1449 The “Runaway” Gallstone: Cholecystoduodenal Fistula Presenting as Gallstone Ileus

Abstract

INTRODUCTION: Gallstone ileus is a rare condition caused by impaction of a gallstone in the ileum after its passage through a biliary-enteric fistula. Diagnosis can often be delayed since symptoms may be intermittent. We present a case of gallstone ileus diagnosed with endoscopic ultrasound and computed tomography. CASE DESCRIPTION/METHODS: A 91-year-old female presented to the Emergency Department with symptoms of left flank pain, nausea, and vomiting. Laboratory studies including liver panel and complete blood count were unremarkable. Initial CT scan of the abdomen showed pericholecystic edema and possible gallstones with pneumobilia. Upper endoscopy revealed an ulcerated area with a fistulous opening containing pigment stone in the first portion of the duodenum. Endoscopic ultrasound findings included thickened gallbladder wall with a fistulous opening in the duodenum consistent with cholecystoduodenal fistula. Over the course of the next couple of days, the patient's symptoms of nausea and vomiting worsened. A repeat CT scan demonstrated signs of small bowel obstruction, pneumobilia, and an impacted stone in the jejunum - findings consistent with Rigler's triad. Patient underwent a laparoscopic-assisted enterotomy with removal of the obstructing intraluminal gallstone. She did well and was discharged home five days later. We postulate that the patient's intermittent obstruction was a result of the stone “tumbling” through the bowel lumen. DISCUSSION: Cholecystoduodenal fistula can be associated with obstruction either in the duodenum (Bouveret's syndrome), or more distally (gallstone ileus). Gallstone ileus can present with vague, intermittent symptoms that evolve over several days. A high index of suspicion is necessary for timely diagnosis. Our case highlights the role of upper endoscopy and endoscopic ultrasound in making an early diagnosis that may allow for expeditious treatment. If initial imaging is not diagnostic, repeat imaging may be helpful in confirming gallstone ileus.