Chronic recurrent multifocal osteomyelitis.

Chronic recurrent multifocal osteomyelitis (CRMO), also known as chronic nonbacterial osteomyelitis, is an orphan disease that manifests as recurrent flares of inflammatory bone pain with or without a fever. The pain is related to one or more foci of nonbacterial osteomyelitis. To distinguish unifocal CRMO from a tumor or an infection, a bone biopsy is required in nearly all patients and a trial of antibiotic therapy in many. CRMO is now considered the pediatric equivalent of SAPHO syndrome, and recent data suggest that CRMO should be classified among the autoinflammatory diseases. The treatment of CRMO is not standardized. Although no randomized placebo-controlled trials are available, there is general agreement that nonsteroidal antiinflammatory drugs constitute the best first-line treatment and that bisphosphonates and biotherapies such as TNFα antagonists are effective in the most severe forms. Although CRMO is considered a benign disease, recent data suggest an up to 50% rate of residual impairments despite optimal management.