An Unusual Case of Aortoduodenal Fistula Associated With Acute Pancreatitis: A Case Report

Abstract

Purpose: Aortoduodenal fistula is a direct communication between the aorta and duodenum, most often secondary to surgery. We present a case of aortoduodenal fistula associated with acute pancreatitis. A 50-year-old lady presented with 2 episodes of massive hematemesis and severe epigastric pain of 12 hour duration. Past medical history was significant for left renal cell carcinoma with metastasis to para-aortic lymph nodes treated by left nephrectomy and chemotherapy 5 yrs prior to presentation. There was no history of alcohol or tobacco abuse. Vital signs showed blood pressure 80/50 mm Hg and heart rate 110/min. Physical examination was significant for pale mucous membranes, severe epigastric tenderness and positive bowel sounds. Lab data showed hemoglobin 8 gm/dl; WBC 20,000/ul; serum creatinine 2 mg/dl; serum amylase and lipase were elevated at more than 6 times and 20 times the upper normal limits of the lab values respectively. Patient was diagnosed with acute pancreatitis and was started on intravenous fluid boluses with bowel rest. Endoscopy showed friable, delicate 4x3 cm blood clot, adherent to the underlying mucosa in the proximal duodenum. Without disturbing it, epinephrine was injected in to the duodenal mucosa surrounding the blood clot. As an effort to stop the bleeding, patient underwent laparotomy, which showed fistula in the aorta communicating with the duodenum at the site of ligament of Trietz. Necrotic debris was found at the aortic end of the fistula. There was mild edema of the pancreas but no evidence of pancreatic necrosis. Patient succumbed to massive blood loss during attempted surgical correction of aortoduodenal fistula. Aortoduodenal fistula is one of the rare and dreaded causes of upper gastrointestinal bleeding. The most common site is the third or fourth part of duodenum. The most common cause of primary aortoenteric fistulas in the U.S. is an atherosclerotic aortic aneurysm. The classic triad of gastrointestinal bleed, pain and a pulsatile mass is present only in 11% of the cases. Endovascular repair and stent graft implantation have important role in the treatment of the aortoenteric fistula. After thorough English literature search, no case report of aortoduodenal fistula associated with acute pancreatitis was found. In our case, aortoduodenal fistula with necrotic debris at the aortic end was most likely secondary to metastasis from renal cell carcinoma. As the other causes of pancreatitis were ruled out, the presence of blood clot in the duodenum and massive blood loss could have triggered intense ischemia and pancreatic inflammation leading to acute pancreatitis in this case.