A case report of primary aortoduodenal fistula: A forgotten cause of gastrointestinal bleeding.

Aortoenteric fistula is one of the uncommon emergencies and is challenging to navigate for diagnostic testing. Here, we present a clinical case of an aortoduodenal fistula with primary etiology. A 73-year-old female patient with a history of hypertension was admitted to the hospital because of a 1-day history of melena. Ultrasound showed an abdominal aortic aneurysm sized (33 × 46) mm and a hematoma on the wall of the aorta. The patient underwent a gastrointestinal endoscopy with no bleeding point detected. However, the patient suddenly fell into a hemorrhagic shock on day 3 of admission. We rapidly performed fluid resuscitation, blood transfusion, a second gastrointestinal endoscopy, and a computed tomography scan of the abdomen with contrast injection that revealed a fistula from the abdominal aorta into the second segment of the duodenum. The patient was indicated for urgent endovascular aortic repair. Although this technique was successful with 3 abdominal aortic stents, the patient died due to multiorgan failure. Delayed diagnosis is the root cause of primary aortoduodenal fistula treatment failure, so it is important for clinicians to keep aortoduodenal fistula in mind as a possible cause of gastrointestinal bleeding in any patient.