Aortoenteric fistula complicating an infected aortic graft - Diagnosis by leukocyte scintigraphy

A 77-year-old man had a 9-month history of recurrent anemia, intermittent melena, malaise, and abdominal pain. An increased erythrocyte sedimentation rate and C-reactive protein level were observed. His anemia gradually worsened, requiring monthly blood transfusions, but endoscopy and a labeled erythrocyte scan failed to identify a source of bleeding. Three years earlier he had an emergency abdominal aortic aneurysm repair with insertion of a prosthetic graft. A contrast-enhanced computed tomographic scan of the abdomen showed abnormal periaortic soft tissue enhancement, and given the increased inflammatory markers and possible graft infection, a Tc-99m HMPAO-labeled leukocyte scan was performed. Imaging confirmed an infected graft but also showed extravasation of cells into loops of small bowel suggestive of a coexisting aortoenteric fistula. The bleeding resolved after excision of the aortoenteric fistula.