Diagnosis of Aortoenteric Fistula in a 65-Year-Old Male With Recently Discovered Dieulafoy Lesion-A Case Report.

Background: Aortoenteric fistulas (AEFs) are an uncommon but often life-threatening cause of gastrointestinal (GI) hemorrhage in patients with a history of abdominal aortic aneurysm (AAA) repair. Dieulafoy lesions are a rare cause of GI bleeding, which can have significant morbidity if not identified promptly. Case Report: In this case, we describe a 65-year-old male with a history of AAA repair, complicated by graft infection, who was admitted for GI bleeding. An initial esophagogastroduodenoscopy (EGD) revealed a Dieulafoy lesion in the gastric fundus, which was treated with endoscopic clips. The patient was discharged after clinical improvement. Two weeks later, he returned with recurrent bleeding and hemodynamic instability. Repeat EGD showed no active bleeding but revealed persistent blood in the stomach and duodenum. Subsequent imaging raised concern for AEF; ultimately, emergent surgical exploration confirmed the diagnosis, revealing graft dehiscence and communication into the duodenum. Conclusion: This case highlights the diagnostic challenge of GI bleeding in patients with a history of AAA repair. AEFs may present with "herald bleeds" that mimic other causes of GI bleeding such as Dieulafoy lesions, delaying definitive diagnosis and treatment. Subtle radiologic findings, such as perigraft air, induration, or loss of normal aortic fat planes, should prompt urgent surgical evaluation, particularly in patients with a history of aortic instrumentation, infected grafts, or recurrent bleeding despite endoscopic therapy. High clinical suspicion, early CT angiography, and timely surgical consultation are critical to improving outcomes in these patients.