{"title": "Chapter 5: Gastrointestinal Disorders", "flashcards": [{"q": "What is the Glasgow-Blatchford score used for?", "a": "Risk stratification of acute upper GI bleeding BEFORE endoscopy, using Hb, blood urea, systolic BP, pulse, presence of melaena/syncope, hepatic disease, and cardiac failure. GBS 0 identifies patients suitable for outpatient management. It is more sensitive than Rockall pre-endoscopy score for predicting need for intervention."}, {"q": "Name three causes of acute lower GI bleeding.", "a": "Diverticular disease (most common in adults >50), colorectal cancer, angiodysplasia (arteriovenous malformations), ischaemic colitis, infective colitis, IBD (UC/Crohn's), haemorrhoids (typically minor/bright red), and post-polypectomy bleeding."}, {"q": "What is the definition of Helicobacter pylori eradication success?", "a": "Confirmed eradication requires urea breath test (UBT) or stool antigen test ≥4 weeks after completing eradication therapy AND ≥2 weeks after stopping PPIs. Upper GI endoscopy with biopsy-based testing (CLO test) is used if endoscopy is indicated anyway. Serology cannot confirm eradication."}, {"q": "Define the Rome IV criteria for irritable bowel syndrome (IBS).", "a": "Recurrent abdominal pain ≥1 day/week in the last 3 months (with symptom onset ≥6 months ago), associated with ≥2 of: related to defaecation; associated with change in stool frequency; associated with change in stool consistency/appearance. Subtypes: IBS-C, IBS-D, IBS-M (mixed), IBS-U (unclassified)."}, {"q": "What are the indications for emergency endoscopy in acute upper GI bleeding?", "a": "Haemodynamic instability unresponsive to resuscitation; ongoing bleeding (red blood per NG tube, continued haematemesis); suspected variceal haemorrhage; known aorto-enteric fistula. For stable patients, endoscopy within 24 hours of presentation is recommended (NICE 2020)."}, {"q": "Name the Forrest classification of peptic ulcer stigmata and their rebleeding risk.", "a": "Ia: spurting arterial haemorrhage (~90% rebleed without treatment); Ib: oozing vessel (~10–30%); IIa: visible vessel (~50%); IIb: adherent clot (~30%); IIc: flat pigmented spot (~7%); III: clean-based ulcer (<5%). Forrest Ia–IIb warrant endoscopic haemostasis plus IV PPI."}, {"q": "What is coeliac disease and which antibody is most diagnostic?", "a": "Coeliac disease is an immune-mediated enteropathy triggered by gluten (gliadin component) in genetically susceptible individuals (HLA-DQ2/DQ8). Villous atrophy causes malabsorption. Most specific antibody: anti-tissue transglutaminase IgA (anti-tTG IgA). Serology must be performed while the patient is on a gluten-containing diet. Small bowel biopsy (Marsh III) confirms diagnosis."}, {"q": "What is the mechanism of action of infliximab in IBD?", "a": "Infliximab is a chimeric IgG1 monoclonal antibody that binds and neutralises soluble and membrane-bound TNF-α. This reduces pro-inflammatory cytokine cascade, decreases leucocyte migration, induces apoptosis of activated T cells and macrophages, and promotes mucosal healing in Crohn's disease and ulcerative colitis."}, {"q": "Name three complications of prolonged nasogastric tube feeding.", "a": "Aspiration pneumonia (most serious); nasal/oropharyngeal erosion; tube displacement (must confirm position before each feed); refeeding syndrome (in malnourished patients: hypophosphataemia, hypokalaemia, hypomagnesaemia); sinusitis; diarrhoea; electrolyte disturbance."}, {"q": "What is the STEP classification of stricturing Crohn's disease?", "a": "Stricturing Crohn's is classified by the Vienna/Montreal classification — B2 (stricturing/stenosing phenotype). Management involves optimising anti-inflammatory therapy; endoscopic balloon dilatation for short strictures (<4 cm, single, accessible); surgical resection for refractory, long, or complex strictures. STEP does not refer to Crohn's but to GI strictures in neonates."