S3396 Sump Syndrome Presenting With Pneumobilia: A Rare Clinical Manifestation

Introduction: Sump syndrome (SS) is a rare complication caused by the accumulation of bile, debris, or duodenal contents in the distal common bile duct (CBD), leading to biliary stasis and inflammation. Symptoms may include abdominal pain, nausea, vomiting, postprandial discomfort, and jaundice. SS is most commonly seen after choledochoduodenostomy (CDD), a surgical procedure used before the advent of endoscopic retrograde cholangiopancreatography (ERCP). However, this case involves a patient with no history of CDD, creating a diagnostic challenge. Case Description/Methods: A 26-year-old man with a history of asthma, GERD, eosinophilic esophagitis, and hiatal hernia presented with 12 hours of worsening right upper quadrant abdominal pain. He denied fever, vomiting, or bowel changes. Exam revealed localized tenderness without peritoneal signs. Labs were unremarkable, but imaging showed pneumobilia. He was admitted and evaluated by gastroenterology. Esophagogastroduodenoscopy (EGD) revealed a duodenal ulcer with a fistulous opening, raising concern for a spontaneous choledochoduodenal fistula. He was started on a proton pump inhibitor and transferred for surgical evaluation. Discussion: SS typically follows CDD, where the distal CBD becomes a reservoir for refluxed contents. However, in rare cases, spontaneous choledochoduodenal fistulas—often secondary to duodenal ulcers—can mimic this physiology. Imaging findings like pneumobilia, biliary dilation, or debris suggest the diagnosis. EGD and magnetic resonance cholangiopancreatography (MRCP) confirmed the fistula in this case. Treatment varies based on severity: surgery such as Roux-en-Y hepaticojejunostomy may be required, though conservative management with acid suppression may suffice in mild cases. Our patient responded well to proton pump inhibitor therapy without need for immediate surgery.