1
Q
Diagnosis: rash, arthritis and acute glomerulonephritis?
A
IgA vasculitis (also known as Henoch–Schönlein purpura)
2
Q
What does sudden-onset neurological symptoms with rapid worsening and drowsiness suggest?
A
A vascular cause with an expanding space-occupying lesion causing rising intracranial pressure and risk of herniation
3
Q
Why is cerebellar haemorrhage considered a neurological emergency?
A
Because its location in the posterior fossa can lead to rapid deterioration due to raised intracranial pressure and potential brainstem compression
4
Q
What features differentiate cerebellar haemorrhage from subdural haemorrhage?
A
Sudden onset with vomiting, gait unsteadiness, and rapidly worsening drowsiness are more typical of cerebellar haemorrhage; subdural haemorrhage usually has a slower progression unless acute
5
Q
What is the most likely diagnosis in a 79-year-old woman with pallor, 2-cm splenomegaly, small axillary lymph nodes, Hb 107 g/L, WCC 34.5 × 10^9/L, and platelets 183 × 10^9/L?
A
Chronic lymphocytic leukaemia (CLL)
6
Q
What clinical and lab features make chronic lymphocytic leukaemia more likely than acute myeloid leukaemia, chronic myeloid leukaemia, myelodysplasia, or myelofibrosis?
A
CLL is suggested by splenomegaly, anaemia, lymphadenopathy, and high white cell count; AML usually presents acutely with thrombocytopenia, CML with very high platelets, myelodysplasia usually has low WCC, myelofibrosis often has abnormal blood counts including low WCC or platelets
7
Q
Why would a white cell differential be requested in suspected chronic lymphocytic leukaemia?
A
To help confirm lymphocytosis and the characteristic morphology of lymphocytes, aiding diagnosis and differentiating from other myeloproliferative disorders
8
Q
What glomerular abnormality is most likely at renal biopsy in a 17-year-old boy with non-blanching rash, swollen knee, visible haematuria, proteinuria, and raised creatinine?
A
Mesangial deposition of IgA (IgA vasculitis/Henoch–Schönlein purpura)
9
Q
Which glomerular abnormalities are associated with other diseases and help differentiate them from IgA vasculitis?
A
Foot process effacement: nephrotic syndrome; Linear IgG deposition: anti-GBM disease; Thickened basement membranes: Alport syndrome; Focal segmental sclerosis: FSGS
10
Q
In a 37-year-old woman with intermittent lightheadedness, normal examination, and a 24-hour ECG showing atrial and ventricular premature beats, nocturnal bradycardia, Mobitz type I AV block, and supraventricular tachycardia, which finding is clinically most important?
A
Supraventricular tachycardia
11
Q
Why can stool cultures be negative in giardiasis despite infection?
A
Because Giardia cysts are shed intermittently, making standard stool cultures and microscopy sometimes falsely negative
12
Q
What is the characteristic pattern of hair loss in alopecia areata?
A
Discrete, non-scaly patches of hair loss without scarring
13
Q
How can alopecia areata be differentiated from trichotillomania, lupus, hypothyroidism, and seborrhoeic dermatitis?
A
Trichotillomania: short hairs of same length; Lupus: scarring and inflammation; Hypothyroidism: diffuse thinning with brittle hair; Seborrhoeic dermatitis: diffuse scaling rather than discrete patches
14
Q
What is a common cardiac cause of recurrent, short-lasting episodes of collapse in a patient with previous myocardial infarction?
A
Ventricular tachycardia
15
Q
What ECG findings suggest a left ventricular aneurysm post-myocardial infarction?
A
Persistent ST-segment elevation with Q waves in the affected territory
16
Q
What is the characteristic feature of an Adie’s (tonic) pupil?
A
A dilated pupil that reacts very slowly to light but constricts slowly on accommodation + Reduced or absent deep tendon reflexes
17
Q
How can Adie’s pupil be differentiated from afferent pupillary defect, Argyll Robertson pupil, Horner’s syndrome, and third cranial nerve palsy?
A
Afferent defect: paradoxical dilatation with swinging torch test; Argyll Robertson: accommodates but does not react, usually bilateral; Horner’s: small pupil with ptosis; Third nerve palsy: ptosis with pupillary involvement and often eye movement abnormalities
18
Q
What is the role of urinary citrate in preventing kidney stones?
A
Citrate binds calcium to form soluble complexes and inhibits crystal growth and aggregation, reducing calcium stone formation
19
Q
What therapy is most useful to reduce recurrent calcium stone formation in patients with low urinary citrate?
A
Potassium citrate supplementation
20
Q
Why are thiazides, allopurinol, penicillamine, and low-calcium diets not first-line in patients with low urinary citrate and normal serum calcium?