}], "quiz": [{"q": "What is the first-line treatment for Clostridioides difficile infection of non-severe severity?", "opts": ["IV vancomycin", "Oral vancomycin 125 mg QDS for 10 days (or fidaxomicin)", "Oral metronidazole 400 mg TDS", "Oral metronidazole remains first-line for all cases"], "ans": 1, "exp": "IDSA/SHEA 2021 guidelines recommend oral vancomycin 125 mg QDS or fidaxomicin 200 mg BD for 10 days as first-line for non-severe CDI. Oral metronidazole is no longer recommended as first-line due to inferior cure rates compared to vancomycin. IV metronidazole is added only if oral route unavailable (ileus)."}, {"q": "Which complication of ulcerative colitis is an absolute indication for urgent colectomy?", "opts": ["Moderate flare requiring IV steroids", "Toxic megacolon (colon diameter >6 cm) with haemodynamic instability or peritonism", "Grade III haemorrhage only", "Pouchitis"], "ans": 1, "exp": "Toxic megacolon (colonic dilatation >6 cm on X-ray) with fever, tachycardia, leukocytosis, and hypoalbuminaemia is a life-threatening complication of severe UC. If there is haemodynamic instability, perforation, or failure to improve within 24–72 hours of intensive medical therapy (IV hydrocortisone, IV ciclosporin), urgent subtotal colectomy is required."}, {"q": "What endoscopic finding is diagnostic of Barrett's oesophagus?", "opts": ["Linear mucosal tear at the GOJ", "Columnar-lined (intestinal-type) mucosa with goblet cells replacing squamous epithelium, ≥1 cm above the GOJ, confirmed on biopsy", "Erythema in the lower oesophagus", "Hiatus hernia"], "ans": 1, "exp": "Barrett's oesophagus requires: macroscopic columnar metaplasia ≥1 cm above the GOJ on endoscopy, AND histological confirmation of specialised intestinal metaplasia (goblet cells) on biopsy. It is a premalignant lesion for oesophageal adenocarcinoma and requires surveillance endoscopy at intervals based on dysplasia grade."}, {"q": "What is the role of faecal calprotectin in clinical practice?", "opts": ["Confirms colorectal cancer diagnosis", "Distinguishes inflammatory bowel disease (elevated) from functional bowel disorder such as IBS (normal) as a non-invasive stool biomarker", "Diagnoses Clostridioides difficile", "Identifies bile acid malabsorption"], "ans": 1, "exp": "Faecal calprotectin is a stool neutrophil-derived protein that rises with GI inflammation. FC >250 µg/g supports IBD and warrants further investigation (colonoscopy); FC <50 µg/g makes IBD very unlikely and supports IBS diagnosis. It reduces unnecessary colonoscopy referrals in patients with bowel symptoms."}, {"q": "What is the classic triad of acute mesenteric ischaemia?", "opts": ["Haematuria, proteinuria, oedema", "Acute severe abdominal pain out of proportion to examination findings, bloody diarrhoea, and a source of thromboembolism", "Fever, rigors, jaundice", "Vomiting, constipation, abdominal distension"], "ans": 1, "exp": "Acute mesenteric ischaemia classically causes severe, acute abdominal pain that is disproportionate to abdominal examination findings (early phase). Bloody diarrhoea, nausea, vomiting, and often an embolic source (AF, recent MI) are present. CT angiography is diagnostic. Mortality remains >50% with delayed diagnosis."}, {"q": "Which cancer screening test is used for colorectal cancer in the UK national programme?", "opts": ["Colonoscopy every 10 years", "Faecal immunochemical test (FIT) every 2 years from age 50–74 (now 45 in some regions)", "CEA blood test annually", "Flexible sigmoidoscopy every 5 years"], "ans": 1, "exp": "England's NHS Bowel Cancer Screening Programme uses FIT (quantitative faecal immunochemical test) for haemoglobin, sent to eligible adults aged 50–74 every 2 years. FIT detects occult blood with higher sensitivity and specificity than guaiac FOB. Positive FIT leads to colonoscopy. A one-off flexible sigmoidoscopy at 55 was also part of the expanded programme."}, {"q": "What investigation is most sensitive for detecting small bowel Crohn's disease?", "opts": ["Barium meal and follow-through", "MR enterography (MRE)", "CT abdomen with contrast", "Capsule endoscopy alone"], "ans": 1, "exp": "MR enterography is the preferred modality for assessing small bowel Crohn's — it evaluates transmural disease activity (mural enhancement, thickening, mesenteric fat stranding), fibrosis vs inflammation distinction, and extra-intestinal complications (fistulae, abscesses) without ionising radiation. It is superior to CT and barium studies for active disease assessment."