Aortocolic fistula, a lethal cause of lower gastrointestinal bleeding: report of a case.

Aortocolic fistula occurs with spontaneous rupture of aortic and iliac aneurysms into the sigmoid colon, or due to involvement of the aneurysmal wall by acute diverticulitis. In the eight cases reviewed, this complication proved uniformly lethal, although sufficient clinical findings were present for diagnosis, and adequate time was available for a planned therapeutic approach. Lower gastrointestinal bleeding in the patient who has an aortic aneurysm and left-lower-quadrant inflammation suggests the presence of an aortocolic fistual. Angiography should be performed during a bleeding episode to confirm the diagnosis. Surgical correction consists of an axillofemoral by pass graft, excision of the aortic aneurysm, and a Hartmann procedure.