The Herald Bleed: A Case Report of an Aortoenteric Fistula causing an Acute Lower Gastrointestinal Bleed

Aortoenteric fistula (AEF) is a rare life-threatening condition. Secondary AEF (SAEF) occurs in patients with abdominal aortic aneurysm (AAA) repair and has a high mortality rate. We present a case of a 66-year-old female who presented to the emergency room with hematochezia and hemodynamic instability. Emergent esophagogastroduodenoscopy (EGD) was negative. Colonoscopy revealed a 5 cm, pulsatile, bleeding, submucosal mass. A stat computed tomography (CT) angiogram of the abdomen and pelvis revealed a large left external iliac artery (LEIA) pseudoaneurysm. Vascular surgery emergently placed a LEIA stent. It appeared the patient had an aorto-bi-iliac (ABI) common iliac artery (CIA) bypass, 15 years ago, for a large AAA that had resulted in a SAEF, with the rare finding of communication with the colon. She had a complicated course involving surgical and medical management but with successful outcomes.