Chronic nonbacterial osteomyelitis in childhood: prospective follow-up during the first year of anti-inflammatory treatment

Abstract

IntroductionChronic nonbacterial osteomyelitis (CNO) is an inflammatory disorder of unknown etiology. In children and adolescents CNO predominantly affects the metaphyses of the long bones, but lesions can occur at any site of the skeleton. Prospectively followed cohorts using a standardized protocol in diagnosis and treatment have rarely been reported.MethodsThirty-seven children diagnosed with CNO were treated with naproxen continuously for the first 6 months. If assessment at that time revealed progressive disease or no further improvement, sulfasalazine and short-term corticosteroids were added. The aims of our short-term follow-up study were to describe treatment response in detail and to identify potential risk factors for an unfavorable outcome.ResultsNaproxen treatment was highly effective in general, inducing a symptom-free status in 43% of our patients after 6 months. However, four nonsteroidal anti-inflammatory drug (NSAID) partial-responders were additionally treated with sulfasalazine and short-term corticosteroids. The total number of clinical detectable lesions was significantly reduced. Mean disease activity estimated by the patient/physician and the physical aspect of health-related quality of life including functional ability (global assessment/childhood health assessment questionnaire and childhood health assessment questionnaire) and pain improved significantly. Forty-one percent of our patients showed radiological relapses, but 67% of them were clinically silent.ConclusionsMost children show a favorable clinical course in the first year of anti-inflammatory treatment with NSAIDs. Relapses and new radiological lesions can occur at any time and at any site in the skeleton but may not be clinically symptomatic. Whole-body magnetic resonance imaging proved to be very sensitive for initial and follow-up diagnostics.

Chronic Non-Bacterial Osteitis/Chronic Recurrent Multifocal Osteomyelitis

“…In a recent prospective German study of 37 pediatric CNO patients, arthritis was present in 38% initially (Beck, Morbach et al 2010). Typically patients are systemically well with no additional features.…”

“…However, although these findings suggest a possible genetic predisposition in selected inflammatory bone disorders, it is not known how genes play a role in the etiology of the various CNO disorders, which appear to have heterogeneous clinical presentation. Despite some CNO patients progressing to a spondyloarthropathy, HLA-B27 is not more common in CNO patients than in the general population (Beck, Morbach et al 2010). …”

“…Although most patients present with a single symptomatic site, other sites of disease become apparent at imaging or during follow-up. The average number of sites per patient at CNO diagnosis has been reported to be 5.0 by using whole body (WB) magnetic resonance imaging (MRI) (Beck, Morbach et al 2010) but during disease course the number per patient can range from 1 to 18 (Khanna, Sato et al 2009). The common sites of skeletal involvement include the long tubular bones and clavicle, but lesions have been described throughout the skeleton.…”

“…In 2005, the term CNO was coined to describe all of these disorders, and the current understanding is that non-infectious inflammatory bone disorders present a clinical spectrum within which CRMO is the most severe form (Girschick, Raab et al 2005). There have been further attempts to classify patients into defined groups (unifocal nonrecurrent, unifocal recurrent, multifocal nonrecurrent, multifocal recurrent) to establish diagnostic criteria and to find prognostic indicators, although such classification criteria have not been uniformly adapted (Beck, Morbach et al 2010).…”

The Contributions of Whole-body Magnetic Resonance Imaging for the Diagnosis and Management of Chronic Recurrent Multifocal Osteomyelitis

“…WB-MRI has evolved into the imaging modality of choice at many institutions worldwide 4,5,6,7 because the absence of ionizing radiation favorably complies with the "as low as reasonably possible" practice mandate and the accuracy for the demonstration of multifocality, symmetry, osseous inflammation, and bone marrow replacing processes. In addition, the superior soft tissue resolution of MRI affords the accurate characterizations of fascia, muscles, tendons, ligaments, vessels, and nerves, which can yield important information toward the differential diagnosis.…”