UKMLA Gastroenterology & Hepatology: High-Yield Pillar

Gastroenterology is the single largest source of acute-take SBAs in the UKMLA. Every on-call in a UK foundation post will deliver an upper GI bleed, a decompensated cirrhotic, a cholangitic sepsis, or an acute pancreatitis within the first fortnight. The content map reflects that with dense coverage of luminal, hepatobiliary, and pancreatic disease — each with its own emergency pathway.

This pillar bundles the full GI + hepatology surface the UKMLA tests, with the UK guideline touchpoints and the ladders you are expected to recite without hesitation.

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1. Why GI dominates acute take SBAs

The UKMLA content map lists 54 GI-related presentations and 30+ conditions. GI bleeding, abdominal pain, jaundice, altered bowel habit, and ascites are among the 20 highest-frequency presentations across all specialties.

Three reasons GI is over-represented:

• Volume of admissions — GI is the single largest medical admission pathway after respiratory.
• Guideline density — NICE NG49 (acute UGI bleed), NICE CG141 (AUGIB), BSG cirrhosis bundles, BSG IBD guidelines (2019 update), and NG225 (IBS 2022) are all live syllabus.
• Pattern recognition plays well in SBA format — Rome IV for IBS, Glasgow-Blatchford for bleed stratification, Glasgow-Imrie for pancreatitis. The UKMLA loves score-based triage.

Use our UKMLA Content Map 2026 pillar to confirm which GI conditions sit in which domain, and the NICE Guidelines pillar to lock the ladder-step management answers.

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2. Upper GI bleed: variceal vs non-variceal

Initial approach (NICE NG141):

1. ABCDE, two large-bore cannulae, crossmatch 4 units.
2. Fluid resuscitation — crystalloid first; transfuse when Hb <70 g/L (higher threshold for cardiac disease or active haemorrhage).
3. Major haemorrhage protocol if shocked — 1:1:1 RBC:FFP:platelets.
4. Reverse anticoagulation: warfarin → Beriplex 25–50 IU/kg + vitamin K 5 mg IV; DOACs → andexanet (factor Xa inhibitors) or idarucizumab (dabigatran).
5. Risk stratify with Glasgow-Blatchford score (GBS):
   • GBS = 0 — consider outpatient endoscopy.
   • GBS ≥1 — admit.
   • Higher GBS → higher risk of needing intervention.
6. OGD within 24 h (within 2 h if unstable and variceal suspected).
7. Rockall score post-endoscopy to predict rebleed and mortality.

Non-variceal bleed (peptic ulcer most common):

• Endoscopic haemostasis (clips, adrenaline injection + thermal, sclerosant).
• IV PPI (omeprazole 80 mg bolus → 8 mg/hr infusion for 72 h) post-endoscopy in high-risk ulcers (Forrest Ia–IIb).
• H. pylori testing + eradication if ulcer confirmed.

Variceal bleed (cirrhosis context):

• Terlipressin 2 mg IV every 4 h (splanchnic vasoconstrictor).
• Prophylactic antibiotics (ceftriaxone 1 g IV daily) — reduces mortality by 17%.
• Band ligation at endoscopy. Sclerotherapy for gastric varices.
• Sengstaken–Blakemore tube as bridge if uncontrolled.
• TIPS if recurrent despite optimal endoscopic therapy.

Secondary prevention:

• Non-variceal — PPI, lifestyle, H. pylori eradication, NSAID cessation.
• Variceal — propranolol (non-selective beta-blocker) + band ligation programme.

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3. Peptic ulcer disease + H. pylori eradication

Common causes: H. pylori (90% of duodenal ulcers, 70% of gastric), NSAIDs, stress (Cushing's/Curling's ulcers), Zollinger–Ellison syndrome (gastrinoma, multiple/refractory/distal ulcers).

