A Rare Cause of Gastrointestinal Bleeding: Aorto-Enteric Fistula

Abstract

Introduction: Aortaenteric fistula (AEF) is defined as an abnormal connection between the gastrointestinal tract (GI) and the aorta. It's a rare cause of GIS bleeding with high mortality and morbidity. Case: A 70-year-old male patient admitted to emergency department with complaints of bright red feces had bloody defecation complaints for 1 month. Aneurysmatic dilatation about 90x82 mm wide extending to infrarenal level bifurcation level in abdominal aorta has been detected 3 months ago and follow-up has been planned. The patient complained of intermittent bloody stools and a palpable mass was observed around the umbilicus. Endoscopy revealed gastritis, hematogenous residues in the stomach and no bleeding detected. Colonoscopy revealed diverticula, polyps and hemorrhoids; active bleeding could not detected.The patient was hypotensive and CT angiography was performed,AEF at AA level at duodenum level 3 detected (Figure 1, 2). The patient underwent aorto-aortic tube graft implant surgery, but died due to Acute Renal Failure+Septic Shock on the postoperative 4th day. Conclusion: Abdominal aortic aneurysm is the most common cause of ARF. Less common causes include reflux esophagitis, peptic ulcer, pancreas pseudocyst, malignancies, embolizing stent erosion, aortitis, penetrating aortic ulcer, enteral stent, foreign bodies, paraaortic radiation, syphilis, tuberculosis and collagen vascular diseases. AEF is divided into primary(PAEF) and secondary(SAEF).The incidence of SAEF ranges between 0.36-1.6%; the incidence of PAEF is reported to be 0.06%.In the development of PAEF, mechanical factors and aortitis are thought to play a role and mostly (>75%) are seen in the 3rd and 4th part of the duodenum. There is no history of aortic surgery in PAEF and the fistula typically occurs in elderly patients, usually due to aneurysm resulting from atherosclerosis. The rupture of aorta to GIS is the most common presentation of AEF. Patients may present with massive or minor bleedings and may present with fatigue, weight loss, sepsis, lower extremity ischemia. AEF is difficultly diagnosed due to its rarity. Before massive bleeding messenger bleeding as described in a self-limiting episodes of bleeding is an important finding. Classic triad; GIS bleeding, abdominal pain, palpable mass is observed in 9-12% of patients. In hemodynamically stable patients, endoscopy may be considered in the diagnosis,but the sensitivity is 50%.In patients with high AEF suspicion, the superiority of bt angiography is higher.Unstable patients with known abdominal aortic aneurysms should be urgently scheduled for operation or endovascular intervention.