Chronic Q Fever Presenting as a Contained Rupture of an Infected Native Aortic Aneurysm: A Case Report.

Introduction: Coxiella burnetti (C. burnetii) is the causative agent of Q fever. Chronic Q fever may lead to various complications, including infected native aortic aneurysms (INAA). Both INAA and chronic Q fever typically present with non-specific symptoms, often resulting in delayed diagnosis. While current guidelines provide recommendations for the management of INAA, there are no specific or standardised protocols addressing INAA in the context of chronic C. burnetii infection. However, antimicrobial therapy should be directed towards the causative pathogen. This case report describes a rare case of INAA secondary to chronic Q fever. Case: A 64 year old man presented with lumbar pain due to contained rupture of a juxtarenal abdominal aortic aneurysm. Urgent open surgical repair with inter-renal clamping, resection of infected tissue, reconstruction with pericardial tube graft and omental flap plasty was performed due to suspicion of infection. Intra-operative samples revealed C. burnetii to be the causative agent of chronic Q fever. Oral antibiotic treatment with doxycycline 100 mg twice daily and hydroxychloroquine 200 mg thrice daily was established. Discussion: C. burnetii infection should be considered as a possible pathogen in a case of culture negative INAA. Early diagnosis, open surgical treatment using bovine material and omental flap plasty, prolonged targeted antimicrobial therapy, and follow up assessment with blood samples and computed tomography scans in close cooperation with infectious disease specialists are recommended to improve outcomes in these rare and challenging cases. Case reports such as this contribute to raising clinical awareness and provide valuable insights into the absence of standardised treatment guidelines.