}, {"q": "What is the difference between ulcerative colitis and Crohn's disease on colonoscopy?", "opts": ["UC affects only the rectum; Crohn's affects only the colon", "UC causes continuous mucosal inflammation from the rectum proximally; Crohn's causes discontinuous transmural inflammation with skip lesions anywhere from mouth to anus", "Both always involve the terminal ileum", "Crohn's never causes rectal involvement"], "ans": 1, "exp": "UC: continuous, superficial (mucosal) inflammation starting in the rectum and extending proximally; no skip lesions; rectal involvement mandatory. Crohn's: discontinuous (skip lesions), transmural inflammation; can affect any GI segment; terminal ileum most common; rectal sparing common; fistulae and granulomas."}, {"q": "What is the Ranson score used for in acute pancreatitis?", "opts": ["Predicting mortality in chronic pancreatitis", "Predicting severity and mortality in acute pancreatitis using admission and 48-hour variables", "Diagnosing aetiology of pancreatitis", "Guiding timing of ERCP"], "ans": 1, "exp": "The Ranson score uses 5 admission criteria (age, WBC, glucose, LDH, AST) and 5 at 48 hours (haematocrit fall, BUN rise, Ca²⁺, PaO₂, base deficit, fluid sequestration). Score 0–2 = mild; 3–4 = moderate; ≥5 = severe (high mortality). Replaced by revised Atlanta classification in current practice but still examined."}, {"q": "Which medication is most appropriate for preventing NSAID-related peptic ulceration?", "opts": ["Antacids PRN", "Proton pump inhibitor co-prescribed with NSAID", "H2 antagonist PRN", "Sucralfate"], "ans": 1, "exp": "PPI co-prescription (e.g. omeprazole 20 mg OD or lansoprazole 15–30 mg OD) significantly reduces NSAID-induced peptic ulcer risk. PPIs are recommended for all patients on long-term NSAIDs with risk factors (age >65, prior ulcer, anticoagulant/corticosteroid co-prescription, H. pylori positive). Misoprostol is an alternative."}, {"q": "What is achalasia and what is its gold-standard investigation?", "opts": ["Intermittent oesophageal spasm; investigation: barium swallow", "Absent peristalsis and failure of LOS relaxation; gold-standard: oesophageal high-resolution manometry", "GORD with stricture; investigation: endoscopy", "Hiatus hernia; investigation: CT chest"], "ans": 1, "exp": "Achalasia is a motility disorder of unknown aetiology characterised by degeneration of myenteric plexus neurones, causing absent oesophageal peristalsis and failure of the lower oesophageal sphincter (LOS) to relax with swallowing. High-resolution manometry (HRM) shows absent peristalsis and incomplete LOS relaxation. Management: pneumatic dilatation, POEM, or laparoscopic Heller myotomy."}, {"q": "What is the mechanism of diarrhoea in bile acid malabsorption (BAM)?", "opts": ["Increased intestinal motility from serotonin", "Unabsorbed bile acids entering the colon cause osmotic and secretory diarrhoea and stimulate colonic motility", "Pancreatic enzyme deficiency", "Mucosal inflammation from autoimmunity"], "ans": 1, "exp": "Bile acids normally absorbed in the terminal ileum; malabsorption (from ileal resection, Crohn's, post-cholecystectomy, or idiopathic) allows excess bile acids to reach the colon. Bile acids stimulate colonic secretion and motility. SeHCAT scan confirms diagnosis; cholestyramine (bile acid sequestrant) or colesevelam is first-line treatment."}, {"q": "Which investigation distinguishes oesophageal from oropharyngeal dysphagia?", "opts": ["CT chest", "Video fluoroscopy (modified barium swallow) for oropharyngeal; OGD for oesophageal", "MRI oesophagus", "Nuclear medicine transit study"], "ans": 1, "exp": "Oropharyngeal dysphagia (aspiration of solids/liquids before swallowing) is best assessed by video fluoroscopy (modified barium swallow), ideally with a speech and language therapist. Oesophageal dysphagia (solids/liquids caught in the chest after swallowing) is evaluated by upper GI endoscopy ± manometry and pH-impedance."