Chronic Nonbacterial Osteomyelitis

Abstract

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disorder that most commonly affects children and adolescents. While initially considered a benign disorder, we now know that CNO is a chronic and sometimes debilitating disease. The pathophysiology of CNO is incompletely understood. Imbalanced expression of pro- and anti-inflammatory cytokines contributes to osteoclast activation and bone inflammation. Animal models support these observations and suggest the involvement of alterations to the gut microbiome in disease pathology. Currently available treatment options inhibit inflammation and/or osteoclast activity and are efficacious in a large proportion of patients. However, prospective studies are missing, and some patients develop complications before “matching” treatment has been established. Here, we discuss disease presentation and outcomes, the current understanding of disease pathology, diagnostic approaches to CNO, available treatment options, and potential future directions.