Treatment of pediatric chronic nonbacterial osteomyelitis – a systematic review

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disease most commonly affecting children and young people. CNO can cause bone pain, hyperostosis and fractures, thereby significantly impacting on patients' wellbeing. The molecular pathophysiology of CNO is characterized by NLRP3 inflammasome activation and a pronounced imbalance between pro- and anti-inflammatory cytokines. In the absence of clinical trials, treatment of CNO remains empiric and is based on personal experience and published case series. This project systematically reviewed the available literature in pediatric CNO following 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses' (PRISMA) guidance accessing Medline, Embase, NCBI PubMed, Cochrane Library Clinical Trials, ClinicalTrials.gov, and WHO ICTRP. Nonsteroidal anti-inflammatory drugs are usually used as first-line treatment. They facilitate pain control and induce early remission in some patients but also associate with later flares. Conventional disease modifying antirheumatic drugs (DMARDs) have been used with mixed success and may be helpful in patients with associated arthritis, skin inflammation, and/or inflammatory bowel disease. Biologic DMARDs, namely TNF inhibitors, are effective for the treatment of bone and associated skin and/or bowel disease. Bisphosphonates induce rapid remission in most patients but may associate with higher relapse rates when compared to TNF inhibitors. The longstanding absence of diagnostic and, until recently, classification criteria as well as defined study endpoints, the small sample size and variable therapeutic approaches challenge interpretation of studies and comparisons between treatments. Prospective randomised controlled trials are urgently needed to improve the evidence base, resulting in approval of treatments for CNO.