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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Caused by persistent gallstone obstruction of cystic duct → gallbladder distension, inflammation, ± secondary infection
- Classic presentation: persistent RUQ pain (>6 h), fever, positive Murphy sign, raised WCC/CRP
- USS: gallstones + gallbladder wall thickening (>3 mm) + pericholecystic fluid = diagnostic triad
- Early laparoscopic cholecystectomy within 1 week of diagnosis (NICE CG188) — NOT delayed surgery
- IV antibiotics (co-amoxiclav or cefuroxime + metronidazole) if septic or awaiting surgery
Overview
Acute cholecystitis occurs when a gallstone becomes persistently impacted in the cystic duct, causing gallbladder distension, wall inflammation, and secondary bacterial infection. Approximately 90% of cases are calculous (gallstone-related); 10% are acalculous (occurring in critically ill patients, post-surgical, or immunocompromised — carrying higher mortality). The gallbladder becomes oedematous and erythematous; untreated, it can progress to empyema (pus-filled), gangrene, or perforation.
Epidemiology
Acute cholecystitis accounts for approximately one-third of the 50,000 cholecystectomies performed annually in the UK. It is the most common acute complication of gallstone disease. Risk factors mirror those for gallstones: female sex, obesity, age >40, multiparity. Acalculous cholecystitis has a higher mortality (up to 30%) and occurs predominantly in ICU patients.
Clinical Features
Symptoms
Persistent severe RUQ or epigastric pain (>6 hours duration — distinguishes from biliary colic)
Pain radiating to right shoulder tip (phrenic nerve irritation)
Fever and malaise
Nausea and vomiting
Anorexia
Rigors (suggests empyema or gangrenous cholecystitis)
Signs
Positive Murphy sign: pain and inspiratory arrest on palpation of RUQ during inspiration (positive in cholecystitis, not biliary colic)
RUQ tenderness with localised guarding
Low-grade pyrexia (37.5–38.5°C)
Palpable gallbladder (occasionally)
High fever with rigors and peritonism (empyema, gangrene, or perforation)
Jaundice (suggests concurrent CBD stone — Mirizzi syndrome or choledocholithiasis)
Investigations
First-line
Abdominal ultrasoundFirst-line: gallstones + gallbladder wall thickening (>3 mm) + pericholecystic fluid. Sonographic Murphy sign (tenderness on probe compression over gallbladder)
BloodsFBC (leucocytosis), CRP (raised), LFTs (may be mildly deranged; significantly raised ALP/bilirubin → suspect CBD stone), U&Es, amylase (exclude pancreatitis)
Blood culturesIf pyrexial or septic
Second-line
MRCPIf LFTs deranged or CBD dilated on USS — to exclude choledocholithiasis
CT abdomenIf USS inconclusive or to assess complications (perforation, abscess, gangrene)
Specialist
HIDA scan (hepatobiliary iminodiacetic acid)If diagnosis uncertain — non-filling of gallbladder confirms cystic duct obstruction (rarely needed in UK practice)
Management
NICE CG188 (Gallstone disease), 20141
Acute management
- IV fluids and nil by mouth
- Analgesia: paracetamol + NSAID (diclofenac) ± opioid for severe pain
- IV antibiotics: co-amoxiclav 1.2 g TDS or cefuroxime 1.5 g TDS + metronidazole 500 mg TDS
- VTE prophylaxis
2
Surgical management
- Early laparoscopic cholecystectomy: within 1 week of diagnosis (NICE CG188)
- Early surgery is safe, reduces total hospital stay, and has no increase in complication rate compared with delayed surgery
- If unfit for surgery: percutaneous cholecystostomy (drainage) as temporising measure
3
Complications requiring intervention
- Gallbladder empyema: percutaneous cholecystostomy if surgery contraindicated; then interval cholecystectomy
- Gangrenous cholecystitis: urgent cholecystectomy
- Perforation: emergency laparotomy with cholecystectomy and peritoneal washout
Complications
- Empyema: Pus-filled gallbladder — high fever, sepsis, systemic toxicity
- Gangrenous cholecystitis: Wall necrosis — risk of perforation
- Gallbladder perforation: Localised (pericholecystic abscess) or free perforation → biliary peritonitis
- Cholecystoenteric fistula: Erosion into adjacent bowel → gallstone ileus (stone impacts at ileocaecal valve)
- Mirizzi syndrome: Impacted stone in Hartmann pouch compressing common hepatic duct
UKMLA Exam Tips
- 1Murphy sign positive in cholecystitis but NOT in biliary colic — key differentiator
- 2Pain >6 hours + fever + positive Murphy sign = cholecystitis (not biliary colic)
- 3Early cholecystectomy within 1 WEEK (not 6 weeks) — NICE CG188 changed practice from delayed approach
- 4Acalculous cholecystitis: think critically ill ICU patient with unexplained sepsis — high mortality
- 5Gallstone ileus: small bowel obstruction + pneumobilia (air in biliary tree) on CT = Rigler triad
practicetest your knowledge on acute cholecystitisApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — gastroenterology and beyond.
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