A
Thiazides are indicated for hypercalciuria; allopurinol is for uric acid stones; penicillamine is for cystine stones; low-calcium diets can increase oxalate absorption and worsen stones
21
Q
What is the most common inherited bleeding disorder that can present with excessive bleeding after dental procedures or minor surgery?
A
Von Willebrand disease (vWD)
22
Q
How can von Willebrand disease be differentiated from factor V Leiden, factor IX deficiency, factor XII deficiency, and antiphospholipid syndrome?
A
Factor V Leiden and antiphospholipid syndrome: increased thrombosis risk, not bleeding; Factor IX deficiency: X-linked, mainly males; Factor XII deficiency: prolonged aPTT without bleeding tendency
23
Q
Most likely complication of cocaine use causing agitation, chest pain, hypertension?
A
Hyperthermia
Sympathomimetic effects can elevate body temperature and cause rhabdomyolysis.
24
Q
What is the normal function of α1-antitrypsin?
A
It inhibits neutrophil elastase, protecting alveolar tissue from proteolytic damage.
25
Which α1-antitrypsin genotype is associated with severe deficiency and early-onset emphysema?
ZZ phenotype
26
Which α1-antitrypsin phenotypes are associated with intermediate deficiency but not as severe as ZZ?
MZ and SZ
27
What is the most likely benefit of erythropoietin therapy in CKD patients with anaemia?
Improved exercise tolerance due to correction of anaemia. It also reduces left ventricular hypertrophy by correcting anaemia.
28
What rare but serious complication has been associated with erythropoietin therapy?
Red cell aplasia, although now rare with newer preparations. NOTE: It may worsen blood pressure control.
29
What secondary endocrine cause of hypercholesterolaemia should always be excluded before starting lipid-lowering therapy?
Hypothyroidism - treat with levothyroxine replacement therapy
30
Why should statins not be started before correcting hypothyroidism?
Because hypothyroidism can itself elevate cholesterol and untreated hypothyroidism increases the risk of statin-induced myopathy.
31
What is the most common type of thyroid carcinoma?
Papillary carcinoma
32
Which thyroid carcinoma is more likely to spread haematogenously (e.g. to bone, lung)?
Follicular carcinoma
33
Which aggressive thyroid carcinoma typically affects the elderly and has a poor prognosis?
Anaplastic carcinoma
34
What is the main cause of pain in Paget’s disease of bone?
Disorganized bone remodeling leading to structurally weak bone
35
What condition presents with proximal girdle pain and raised ESR, but normal bone biochemistry?
Polymyalgia rheumatica
36
What commonly precipitates an acute gout flare early in treatment?
Initiation of urate-lowering therapy (e.g., allopurinol/febuxostat) mobilizes urate deposits and can trigger an acute flare.
37
Should allopurinol be stopped during an acute gout flare?
No—continue urate-lowering therapy and treat the flare with anti-inflammatories (e.g., NSAID, colchicine, or corticosteroid).
38
How does alcohol increase gout risk and flares?
Alcohol (especially beer/spirits) raises purine load and reduces renal urate excretion, increasing serum urate and flare risk.
39
How can calcium pyrophosphate deposition disease (pseudogout) be distinguished from gout flares triggered by ULT?
Typically affects older patients, often monoarticular knees/wrists, rhomboid weakly positively birefringent crystals, chondrocalcinosis on imaging; not precipitated by starting urate-lowering therapy.
40
Which chromosomes are involved in the classic translocation of Burkitt lymphoma?
Chromosome 8 (c-Myc) and chromosome 14 (Ig heavy chain).
41
What is the function of c-Myc in normal physiology?
A transcription factor regulating cell cycle progression, proliferation, and apoptosis.
42
Which genetic abnormality is associated with chronic myeloid leukaemia (CML)?
BCR-ABL fusion gene from t(9;22) (Philadelphia chromosome).
43
Which genetic abnormality is associated with B-cell follicular non-Hodgkin lymphoma?
Overexpression of BCL-2 due to t(14;18).
44
In a patient planned for splenectomy due to ITP, when is the optimum time for pneumococcal vaccination?
1 month (ideally 4–6 weeks) before surgery.
45
Why should pneumococcal vaccination be given before splenectomy?
To allow time for adequate antibody response and reduce risk of overwhelming post-splenectomy infection (OPSI) aka. overwhelming post-splenectomy infection – a life-threatening sepsis, often due to encapsulated organisms like pneumococcus, meningococcus, and Haemophilus influenzae.
46
If pneumococcal vaccination cannot be given before splenectomy, what should be done?
Splenectomy should not be delayed; vaccination should be given as soon as possible afterwards.
47
What are the common MODY genes and a key management point?
