# PLAB 1 Gastroenterology Questions: 10 Free Practice MCQs

> 10 free PLAB 1 gastroenterology questions with answers and explanations, from a bank of 13 gastroenterology questions. Try them now, no sign up.

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Last updated: 2026-10-29

Ten PLAB 1-style gastroenterology questions with the answer and the reasoning behind it. They come from the UK.med bank, which has 13 gastroenterology questions and many more across every topic.

1. 1 / 10  
A 28-year-old male with a history of Ulcerative Colitis presents with a 5-day history of bloody diarrhoea. He reports passing 8 bloody stools per day. On examination, he is febrile (38.2°C), tachycardic (102 bpm), and has mild lower abdominal tenderness. His CRP is 65 mg/L.  
Which of the following is the most appropriate next step in management according to Truelove and Witts criteria?  
Show answer

**Answer: C.** Admit for intravenous corticosteroids and monitor for toxic megacolon

**Why:** NICE NG130 states that acute severe ulcerative colitis (defined by Truelove and Witts criteria as >= 6 bloody stools/day plus at least one sign of systemic toxicity: temp > 37.8°C, HR > 90 bpm, Hb < 105 g/L, or ESR/CRP elevated) requires immediate admission for IV corticosteroids (typically IV Hydrocortisone 100mg QDS).

  * **A.** Mesalazine is for mild-to-moderate colitis; a severe flare represents a medical emergency and cannot be treated with outpatient 5-ASA.
  * **B.** Oral steroids are suitable for moderate flares. Severe flares must be admitted to hospital for IV treatment due to the high risk of bowel perforation and toxic megacolon.
  * **D.** Full colonoscopy is contraindicated in acute severe colitis due to the high risk of perforation; a flexible sigmoidoscopy without bowel preparation is preferred if diagnosis is needed.  
Sources: NICE NG130
2. 2 / 10  
A 31-year-old woman with established ulcerative colitis reports 5 days of increased urgency and 6 bloody stools daily. She is afebrile, haemodynamically stable and has no focal peritonism; stool tests are being sent to exclude infection.  
What is the most likely explanation for her current symptoms?  
Show answer

**Answer: A.** An inflammatory exacerbation of ulcerative colitis

**Why:** Increased bloody stool frequency and urgency are typical of an ulcerative colitis exacerbation. Infection, including C. difficile, should be assessed because it can mimic or trigger a flare.

  * **B.** Appendicitis usually causes focal right iliac fossa pain and does not explain this pattern of bloody diarrhoea.
  * **C.** Obstruction more typically causes colicky pain, distension and vomiting rather than frequent bloody stools.
  * **D.** Cholecystitis causes right upper quadrant pain and does not account for bloody diarrhoea.  
Sources: NICE NG130, ulcerative colitis management
3. 3 / 10  
A 54-year-old man with decompensated alcoholic liver cirrhosis is admitted with worsening abdominal distension due to tense ascites. He is comfortable at rest. On examination, there is shifting dullness and fluid thrill.  
What is the recommended pharmacological first-line therapy for the management of his ascites?  
Show answer

**Answer: A.** An aldosterone antagonist, such as Spironolactone 100mg daily

**Why:** In cirrhotic patients, portal hypertension and splanchnic vasodilation activate the renin-angiotensin-aldosterone system (RAAS), leading to renal sodium and water retention. Spironolactone (an aldosterone antagonist) is the first-line diuretic of choice, started at 100mg and titrated up to 400mg daily. Furosemide can be added if response is inadequate. Sodium restriction (<2g/day) is also recommended.

