A 68-year-old woman presents with 2 days of colicky abdominal pain, bilious vomiting, and distension. She has had intermittent self-limiting episodes of similar pain over the past year. Plain abdominal radiograph shows dilated small bowel loops, a radio-opaque shadow in the right iliac fossa, and gas outlining the biliary tree. What is the most likely diagnosis?

• A Sigmoid volvulus
• B Gallstone ileus ✓
• C Caecal carcinoma causing large bowel obstruction
• D Adhesive small bowel obstruction

Explanation

The combination of small bowel obstruction, pneumobilia, and an ectopic radio-opaque stone is Rigler's triad, diagnostic of gallstone ileus. It results from a cholecystoduodenal fistula formed after repeated attacks of cholecystitis; the stone impacts usually at the terminal ileum, the narrowest point of the small bowel. The history of recurrent colic before obstruction is typical of a stone migrating down the gut. Sigmoid volvulus gives a coffee bean sign without pneumobilia, and adhesive obstruction does not explain air in the biliary tree.

Reference: Bailey and Love's Short Practice of Surgery, 28th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.