S3566 Uncovering an Unusual Cause of Biliary Obstruction, Cholangitis, and Associated Pancreatitis: Lemmel’s Syndrome

Introduction: Common bile duct (CBD) stones and periampullary obstructing tumors cause most cases of biliary obstruction (BO). Rarely, it is due to a duodenal diverticulum (DD), known as “Lemmel's Syndrome.” Although DD is usually asymptomatic, it can occasionally result in biliary-pancreatic or other complications. We present a case of recurrent Lemmel's syndrome, cholangitis, and pancreatitis secondary to DD, successfully treated with endoscopic retrograde cholangiopancreatography (ERCP). Case Description/Methods: An 87-year-old man with a history of gastroesophageal reflux disease, BPH, and remote cholecystectomy presented with severe abdominal pain and fever (38.4°C). Pertinent labs showed AST of 411, ALT of 332, total bilirubin of 4.2, direct bilirubin of 2.5, and lipase of 755. A computed tomography abdomen indicated acute pancreatitis with pancreatic necrosis or a duodenal ulcer penetrating the pancreas, along with a dilated biliary system. The patient was started on antibiotics. Magnetic resonance cholangiopancreatography (MRCP) suggested a DD versus an abscess or duodenal ulceration. Endoscopic ultrasound showed biliary sludge without stones. ERCP revealed a DD with the papilla in the middle and dilated bile ducts. A careful papillotomy was performed, resolving the symptoms and normalizing liver enzymes and bilirubin. Later, he returned with a similar presentation, which resolved after ERCP with papillotomy extension and stenting of the CBD and the pancreatic duct. Discussion: Lemmel's syndrome occurs when a periampullary diverticulum (PAD) causes BO without another cause. Depending on the diagnostic method, DD is found in approximately 22% to 27% of some populations, with most cases being asymptomatic and only a small percentage developing serious complications. The mechanisms of BO in the presence of DD are attributed to direct mechanical compression of the biliary system by the PAD, CBD stone formation, and chronic irritation of the ampulla by the PAD, leading to ampullary fibrosis. In some instances, the location and position of the diverticulum can cause functional flow obstruction of the ampulla. Occasionally, an enterolith obstructs the diverticulum and hence the ampulla of Vater. Diagnosis of the DD can be made with a computed tomography scan, MRCP, or endoscopic retrograde cholangiopancreatography (ERCP). Imaging may initially misinterpret the DD as pancreatic necrosis or an abscess. Treatment is usually reserved for symptomatic patients and those with complications, ranging from ERCP to surgical excision. In conclusion, although DD causing biliary obstruction is rare, it should be considered in the differential diagnosis when other causes are excluded. Early diagnosis and management are associated with satisfactory outcomes.