Vascular-enteric fistula: Diagnosis by colonoscopy

Abstract

A 67-year-old man had a past history of abdominal aortic aneurysm repair in 1982 with an aortobifemoral graft. He was admitted to his local hospital on October 26, 1992 with a 2 week history of fever, chills and left lower leg swelling. He was found to be confused with a tender and swollen left calf. Blood cultures were positive for Bacteriodes species. He was started on antibiotics and heparinized for a presumed left leg thrombosis. The patient developed guaiac-positive stools and underwent upper endoscopy and barium enema, which were reportedly normal. ACT scan of the abdomen revealed a small quantity of air in the perigraft area on the left limb of the aortobifemoral graft. He was transferred to our hospital for further care on November 5, 1992. On examination he was found to be thin, afebrile, and confused. Abdominal examination was remarkable for absence of masses, no tenderness, and normal bowel sound. The rectal exam was normal with a negative guaiac test. Extremity exam revealed a tender swollen left calf which exhibited a 6 cm superficial ulcer with an erythematous margin. Laboratory data included BUN and creatinine of 13 and 1.3 mg/dl, respectively, a WBC of 18,000/ram 3 with 15,000/ mm 3 neutrophils and 700/mm 3 bands, a prothrombin time of 15 seconds, a partial thromboplastin time of 35 seconds and a normal UA. Chest x-ray showed small bilateral pleural effusions. A transjugular Greenfield filter was placed. A tagged WBC scan revealed increased uptake in the left limb of the graft. A diagnosis of infected aortobifemoral graft was made and the patient was scheduled for surgery. A repeat blood culture grewPseudomonas aeroginosa which prompted a GI consult to evaluate for a possible bowel source. Colonoscopy was performed on November 16 which revealed a 3 cm large foreign body in the sigmoid colon protruding through the wall and crossing the lumen (Fig. 1). No associated pulsation or bleeding was noted. A diagnosis of paraprosthetic sigmoid fistula was made and the patient underwent surgical graft removal and extra anatomic biaxillofemoral graft placement. A sigmoid colectomy with colostomy and Hart-