A 65-year-old woman presents with a 3-day history of colicky central abdominal pain, vomiting, and absolute constipation. CT shows dilated small bowel loops with a 'beak sign' in the right iliac fossa and a calcified density. The most likely diagnosis is:
- A Adhesive small bowel obstruction
- B Gallstone ileus with obstruction at the terminal ileum ✓
- C Mesenteric ischaemia
- D Intussusception with lead point
Correct answer: B. Gallstone ileus with obstruction at the terminal ileum
Explanation
Gallstone ileus classically presents in elderly women with small bowel obstruction from a large gallstone (usually >2.5 cm) eroding through a cholecystenteric fistula. The CT triad (Rigler's triad): small bowel obstruction, ectopic calcified stone (often at terminal ileum — the narrowest fixed segment), and pneumobilia. The 'beak sign' at the obstruction point and a calcified density confirm the diagnosis. Treatment is enterolithotomy; the cholecystenteric fistula is addressed in a planned second stage.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.