[Aorto-intestinal fistula versus angiodysplasia. A difficult differential diagnosis in gastrointestinal bleeding]

A 63-year-old patient had recurrent tarry stools and haemoglobin levels of around 7.0 g/dl. Ten years previously he had undergone an aortobifemoral bypass operation for peripheral vascular disease in the legs. Eight gastroscopies and five coloscopies over ten weeks failed to discover a bleeding source. Although an aorto-intestinal fistula was considered early on, extensive diagnostic tests failed to reveal it. Digital subtraction angiography was suggestive of an angiodysplasia of the terminal ileum, a diagnosis supported when coloscopy during exploratory laparotomy visualized blood trickling from the terminal ileum. As a result of this finding a right hemicolectomy was performed. But recurrent bleedings necessitated relaparotomy which finally revealed a fistula between the ascending duodenum and the proximal bypass graft anastomosis. Nine months after resection of the proximal anastomotic area and interposition of a Dacron prosthesis the patient has been free of symptoms.