Common genes: GCK (MODY2), HNF1A (MODY3), HNF4A (MODY1). GCK causes mild stable hyperglycaemia often not needing treatment; HNF1A/HNF4A are usually very sensitive to low-dose sulfonylureas.
48
Which MODY subtype is associated with mild, stable fasting hyperglycaemia often not requiring treatment?
MODY2 (glucokinase mutation).
49
Which MODY subtypes are usually very sensitive to sulfonylureas?
HNF1A (MODY3) and HNF4A (MODY1).
50
What are the typical clinical features of Hodgkin lymphoma in adolescents?
Single or few painless lymph nodes, often cervical, with possible mediastinal involvement; systemic 'B' symptoms may be absent.
51
Which symptoms are more typical of depression rather than dementia?
Loss of libido, agitation, and subjective complaints of poor memory without objective deficits.
52
In massive haemoptysis requiring embolisation, which artery is usually targeted?
Bronchial artery. In ~90% of severe cases, the source of bleeding originates from the bronchial arteries rather than pulmonary arteries. Approximately 5% of cases originate from the pulmonary arteries.
53
What is the most likely cause of acute kidney injury with leukocyturia (sterile pyuria) and modest proteinuria in a patient taking NSAIDs?
Tubulointerstitial nephritis. Other implicated drugs: antibiotics (e.g., penicillins, cephalosporins), proton pump inhibitors.
54
How does acute tubular necrosis typically present on urinalysis?
Bland urinalysis with muddy brown casts and minimal proteinuria.
55
What is the typical urinalysis finding in tubulointerstitial nephritis (TIN)?
Leukocyturia and mild proteinuria
56
What is the gold standard initial test for suspected insulinoma?
Prolonged (72-h) fast - done to confirm hypoglycemia before imaging, ensuring true insulinoma-related low glucose
57
Why is flecainide preferred for restoring sinus rhythm in young AF patients?
Negatively inotropic but effective in accessory pathways
58
Most likely clinical feature in lichen planus with pruritic violaceous papules and linear lesions?
Involvement of buccal mucosa
59
Diagnosis: haemoptysis, positive IgE/IgG for Aspergillus, lung lesion with crescent radiolucency?
Aspergilloma - Aspergillus thrives in poorly drained and avascular cavitary spaces within the lung. Once harbored within a cavitary airspace, it adheres to the wall with its conidia, then germinates and, in the process, evokes an inflammatory reaction. The organism, along with the inflammatory debris, forms an amorphous mass identified as an aspergilloma, and a solid lesion with an adjacent crescentic shaped radiolucency on chest X-ray strongly suggest an aspergilloma within an existing lung cavity. Angio-invasive aspergillosis will not present with a solid mass and only occurs in someone who is immunosuppressed. Patients with allergic bronchopulmonary aspergillosis have proximal bronchiectasis and present with productive cough and wheeze and not likely haemoptysis.
60
What is the most likely diagnosis in a patient with elbow pain and tingling in the medial aspect of the hand?
Ulnar nerve entrapment.
61
Where is the ulnar nerve most commonly entrapped?
At the elbow, near the medial epicondyle.
62
What occupational factor in this case likely contributed to ulnar nerve entrapment?
Repetitive heavy use of the elbow, such as using a sledgehammer.
63
Which part of the hand is affected in ulnar nerve entrapment?
The medial aspect of the hand, including the little finger and ulnar half of the ring finger.
64
What is the most likely cause of a chronic ulcer over the medial malleolus in a patient with prior DVT?
Venous ulceration due to post-thrombotic damage to venous valves.
65
Why is ankle–brachial pressure index measured before compression therapy?
To ensure adequate arterial supply, since compression is contraindicated in significant arterial insufficiency.
66
Where are venous ulcers classically located?
Over the medial malleolus.
67
What is the mainstay of treatment for venous ulcers once arterial supply is confirmed adequate?
Compression bandaging to aid venous return via the calf muscle pump.
68
What systemic manifestation of SLE is suggested by the right-sided pleural effusion?
Serositis, which is a common feature of SLE.
69
What autoantibody test is strongly positive, supporting the diagnosis of SLE?
Antinuclear antibodies at a 1:600 dilution.
70
What pulmonary function abnormality is most characteristic of idiopathic pulmonary fibrosis?
A reduced transfer factor for carbon monoxide (DLCO), typically around 50% of predicted value.
71
What type of lung disease pattern is seen in idiopathic pulmonary fibrosis?
A restrictive pattern with reduced lung volumes and impaired gas transfer.
72
What liver function test pattern is typical of primary sclerosing cholangitis?
A cholestatic pattern with markedly raised alkaline phosphatase and gamma-glutamyl transferase. Associated with ulcerative colitis - up to 10% of patients with UC develop PSC
73
What type of liver disease shows hepatocellular enzyme elevation (ALT/AST) rather than cholestatic enzymes?
