OGBN P13 Management of Bouveret Syndrome: an endoscopic approach
Authors: Sanyang Nyimasata , Shanti Hiba , Patel Ameet 
Published: December 2022

Abstract

Background
Bouveret syndrome is rare complication of gallstones with 600 reported cases since 1950. The syndrome occurs when adhesions develop between the gallbladder to surrounding hollow viscera leading to fistula formation. Large gallstones migrate into the enteric system and become impacted in the stomach or duodenum causing gastric outflow obstruction. Bouveret syndrome accounts for 1–4% of gallstone ileus cases. It is more common in co-morbid women in their 7th and 8th decades. Most common symptoms are vomiting and abdominal pain. Upper gastrointestinal bleeding is reported in 15% of cases. CT scan has the highest sensitivity at 79–93% to make the diagnosis. Of note 15–25% of gallstones are isoattenuating. Riglers triad is a diagnostic marker and consists of aerobilia, a gastric outflow obstruction or dilated bowel and the presence of a calculus outside of the biliary tree. The diagnosis was associated with mortality rates as high as 30% but with modern advances mortality has decreased to approximately 12%. Treatment options are surgical or endoscopic retrieval. Endoscopic management carries less risk especially in the frail elderly patient. This approach has low success rates. We present a case of successful endoscopic management of Bouveret syndrome and discuss surgical and endoscopic management strategies.

Methods
A frail 83 year old female attended ED with epigastric pain, vomiting and signs of sepsis. She had a recent diagnosis of severe cholecystitis that was managed conservatively. On examination she had tenderness in the right upper quadrant. Bloods revealed an AKI, a CRP 189 and normal liver function tests. Axial imaging showed aerobilia with a CBD dilated at 14mm and there was a 3.5cm calculus impacted in the duodenum with a cholecysto-duodenal fistula.
Her medical history included diabetes mellitus, atrial fibrillation, hypertension, primary hyperparathyroidism, reflux and cauda equina (operated). On OGD there was a large stone which had eroded into the first part of the duodenum. A combination of mechanical lithotripsy and the Kudo snare were used to fragment the stone. 2 large fragments were retrieved using a bag to avoid gallstone ileus.

Results
The patient had an uneventful but slow recovery. She re-established oral intake on the second post-operative day. She was discharged 2 weeks later without complication.

Conclusions
The success of endoscopic management is reported as low as 10%. Endoscopic intervention is attempted in 61% of cases. Success is more likely with stones &lt;4cm and if the site of impaction is the stomach or D1/D2.
Surgical management is associated with a morbidity rate of 26% but was successful in 78%. Laparoscopic surgery is possible but less successful in stones &gt;5cm. Endoscopic techniques have evolved and should be considered for extraction of stones in the first instance. If not feasible surgery can be considered. The literature shows that success is more likely when various endoscopic techniques are utilized including mechanical lithotripsy, nets and baskets, extracorporeal shock wave lithotripsy, electrohydraulic lithotripsy, laser lithotripsy and duodenal stenting.
There is a risk of distal migration of stone fragments causing gallstone ileus in the more distal small bowel. Bouveret syndrome can be resolved with endoscopy in expert hands.