Investigation:

• H. pylori testing — carbon-13 urea breath test OR stool antigen. Stop PPI 2 weeks before and antibiotics 4 weeks before testing (false negatives).
• OGD for alarm symptoms (age >55 + dyspepsia; weight loss; dysphagia; GI bleed; anaemia; recurrent vomiting; palpable mass).

Eradication (NICE CG184):

• First-line: 7-day triple therapy — PPI BD + amoxicillin 1 g BD + (clarithromycin 500 mg BD OR metronidazole 400 mg BD).
• Penicillin-allergic: PPI BD + clarithromycin 500 mg BD + metronidazole 400 mg BD.
• Second-line: the other clarithromycin/metronidazole combination, or bismuth quadruple therapy.
• Test of cure with urea breath test at ≥6–8 weeks after treatment.

Gastric ulcer follow-up OGD at 6–8 weeks to confirm healing and exclude malignancy (duodenal ulcers do not need repeat OGD unless symptomatic).

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4. IBD: UC vs Crohn's

Acute severe UC (Truelove & Witts criteria — all 3 of):

• ≥6 bloody stools/day.
• Plus any of: temperature >37.8, pulse >90, Hb <105, ESR >30, CRP >30.

Management:

1. IV hydrocortisone 100 mg QDS + LMWH (paradoxically increased VTE risk in active IBD).
2. Day 3 assessment: if CRP >45 or >8 stools/day → rescue therapy with IV ciclosporin or infliximab.
3. Surgery (subtotal colectomy) if no response after 72 h of rescue therapy, or toxic megacolon (diameter >6 cm + systemic toxicity).

Maintenance ladder:

• UC mild–moderate — 5-ASA (mesalazine) topical ± oral. Azathioprine if steroid-dependent. Biologics (anti-TNF/vedolizumab/ustekinumab) if refractory.
• Crohn's induction — prednisolone or budesonide (ileal disease). Exclusive enteral nutrition first-line in paediatric Crohn's.
• Crohn's maintenance — azathioprine/methotrexate → biologics.

Colorectal cancer surveillance: colonoscopy 10 years after IBD diagnosis, then risk-stratified (1/3/5 yearly).

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5. IBS — Rome criteria and red flags

Rome IV criteria: recurrent abdominal pain ≥1 day/week in last 3 months, associated with ≥2 of:

1. Related to defaecation.
2. Change in stool frequency.
3. Change in stool form.

Subtypes: IBS-C (constipation), IBS-D (diarrhoea), IBS-M (mixed), IBS-U.

Red flags that exclude primary IBS diagnosis:

• Age >50 with new symptoms.
• Rectal bleeding, nocturnal symptoms.
• Unexplained weight loss.
• Family history of bowel/ovarian cancer.
• Anaemia.
• Abdominal or rectal mass.
• Raised inflammatory markers.

Investigations to rule out alternatives: FBC, CRP, coeliac serology (tTG-IgA + IgA level), faecal calprotectin (distinguishes IBS from IBD — <50 μg/g suggests IBS), CA125 in women with bloating to exclude ovarian malignancy.

Management (NICE NG225, 2022 update):

• First-line — dietary (regular meals, adjust fibre, limit caffeine/fat/alcohol), low-FODMAP diet via dietitian.
• Pharmacological — antispasmodics (mebeverine, hyoscine), laxatives (not lactulose — worsens bloating), loperamide for diarrhoea.
• Second-line — tricyclic antidepressant (amitriptyline 5–10 mg nocte) for pain; SSRI if TCA fails.
• CBT and psychological therapies for refractory.

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6. Coeliac disease — serology, biopsy, management

Presentation: diarrhoea, weight loss, iron-deficiency anaemia, dermatitis herpetiformis, osteoporosis, subfertility, recurrent mouth ulcers. Screen in T1DM, autoimmune thyroid disease, first-degree relatives, Down's/Turner's syndrome.