Autoimmune hepatitis.
74
What is the mode of inheritance of hereditary haemorrhagic telangiectasia (also known as Osler–Weber–Rendu syndrome)?
Autosomal dominant.
75
What clinical feature most strongly favours L5 radiculopathy over peroneal nerve palsy?
Weakness of ankle inversion.
76
Which muscle is responsible for ankle inversion and which nerve supplies it?
Tibialis posterior, supplied by the tibial nerve (L4/L5).
77
Which muscle is typically affected in both L5 radiculopathy and peroneal nerve palsy, leading to foot drop?
Extensor hallucis longus.
78
Where is Tinel’s sign elicited in suspected peroneal nerve palsy?
Lateral to the knee, near the fibular neck.
79
What is the most likely initial haemodynamic response to the Valsalva manoeuvre?
Increased intrathoracic pressure reduces venous return to the heart, causing decreased cardiac output and an initial rise in JVP.
80
What is the preferred antihypertensive in a patient taking lithium for bipolar disorder, and why?
Amlodipine, because ACE inhibitors, ARBs, and thiazide diuretics reduce renal lithium clearance and increase the risk of lithium toxicity.
81
In a trial where 150/1000 placebo patients and 100/1000 statin patients had cardiovascular events, what is the number needed to treat (NNT) to prevent one event?
20, because the absolute risk reduction is 5% (15% – 10%), so NNT = 1 / 0.05 = 20.
82
What is the most appropriate initial IV treatment for arrhythmias and hypotension in tricyclic antidepressant overdose?
Sodium bicarbonate, which corrects acidosis and reduces TCA binding to the myocardium.
83
What toxidrome is characterised by reduced consciousness, respiratory depression, and pinpoint pupils?
The opioid toxidrome, typically caused by opioids such as dihydrocodeine.
84
Which immunoglobulin mediates hyperacute rejection in organ transplantation?
IgG, due to pre-existing humoral immunity against donor antigens.
85
What condition presents postpartum with severe headache, seizures, focal neurological signs, and raised intracranial pressure?
Cerebral venous sinus thrombosis.
86
Why is postpartum cerebral venous sinus thrombosis more likely than eclampsia in a woman with headache, seizures, drowsiness, and focal neurology?
Eclampsia usually occurs during pregnancy or within 48 hours postpartum and presents with hypertension, proteinuria, and seizures; focal neurological deficits and signs of raised intracranial pressure point instead to venous sinus thrombosis.
87
What dominant cellular process explains the effectiveness of chemotherapy in curing testicular cancer?
Apoptosis, or programmed cell death.
88
What neurological condition presents with the triad of ataxia, ophthalmoplegia, and areflexia?
Miller Fisher syndrome, a variant of Guillain–Barré syndrome often associated with anti-GQ1b antibodies.
89
In congestive heart failure with persistent oedema despite high-dose diuretics, what hormone level is most likely elevated?
Plasma aldosterone concentration – due to activation of the renin–angiotensin–aldosterone system from reduced renal perfusion.
90
What is the most appropriate confirmatory investigation for acromegaly?
Failure of growth hormone suppression on an oral glucose tolerance (growth hormone suppression) test confirms the diagnosis.
91
What is the most likely pulmonary complication of CREST syndrome presenting with progressive breathlessness, basal crackles, and lower-zone shadowing on chest X-ray?
Interstitial lung disease, most commonly non-specific interstitial pneumonitis (NSIP).
92
What is the mechanism of hypokalaemia caused by thiazide diuretics such as bendroflumethiazide?
Increased potassium loss in the distal tubule due to enhanced sodium delivery, which stimulates aldosterone-sensitive sodium reabsorption in exchange for potassium (and hydrogen).
93
What is the recommended post-exposure prophylaxis (PEP) for HIV after a high-risk needlestick injury?
Three-drug antiretroviral therapy for 1 month (28 days).
94
What is the recommended post-exposure prophylaxis for an immunocompromised, varicella-seronegative patient exposed to chickenpox?
Varicella zoster immunoglobulin (passive immunisation to reduce the risk of infection).
95
What is the most likely cause of acute hepatitis in an HIV-positive man with jaundice and markedly raised AST/ALT after recent unprotected anal sex, and who is hepatitis B immune?
Acute hepatitis C infection.
96
What is the most likely acid–base disturbance in a patient with pH 7.24, bicarbonate 12 mmol/L, and PCO2 3.9 kPa?
Metabolic acidosis, indicated by low pH and markedly reduced bicarbonate, with respiratory compensation (low PCO2).
97
What cognitive deficit is commonly associated with a dominant (usually left) parietal lobe lesion causing difficulty in reading?
