Q fever as a cause of large vessel vasculitis: Epidemiological analysis and case report

Q fever is a zoonosis caused by Coxiella burnetii with a wide spectrum of clinical manifestations and may trigger or mimic autoimmune diseases, including vasculitis. We retrospectively analyzed epidemiological data on Q fever and present a 51-year-old patient. Initially, in October 2024, the patient was hospitalized at the Clinic for Cardiology, University Clinical Center of the Republic of Srpska (UKC RS), where a descending thoracic aortic aneurysm with extension to the abdominal aorta was confirmed. Due to elevated inflammatory markers, the patient was treated with penicillin antibiotics, together with antiplatelet and antihypertensive therapy, without indication for surgical treatment. In March 2025, the patient was re-hospitalized at the Emergency Center of UKC RS and treated for left-sided pleuropneumonia in consultation with a pulmonologist, receiving fluoroquinolone antibiotics. In April 2025, due to fever of unknown origin, the patient was admitted to the Clinic for Infectious Diseases of UKC RS, where serological testing confirmed subacute Q fever, while paired serum samples, demonstrating seroconversion, indicated a chronic form of the disease. PET/CT imaging revealed aortitis, while immunological workup was unremarkable. Initial antibiotic therapy did not lead to clinical improvement; therefore, in consultation with a rheumatologist, pulse corticosteroid therapy was administered for three days, resulting in a good clinical response. Transesophageal echocardiography raised suspicion of aortic valve endocarditis, which was not confirmed by cardiac MRI, and the patient was regularly followed by a cardiologist. The patient was discharged with recommendations for continuation of therapy (doxycycline, rifampicin, corticosteroids, and hydroxychloroquine). During follow-up, rifampicin was discontinued, and corticosteroid therapy (deflazacort) was gradually tapered and completely stopped in December 2025. Control imaging of the aorta showed a stable finding, and the patient remains under follow-up by a vascular surgeon and rheumatologist.