Prompt diagnosis of aortoenteric fistulas is imperative for patient survival. The clinical signs of aortoenteric fistula include hematemesis, melena, sepsis, and abdominal pain, but the condition also may be clinically occult. Because clinical signs may not be present or may not be sufficiently specific, imaging is most often necessary to achieve an accurate diagnosis.
Aortic fistulas can be primary (associated with complicated abdominal aortic aneurysm) or secondary (associated with graft repair). A primary aortoenteric fistula forms when a large abdominal aortic aneurysm closely abuts bowel loops, usually the 3rd or 4th parts of the duodenum. Due to long-standing pressure, the aneurysm slowly erodes into the bowel wall. These are most commonly due to infected mycotic aneurysms.
Secondary aortoenteric fistulas are seen as a complication of aortic reconstructive surgery with or without the placement of an aortic stent-graft. Secondary fistulas that result from perigraft infection may occur between 2 weeks and 10 years after surgery.
In this case, the patient had generalized abdominal pain with the incidental finding of a pulsatile abdominal mass.
A diagnosis of primary aortoenteric fistula has been made based on the CT findings.