  * **B.** Loop diuretics alone are less effective than Spironolactone in cirrhotic ascites and carry a high risk of inducing renal impairment and electrolyte imbalance.
  * **C.** Therapeutic paracentesis is reserved for tense ascites causing discomfort, respiratory compromise, or refractory ascites, and should be followed by diuretic maintenance.
  * **D.** Tolvaptan is used to treat severe hyponatraemia in SIADH or heart failure, but is not a first-line treatment for routine cirrhotic ascites.  
Sources: EASL Clinical Practice Guidelines; NICE CKS Cirrhosis
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5. 4 / 10  
A 58-year-old man with alcohol related cirrhosis presents with haematemesis and melaena. He is hypotensive and tachycardic, and variceal bleeding is suspected while resuscitation and urgent endoscopy are arranged.  
What is the most appropriate initial medical management alongside resuscitation?  
Show answer

**Answer: A.** Give terlipressin and prophylactic antibiotics at presentation

**Why:** Suspected variceal bleeding warrants terlipressin and prophylactic antibiotics alongside resuscitation and urgent endoscopic management. Balloon tamponade is reserved as a bridge in selected uncontrolled bleeds.

  * **B.** A proton pump inhibitor is not the specific initial treatment for suspected variceal haemorrhage.
  * **C.** The HALT-IT trial found no benefit from tranexamic acid in acute gastrointestinal bleeding.
  * **D.** A balloon tamponade tube is a temporary rescue option for uncontrolled bleeding, not routine first-line care.  
Sources: NICE CG141, recommendations 1.5.1 to 1.5.3
6. 5 / 10  
A 42-year-old female presents with sudden onset, severe epigastric pain radiating to her back, accompanied by persistent vomiting. On examination, she has severe epigastric tenderness.  
Which of the following investigations is most appropriate to confirm the diagnosis of acute pancreatitis?  
Show answer

**Answer: D.** Serum lipase or amylase measurement

**Why:** According to British Society of Gastroenterology (BSG) guidelines, the diagnosis of acute pancreatitis requires 2 of the following 3 criteria: (1) typical severe abdominal pain, (2) serum amylase or lipase activity >= 3 times the upper limit of normal, and (3) characteristic findings on cross-sectional imaging (CT or MRI). Measurement of amylase or lipase is the standard diagnostic test.

  * **A.** Ultrasound is the first-line imaging to identify the etiology (e.g. gallstones) but is not the diagnostic test to confirm acute pancreatitis itself.
  * **B.** CT scan is not recommended routinely at presentation unless the diagnosis is unclear, as early scans (under 48-72 hours) often underestimate pancreatic necrosis.
  * **C.** ERCP is a therapeutic procedure for acute gallstone pancreatitis with ascending cholangitis or persistent biliary obstruction, not a diagnostic test.  
Sources: BSG Guidelines
7. 6 / 10  
A 29-year-old woman with ulcerative colitis presents with 9 bloody stools daily, temperature 38.2 C, pulse 108 beats per minute and raised inflammatory markers. She has diffuse abdominal tenderness but no guarding or radiographic colonic dilatation.  
Which diagnosis best describes this presentation?  
Show answer

**Answer: C.** Acute severe ulcerative colitis

**Why:** The frequency of bloody stools with fever and tachycardia in a patient with known ulcerative colitis is consistent with acute severe ulcerative colitis. She needs urgent admission and assessment for complications and treatment response.

  * **A.** Diffuse bloody diarrhoea and systemic inflammation do not fit a focal appendiceal process.
  * **B.** There is no perianal disease or prior Crohn diagnosis; the history supports ulcerative colitis.
  * **D.** Diverticulitis is uncommon at this age and would not usually cause this diffuse colitis picture.  
Sources: NICE NG130, recommendations 1.2.21 to 1.2.27
8. 7 / 10  
A 58-year-old man with a history of alcohol-related liver cirrhosis presents to the emergency department vomiting large amounts of fresh blood. On examination, he is pale, clammy, and confused. His pulse is 120 bpm, and blood pressure is 85/50 mmHg.  
What is the recommended immediate medical management prior to emergency endoscopy?  
Show answer

**Answer: B.** Intravenous Terlipressin, prophylactic intravenous antibiotics (e.g. Ceftriaxone), and fluid resuscitation

**Why:** NICE guideline CG141 outlines the management of acute upper GI bleeding. For patients with suspected variceal bleeding (e.g. history of cirrhosis/portal hypertension), vasoactive drugs (Terlipressin) and prophylactic antibiotics (which reduce bacterial infection rates and mortality) should be given at presentation, prior to endoscopy. Endoscopy should be performed within 24 hours (or immediately if unstable).

