Q fever as a rare cause of osseous granulomatous inflammation – a case report

Abstract

Introduction Granulomatous osteomyelitis is uncommon and infectious causes should be considered first. Mycobacterial infection is the most common infectious cause in Australia. Others include fungi, Nocardia, Bartonella, Brucellosis and Q fever. Case report A 5-year-old boy from a rural location presented with a 4-month history of left knee pain. MRI showed a lesion in the epiphysis of the left distal femur with radiological features suggestive of chondroblastoma. Open biopsy showed abundant purulent material. Samples were sent for histopathology and microbiology. Pathological findings Necrotising granulomatous inflammation was present. Histochemical stains and cultures for mycobacteria and fungi were negative, as was PCR for Mycobacterium tuberculosis. In view of the rural background (with exposure to farm animals), PCR and serology Q fever and brucellosis were suggested. Coxiella burnetii DNA was detected on PCR and a diagnosis of Q fever osteomyelitis was made. Discussion Q fever is a zoonotic infection caused by Coxiella burnetii. It is spread by inhalation of infected material, mainly from sheep and goats. Q fever osteomyelitis is rare (although probably under-reported) and should be considered in the setting of granulomatous osteomyelitis, a history of farm animal contact, in osteomyelitis in which no organism has been identified, and in chronic recurrent multifocal osteomyelitis.