A 72-year-old woman with a history of symptomatic gallstones presents with four days of colicky central abdominal pain, bilious vomiting, and distension. Plain abdominal radiograph shows dilated small bowel loops, gas within the biliary tree, and a calcified opacity in the right iliac fossa. What is the most likely diagnosis?

• A Gallstone ileus via a cholecystoduodenal fistula ✓
• B Caecal volvulus
• C Adhesive small bowel obstruction
• D Emphysematous cholecystitis with ileus

Explanation

The combination shown, pneumobilia, small bowel dilatation, and an ectopic radio-opaque gallstone, constitutes Rigler's triad of gallstone ileus. B large stone erodes through the gallbladder wall into the duodenum, forming a fistula, then impacts at the narrow terminal ileum. Adhesive obstruction would not explain pneumobilia, and emphysematous cholecystitis does not produce mechanical small bowel obstruction.

Reference: Sabiston Textbook of Surgery, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.