The Challenges of diagnosing and managing a ruptured abdominal aortic aneurysm with primary aortoduodenal fistula.

Primary aortoduodenal fistula is a rare and highly morbid complication of an abdominal aortic aneurism (AAA). Patient X presented with a ruptured AAA complicated by a primary aortoduodenal fistula in 2016 which was treated surgically but has since suffered from repeated admissions due to sepsis as a result of ongoing graft infections. The diagnosis of aortoduodenal fistula is complicated with no imaging technique providing a definitive diagnosis meaning that maintaining clinical suspicion is important. There is a paucity of evidence regarding how to surgically approach the repair of an aortoduodenal fistula, although there is a shift towards multiple-step procedures in elective repair.

Primary aortoduodenal fistula and chronic Q fever infection

We report a case of chronic Q fever presenting with catastrophic bleeding from an infected abdominal aortic aneurysm causing a primary aortoduodenal fistula in an 80-year-old retired farmer. This presentation is rarely reported in literature and only through case reports. Early diagnosis and definitive surgery were critical to a successful outcome. Serological diagnosis of Q fever was initiated on the patient’s past exposure to animal reservoirs. Complicating the case was ongoing gastrointestinal bleeding postsurgery, with multiple endoscopies undertaken before a culprit remnant fistula was found. This case highlights the value in considering Coxiella burnetii as an underlying cause in patients with known risk factors presenting with primary aortoduodenal fistulas. Though rare, it represents a readily treatable cause.