Severe Localized Q Fever, a Diagnostic Challenge: Report of Two Cases and Review of the Literature

Abstract

Coxiella burnetii (C. burnetii) can cause asymptomatic infections and acute, chronic, or localized manifestations affecting multiple organs. Doxycycline is the most effective treatment for Q fever. We report two cases of localized C. burnetii infections with no evident epidemiological link. Case reports: We present the case of a 51-year-old male patient admitted for low fever, dry cough, and malaise. The physical examination was unremarkable except for painful hepatomegaly. He was diagnosed with a liver abscess based on inflammatory markers, positive serology for C. burnetii, and abdominal computed tomography (CT) showing a large lesion (112/86/93 mm) within the right liver lobe. Blood cultures and the fluid obtained by percutaneous catheter drainage were negative. After 28 days of treatment with doxycycline, he was discharged well. At the three-month reevaluation, blood tests were normal, and a CT scan showed a minimal residual lesion. The second case was an 81-year-old female with many comorbidities, almost simultaneous acute ischemic stroke, and double-valve (native and prosthetic) infective endocarditis (IE). C. burnetii infection was confirmed by high titers of antibodies (phase I and II IgG), most probably the direct cause of both manifestations. These two cases presented with very rare manifestations of C. burnetii infections, highlighting its diagnostic difficulties. Conclusions: A clear distinction between acute and chronic Q fever is difficult in rare localized infections, as are organ abscesses. Coxiella burnetii may cause stroke and infective endocarditis, especially in the elderly. Even in the absence of epidemiological clues, in patients with localized infections, the C. burnetii etiology should be considered.