Intraosseous and intraarticular pneumatosis in anaerobic osteomyelitis

Abstract

A 14-year-old diabetic girl presented with fever and pain and swelling of the left hip for 1 week. There was no history of trauma or biopsy. Laboratory examination revealed leucocytosis with raised erythrocyte sedimentation rate and C-reactive protein. CT revealed gas within the femur, left hip joint and surrounding soft tissues (Figs. 1 and 2). There was marrow and soft-tissue oedema with multiple cortical breeches. Cultures from purulent material in the soft tissues yielded mixed skin flora and Bacteroides fragilis. Bone biopsy confirmed osteomyelitis. Intraosseous gas has been reported after biopsy, penetrating wounds and fractures. Very few cases of intraosseous and intraarticular pneumatosis have been reported in the setting of osteomyelitis [1, 2]. In the absence of direct communication of bone with air, it is highly suggestive of osteomyelitis, and the pathogens are usually anaerobic and/or polymicrobial. The presumed mechanism is anaerobic metabolism with production of hydrogen and carbon dioxide gases [1]. The presence of intraosseous gas usually signifies fulminant infection requiring aggressive treatment. The other rare causes of intraosseous gas are lymphangiomatosis of bone, necrosis and neoplasm [1].