Diagnosis (NICE NG20):

1. Maintain gluten intake (≥1 meal containing gluten per day for ≥6 weeks before testing — false negatives otherwise).
2. Tissue transglutaminase IgA (tTG-IgA) + total IgA.
3. If IgA-deficient → IgG-based testing (DGP-IgG or EMA-IgG).
4. OGD + duodenal biopsies — villous atrophy, crypt hyperplasia, intraepithelial lymphocytes (Marsh classification).
5. HLA-DQ2/DQ8 — negative predictive value rules out coeliac; not diagnostic alone.

Management:

• Lifelong gluten-free diet — only effective treatment.
• Dietitian input essential.
• Annual review — weight, symptoms, adherence, tTG, FBC, ferritin, folate, B12, vitamin D, calcium, TFT.
• Pneumococcal vaccine 5-yearly (functional hyposplenism).
• DEXA at diagnosis (osteoporosis risk).

Complications: osteoporosis, T-cell lymphoma (EATL), small-bowel adenocarcinoma, ulcerative jejunitis, refractory coeliac.

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7. Acute pancreatitis (Glasgow-Imrie, management)

Causes (I GET SMASHED): Idiopathic, Gallstones, Ethanol, Trauma, Steroids, Mumps/other infections, Autoimmune, Scorpion bite, Hyperlipidaemia/hypercalcaemia/hypothermia, ERCP, Drugs (azathioprine, valproate, thiazides).

Diagnosis (2 of 3):

1. Epigastric pain radiating to back.
2. Amylase or lipase >3× ULN (lipase more specific, longer half-life).
3. Imaging (CT, MRI, USS) consistent with pancreatitis.

Severity — Glasgow-Imrie score at 48 h (PANCREAS): PaO₂ <8 kPa, Age >55, Neutrophilia >15, Calcium <2, Renal (urea >16), Enzymes (LDH >600, AST >200), Albumin <32, Sugar >10. ≥3 = severe. Other tools: APACHE II, modified CT severity index.

Management (UK BSG/AUGIS):

• IV fluids — aggressive resuscitation with Hartmann's, titrated to urine output >0.5 mL/kg/h.
• Analgesia — IV morphine; pethidine no longer preferred.
• NG tube if vomiting; early enteral nutrition within 72 h improves outcomes.
• IV antibiotics — only if infected necrosis or cholangitis suspected (not prophylactic).
• Urgent ERCP within 72 h if gallstone pancreatitis + cholangitis OR biliary obstruction.
• HDU/ICU if severe.
• Cholecystectomy during same admission for mild gallstone pancreatitis (NICE recommendation).

Complications: pseudocyst (drain if >6 cm, persistent, or symptomatic), necrosis, abscess, chronic pancreatitis, ARDS, AKI, DIC.

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8. Gallstone disease ladder: biliary colic → cholecystitis → cholangitis

Biliary colic: analgesia, elective laparoscopic cholecystectomy.

Acute cholecystitis: IV fluids, IV antibiotics (co-amoxiclav + metronidazole), analgesia. Laparoscopic cholecystectomy within 1 week (Tokyo/NICE recommendation).

Ascending cholangitis (medical emergency):

1. Sepsis six.
2. IV antibiotics (piperacillin-tazobactam).
3. ERCP with biliary decompression within 24 h (or percutaneous transhepatic cholangiography if ERCP contraindicated).
4. Cholecystectomy after recovery.

Mirizzi syndrome = stone in cystic duct or neck compressing CBD → obstructive jaundice without choledocholithiasis.

For integrated sepsis management and the sepsis six, see our UKMLA Acute & Emergency Presentations pillar.

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9. Hepatitis B and C — serology interpretation

Hepatitis B serology — the UKMLA's favourite viral-liver SBA:

Patterns:

• Vaccinated: anti-HBs +, everything else −.
• Cleared infection: anti-HBs +, anti-HBc IgG +.
• Acute infection: HBsAg +, anti-HBc IgM +, HBeAg ±.
• Chronic infection: HBsAg + for >6 months, anti-HBc IgG +.
• Chronic infection, high infectivity: as above + HBeAg + + high HBV DNA.