Acalculia, which is part of Gerstmann syndrome along with finger agnosia, agraphia, and left–right disorientation.
98
What is the most likely causative organism in a patient with fever, headache, photophobia, neck stiffness, and CSF showing mildly elevated protein, normal glucose, and lymphocyte-predominant pleocytosis with some neutrophils?
Enterovirus, the most common cause of viral meningitis.
99
What is the most appropriate initial management for acute theophylline overdose within 1 hour of ingestion?
Activated charcoal, to adsorb theophylline and reduce absorption.
100
What explains a normal pulse oximetry reading (98%) with a low oxygen saturation by multi-wavelength spectrophotometry (55%) in an unconscious patient?
Carbon monoxide poisoning, because CO forms carboxyhaemoglobin that falsely elevates two-wavelength pulse oximetry readings while true oxygen saturation is low.
101
What is the most useful investigation to determine if a large goitre is causing breathlessness?
Respiratory flow–volume loop, which can show reduced peak inspiratory and expiratory flows indicative of upper airway obstruction.
102
What is the most useful investigation to assess suitability for surgical resection in a patient with suspected localized non-small cell lung carcinoma and possible metastatic symptoms?
PET-CT scan, as it accurately stages both mediastinal lymph nodes and distant metastases.
103
What is the most common physical finding in constrictive pericarditis?
Hepatomegaly, which is the earliest and most consistent physical sign - it is a sign of chronic right-sided heart failure.
104
What is the most likely cause of acute myocardial infarction in a young postpartum woman with no conventional cardiovascular risk factors?
Coronary artery dissection, a well-recognised cause of postpartum myocardial infarction.
105
What is the most useful investigation to confirm primary biliary cholangitis in a patient with cholestatic liver function tests?
Antimitochondrial antibodies, present in over 90% of patients with PBC.
106
A patient has neck and arm pain with numbness in the index and middle fingers, reduced forearm pronation and wrist flexion, and diminished triceps reflex. What is the most likely site of the lesion?
C7 nerve root, affecting the C7 dermatome and myotome.
107
In a patient with urge incontinence and low post-void residual, antagonism of which neurotransmitter is most likely to improve symptoms?
Acetylcholine – blocking muscarinic receptors reduces detrusor overactivity.
108
In lipodermatosclerosis associated with chronic venous insufficiency, which tissue layer is primarily involved in the pathophysiology?
Hypodermis – chronic inflammation and fibrosis replace the subcutaneous fat, sometimes extending into the papillary dermis.
109
After successful DC cardioversion in a patient with atrial fibrillation and prior transient ischaemic attack, how long should anticoagulation with warfarin be continued?
Lifelong, due to ongoing high risk of thromboembolism even after restoration of sinus rhythm.
110
Which factor most contributes to a high Waterlow score for pressure ulcer risk in elderly patients?
Continence – incontinence increases skin breakdown risk and raises the Waterlow score.
111
What is the most useful urine test to assess future cardiovascular risk in a patient with diabetes and hypertension?
Urine albumin:creatinine ratio, as albuminuria is an independent predictor of cardiovascular risk and is more sensitive than total protein measurement.
112
What is the most appropriate initial treatment for erythrodermic psoriasis with widespread erythema and scaling?
Topical white soft paraffin to soothe the skin, restore the barrier, reduce inflammation, and prevent dehydration and infection.
113
A patient presents with sudden-onset dyspnoea, tachypnoea, normal chest X-ray, mild hyperoxaemia, and respiratory alkalosis. What is the most likely diagnosis?
Hyperventilation – indicated by respiratory alkalosis (low PCO2, high pH) with normal imaging and oxygenation.
114
Match the following proteins with their associated cardiovascular disorders: Desmin, Elastin, Fibrillin, Myosin.
Desmin → desminopathy causing cardiomyopathy and arrhythmias; Elastin → supravalvular aortic stenosis in Williams syndrome; Fibrillin → aortic dissection in Marfan syndrome; Myosin (MyBPC) → hypertrophic cardiomyopathy.
115
What is the most appropriate treatment for onychomycosis unresponsive to 6 months of topical therapy in an adult with type 1 diabetes and nail culture positive for Trichophyton rubrum?
Oral terbinafine; indicated when topical treatment fails or disease is extensive.
116
Which condition is most strongly associated with Helicobacter pylori infection?
Duodenal ulcer; over 90% of patients with duodenal ulcers are H. pylori positive.
117
What is the most likely cause of bilateral leg pain on walking, relieved by sitting, in an elderly patient with normal foot pulses?
Spinal stenosis; neurogenic claudication presents with leg pain on walking relieved by sitting, and pulses are usually normal.
