Aorto‐appendiceal fistula presenting with bleeding per rectum

Abstract

Aorto-appendiceal fistula presenting with bleeding per rectumFistula formation between the gastrointestinal tract and aortic graft is an infrequent but well recognized complication. There have been seven previously reported cases of graft appendiceal fistula in the literature between 1969 and 1992. 1-4 We report an eighth case of aorto-appendiceal fistula presenting with bleeding per rectum.A 75-year-old man presented to a major hospital having passed approximately 400 mL of liquid dark red stool. His past history included an elective aortobiiliac aneurysm repair with a dacron graft 12 years earlier and a left hemicolectomy with splenectomy 5 years previously for carcinoma of the colon.On admission, he was haemodynamically stable with a haemoglobin level of 14.9 g/dL and evidence of fresh blood on rectal examination. He continued to bleed intermittently with a drop in haemoglobin level at 24 h and a nuclear labelled red cell scan performed was inconclusive. Colonoscopy performed showed fresh blood in the colon but no site of active bleeding was seen.At 48 h, he continued to bleed with signs of haemodynamic instability. A repeat nuclear labelled red cell scan showed positive gastrointestinal blood loss which appeared to arise from the caecum. Following resuscitation, an emergency laparotomy was undertaken. At laparotomy, the appendix was found adherent to the distal end of the right limb of the aortic graft. An appendicectomy, excision of the infected right limb graft and iliac artery was performed. An in-situ replacement with a 8-mm gelsoft plus dacron was used. His postoperative course was uneventful and he was discharged home at 2 weeks with ongoing antibiotics.The diagnosis and management of an aorto-appendiceal fistula can be complex and challenging. The majority of the previous cases presented with a history of gastrointestinal bleeding with or without shock.In this case report, the patient had a history of aortic reconstruction many years previously and there was a low index of suspicion of an aorto-enteric fistula. Nevertheless, the investigations undertaken were prompt and appropriate. Endoscopy is generally accepted as a first line investigation of choice. It is also useful to exclude other causes of gastrointestinal haemorrhage. Colonoscopy has only been useful in one previous report in demonstrating a fistula. 3 Tagged red cell scan has not been mentioned as a common tool in the literature in the investigation of an aorto-enteric fistula. However, as in one other case reported, a red cell scan assisted in identifying the site of bleeding. 2 As the bleeding is intermittent, a labelled red cell scan has a higher chance of identifying the bleeding site as the patient is scanned over a longer period of time. Other investigations mentioned in the literature which may be helpful were angiography and computed tomography scan. A barium gastrointestinal study may also be useful if the patient is stable but generally most diagnostic tests had a poor yield. 5 Often, the site of an aorto-enteric fistula is not ap...