Treatment: tenofovir or entecavir for chronic HBV with active disease (eALT or fibrosis). Pegylated interferon less used.

Hepatitis C:

• Screen with anti-HCV antibody; confirm active infection with HCV RNA PCR.
• Genotype determines therapy (less relevant now — pan-genotypic DAAs dominate).
• Direct-acting antivirals (DAAs) — 8–12 weeks, >95% sustained virological response. Glecaprevir-pibrentasvir or sofosbuvir-velpatasvir.
• Screen for HCC (USS + AFP 6-monthly) if cirrhotic — even after SVR.

Needlestick occupational exposure:

• HBV — booster vaccine ± immunoglobulin depending on source and recipient antibody titre.
• HCV — no PEP; serial PCR, treat if infection established.
• HIV — PEP within 72 h (preferably <1 h) — raltegravir + tenofovir/emtricitabine.

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10. Alcoholic liver disease + alcohol withdrawal (CIWA-Ar)

Spectrum: steatosis → alcoholic hepatitis → cirrhosis.

Alcoholic hepatitis — severity (Maddrey's discriminant function ≥32):

• Jaundice, ascites, coagulopathy.
• Glasgow Alcoholic Hepatitis Score (GAHS) ≥9 → consider steroids.
• Prednisolone 40 mg daily 28 days — Lille score at day 7; stop if non-responder (>0.45).
• Nutrition — high-calorie (35 kcal/kg), high-protein (1.2–1.5 g/kg); avoid protein restriction.
• Thiamine (Pabrinex) — prevent Wernicke's encephalopathy.

Alcohol withdrawal (CIWA-Ar guides management):

• 6–12 h after last drink: tremor, anxiety, tachycardia.
• 12–48 h: alcoholic hallucinosis, seizures.
• 48–96 h: delirium tremens (20% mortality untreated).

Management:

• Chlordiazepoxide (long-acting benzo) first-line; lorazepam in liver failure (non-hepatic metabolism).
• Symptom-triggered regimen using CIWA-Ar (score every 1–2 h, dose when >8).
• Pabrinex 2 pairs IV TDS for 3 days then oral thiamine — Wernicke's prevention.
• Magnesium, phosphate, potassium replacement.
• Seizure — benzodiazepine bolus (IV lorazepam).
• Delirium tremens — high-dose benzodiazepines ± haloperidol; ICU if refractory.

For alcohol dependence pharmacotherapy and CIWA details, see our UKMLA Psychiatry + Mental Health Act pillar.

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11. Non-alcoholic fatty liver disease (NAFLD / MASLD)

Renamed 2023 as MASLD (metabolic dysfunction-associated steatotic liver disease). Prevalence in the UK exceeds 25% of adults. Commonest cause of deranged LFTs.

Spectrum: simple steatosis → steatohepatitis (MASH) → fibrosis → cirrhosis → HCC.

Diagnosis: incidental USS steatosis + risk factors (obesity, T2DM, dyslipidaemia, metabolic syndrome). Exclude viral, autoimmune, hereditary (haemochromatosis, Wilson's, alpha-1-antitrypsin) causes.

Risk stratification:

• FIB-4 score (age, AST, ALT, platelets) — low risk if <1.3 in under-65s.
• ELF test (Enhanced Liver Fibrosis) — NICE NG49; ≥10.51 = advanced fibrosis, refer hepatology.
• Transient elastography (FibroScan) — ≥8 kPa = significant fibrosis.

Management:

• Weight loss ≥10% body weight can regress fibrosis.
• Mediterranean diet, exercise ≥150 min/week.
• Optimise metabolic comorbidities — statins, antihypertensives, T2DM control (pioglitazone has evidence in MASH; GLP-1 agonists emerging).
• Surveillance for HCC if cirrhotic (USS + AFP 6-monthly).

