserts. The classic presentation is a biconvex or lens-shaped mass on brain CT scan, due to the limited ability of blood to expand within the fixed attachment of the dura to the cranial sutures. EDHs do not cross suture lines.

Answer 461

D-Pronator quadratus The muscles attached to the posterior surface of the ulnar shaft are the anconeus, supinator, abductor pollicis longus, extensor pollicis longus & extensor indicis. The pronator quadratus travels over the distal anterior surface of the ulnar shaft to the distal quarter of the radius.

Answer 462

The gubernaculum is a band of mesenchyme which extends from the lower pole of the testis to the scrotum. The gubernaculum helps to dilate the inguinal bursa. It provides a continuous pathway for the descending testis. Embryonic structure Male derivative Female derivative Gubernaculum Gubernaculum testis Round ligament of ovary and uterus Urogenital sinus Urinary bladder Urethra Bubouretral glands Urinary bladder Urethra Mesonephric tubules Datadidymtia Parophoron Mesonephric duct Appendix of epididymis Epididymis Ductus deferens Ejaculatory ducts Seminal vesicle Paramesonephric duct Arostadieutictslis Paratubal cyst Uterine tube Upper part of vagina

Answer 463

MRI has become increasingly important in imaging of the small bowel, for example in Crohn's disease, where repeated imaging with ionising radiation can incur a significant radiation dose over time. Ref: Bailey & Love's Short Practice of Surgery, 27th Edition, Chapter 14

Answer 464

Clostridial organisms are gram-positive, obligate anaerobes, which produce resistant spores. Clostridium difficile is the cause of pseudomembranous colitis, where destruction of the normal colonic bacterial flora by antibiotic therapy allows an overgrowth of the normal gut commensal C. diff to pathological levels. Any antibiotic may cause this phenomenon, although the quinolones such as ciprofloxacin seem to be the highest risk. The fibrinous exudate is typical and differentiates the colitis from other inflammatory diseases.

Answer 465

E-None of the above Environmental factors are important in the pathogenesis of urothelial carcinoma and include cigarette smoking, various occupational carcinogens, and prior cyclophosphamide or radiation therapy. A family history of bladder cancer is a known risk factor. Squamous cell carcinoma is related to Schistosoma haematobium infections in areas where it is endemic. Acquired genetic aberrations have been identified in urothelial carcinoma.A model for bladder carcinogenesis has been proposed in which the tumour is initiated by deletions of tumour-suppressor genes on 9p and 9q, leading to the formation of superficial papillary tumours, which may then acquire TP53 mutations and progress to invasive disease. A second pathway, possibly initiated by TP53 mutations, leads first to carcinoma in situ and then, with loss of genes from chromosome 9, progresses to invasion. Additional genetic alterations in superficial tumours include mutations in telomerase, as well as mutations in fibroblast growth factor receptor 3 (FGFR3) and components of the RAS and P|3K/AKT pathways. Muscle invasive tumours often have mutations involving both TP53 and RB

Answer 466

Similar to neutrophils, once thought to be a single cell type, the macrophage demonstrates plasticity and phenotypic variance depending upon its environment. M1 macrophages express proinflammatory cytokines and proteolytic substances; they are predominant in viral and bacterial infection. M1 macrophages stimulate proinflammatory helper T cells. While M1 macrophage products facilitate a beneficial inflammatory response against invading microbes, they can result in a dangerous inflammatory state for the human host. High concentrations of M1-type cytokines correlate with mortality in sepsis models. M2 macrophages are essential for tissue remodeling and wound healing; they express a variety of antiinflammatory markers, including IL-10.

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