Gallstone Ileus With Prior CT Showing the Stone Before Fistula Formation: A Case Report

Gallstone ileus is an uncommon cause of mechanical bowel obstruction, and imaging obtained before the fistula forms is rarely available.A 98-year-old woman with known cholelithiasis presented with one to two weeks of decreased appetite, nausea, vomiting, and vague abdominal pain.Contrast-enhanced CT showed small bowel obstruction, pneumobilia, a cholecystoduodenal fistula, and a 3.6 cm hypoattenuating gallstone at the jejunal transition point.CT obtained 10 months earlier, during an emergency department visit for epigastric pain, had shown a large gallstone within the gallbladder with no pneumobilia or fistula, and she had been referred for surgical evaluation.She underwent enterolithotomy, and a 4.5 cm gallstone was removed from the jejunum approximately 50 cm distal to the ligament of Treitz.Cholecystectomy and fistula repair were deferred because of her age and comorbidities, and she was tolerating a diet at the two-week follow-up.The two CT examinations bracket the interval in which the fistula formed and the stone migrated.A large gallstone found on imaging is an opportunity to discuss elective cholecystectomy when surgical risk is acceptable.