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12. Cirrhosis complications (ascites, SBP, varices, HE)

Decompensation triggers: infection, GI bleed, constipation, drugs (NSAIDs, sedatives), electrolyte disturbance, HCC.

Ascites:

• Diagnostic paracentesis in all new ascites — calculate SAAG (serum-ascites albumin gradient).
• SAAG ≥11 g/L = portal hypertension (cirrhosis, cardiac, Budd-Chiari).
• SAAG <11 g/L = non-portal (malignancy, nephrotic, TB, pancreatic).
• Ascitic PMN ≥250 cells/μL → spontaneous bacterial peritonitis (SBP).

SBP management:

• IV cefotaxime or piperacillin-tazobactam for 5 days.
• IV albumin 1.5 g/kg day 1, 1 g/kg day 3 — prevents HRS.
• Prophylaxis with oral ciprofloxacin after recovery (indefinite).

Hepatic encephalopathy (West Haven grades I–IV):

• Precipitants: infection, constipation, GI bleed, diuretic-induced hypokalaemia/hyponatraemia, sedatives.
• Lactulose — titrate to 2–3 soft stools/day.
• Rifaximin for recurrent episodes (non-absorbable antibiotic reduces ammonia-producing gut flora).
• Address precipitant.

Varices (primary prophylaxis):

• Propranolol OR endoscopic band ligation for medium/large varices at screening OGD.
• Surveillance 1–3 yearly depending on initial findings.

Hepatorenal syndrome:

• Type 1: rapid (<2 weeks). Type 2: insidious.
• Triggers: SBP, large-volume paracentesis without albumin, GI bleed.
• Terlipressin + albumin — splanchnic vasoconstriction restores renal perfusion.
• Transplant is definitive.

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13. Acute liver failure — King's College criteria

Definition: encephalopathy + coagulopathy (INR >1.5) in a patient without pre-existing liver disease within 26 weeks of jaundice onset.

Causes: paracetamol (50% UK cases), viral hepatitis (A, B, E), drug-induced (anti-TB, AEDs, herbal), autoimmune, Budd-Chiari, pregnancy (HELLP, AFLP), Wilson's, ischaemic.

King's College criteria for liver transplantation:

Paracetamol-induced:

• Arterial pH <7.3 at >24 h after ingestion, OR
• All three: PT >100 s (INR >6.5), creatinine >300 μmol/L, grade III–IV encephalopathy.

Non-paracetamol:

• PT >100 s (INR >6.5), OR
• Any 3 of: aetiology (non-A non-B hepatitis or drug), jaundice >7 days before encephalopathy, age <10 or >40, PT >50 s (INR >3.5), bilirubin >300 μmol/L.

Management:

• ICU admission.
• N-acetylcysteine for paracetamol overdose (use at any timing if ALF established).
• Address precipitant.
• Refer transplant centre early — do not wait for criteria.
• Avoid lactulose (minimal role in ALF HE), manage ICP with mannitol/hypertonic saline if cerebral oedema.

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14. Bowel obstruction: SBO vs LBO + when to operate

Initial management ("drip and suck"):

• IV fluids, electrolytes.
• NG tube — decompression, prevent aspiration.
• Catheterise — urine output monitoring.
• Analgesia, antiemetic.
• Bloods + lactate (>2 = concern for ischaemia).
• CT abdomen with contrast — identifies cause, ischaemia, perforation.

Operate urgently if:

• Closed-loop obstruction (e.g., sigmoid volvulus with competent ileocaecal valve).
• Peritonitis, perforation, ischaemia.
• Caecal diameter >10 cm (imminent perforation).
• Failure to resolve with conservative management after 48–72 h.

