Children and adolescents
Chronic nonbacterial osteomyelitis (CNO/CRMO)
Recurrent bone pain from sterile bone inflammation, often multifocal. It can mimic infection or malignancy.
What to look for
- Bone pain, sometimes with swelling, often in the metaphyses, clavicle, pelvis or spine
- Normal or mildly raised inflammatory markers
- May come with psoriasis, palmoplantar pustulosis or IBD
What to do
- Whole-body MRI is the preferred imaging.
- Biopsy is often needed to exclude infection and malignancy, especially for a single lesion or atypical features.
- NSAIDs are first-line. Bisphosphonates or TNF inhibitors are used for refractory or spinal disease.
- Classification criteria were published by EULAR/ACR in 2025.
About this urgency level
Specialist evaluation helps, but these are usually less time-sensitive than new inflammatory arthritis or connective tissue disease.
Timeframes are typical targets. Local pathways, capacity and clinical judgment come first.