Bouveret Syndrome

Bouveret syndrome is gastric outlet obstruction caused by a large gallstone that has passed through a cholecystoduodenal fistula and impacted in the duodenal bulb or the pylorus. It is a rare form of gallstone ileus.

It accounts for 1% to 3% of gallstone ileus cases. Patients are mostly women over 65 years with comorbidity, and mortality is 12% to 30%. The stone is usually over 2.5 cm.

The Rigler triad on imaging is pneumobilia, bowel obstruction and an ectopic stone.

Pathophysiology.

Chronic cholecystitis causes adhesions between the gallbladder and duodenum, and pressure necrosis of the wall creates a fistula. A large stone passes into the duodenum and impacts at the narrowest point, producing obstruction.

Nausea, persistent vomiting (often with undigested food or bile stained), epigastric pain, early satiety, dehydration, weight loss, abdominal distension and, in some, haematemesis. A history of gallstones or previous biliary colic is frequent.

Red flags.

• Dehydration with acute kidney injury.
• Haematemesis.
• Peritonitis (perforation).
• Cholangitis.

CT is the best test: dilated stomach, pneumobilia, a gallbladder with thick wall adherent to the duodenum, and an ectopic stone in the duodenum or pylorus. Upper endoscopy shows an obstructing stone and often lesions of pressure necrosis. Ultrasound may show pneumobilia or a contracted gallbladder. Send electrolytes, renal function and lactate.

Differential diagnosis.

• Gastric outlet obstruction from peptic ulcer or cancer.
• Gallbladder carcinoma with fistula.
• Bezoar.
• Duodenal tumour.
• Superior mesenteric artery syndrome.

Resuscitate with intravenous fluids, correct electrolytes and pass a nasogastric tube.

• Pantoprazole: 40 mg IV once daily while nil by mouth; maximum 80 mg daily; monitor magnesium and symptoms; reduce to 20 mg daily in severe hepatic impairment.
• Piperacillin-tazobactam (cholangitis or sepsis): 4.5 g IV every 6 hours for 4 to 7 days; maximum 18 g daily; monitor renal function and counts; reduce for creatinine clearance under 40 mL/min.

Endoscopic removal (net, basket or fragmentation by mechanical, electrohydraulic or laser lithotripsy) is tried first in suitable patients, and succeeds in under a quarter of cases. Surgery is needed when endoscopy fails: enterolithotomy through gastrotomy or duodenotomy, with or without cholecystectomy and fistula repair. Fistula repair is usually staged, because of high risk in older adults.

Monitoring. Fluid balance, electrolytes and nutrition; observation for recurrent obstruction or cholangitis.

Referral and escalation. Advanced endoscopy and general surgery; critical care for sepsis.

Special groups. Older adults need early nutritional support and comorbidity optimisation.