Sigmoid volvulus — flexible sigmoidoscopy with decompression first-line (success >80%). Elective sigmoidectomy for recurrence.

Pseudo-obstruction (Ogilvie's syndrome) — colonic dilatation without mechanical cause. Stop opioids, correct electrolytes, neostigmine under cardiac monitoring if caecum >10 cm. Colonoscopic decompression if failed.

For peri-operative and surgical SBA patterns, see our upcoming UKMLA Surgery: Acute Abdomen & Peri-op pillar.

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15. C. difficile — diagnosis and management

Risk factors: recent antibiotics (especially 4Cs — ciprofloxacin, clindamycin, co-amoxiclav, cephalosporins), PPI use, age >65, hospitalisation, immunocompromise.

Diagnosis:

• Watery diarrhoea >3 stools/day with risk factors.
• Stool glutamate dehydrogenase (GDH) screen — sensitive.
• Positive GDH → toxin A/B EIA or PCR to confirm active infection.
• GDH + /toxin − = carriage (do not treat).

Severity (Public Health England/UKHSA):

• Mild — <3 loose stools/day, no WCC rise.
• Moderate — 3–5 stools, WCC <15.
• Severe — WCC >15, temperature >38.5, creatinine rise >50% baseline, abdominal pain.
• Life-threatening — hypotension, ileus, toxic megacolon.

Management (NICE NG199):

• Stop causative antibiotic; isolate patient; enteric precautions.
• First episode: oral vancomycin 125 mg QDS 10 days.
• Recurrent (within 12 weeks): fidaxomicin 200 mg BD 10 days.
• Life-threatening: oral vancomycin 500 mg QDS + IV metronidazole 500 mg TDS; surgical review for subtotal colectomy.
• Refractory/multiply recurrent: faecal microbiota transplant (FMT) — high efficacy.

Do NOT use loperamide — risks toxic megacolon.

Prevention: antibiotic stewardship, hand hygiene (soap and water — alcohol gel ineffective against spores), isolation, chlorine-based cleaning.

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Exam technique — GI SBA archetypes

Five high-frequency paediatric-to-adult GI stem patterns:

1. "Cirrhotic + vomiting blood" → ABCDE, terlipressin + ceftriaxone + urgent OGD with banding.
2. "RUQ pain + fever + jaundice" → Charcot's triad = cholangitis → sepsis six + ERCP within 24 h.
3. "Young woman + bloody diarrhoea + abdominal pain + weight loss" → UC until proven otherwise → flex sig + faecal calprotectin + biopsy.
4. "40-year-old + epigastric pain radiating to back + amylase >3×ULN" → pancreatitis → Glasgow-Imrie score + aggressive fluids + early enteral feeding.
5. "Elderly + central colicky pain + vomiting + distension" → SBO → drip and suck + CT + surgical review.

Traps to avoid:

• Don't give loperamide in C. diff.
• Don't give NSAIDs in cirrhosis.
• Don't operate on a sigmoid volvulus first — decompress endoscopically.
• Don't wait for transplant criteria in ALF — refer early.
• Don't use steroids in alcoholic hepatitis without assessing Maddrey/GAHS and excluding sepsis.

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Summary — five reflexes that win GI SBAs

1. Upper GI bleed → GBS → OGD within 24 h, terlipressin + antibiotics if variceal.
2. Charcot's triad → cholangitis → ERCP within 24 h.
3. Acute severe UC → IV steroids → rescue at day 3 with infliximab or ciclosporin, surgery if no response.
4. Paracetamol overdose + ALF → King's criteria → refer transplant centre early; NAC regardless of timing.
5. C. diff → stop antibiotic + oral vancomycin first-line; never loperamide; FMT for recurrent.

Combine this with the UKMLA Cardiology Masterclass and Respiratory Masterclass for a coherent medical acute-take revision stack. GI questions reward candidates who recognise pattern → score → ladder in one breath. Drill the five reflexes above until they fire automatically.