118
What additional test is most useful to support a diagnosis of syndrome of inappropriate antidiuretic hormone (SIADH) in a patient with hyponatraemia, high urine osmolality, and normal adrenal function?
Thyroid function tests; ruling out hypothyroidism is necessary before confirming SIADH.
119
Which receptor is primarily targeted to mediate the antipsychotic effects of risperidone?
Dopamine D2 receptor antagonism; risperidone’s main antipsychotic effect is via blockade of D2 receptors.
120
Which drug is most effective for maintaining sinus rhythm after successful DC cardioversion in atrial fibrillation?
Amiodarone; it is superior to sotalol and other antiarrhythmics in reducing recurrence of atrial fibrillation.
121
Which antiarrhythmic drugs are most effective at maintaining sinus rhythm after DC cardioversion for atrial fibrillation?
Class IA (disopyramide, quinidine), Class IC (flecainide, propafenone), and Class III (amiodarone, dofetilide, dronedarone, sotalol) all reduce recurrence. Amiodarone is the most effective, superior to propafenone and sotalol.
122
What is the most likely cause of morphine toxicity in a patient with renal cell carcinoma, liver metastases, and the following labs: urea 18 mmol/L, creatinine 200 µmol/L, albumin 28 g/L, ALT 300 U/L, ALP 1050 U/L?
Renal impairment. Morphine is metabolised to active glucuronide metabolites that are excreted renally. Impaired renal function leads to accumulation of morphine-6-glucuronide, a potent opioid agonist.
123
A 45-year-old man with a 2-year history of fatigue, weight loss, pruritus, and longstanding diarrhoea presents with mild jaundice. Labs: albumin 38 g/L, bilirubin 95 µmol/L, ALT 50 U/L, ALP 315 U/L. What is the most likely diagnosis?
Primary sclerosing cholangitis (PSC). Often associated with ulcerative colitis, PSC presents with cholestatic liver function derangement, pruritus, and fatigue. Male sex and chronic diarrhoea support PSC over primary biliary cholangitis.
124
A 68-year-old man is prescribed isosorbide mononitrate 30 mg twice daily for angina. What is the primary mechanism of action of this drug?
Isosorbide mononitrate acts as a nitric oxide donor, stimulating guanylate cyclase to increase cyclic guanosine monophosphate (cGMP) levels, which mediates vasodilation and reduces myocardial oxygen demand.
125
What is the site of origin of circulating B-type natriuretic peptide in chronic heart failure?
Cardiac ventricles – BNP is released by ventricular myocytes in response to increased wall stress and high filling pressures.
126
What is the most likely diagnosis in a patient with progressive upper and lower limb weakness, dysphagia, tongue fasciculations, and brisk jaw jerk?
Motor neurone disease – the combination of upper and lower motor neuron signs, progressive weakness, and bulbar involvement is characteristic of MND/ALS.
127
Which antimicrobials are known to cause QT interval prolongation?
Erythromycin, clarithromycin, moxifloxacin, fluconazole, and ketoconazole – all can prolong the QT interval and increase risk of torsades de pointes.
128
A 25-year-old man returns from Borneo with 5 days of foul-smelling diarrhoea, abdominal pain, bloating, and flatulence. Stool microscopy shows motile trophozoites and cysts. What is the most likely causative organism?
Giardia intestinalis (causing giardiasis), a protozoal infection associated with travel to endemic areas and small bowel malabsorption.
129
Which condition is characterized by a 2-month history of progressive proximal muscle weakness, shortness of breath, elevated ESR, and markedly raised creatine kinase in a 43-year-old woman?
Polymyositis – presents with proximal muscle weakness, possible interstitial lung disease, high CK, and elevated ESR; distinguished from CIDP, myasthenia gravis, PMR, and inclusion body myositis by age, clinical features, and laboratory findings.
130
Which condition is suggested by elevated serum IgG and a higher ALT than AST in a 55-year-old woman with mild alcohol intake and chronic paracetamol use?
Autoimmune hepatitis – indicated by raised IgG, ALT>AST, and absence of other causes such as alcohol, drugs, gallstones, or PBC; autoantibody testing can confirm the diagnosis.
131
How should a 58-year-old man with right lower lobe pneumonia, confusion, urea 7.5 mmol/L, and mild comorbidities be managed initially?
Admit to medical ward – his CURB-65 score is 2 (confusion + urea >7 mmol/L), indicating the need for hospital admission but not necessarily high-dependency care.
132
Which coronary artery is most likely involved in a posterior STEMI presenting with ST depression and tall R waves in V1–V3?
Circumflex – posterior myocardial infarctions produce reciprocal changes (ST depression, tall R waves) in V1–V3, and the circumflex artery supplies the posterior wall in left-dominant systems.
