A 70-year-old woman presents with distension, vomiting, and obstipation. Abdominal radiograph shows dilated small bowel loops, pneumobilia, and a calcified density in the right iliac fossa. She has no previous history of biliary surgery. The most likely diagnosis is:

• A Cholangiocarcinoma with duodenal invasion
• B Empyema of the gallbladder with ileus
• C Gallstone ileus secondary to cholecystoduodenal fistula ✓
• D Post-inflammatory choledochoduodenal fistula with pancreatitis

Explanation

The combination of small bowel obstruction, pneumobilia, and an ectopic calcified gallstone constitutes Rigler's triad, diagnostic of gallstone ileus from a cholecystoduodenal fistula. It typically occurs in elderly women after repeated episodes of cholecystitis erode the gallbladder into the duodenum. The stone impacts at the narrowest point, usually the terminal ileum. Empyema does not cause pneumobilia, and malignancy does not produce an ectopic luminal calcified stone with mechanical obstruction.

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

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Written and medically reviewed by the StethoPrep medical team.