Enteric fistulization of a common iliac artery aneurysm: an unusual cause of gastrointestinal hemorrhage and shock.

A 78-year-old man with a history of recent unexplained lower gastrointestinal bleeding presented to the emergency department with the acute onset of abdominal pain, tenesmus, and shock. Computed tomography of the abdomen showed a fistula between a common iliac artery aneurysm and the small intestine. Laparotomy demonstrated a saccular aneurysm of the common and proximal internal iliac arteries with fistulous communication to the distal ileum. Aneurysmectomy, arteriorrhaphy, and segmental ileal resection with primary anastomosis were successfully performed. This case illustrates a rare complication of an uncommon aneurysm, emphasizing the need for emergency physicians to consider complicated vascular disease in the evaluation of a patient with abdominal pain and shock.