133
Which psychiatric disorder is most likely in a patient with a fixed belief of worms under the skin and self-inflicted lesions?
Delusional disorder – specifically delusional parasitosis, characterized by a fixed false belief of infestation, with secondary anxiety and self-harm; factitious disorder and somatic symptom disorder do not involve such fixed delusions.
134
Which investigation is most appropriate to assess sustained response to hepatitis C antiviral therapy?
HCV viral load – monitoring the viral RNA level confirms sustained virological response; antibody levels, liver biopsy, ALT, or CRP are not used to assess treatment response.
135
Which is the most appropriate treatment for a toxic thyroid nodule causing hyperthyroidism?
Radioiodine – definitive treatment for an autonomously functioning thyroid nodule; carbimazole or propylthiouracil may control symptoms temporarily, but do not cure the underlying overactive nodule. Prednisolone is not indicated, and total thyroidectomy is unnecessary given localized disease.
136
An 87-year-old woman with hypernatremia, hyperkalaemia, and acute kidney injury – what is her approximate serum osmolality?
390 mosmol/kg – calculated using the formula: (2 × Na) + (2 × K) + glucose + urea, all in mmol/L.
137
Which drug is most likely causing breathlessness and nasal blockage in a patient with a history of angina and blocked nose?
Aspirin – it can exacerbate asthma and is associated with nasal polyps, leading to both respiratory and nasal symptoms.
138
What is the most likely reason a 17-year-old girl with sickle cell trait and a previous blood transfusion was deferred from donating blood?
Previous blood transfusion – donors who have received a transfusion are deferred to reduce the risk of transmitting prion diseases such as variant Creutzfeldt–Jakob disease.
139
What is the most likely diagnosis for a 76-year-old man with a 3-year history of a gradually enlarging, well-demarcated, scaly red patch on his shin?
Bowen’s disease – a slowly enlarging, well-demarcated, scaly patch on sun-exposed skin in an older adult is typical of this intraepidermal squamous cell carcinoma in situ.
140
What is the most likely cause of hypophosphataemia in a 55-year-old woman with hypercalcaemia, polyuria, and elevated PTH?
Reduced renal reabsorption of phosphate – elevated parathyroid hormone decreases renal tubular phosphate reabsorption, leading to hypophosphataemia despite hypercalcaemia.
141
What is the most likely diagnosis in a 72-year-old man with right arm pain, numbness in the thumb, and reduced biceps reflex?
C6 radiculopathy – sensory loss in the thumb and diminished biceps reflex indicate nerve root compression at the C6 level.
142
Which finding in a woman with a ventricular septal defect indicates the highest risk for pregnancy?
Pulmonary hypertension – elevated pulmonary pressures significantly increase maternal and fetal risk during pregnancy, making it the most concerning finding.
143
What is the most appropriate test to assess whether a treatment reduced pain in patients measured before and after intervention on a 10-point scale?
Wilcoxon signed-rank test – this non-parametric test compares paired, related samples when normality cannot be assumed.
144
What is the most likely diagnosis in a 72-year-old man with an inferior altitudinal visual field defect, normal visual acuity, and mild superior optic disc swelling?
Retinal artery occlusion – the altitudinal field defect and disc swelling indicate an arterial vascular event rather than venous or inflammatory causes.
145
What is the most likely diagnosis in an 85-year-old woman with chronic breathlessness, nocturnal cough, and basal bronchiectasis on CT without honeycombing or ground-glass changes?
Chronic aspiration – recurrent micro-aspiration can cause basal fibrosis with dilated bronchi, distinguishing it from idiopathic pulmonary fibrosis or radiation pneumonitis.
146
What is the most likely cause of hypocalcaemia in a 56-year-old man with stage 4 chronic kidney disease, high phosphate, raised PTH, and elevated alkaline phosphatase?
Deficiency of 1,25-dihydroxycholecalciferol – advanced CKD impairs renal 1-alpha hydroxylation of vitamin D, reducing calcium absorption and causing secondary hyperparathyroidism.
147
What is the most likely cause of right iliac fossa pain with mesenteric adenitis and erythema nodosum in a 23-year-old man with mild diarrhoea?
Yersinia enterocolitica infection – it can mimic appendicitis, cause mesenteric lymphadenitis, and is associated with reactive skin manifestations such as erythema nodosum.
148
What is the most likely cause of pancytopenia with nucleated red cells and myelocytes on blood film in a 78-year-old man with haematuria?
Bone marrow metastases – the leukoerythroblastic blood film (nucleated red cells, myelocytes, metamyelocytes) suggests marrow infiltration, which can occur secondary to metastatic cancer.
149
What associated finding in a patient with squamous cell lung carcinoma is a contraindication to surgical resection?
