Recurrent Gastrointestinal Bleeding from an Occult Source

Abstract

Purpose: An 81-year old male with a history of hypertension, hyperlipidemia, smoking, and peptic ulcer disease (PUD) presented with two episodes of maroon stools for three days and was found to be orthostatic. His PUD was thought to have accounted for a previous upper gastrointestinal (GI) bleed. A colonoscopy revealed three polyps and few diverticuli throughout the colon that were considered the source of the bleeding. Two months later,the patient had massive lower GI bleeding and developed hypovolemic shock with a positive bleeding scan in the splenic flexure; however, angiography was negative. A repeat colonoscopy revealed transverse/descending colon diverticular disease and the patient was scheduled for a left hemicolectomy for presumed diverticular bleeding. Intraoperatively, an Aortoenteric fistula secondary to an Aorto-bi-iliac bypass graft placed during an Abdominal Aortic Aneurysm (AAA) repair 14 years prior was found. The patient had an Aortoenteric fistula repair and did well postoperatively without further bleeding. Results: It is well recognized that Aortoenteric fistulas can present with signs of upper or lower GI bleeding. Patients have an initial bleed manifested by hematochezia followed by a massive bleed causing hypovolemic shock. The key to diagnosis is a high index of suspicion in the setting of previous AAA repair, which warrants angiography. Diagnosis can be extremely difficult and is most often made in emergent laparotomy. The mortality rate for an untreated aortoenteric fistula is 100% and emergent surgery is the treatment of choice in the setting of secondary GI bleeding. Conclusion: We advocate that Aortoenteric Fistulas can mask as upper GI bleeding or lower GI bleeding mimicking diverticulosis. Aortoenteric Fistulas should be highly considered in patients with previous AAA repair or risk factors for AAA. Aortoenteric Fistulas should be ruled out first in any patient with a GI Bleed and previous aortic surgery.Figure: Aorto-bi-iliac Bypass Graft placed for Extensive AAA with Distal Anastomotic Aneurysm Predisposing to a Fistula from the Right Iliac Artery to the Terminal Ileum, which caused the patient's Massive Lower GI Bleeding and Upper GI Bleeding.