Secondary aortoduodenal fistulas complicating aortic reconstructive surgery are far more common. The third and fourth parts of the duodenum are the most common sites in all types of aortoenteric fistula. Diagnosis of a primary aortoenteric fistula is difficult, especially in the absence of melena or hematemesis. Upper GI endoscopy can rule out other causes of bleeding but rarely diagnose fistulae. CT can show AAA, extraluminal gas and secondary findings as in this case with the patient actively bleeding.
Surgical exploration is often necessary.
The diagnosis of aortoduodenal fistula should always be considered in patients with large untreated AAA and upper or lower GI bleeding of unknown etiology. Two Case Reports and a Review of the Literature. Taheri SA, Kulaylat MN, Grippi J, Ricotta J, Kale J, Bernhard H. Surgical Treatment of Primary Aortoduodenal Fistula. Ann Vasc Surg. Primary Aortoduodenal Fistula.