The Advantage of Contrast-enhanced Helical Computed Tomography in the Diagnosis of Arterio-enteric Fistula in an Elderly Patient

Abstract

■Arterio-enteric fistula is a rare but critical cause of gastrointestinal bleeding. Most of the cases in the literature resulted from complications of aortoiliac surgery 1 . A few cases developed in patients who had pelvic irradiation 2 or non-Hodgkin’s lymphoma 3 . Very rarely, the fistula occurred in patients with advanced ovarian cancer 4 . We report a case of advanced ovarian cancer with gastrointestinal bleeding caused by a rare arterioenteric fistula that was initially overlooked on angiography but correctly diagnosed on contrast-enhanced helical computed tomography (CT), which seems to be a useful tool for detecting unusual bleeders and is usually available in the emergency room. A 66-year-old female presented to our emergency department because of continuously massive anal bleeding. She was diagnosed with a stage IIIc ovarian adenocarcinoma with peritoneal carcinomatosis 2 years prior to this admission. She had received maximal debulking surgery and six cycles of chemotherapy. Upon arrival, her body temperature was 37.9°C, pulse rate was 156 beats/min, respiratory rate was 24 breaths/min, and blood pressure was 40/31 mmHg. Laboratory data showed a hemoglobin level of 6.7 g/dL and a white cell count of 17,200/mm 3 with a left shift. Prolonged prothrombin time and partial thromboplastin time were noted. The patient received fluid resuscitation, a blood transfusion, and empirical antibiotics. After stabilization of her vital signs, she underwent an emergency angiography in which no active bleeder was identified from the gastroduodenal artery, superior mesenteric artery or inferior mesenteric artery. A pelvic angiography showed an aneurysm in the left external iliac artery but without evidence of bleeding (Figure A). Despite medical stabilization, the bleed from the lower gastrointestinal tract persisted. A contrast-enhanced helical CT of the abdomen was subsequently performed in which a pooling of contrast material from the left external iliac artery was also seen (Figure B). This abnormal pooling of contrast material then drained into the sigmoid colon (Figure C). Owing to suspicion of an arterio-enteric fistula between the left external iliac artery and sigmoid colon, an emergent operation was performed. The surgical ligation was successful; however, a massive amount of infected bloody ascites was found. Two months after admission, she died of sepsis and multiple organ failure despite aggressive treatment. The predominant causes of lower gastrointestinal bleeding are diverticulitis, ischemic colitis, hemorrhoids, and arteriovenous malformations 5 . Poor control of active hemorrhage occurred in 37% of patients, and the mortality rate due to rebleeding could be as high as 3.5% of all cases of lower gastrointestinal bleeding 5 . It