Chronic recurrent multifocal osteomyelitis: experience from a single pediatric rheumatology center over the past ten years

Results We followed seven patients diagnosed as CRMO, 6 female and 1 male. Bone pain was the leading symptom; median age of first complaint was 11 years (range 8-14 ys). The majority of bone lesions were located in the metaphyses of the long bones (10 sites, 63%), clavicle (3 sites, 19%) and pelvis (2 sites, 12%). Five patients had more than one lesion at onset. Of the latter, one patient remained with only one bone focus. Bilateral involvement was presented in two cases. The male patient also had fever and severe acne, so received diagnosis of SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome. Blood examination revealed slight increased eritrosedimentation rate and normal C-reactive protein in all cases. In two cases, at any disease relapse, urine analysis revealed proteinuria without other signs of renal involvement. One patient underwent renal biopsy that showed a mesangial glomerulonephritis. In all patients X-rays were suggestive of osteomyelitis. In all patients diagnosis was formalized after biopsy, except for patient with SAPHO. The biopsy showed scattered inflammatory infiltrate and leukocytes with no evidence of bacteria or malignancies in any cases. No patients responded to non-steroidal anti-inflammatory drugs (NSAIDs) therapy. All patients received corticosteroids but only two of them reached clinical remission. Of the remaining, one received methotrexate and then infliximab with no benefit so switched to bisphosphonate with partial response and 3 received bisphosphonate with good clinical response. The patient with SAPHO received Infliximab with good response. After 4 years, patient with SAPHO is still on infliximab therapy as an attempt of withdrawal provoked a flare of the disease. Four patients are clinically asymptomatic with no therapy, one patient is on bisphosphonate therapy, and one patient showed recurrent course despite biphosphonate and biological antiTNFa therapy.