A 72-year-old woman presents with 3 days of colicky abdominal pain, distension, and bilious vomiting. Plain radiograph shows dilated small bowel loops, pneumobilia, and an ectopic calcified shadow in the right iliac fossa. The most likely site of intestinal obstruction is the:

• A Duodenojejunal flexure
• B Ileocaecal valve on the colonic side
• C Sigmoid colon
• D Terminal ileum ✓

Explanation

The triad of small bowel obstruction, pneumobilia, and an ectopic gallstone indicates gallstone ileus from a cholecystoduodenal fistula. The stone typically impacts at the narrowest point of the small intestine, the terminal ileum near the ileocaecal valve, producing mechanical obstruction. The sigmoid colon is the usual site of impaction only in the rare variant where a large stone causes colonic obstruction after passing through the ileocaecal valve.

Reference: Bailey and Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.