Commentary on: radiological diagnosis of chronic recurrent multifocal osteomyelitis using whole-body MRI-based lesion distribution patterns

Clinical characteristics and outcomes of chronic nonbacterial osteomyelitis in children: a multicenter case series

OBJECTIVE

The aim of this study was to evaluate demographic, clinical, laboratory, imaging, histopathology characteristics, and treatment responses of children with Chronic nonbacterial osteomyelitis (CNO).

METHODS

Retrospective multi-center case series study of pediatric patients diagnosed with CNO treated at five tertiary centers in south China.

RESULTS

Totally there were 18 patients diagnosed as CNO between 2014 and 2020. The median age of onset was 9.2 years (range 3.7-13.1) and 55.6% were female. Median delay in diagnosis was 10.9 months (range 1.0-72.0). The most frequent presenting symptoms were bone pain (100%) and fever (44.4%). Most patients had more than one lesion (median of 5, range 1-7). Most frequently affected bones were tibiofibula (88.9%) and femur (77.8%). The MRI characteristics mainly presented as bone edema and hyperintensity in bone marrow. Bone biopsy was conducted in 11 patients (61.1%) with inflammatory cells infiltration manifested as chronic osteomyelitis, and none showed bacterial infection or tumor. In treatment, non-steroid anti-inflamatory drugs (NSAIDs) is used as the first-line drug followed by steriods, methotexate (MTX), salazosulfadimidine (SASP), Bisphosphonates and TNF-α inhibitor. Two refractory cases received combination therapy with Bisphosphonates and TNF-α inhibitor, and achieved good therapeutic effect.

CONCLUSIONS

The present study described a multicenter series of CNO from south China and highlighted the clinical features, laboratory tests, imaging characteristics and treatment outcomes. Increasing awareness of this disease is important to decrease time to diagnosis, improve access to treatment, and reduce complications.

Chronic nonbacterial osteomyelitis in children: a multicenter case series

Chronic nonbacterial osteomyelitis (CNO) is a primary autoinflammatory bone disease that presents more frequently in children and is characterized by inflammatory bone lesions in the absence of an infectious etiology. There is little information of this disease in Latin America. The objective of the study was to evaluate demographic, clinical, laboratory, imaging, histopathology characteristics, and treatment responses of pediatric CNO patients. The clinical records of 19 patients with CNO diagnosed between 2007 and 2019 at three tertiary centers in Santiago, Chile were reviewed. The median age of onset was 10 years and 47% were female. Median delay in diagnosis was 12 months. All patients had a pattern of recurrent multifocal disease. 37% of patients had positive antinuclear antibodies and 16% HLA-B27 positivity. 21% of patients presented arthritis or other rheumatologic comorbidity, although no association with psoriasis, inflammatory bowel disease (IBD) or palmoplantar pustulosis (PPP) was observed. Eighteen patients received treatment with nonsteroidal anti-inflammatory drugs with partial response. Twelve patients received methotrexate, and half of them received steroids at the same time reaching remission in 50%. Of the five patients who received bisphosphonates, 60% achieved remission. All four patients who received adalimumab had comorbid arthritis and 75% achieved remission. In a series of Chilean children with CNO, all patients presented with multifocal lesions. Comorbid autoimmune diseases including arthritis were frequent, but no association was observed with psoriasis, IBD, or PPP.