An Unusual Case of Choledochoduodenal Fistula Secondary to Peptic Ulcer Presenting With Cholangitis and Pneumobilia

Choledochodoudenal fistula is an uncommon bilio-enteric fistula with clinical presentation ranging from having no symptoms to frank cholangitis. The causes of choledochodoudenal fistula are multiple, with bile duct stones being the most common. Duodenal ulcer is rarely the source of choledochodoudenal fistula. Clinical diagnosis defies acumen, and high-quality imaging including endoscopic or radiologic imaging is required for confirmation. Management of choledochodoudenal fistula is not standardized and remains challenging. We report an unusual case of a choledochodoudenal fistula caused by a duodenal ulcer that presented with pneumobilia and cholangitis. Treatment demanded medical, endoscopic, radiologic, and, ultimately, surgical intervention.