Chronic non-bacterial osteomyelitis: a retrospective international study on clinical manifestations and response to treatment

Clin Exp Rheumatol. 2020 Nov-Dec;38(6):1255-1262. Epub 2020 Aug 5.

Abstract

Objectives: Chronic non-bacterial osteomyelitis (CNO) is a rare non-infectious bone inflammatory disorder; when multifocal, it is referred to as Chronic Recurrent Multifocal Osteomyelitis (CRMO). This study evaluates the demographic, clinical and radiological characteristics of a multi-centre cohort of patients with CNO/CRMO.

Methods: Demographic and clinical data of patients with an established diagnosis of CNO/CRMO followed at paediatric rheumatology centres across Europe (Italy, France, Slovenia) and India were retrospectively collected.

Results: There were no demographic differences across countries, but time to diagnosis was significantly longer in India (p=0.041). Pain was almost invariably present at disease onset; functional impairment was more frequent among Italian and Slovenian patients (p=0.001). The number of sites of bone involvement was similar between genders and countries, with long bone metaphises being the most common site. Raised acute phase reactants, detected in >50% of patients, were not associated with clinical manifestations or response to treatment. Comorbidities, evinced in 37% of patients, were equally distributed between genders and nationalities. Imaging approach was similar across countries, without any association between radiological findings and clinical manifestations. NSAIDs were almost invariably used as first-line treatment, but response rate was significantly lower in Italy (p=0.02). Methotrexate was used in 28% of case, with an overall rate of response of 82%. Health conditions and rate of permanent deformities were similar across different countries.

Conclusions: The differences in clinical presentation, radiological features and response to treatment described in this multinational cohort of CNO/CRMO might provide novel insights into this still elusive disease.

MeSH terms

  • Child
  • Chronic Disease
  • Europe / epidemiology
  • Female
  • France
  • Humans
  • India
  • Italy / epidemiology
  • Male
  • Osteomyelitis* / diagnostic imaging
  • Osteomyelitis* / drug therapy
  • Osteomyelitis* / epidemiology
  • Retrospective Studies

Supplementary concepts

  • Chronic recurrent multifocal osteomyelitis