Primary aorto-duodenal fistula: A case report and review of literature

Aortoenteric fistula (AEF) is a rare condition where abnormal communication exists between the abdominal aorta and any part of the GI tract, most commonly, the third/fourth part of the duodenum. The incidence rate of primary aorto-duodenal fistula (PADF) on autopsy is 0.04 to 0.7%, and the post-operative incidence rate of a secondary AEF is 0.5 to 2.3%. An AEF can be diagnosed using either an upper gastrointestinal endoscopy (UGIE) or a contrast-enhanced computed tomography (CECT) angiography of the abdomen, and urgent repair is required by surgical or endovascular means. We report the case of a 64-year-old gentleman with a bleeding PADF. He was evaluated using UGIE and CT angiography of abdomen and underwent total endovascular repair of the aneurysm. PADF is a rare cause of GI bleeding, accounting for only 0.2% of all GI bleeds. The patient can initially show signs of a herald bleed but can also present with the classical triad of pulsatile abdominal lump, GI bleed, and abdominal pain. Endoscopy should be the initial investigation of choice for a stable patient. A negative EGD does not rule out the possibility of a PADF. CECT abdominal angiography can also be a useful diagnostic modality; some consider it superior to UGIE or aortography. PADF is a rare but life-threatening condition that requires prompt recognition and intervention, either by surgery or endovascular repair.