Abstract / Summary
Persistent localized infection caused by Coxiella burnetii can lead to fatal vascular graft infection (VGI). Q fever graft infection secondary to endovascular aortic repair (EVAR) is extremely rare and presents with a highly insidious clinical course. Due to the inherent difficulty of obtaining positive results from conventional microbial cultures, such infections are highly susceptible to clinical misdiagnosis or therapeutic delays; once complicated by an aorto-enteric fistula or aneurysm rupture, patient mortality is catastrophically high. A 73-year-old male patient, who had undergone EVAR for an abdominal aortic aneurysm (AAA) over 3 years prior, was admitted with a 12-day history of recurrent fever accompanied by persistently elevated inflammatory markers. An 18F-FDG PET-CT scan demonstrated irregular soft-tissue thickening and pathological air pockets around the aortic stent graft, accompanied by intense glucose hypermetabolism, features clearly indicative of VGI. Emergency laparotomy revealed dense inflammatory adhesions between the aneurysmal wall and the sigmoid colon, confirming the formation of an aorto-colic fistula. This finding constituted a major clinical criterion according to the Management of Aortic Graft Infection Collaboration (MAGIC) guidelines. The patient subsequently underwent partial aneurysmectomy, complete explantation of the infected stent graft, and in situ reconstruction using a rifampicin-bonded synthetic graft. Concurrently, to block intestinal contamination, primary closure of the colonic defect and a sigmoid colostomy (Hartmann's procedure) were performed. Postoperatively, an indirect immunofluorescence assay (IFA) revealed both phase I and phase II IgG titers of 1:512, highly suggestive of persistent C. burnetii infection. The patient has been initiated on a long-term targeted regimen of doxycycline combined with hydroxychloroquine based on the serological profile. Coxiella burnetii should be considered as a differential diagnosis in case of unexplained, culture-negative VGI following abdominal aortic repair. When clinical manifestations align with the MAGIC diagnostic criteria and 18F-FDG PET-CT confirms a hypermetabolic peri-graft lesion, a diagnosis of persistent Q fever should be strongly considered, even if the serological antibody titers fall below the traditional diagnostic threshold of 1:800. Successful management hinges on early recognition followed by thorough surgical debridement of the infectious source and vascular reconstruction. Postoperatively, a long-term (18 to 24 months) dual-antibiotic regimen of doxycycline and hydroxychloroquine is recommended to completely eradicate the intracellular pathogen by manipulating the intralysosomal microenvironment of host macrophages.