Chronic nonbacterial osteomyelitis (CNO) and chronic recurrent multifocal osteomyelitis (CRMO)

Abstract

Chronic nonbacterial osteomyelitis (CNO) is an inflammatory bone disorder that most frequently affects children and adolescents. Chronic recurrent multifocal osteomyelitis (CRMO) is a severe form of CNO, usually characterized by symmetrical inflammatory bone lesions and its waxing and waning character. Sometimes severe and chronic pain can significantly affect the quality of life and psychosocial development of individuals affected. In the absence of prospectively tested and widely accepted diagnostic criteria or disease biomarkers, CNO remains a diagnosis of exclusion, and infections, malignancy and other differentials require consideration (1). The pathophysiology of CNO is not fully understood, but imbalanced cytokine expression and increased inflammasome activation in monocytes from CNO patients contribute to a pro-inflammatory phenotype that contributes to bone inflammation (2). Currently, no medications are licensed for the use in CNO. Most patients show at least some response to nonsteroidal anti-inflammatory drugs, others require more aggressive treatment that can include corticosteroids, cytokine-blocking agents and/or bisphosphonates (3). While under the care of an experienced team and sufficient treatment, the prognosis is good, but some patients will develop sequalae which can include vertebral compression fractures (1).

Two phenotypes of Chronic Recurrent Multifocal Osteomyelitis with different patterns of bone involvement

“…Thus, it can represent an additional factor contributing to the development of enteropathic CRMO. Indeed, such correlation was proposed in two CRMO studies 27,30 . A recent report also describes successful deployment of a Crohn-disease exclusion diet in a paediatric patient with enteropathic CRMO 31 .…”

Mind the Localized Skeletal Pain: Chronic Recurrent Multifocal Osteomyelitis

“…Studies suggest that bone inflammation may be the result of an imbalance between pro- and anti-inflammatory cytokine expression from innate immune cells and subsequent osteoclast differentiation and activation, resulting in osteolytic lesions [ 2 ]. Environmental and genetic factors, as reported by finding of CRMO in siblings and positive family history of autoimmune diseases, may interplay with the underlying bone inflammation [ 3 ]. Infections are not involved in disease etiology.…”

Osteomyelitt i barns kjeve

“…Forløpet hos barn med ikke-bakteriell osteomyelitt og kronisk residiverende multifokal osteomyelitt er beskrevet som uforutsigbart -fra milde varianter med selvbegrensende forløp til alvorlige forløp med større destruksjoner av benvev (6). Min erfaring med barn med ikkebakteriell osteomyelitt i mandibelen er at prognosen etter introduksjonen av moderne barnerevmatologisk behandling er adskillig bedre enn tidligere.…”

“…En vanlig årsak til osteomyelitt i mandibelen er odontogen infeksjon (5). Ikke-bakteriell osteomyelitt er en utelukkelsesdiagnose og antas å vaere en autoinflammatorisk tilstand uavhengig av lokalisasjon (6). Tilstanden rammer hyppigst i barneskolealder, med en antatt årlig insidens på 4 per 1 000 000 barn (7).…”