1268 The Hidden Gallbladder: An Unusual Case of Bouveret Syndrome

Abstract

INTRODUCTION: Bouveret syndrome is the most infrequent variant of gallstone ileus characterized by a biliary fistula with the stomach or small intestine. The fistula occurs from recurrent gallbladder inflammation causing adhesion to the GI tract followed by local necrosis. Patients generally present nausea, vomiting, and abdominal pain/distention with variable lab abnormalities, with jaundice and hepatic enzyme alternations in only 1/3 of patients. 43-68% of patients have a history of recurrent biliary colic and given the delay in diagnosis, patients can present very late with dehydration and weight loss. CT scan is diagnostic modality of choice with an overall 93% sensitivity, 100% specificity, and 99% diagnostic accuracy. We present a rare case of Bouveret Syndrome missed by CT scan and diagnosed by ERCP. CASE DESCRIPTION/METHODS: Our patient is an 81-year-old male who presented with jaundice and intermittent fever/chills. He reported 7 months of intermittent nausea, vomiting, and abdominal pain and reportedly lost approximately 80 pounds in the past year. The patient denied any prior cholecystectomy. He was noted to have total bilirubin of 8.1 and an alkaline phosphatase of 523. RUQ U/S showed a 1.5 cm common bile duct (CBD) and non-visualization of the gall bladder. CT scan was performed showing CBD of 2.0 cm but no clear cholelithiasis and reported absence of the gallbladder. Patient subsequently had EUS/ERCP. EUS showed a shrunken decompressed gallbladder with cholelithiasis (Figure 1) and bilious output into the lesser curvature of the stomach concerning for fistulous process. ERCP showed dilated CBD with multiple large gallstones with sphincterotomy and balloon extraction (Figure 2). Impaction cholangiogram with cinematic fluoroscopy confirmed a cholecystogastric fistula (Figure 3). The patient was a poor surgical candidate but had improvement in his symptoms and liver function tests and was safely discharged home. DISCUSSION: Bouveret syndrome is a very rare complication of gallstone ileus that can have high mortality due to its late and nonspecific presentation. There have been approximately 300 cases of documented Bouveret syndrome with 60% of cases involving a cholecystoduodenal fistula. 5% of cases present with a cholecystogastric fistula. As CT is the mainstay of diagnosis, our case is further unique in that CT scan and RUQ U/S reported an absent gallbladder (which the patient denied), likely due to the contracted nature noted on EUS and required endoscopic visualization and ERCP to confirm.