Gastrointestinal

Question 1

What do the following cells of the stomach secrete, and where in the stomach are they located?

1. Mucous neck cells
2. Parietal Cells
3. Chief Cells

Answer 1

1. mucous; widespread distribution
2. intrinsic factor and HCl; fundus
3. digestive enzymes; fundus

Question 2

Name 3 chemical mediators which regulate gastric acid secretion, and how they do so

Answer 2

1. HISTAMINE - released in response to alkaline pH; acts on H2 receptors which increases expression of H+/K+ pump
2. AcH - raises intracellular Ca which acts to increase expression of H+/K+ pump
3. PROSTAGLANDINS - act to reduce the expression of the H+/K+ pump

Question 3

How does H. pylori result in the formation of peptic ulcers?

Answer 3

• bacteria secretes urase, which leads to gastritis

- inflammation disrupts the gastric mucosa - stomach acid can infiltrate thus leading to ulceration

Question 4

How does NSAID use lead to the development of peptic ulcers?

Answer 4

prevents the formation of prostaglandins, which reduce acid secretion and increase mucous and bicarbonate secretion

Question 5

1. What drug classes are used in H. pylori eradication therapy?
2. How long is the course of treatment?
3. As well as drugs, what additional advice is given?

Answer 5

1. antibiotics (2 to reduce resistance) and PPI (reduce stomach acidity to aid healing)
2. 7 days
3. avoid NSAIDs; avoid alcohol (interraction with metronidazole)

Question 6

As part of H. pylori eradication therapy, which antibiotics are used first line in:

1. patients without penicillin allergy
2. patients with penicillin allergy

Answer 6

1. amoxicillin and clarythromycin/metronidazole

2. clarythromycin and metronidazole

Question 7

1. Name 2 adverse effects of PPIs
2. Name 2 warnings associated with the use of PPIs
3. Which drug interracts with PPIs?

Answer 7

1. headache; GI disturbance
2. increased fracture risk
   can mask symptoms of gastro-oesophageal cancer
3. reduce effect of clopidogrel

Question 8

1. What is the MOA of ranitidine?

2. name 2 warnings associated with the use of ranitidine

Answer 8

1. histamine antagonist
2. excreted kidneys - requires dose reduction in those with renal impairment
   can disguise symptoms of gastro-oesophageal cancer

Question 9

1. What is the MOA of antacids?
2. What is the MOA of alginates?
3. Name 2 adverse effects of alginates and antacids
4. Name 6 interractions with antacids and alginates

Answer 9

1. buffers stomach acid
2. increases viscosity of stomach contents, forming a floating raft which prevents reflux
3. diarrhoea (Mg salts)
   constipation (Al salts)
4. ACEi
   cephalospotins, ciprofloxacin, tetracyclines
   bisphosphonates
   digoxin
   levothyroxine
   PPIs
   *should be separated by 2 hours between administering these drugs

Question 10

1. What is the MOA of bulk forming laxatives?

2. Name an example of bulk forming laxatives

Answer 10

1. increases the bulk of stools which aids peristalsis by stimulating stretch receptors
2. iphalghula husk

Question 11

1. What is the MOA of osmotic laxatives?
2. Name 2 examples of osmotic laxatives?
3. Which osmotic laxative is useful at treating constipation associated with hepatic encephalopathy
4. Name adverse effects of osmotic laxatives

Answer 11

1. hold water in the gut lumen thus maintains stool volume and aids peristalsis
2. lactulose; macrogol
3. lactulose
4. flatulance, abdo cramps and nausea; diarrhoea; electrolyte disturbance

Question 12

1. What is the MOA of irritant and stimulant laxatives?
2. Name 2 examples
3. name side effects of irritant/stimulant laxatives

Answer 12

1. increase water and electrolyte secretion from the colonic mucosa
2. senna; bisacodyl
3. abdominal cramps and pain, diarrhoea

Question 13

1. What is the MOA of faecal softeners?

2. Name 2 examples of faecal softeners

Answer 13

1. act by decreasing surface tension and increasing penetration of intestinal fluid into the faecal mass
2. co-danthrusate
   decussate sodium

Question 14

1. Name 3 opioids used in the treatment of diarrhoea
2. how do opioids treat diarrhoea?
3. Name 3 side effects associated with the use of opioids in the management of diarrhoea
4. name 4 warnings against the use of opiates for diarrhoea

Answer 14

1. codeine phosphate; loperamide; dipenoxylate
2. increases non-propulsive contractions of the gut to increase water absorption but reduces peristalstic contractions
3. constipation
   abdominal cramps
   flatulance
4. acute UC
   acute bloody diarrhoea
   C diff infection

Question 15

Which 4 drugs are used in the management of an acute UC flare?

Answer 15

1. mesalazine suppositories/enemas
2. increased oral mesalazine dose
3. oral prednisolone
4. IV hydrocortisone

Question 16

1. What is the MOA of aminosalycyclates?
2. Name 2 examples of aminosalycyclates
3. Name 4 adverse effects of Aminosalycylates

Answer 16

1. release 5-ASA which has anti-inflammatory and immunsuppressive effects, whilst acting topically on the gut
2. mesalazine, sulfasalazine
3. GI upset
   headache
   thrombocytopenia
   renal impairment

Question 17

What is the indication of corticosteroids for IBD?