}, {"q": "A patient develops severe epigastric pain radiating to the back, serum lipase 4× ULN, and a history of gallstones. What is the most likely diagnosis and what is the most important immediate management?", "opts": ["Peptic ulcer perforation — IV antibiotics", "Acute gallstone pancreatitis — aggressive IV fluid resuscitation and analgesia", "Acute cholecystitis — laparoscopic cholecystectomy immediately", "Aortic aneurysm — CT aortogram"], "ans": 1, "exp": "Gallstones are the most common cause of acute pancreatitis (40%). The revised Atlanta criteria use epigastric pain, lipase ≥3× ULN, and characteristic CT changes (two of three). Management: aggressive crystalloid resuscitation (Hartmann's preferred), analgesia, antiemetics, nutritional support, and monitor organ function. ERCP within 24–72 hours if cholangitis; cholecystectomy before discharge for mild attacks."}, {"q": "What is the most common cause of acute hepatitis in the UK in otherwise healthy young adults?", "opts": ["Hepatitis A", "Alcohol-related hepatitis or paracetamol overdose combined; viral hepatitis B and C via blood-borne routes", "Hepatitis D", "Autoimmune hepatitis"], "ans": 1, "exp": "Acute hepatitis causes in the UK: alcohol and paracetamol overdose are the most common causes of acute liver failure (ALF). In young adults, viral hepatitis B (sexually transmitted) and hepatitis A (food/travel) are important. Acute hepatitis C rarely presents acutely (usually subclinical). Autoimmune hepatitis affects all ages."}, {"q": "Which scoring system guides liver transplant listing for acute liver failure?", "opts": ["Child-Pugh", "King's College Criteria (KCC)", "MELD score", "Ranson score"], "ans": 1, "exp": "King's College Criteria (O'Grady criteria) predict poor prognosis in ALF and guide transplant listing. Paracetamol-induced ALF: pH <7.3 after resuscitation, OR all three of PT >100s + creatinine >300 µmol/L + Grade 3–4 encephalopathy. Non-paracetamol: PT >100s alone, or any 3 of age <10 or >40, non-A/non-B or drug aetiology, bilirubin >300 µmol/L, PT >50s."}, {"q": "What complication of Crohn's disease causes pneumaturia and faecaluria?", "opts": ["Stricturing disease", "Enterovesical fistula", "Colovaginal fistula", "Perianal fistula"], "ans": 1, "exp": "Enterovesical fistula in Crohn's disease forms between the small bowel (or inflamed colon) and the urinary bladder, causing pneumaturia (air bubbles in urine) and faecaluria (faecal particles in urine) with recurrent UTIs. It requires surgical resection of the diseased bowel segment and fistula closure."}, {"q": "What is the role of chromoendoscopy in IBD surveillance?", "opts": ["Replaces histological sampling", "Enhances detection of dysplastic lesions by applying dye (indigo carmine or methylene blue) to highlight mucosal architecture during colonoscopy", "Confirms the diagnosis of IBD", "Reduces patient preparation requirements"], "ans": 1, "exp": "Chromoendoscopy — dye spraying (indigo carmine 0.1%, methylene blue 0.1%) during colonoscopy — improves mucosal surface visualisation and increases detection of flat and subtle dysplastic lesions in IBD surveillance. NICE and BSG recommend chromoendoscopy with targeted biopsies over random four-quadrant biopsies as the standard of care."}, {"q": "What is the most common cause of small bowel obstruction in adults?", "opts": ["Hernias", "Postoperative adhesions", "Malignancy", "Volvulus"], "ans": 1, "exp": "Postoperative adhesions (fibrous bands from prior abdominal or pelvic surgery) account for approximately 60–70% of small bowel obstructions in adults. Hernias (inguinal, femoral, incisional) are the second most common cause. Malignancy, volvulus, and Crohn's strictures account for the remainder."}, {"q": "What is the recommended surveillance interval after low-risk adenoma removal at colonoscopy?", "opts": ["1 year", "5 years (NICE/BSG 2020 guidelines for 1–2 adenomas <10 mm with low-grade dysplasia)", "10 years", "3 years"], "ans": 1, "exp": "BSG 2020 post-polypectomy surveillance: low-risk adenoma (1–2 tubular adenomas <10 mm, low-grade dysplasia) → 5-year surveillance colonoscopy. High-risk (≥3 adenomas, or ≥1 ≥10 mm, or villous features, or high-grade dysplasia) → 3-year surveillance. No increased risk (1–2 adenomas <10 mm, LGD) → back to NHS screening programme (no early surveillance in some protocols)."}]}