Clinical Characteristics and Short-term Outcomes of Paediatric Patients with Chronic Recurrent Multifocal Osteomyelitis

Objective: Chronic recurrent multifocal osteomyelitis (CRMO) is the most common autoinflammatory disease of the bone characterized by pain and inflammatory lesions without an infectious agent. The aim of this study is to evaluate the clinical, laboratory, and imaging features and treatments of paediatric patients with CRMO followed in our pediatric rheumatology clinic. Material and Methods: Medical records of ten patients diagnosed with CRMO according to Bristol diagnostic criteria between January 2018 and June 2021 were retrospectively reviewed. Results: The mean age at diagnosis was 9.3 years, and eight of the patients were male. One patient had concomitant psoriasis, two patients had familial Mediterranean fever and one patient had a history of immunoglobulin A vasculitis. Half of the patients had a moderate acute phase reactant elevation. The most frequently involved bones were the lower extremity bones. While localized magnetic resonance imaging (MRI) was the most commonly used imaging modality in the diagnosis of CRMO, silent bone lesions (15%) were detected only by the whole-body MRI. Non-steroidal anti-inflammatory drug (NSAID) was given to all patients. As second-line therapy, methotrexate and pamidronate were employed on seven and five patients respectively. Three of the patients received anti-TNF treatment (etanercept and infliximab) as the third-line therapy. Imaging with whole-body MRI is important due to clinically silent bone lesions, especially in the course of CRMO. Conclusion: Concomitant familial Mediterranean fever was not rare in cases with CRMO and treatment of CRMO might be challenging due to the need for anti-TNF treatment in a considerable number of patients.