Clinical features:
(1) One or more risk factors for an aortoenteric fistula (see previous section), with most cases associated with an abdominal aortic aneurysm.
(2) Some patients will complain of a recent onset of back pain.
(3) A "herald", "sentinel", or "signal" bleeding episode (brief episode of bleeding that stops for hours or days, only to be followed by massive hemorrhage).
(4) The patient has evidence of upper GI bleeding with hematemesis and/or melena. Massive hemorrhage is associated with shock. Patients with an aortic aneurysm may have a palpable abdominal midline mass.
(5) The bleeding usually is from second or third portion of the duodenum.
(6) Endoscopy may be difficult due to the severe bleeding but can help exclude varices and peptic ulcer disease.
(7) An abdominal CT scan is usually diagnostic. In aortic aneurysms extraluminal gas may be present.
(8) The presence of a positive blood culture worsens the prognosis in patients with fistulas secondary to infection.
