A 75-year-old woman presents with vomiting, abdominal distension, and absolute constipation for two days. Plain abdominal X-ray shows dilated small bowel loops with air-fluid levels, air in the biliary tree, and a calcified opacity in the right lower quadrant. What is the most specific sign confirming the diagnosis?

• A Dilated small bowel loops with air-fluid levels
• B Air in the biliary tree
• C Calcified opacity in the right lower quadrant ✓
• D Absence of colonic gas

Explanation

This is Rigler's triad for gallstone ileus: small bowel obstruction, pneumobilia, and an ectopic gallstone. The calcified gallstone in the right lower quadrant (site of impaction) is the most specific finding, as it confirms the underlying pathology. Dilated loops and pneumobilia are seen in other conditions. Absence of colonic gas is nonspecific.

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.