[Two cases of aortoenteric fistula with gastrointestinal bleeding].

Aortoenteric fistula (AEF) is a life-threatening condition that can present with gastrointestinal (GI) bleeding. AEFs have been classified into primary and secondary types. Primary AEF (PAEF) is a direct communication between the aorta and the GI tract. Secondary AEF (SAEF) is the result of a previous abdominal aortic aneurysm repair involving placement of a synthetic aortic graft. Diagnosis of AEF, especially PAEF, is difficult largely because AEF is so rarely encountered in practice. Computed tomography (CT) and endoscopic gastroduodenoscopy (EGD) are most frequently used to diagnose AEF, with abdominal contrast-enhanced CT being the preferred initial diagnostic test of choice. Although EGD can exclude other common causes of GI hemorrhage, it cannot be used to rule out AEF when another source of bleeding is identified, as the two conditions can coexist. We discuss here two patients with GI bleeding who were diagnosed as PAEF and SAEF. We tried to diagnose and treat with EGD, but failed. That bleeding was due to an AEF became evident when abdominal CT scans revealed direct extravasation of contrast media from the abdominal aorta into the GI tract. The lack of awareness of AEF, coupled with the inaccessibility to the distal duodenum via EGD, were probably responsible for initial misdiagnosis and delay of appropriate management. We suggest that the diagnosis of AEF remains dependent on the clinician's heightened suspicion.