Gallstones and biliary colic

Overview

•5 Fs: Fat, Female, Fertile/pregnant, Forty, Family history
•OCP/HRT - exogenous oestrogen increases biliary cholesterol
•Crohn's disease/ileal resection - impaired enterohepatic circulation of bile salts
•Haemolytic anaemia (e.g. sickle cell) - excess bilirubin → pigment stones

Presentation

•RUQ or epigastric pain - severe, often constant during episode; radiates to right shoulder tip or interscapular region
•Triggered by fatty meals - CCK-mediated gallbladder contraction against obstructing stone
•Duration - typically 30 minutes to 8 hours; resolves spontaneously when stone disimpacts
•Nausea and vomiting - common
•Jaundice and pruritus - if stone migrates into CBD; obstructive jaundice with pale stools and dark urine
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Cholestatic pruritus is caused by hyperbilirubinaemia (conjugated bilirubin accumulating in skin) - NOT by raised ALP alone. Severity of itch does not correlate with bilirubin level.

Investigations

🥇 First-line

•Abdominal ultrasound - identifies gallstones (echogenic foci with acoustic shadowing), gallbladder wall thickening (>3 mm suggests cholecystitis), CBD dilatation (>6 mm suggests obstruction)
•LFTs - obstructive pattern: disproportionately raised ALP and bilirubin, only mildly raised ALT
•FBC, CRP - raised WBC/CRP indicate cholecystitis or cholangitis
•Serum amylase/lipase - to exclude concurrent acute pancreatitis

🏆 Gold standard

•MRCP - near 100% sensitivity for CBD stones; non-invasive; used when USS inconclusive or CBD stones suspected

🥈 Second-line

•CT abdomen - reserved for inconclusive USS or suspected abscess/perforation; less sensitive for small stones

Differential Diagnosis

Key differentials in gallstone disease
ConditionKey features
Acute cholecystitisRUQ pain >6 hours, fever, positive Murphy's sign, raised WBC/CRP
Acute cholangitisCharcot's triad: RUQ pain + fever + jaundice; surgical emergency
Gallstone pancreatitisEpigastric pain radiating to back, markedly raised amylase
Pancreatic malignancy / cholangiocarcinomaPainless progressive jaundice, weight loss, palpable non-tender gallbladder (Courvoisier's sign)
Gallstone ileusSmall bowel obstruction + pneumobilia on AXR; Rigler's triad
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Courvoisier's law: painless obstructive jaundice + palpable non-tender gallbladder = malignancy (pancreatic carcinoma or cholangiocarcinoma) until proven otherwise - NOT gallstones, as chronic inflammation causes a shrunken fibrotic gallbladder. UC is a risk factor for PSC which predisposes to cholangiocarcinoma.

Management

•First-line analgesia: diclofenac orally or rectally (if vomiting) - NSAID; reduces sphincter of Oddi spasm
•Paracetamol - for mild to moderate pain
•Lifestyle advice - low-fat diet, weight loss
•Definitive treatment: laparoscopic cholecystectomy - offered within 6 weeks of presentation (NICE CG188)
•Second-line analgesia: morphine IM - severe pain not controlled by NSAIDs
•CBD stones: ERCP for clearance - before or instead of cholecystectomy in those unfit for surgery

Complications

•Gallstone ileus - large stone erodes through gallbladder wall into duodenum → lodges at ileocaecal valve → small bowel obstruction; AXR shows Rigler's triad: dilated small bowel loops + pneumobilia + ectopic radio-opaque stone
•Mirizzi's syndrome - stone impacted in cystic duct/Hartmann's pouch compresses CBD externally → obstructive jaundice without CBD stones
•Choledocholithiasis - stone in CBD → obstructive jaundice, raised ALP/bilirubin, dilated CBD on USS
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Gallstone ileus on AXR: background history of recurrent RUQ pain (chronic cholecystitis) + acute small bowel obstruction + pneumobilia = gallstone ileus until proven otherwise.