  * **A.** IV PPIs are not recommended \*before\* endoscopy in suspected variceal bleeding. A Sengstaken-Blakemore tube is a rescue therapy for uncontrolled bleeding, not a routine pre-endoscopy step.
  * **C.** Tranexamic acid is not recommended by NICE for variceal bleeding. Oral medications are contraindicated in an actively vomiting patient.
  * **D.** Gastric lavage with iced water is obsolete and not supported by evidence. Adrenaline infusions are not a standard pre-endoscopy treatment for variceal bleeds.  
Sources: NICE CG141
9. 8 / 10  
A 32-year-old woman presents with a 6-month history of abdominal bloating, intermittent diarrhoea, and fatigue. She has a family history of coeliac disease. She has been on a gluten-free diet for the past month and reports feeling slightly better.  
What must the GP advise before performing diagnostic serological tests for coeliac disease?  
Show answer

**Answer: D.** Resume eating gluten (at least one meal containing gluten per day) for 6 weeks before the blood test

**Why:** NICE guideline NG20 outlines that to diagnose coeliac disease, patients must be eating a gluten-containing diet. Serological screening is with IgA tissue transglutaminase (tTG). If IgA tTG is positive, the patient is referred to a gastroenterologist for a confirmatory duodenal biopsy showing villous atrophy. Total IgA must also be checked, as IgA deficiency (found in 2% of coeliac patients) can cause false-negative tTG results.

  * **A.** Antibody levels (tTG) fall rapidly once gluten is excluded. Testing a patient who has been gluten-free for a month carries a high risk of a false-negative result.
  * **B.** HLA typing has high negative predictive value but low positive predictive value (many healthy people carry the genes). It is not used for primary diagnosis in primary care.
  * **C.** Serological testing (IgA tTG and total IgA) is the required first-step screening in primary care. Biopsy is performed subsequently to confirm the diagnosis.  
Sources: NICE NG20
10. 9 / 10  
A 25-year-old woman with ulcerative colitis has 8 bloody stools per day, fever of 38.5 C, pulse 110 beats per minute and abdominal tenderness. Symptoms have worsened over 3 days despite maintenance azathioprine; abdominal radiography shows no colonic dilatation.  
What is the most appropriate initial management?  
Show answer

**Answer: D.** Admit for acute severe ulcerative colitis care, start intravenous corticosteroids and involve gastroenterology and colorectal surgery

**Why:** This presentation meets clinical features of acute severe ulcerative colitis and requires inpatient care. NICE recommends intravenous corticosteroids first, with daily assessment for surgery; if there is little improvement after 72 hours, consider intravenous ciclosporin or surgery, with infliximab only in selected circumstances.

  * **A.** Cyclophosphamide is not recommended rescue therapy for acute severe ulcerative colitis.
  * **B.** Supportive fluids may be needed, but they do not replace admission and prompt treatment of acute severe disease.
  * **C.** Systemic toxicity and frequent bloody stools make outpatient treatment unsafe.  
Sources: NICE NG130, recommendations 1.2.21 to 1.2.27
11. 10 / 10  
A 34-year-old woman with ulcerative colitis in remission develops new bloody diarrhoea and urgency after stopping her maintenance mesalazine. She has no focal abdominal pain or vomiting and is haemodynamically stable.  
What is the most likely cause of the new symptoms?  
Show answer

**Answer: B.** An ulcerative colitis inflammatory flare after interruption of maintenance treatment

**Why:** The known ulcerative colitis, typical bowel symptoms and interruption of maintenance therapy make an inflammatory flare most likely. Check for infection and assess severity before adjusting treatment.

  * **A.** There is no history or feature suggesting Crohn disease; the known colitis and bloody urgency point to relapse.
  * **C.** Diverticulitis usually causes focal abdominal pain and does not typically cause this pattern of frequent bloody stool.
  * **D.** Appendicitis causes evolving focal pain rather than isolated bloody diarrhoea and urgency.  
Sources: NICE NG130, ulcerative colitis management

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