Chronic recurrent multifocal osteomyelitis in children: nine years’ experience at a statewide tertiary paediatric rheumatology referral centre

Objective To describe the clinical features, management and outcome of 34 children with chronic recurrent multifocal osteomyelitis (CRMO) diagnosed at a single centre over 9 years. Methods All children identified with CRMO for the period 2005-13 were identified from a prospectively collected database, with additional data from hospital records. Results Thirty-four patients, 21 female and 13 male, were identified. The average age at symptom onset was 9.8 years (range 3.8-17.9) and at diagnosis was 10.9 years (range 5.2-18.2), with an average delay in diagnosis of 12 months. Follow-up was 0.3-7.9 years (average 2.1), with 104 individual bony lesions identified, with a median of 3 (range 1-9) per patient. Six patients had unifocal disease. The sites involved included the tibia (n = 19), femur (n = 14), clavicle (n = 12), vertebrae (n = 10) and fibula (n = 8). Approximately half of patients had an inflammatory arthritis at diagnosis, and two-thirds in total eventually developed an arthritis. Pustulosis occurred in eight patients (24%), severe acne in four (12%) and psoriasis in three (9%). NSAIDs were used in 91%, CSs in 82% and MTX in 38%. Two patients were treated with anti-TNF agents. Episodic disease was most common (79%), while 21% had a monophasic pattern. Clinical remission occurred in 94% of children, with prolonged remission in 17%. Seven patients did not require medications for >12 months. Conclusion CRMO is more common than previously recognized, but diagnosis may be delayed. Episodic multifocal disease was most common, but some had unifocal and/or monophasic disease. Most patients responded to NSAIDs and/or intermittent CSs, but many required DMARDs.