Answer 17

indice remission

Question 18

1. Which immunosuppressant is indicated for management of IBD?
2. What is it used to do?
3. Name 2 adverse effects of this drug

Answer 18

1. azathioprine
2. maintain remission
3. bone marrow suppression
   hepatotoxicity

Question 19

Name 2 TNF-alpha antagonists indicated for the management of IBD

Answer 19

1. adalibumab

2. infliximab

Question 20

1. Name 3 antimuscarinics used to manage symptoms of IBS
2. How do they do this?
3. Name 4 side effects
4. Name 2 contraindications of these drugs

Answer 20

1. dicycloverine
   hycosine butylbromide
   propatheline
2. reduce smooth muscle tone and peristaltic contraction
3. tachycardia
   dry mouth
   constipation
   urinary retention
4. closed-angle glaucoma
   arrythmia

Question 21

Name risk factors which lead to the recommendation of empiric antibiotic therapy for GI infections

Answer 21

1. fever, >6 stools/day, volume depletion warranting hospitalisation
2. features suggestive of invasive bacterial infection (bloody/mucoid stools)
3. host factors which increase the risk for complications - >70; comorbidities (cardiac disease, immunocompromised)

Question 22

1. Name 3 drugs used in multimodal analgesia?

2. What is the indication of multimodal analgesia?

Answer 22

1. IV paracetamol
   bupivacaine (local anaesthetic) epidural infusion
   hydromorphone (opioid) epidural infusion
2. control pain preoperatively

Question 23

1. What is breakthrough pain?
2. Which drug is useful to control breakthrough pain?
3. How is an adequate PRN dose of this drug calculated?
4. What should be done if the patient is constantly requiring their rescue dose?

Answer 23

1. sudden increase in pain in patients who have chronic pain
2. oromorph
3. divide the total daily dose (regular dose + number of rescue doses) by 6
4. increase regular dose

Question 24

1. How do antihistamines function as antiemetics?
2. name 2 antihistamines used as antiemetics
3. name 3 warnings when using these antihistamines

Answer 24

1. inhibit histamine receptors found within the vomiting centre, which are involved in vestibular inputs
2. cyclizine; promethazine
3. hepatic enceophalopathy
   prostatic enlargement

Question 25

1. How do dopamine antagonists function as antiemetics? 2. Name 2 examples 3. name 3 side effects 4. name 5 warnings/cautions for their use 5. name 3 interractions

Answer 25

1. inhibits D2 receptors in the chemoreceptor trigger zone; promotes relaxation of the stomach and lower oesophageal sphincter 2. doperidone; metoclopramide 3. diarrhoea extrapyramidal side effects QT elongation and arrythmia ``` 4. <18 years cardiac conduction abnormalities hepatic impairment intestinal obstruction and perforation parkinson's disease ``` 5. antipsychotics dopaminergic agents for PD drugs that prolong the QT interval

Question 26

1. How do serotonin antagonists act as antiemetics? 2. Name an example? 3. Name a warning

Answer 26

1. serotonin is released by the gut in response to emetogenic stimuli; acts on serotonin receptors in the CTZ 2. odansetron 3. QT elongation (and thus interracts with other QT prolonging drugs)

Question 27

What are the indications for IV fluids?

Answer 27

prescribed for patients whose fluid needs can't be met by oral or enteral routes - nil by mouth - vomiting/severe diarrhoea - patient is hypovolaemic as a result of blood loss

Question 28

1. What are crystalloids? 2. What are colloids? 3. Which type of fluid is used less often and why?

Answer 28

1. solutions of small molecules in water 2. solutions of larger organic molecules 3. colloids, ad they carry a risk of anaphylaxis

Question 29

1. Name 2 crystalloids used for fluid resuscitation and maintenance 2. Name 2 crystalloids used for maintenance only

Answer 29

1. Normal saline (0.9% NaCl) Hartmann's Solution 2. sodium chloride 0.18%/glucose 4% 5% dextrose

Question 30

Name considerations for IV fluid therapy in the initial assessment (5)

Answer 30

1. has enteral fluid intake been reduced? 2. is patient experiencing dizziness/syncope? 3. is the patient thirsty? 4. is the patient experiencing abnormal fluid loss 5. does the patient have co-morbidities affecting their ability to handle fluids? (HF; renal failure)

Question 31

Name examination findings which indicate the patient is hypovolaemic

Answer 31

1. tachypnoea 2. decreased sats 3. bilateral crackles 4. tachycardia 5. hypotension 6. prolonged cap refil time 7. non visible JVP 8. decreased GCS 9. decreased urine output

Question 32

What kind of IV fluid therapy is indicated if: 1. the patient is hypovolaemic 2. the patient is euvolaemic but can't take oral/enteral fluids 3. patient is hypervolaemic

Answer 32

1. resuscitation fluids are required 2. maintenance fluids are required 3. DO NOT ADMINISTER IV FLUIDS

Question 33

1. How are resuscitation fluids administered? | 2. What is the maximum amount of resuscitation fluid which can be administered within 24 hours?

Answer 33

1. give an initial fluid bolus of 500ml crystaloloid over <15mins reassess with the patient give further fluid bolus of 250-500ml crystalloid 2. 2000ml

Question 34

What is the function of maintenance fluids?

Answer 34

to maintain daily fluid, electrolyte and glucose requirements in patients who are haemodynamically stable but unable to meet these needs orally/enterally