Gastrointestinal: Aortoenteric fistula

A 65 year old man with diabetes mellitus and hypertension, presented with recurrent hematemesis and melena of 20 days’ duration requiring multiple blood transfusions. Physical examination was unremarkable except for pallor. An upper gastrointestinal endoscopy up to the duodenojejunal flexure and a colonoscopy were performed and found to be normal. He underwent a contrast enhanced computed tomogram (CECT) of the abdomen. The CECT of the abdomen revealed an atherosclerotic aortic aneurysm adherent to the third part of duodenum and adjacent inferior vena cava suggesting an aortoenteric fistula missed on endoscopy (Figure 1A and 1B). He was considered a high risk candidate for surgery and therefore was subjected to endovascular stent graft placement (Advanta V12 covered stent 16 mm ¥ 61 mm, Atrium; Figure 2A and 2B). He did not develop any further bleeding following discharge from hospital. Aortoenteric fistulas are a rare cause of acute gastrointestinal (GI) hemorrhage, but they are associated with high mortality if undiagnosed or untreated. The third portion of the duodenum is the most common site for aortoenteric fistulas. Most patients present with an initial ‘herald’ hemorrhage that is manifested by hematemesis, melena or hematochezia. This may be followed by massive bleeding and exsanguination. The classic presentation is that of an elderly patient with massive upper GI hemorrhage, a pulsatile abdominal mass and abdominal (or back) pain. However, this triad is present in only 11% of patients. Our case was unusual with respect to the intermittent character of the hemorrhage lasting for almost a month. Intermittent bleeding is possible when a blood clot temporarily seals the fistula. A negative upper GI endoscopy can be explained by thrombus formation, presence of a tiny fistula or hypotension. The most common cause of primary aortoenteric fistulas is an atherosclerotic aortic aneurysm (as was seen in our case); other causes include infectious aortitis due to syphilis or tuberculosis. Secondary aortoenteric fistulas are caused by a prosthetic abdominal aortic vascular graft eroding into the duodenum, penetrating duodenal ulcer, tumour invasion, trauma, radiation therapy, and foreign body perforation. CECT of the abdomen is helpful with a detection rate of 30–61%. Surgery is generally the preferred mode of treatment. Age and major coexisting illnesses increase the morbidity and mortality associated with surgery. The advent of interventional radiology and endovascular stent graft placement has resulted in a quicker, safer and more successful management of this life threatening entity.