Pediatric chronic nonbacterial osteomyelitis.

BACKGROUND AND OBJECTIVES Little information is available concerning the natural history and optimal treatment of chronic nonbacterial osteomyelitis (CNO). We conducted a retrospective review to assess the clinical characteristics and treatment responses of a large cohort of pediatric CNO patients. METHODS Children diagnosed with CNO at 3 tertiary care centers in the United States between 1985 and 2009 were identified. Their charts were reviewed, and clinical, laboratory, histopathologic, and radiologic data were extracted. RESULTS Seventy children with CNO (67% female patients) were identified. Median age at onset was 9.6 years (range 3-17), and median follow-up was 1.8 years (range 0-13). Half of the patients had comorbid autoimmune diseases, and 49% had a family history of autoimmunity. Patients with comorbid autoimmune diseases had more bone lesions (P < .001), higher erythrocyte sedimentation rate (P < .05), and higher use of second line therapy (P = .02). Treatment response to nonsteroidal antiinflammatory drugs (NSAIDs), sulfasalazine, methotrexate, tumor necrosis factor α inhibitors, and corticosteroids was evaluated. The only significant predictor of a positive treatment response was the agent used (P < .0001). Estimated probability of response was 57% for NSAIDs, 66% for sulfasalazine, 91% for methotrexate, 91% for tumor necrosis factor α inhibitors, and 95% for corticosteroids. CONCLUSIONS In a US cohort of 70 children with CNO, coexisting autoimmunity was a risk factor for multifocal involvement and treatment with immunosuppressive agents. Disease-modifying antirheumatic drugs and biologics were more likely to lead to clinical improvement than NSAIDs.