Superior vena cava obstruction – indicates locally advanced, invasive disease, making surgery high-risk and generally inoperable. Other findings like finger clubbing, hypercalcaemia, hypertrophic pulmonary osteoarthropathy, or TLCO >50% do not preclude surgery.
150
Damage to which area of the brain is most likely to produce a rightward gaze palsy in a patient with left hemiparesis and left upper motor neuron facial weakness?
Right frontal lobe – frontal eye fields control voluntary conjugate gaze; a lesion here causes eyes to deviate toward the side of the lesion, producing a gaze palsy.
151
A 26-year-old woman with recurrent DVT and two first-trimester miscarriages has prolonged APTT and positive anticardiolipin antibodies. What is the most appropriate treatment?
Warfarin – she meets clinical and laboratory criteria for antiphospholipid syndrome (APLS). Long-term anticoagulation with warfarin is indicated for VTE prevention. Direct oral anticoagulants are less effective in APLS, and low-molecular-weight heparin is preferred only if planning pregnancy.
152
Which drug is most likely to cause hand tremor in a renal transplant patient?
Tacrolimus – tremor is a common, dose-related adverse effect, particularly in the early post-transplant period when immunosuppressant levels are higher.
153
Which drug is most likely to cause hand tremor in a renal transplant patient?
Tacrolimus – tremor is a common, dose-related adverse effect, particularly in the early post-transplant period when immunosuppressant levels are higher.
154
In a healthy subject, what is most likely to decrease pulmonary vascular resistance?
Epoprostenol (prostacyclin) – it causes pulmonary vasodilation, reducing pulmonary vascular resistance. Hypoxia, endothelin, and noradrenaline increase resistance, while hypocapnia has variable effects.
155
A 45-year-old woman presented with a 5-year history of pain in her right hand, spreading to the whole arm and the scapular and pectoral areas. On examination, there was wasting of the small muscles of her right hand, mild weakness of her right hand and wrist, absent biceps, supinator and triceps reflexes, and impaired pinprick and temperature sensation throughout her right arm. What is the most likely diagnosis?
Syringomyelia – the combination of lower motor neuron signs and spinothalamic sensory loss (pain and temperature) is characteristic. Cervical spondylosis usually affects multiple levels but without this sensory pattern, malignancy would have a shorter history, MS typically causes upper motor neuron signs, and subacute combined degeneration affects the posterior columns.
156
A 65-year-old man with atrial fibrillation was started on digoxin 250 µg daily, with his physician explaining that the full effect would take at least a week. On which pharmacokinetic variable is this explanation based?
Half-life – digoxin has an average half-life of ~36 hours; steady-state concentrations are achieved after about 5 half-lives, i.e., roughly 1 week, explaining the delayed full therapeutic effect.
157
A 45-year-old man with trisomy 21 had a karyotype of 47,XY,+21. What term best describes this karyotype?
Aneuploid – this describes the presence of an abnormal number of chromosomes (extra chromosome 21) without an abnormal number of complete chromosome sets.
158
A 60-year-old man treated with intravenous aciclovir developed a risk of renal injury. What is the mechanism?
Crystalluria – aciclovir can precipitate in renal tubules, especially if hydration is inadequate, leading to acute kidney injury.
159
A 70-year-old woman presents with sudden painless diplopia, left eye movement limitation in all directions, mild ptosis, a dilated poorly reactive left pupil, and loss of pinprick sensation on the right forehead. What is the most likely site of the lesion?
Left cavernous sinus – involvement of cranial nerves III, IV, V1, and VI localizes the lesion to the cavernous sinus.
160
A 17-year-old girl presents with erythema nodosum, and imaging shows a 12-cm complex anterior mediastinal mass encasing great vessels with mildly enlarged lymph nodes. Serum LDH is elevated, ACE is normal, and tumour markers are normal. What is the most likely diagnosis?
Hodgkin disease – anterior mediastinal mass in an adolescent with erythema nodosum, elevated LDH, and aggressive CT features suggests Hodgkin lymphoma; normal AFP and β-hCG make germ cell tumours unlikely.
161
A 16-year-old boy has a 9-month history of painless right-sided neck swelling with enlarged pre-auricular and jugulodigastric lymph nodes; chest X-ray is normal. What is the next most useful investigation?
Excision biopsy of cervical lymph node – longstanding, painless, progressive lymphadenopathy in an adolescent suggests Hodgkin lymphoma, and excision biopsy provides adequate tissue for definitive diagnosis; fine-needle aspiration is usually insufficient.
162
A 24-year-old woman with recurrent joint pains has antinuclear antibodies detected. Which isotype is most indicative of systemic lupus erythematosus?
IgG – IgG antinuclear antibodies are the isotype most commonly associated with systemic lupus erythematosus.
MRCP Part 1
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