1 Pediatric Infectious Diseases Unit, 3Orthopedic Service, Hospital Dona Estefânia – Centro Hospitalar de Lisboa Central - EPE
2 National Institute of Health Dr. Ricardo Jorge (CEVDI/INSA), Águas de Moura
Introduction: Q fever is a worldwide zoonosis caused by Coxiella burnetii. It is a rare disease in children and the clinical presentation is variable. We present a rare case of chronic Q fever with osteoarticular involvement.
Case Report: A six year-old-girl presented to the hospital with a three months history of pain and functional impairment in the right knee. She denied fever. The patient had contact with farm animals. At presentation she was apyrexial and showed only discrete inflammatory signs of the right knee. A magnetic resonance imaging revealed signs of osteomyelitis of the right distal femur and epiphysis. Histological analysis showed noncaseating granulomas. Cultures for bacteria and fungi, including atypical mycobacteria were negative. Results of Mantoux, granulomatosis study and serologic tests for Borrelia burgdorferi, Bartonella spp and Francisella tularensis were also negative. Chronic Q fever was suggested by the presence of antibody titters anti-C. burnetii phase I IgG of 6400 and IgA of 200, although PCR from femur biopsy and blood sample were negative. No C. burnetii growth was achieved by buffy-coat inoculation in cell cultures. Antimicrobial therapy with rifampicin and ciprofloxacin was started. The patient has now been followed for nine months with progressive clinical recovery and gradual decrease in antibody titers (with phase I IgG=1600 and IgA=50 in last IFA evaluation).
Comments: Q fever osteomyelitis is a rare diagnosis in children. The choice of antimicrobial treatment is difficult regarding limited data available. Duration of therapy must be guided by clinical and serologic responses.