Primary aortoenteric fistula in the Emergency Department.

A primary aortoenteric fistula is a rare, life-threatening cause of gastrointestinal bleeding. Primary aortoenteric fistula results most commonly from an abdominal aortic aneurysm, with the fistula forming most often between the aorta and the third portion of the duodenum. Often, the classic triad of abdominal pain, gastrointestinal bleeding, and pulsatile mass is absent. A heraldic bleed frequently precedes lethal exsanguination from a primary aortoenteric fistula. Patient survival is dependent on prompt diagnosis and emergent therapeutic laparotomy.