Primary Aortoenteric Fistula — An Uncommon Cause for GI Bleeding

Abstract

A 68-year-old white male presented to an emergency room with acute onset of abdominal pain and hematochezia. The patient's pain had subsided upon reaching the ER. Physical exam revealed stable vital signs and a tender abdomen without masses or bruits. Diagnostic testing included a tagged red blood cell scan suggesting bleeding within the sigmoid colon, followed by endoscopy which did not identify a culprit lesion. Within 24 hours of hospitalization the abdominal discomfort and bleeding returned. Further imaging with CT angiogram visualized an infrarenal aneurysm with a subtle leak of contrast into the duodenum. He was transferred to a tertiary care center and became hemodynamically unstable with persistent hematochezia upon arrival. Upper endoscopy was repeated but was limited by active pooling of blood. Angiography immediately followed this procedure and confirmed an aortoduodenal fistula (figures 1 and 2). The patient was taken emergently to the operating room for surgical repair and died intraoperatively from massive exsanguination. A primary aortoenteric fistula (PAEF) is a rare diagnosis. Unlike a secondary aortoenteric fistula, a PAEF is an abnormal communication between the aorta and enteric system that develops without prior history of aortic graft placement. The natural history is self-limited bleeding which can escalate to massive exsanguination within 24 hours. For this reason, early suspicion, diagnosis, and treatment are paramount to patient survival. Unfortunately, the bleeding pattern in a PAEF can make diagnostic studies misleading, and current technology may preclude a perfect diagnostic tool. The experience of this case suggests the need for heightened physician awareness of PAEFs and a lower threshold for surgical intervention. [figure 1][figure 2]Figure 1Figure 2