1537 Colonic Gallstone Obstruction in the Setting of Cholecystocolonic Fistula

Abstract

INTRODUCTION: Gallstone ileus is a relatively rare complication of cholelithiasis, estimated to account for approximately 1%-4% of all cases of mechanical intestinal obstruction. Cholecystoenteric fistulas form as a result of an inflamed gallbladder adhering to adjacent small bowel or colonic tissue, opening a channel by which gallstones can enter the intestinal tract. Fistula formation is most commonly to the duodenum (32.5-96.5%) but can also infrequently occur in the colon leading to gallstone impaction past the ileocecal valve. CASE DESCRIPTION/METHODS: Our patient is a 63 year old female who presented to the emergency room with one week of nonradiating stabbing left lower quadrant abdominal pain and constipation. She reported associated anorexia, and nausea without emesis. She was afebrile and hemodynamically stable. On exam, she was tender to palpation in the lower quadrants. No stool was present in the rectal vault. She had a negative Murphy's sign. Labs revealed WBC count 18.6 thousand/mcL, normal AST, normal ALT, and alkaline phosphatase 158 unit/L. Computed tomography (CT) scan abdomen/pelvis revealed gallbladder wall thickening with pneumobilia, cholelithiasis, normal common bile duct, and a large curvilinear hyperdensity in the distal colon (A). This was suspected to be a displaced gallstone in the sigmoid colon related to a fistula between the gallbladder and hepatic flexure (B). Removal of the stone was attempted by flexible sigmoidoscopy with snare and basket but was unsuccessful. She was then taken for exploratory laparotomy, transverse colotomy with extraction of 5 × 3.4 cm gallstone, loop transverse colostomy, and ventral hernia repair (C). She received IV antibiotics for 5 days and was discharged home. DISCUSSION: This case highlights a rare etiology of colonic gallstone obstruction in a patient without risk factors including underlying malignancy, colonic stricture, or diverticulum. Optimal surgical management of gallstone ileus with associated fistula is still being defined as few cases have been reported in the literature. One large retrospective survey found enterotomy with stone extraction to be associated with improved survival outcomes and decreased postoperative complications compared to surgery with fistula closure and bowel resection. Our patient had stable gallbladder changes and persistent cholecystoenteric fistula on CT scan over the next three months and expressed several gallstones through her colostomy without requiring further surgery.