Chronic non-bacterial osteomyelitis (CNO) is a rare auto-inflammatory bone disease characterized by pain and locally increased bone turnover affecting both children and adults. CNO is chronic in nature and has a high disease burden. CNO covers a spectrum of variants: it includes chronic recurrent multifocal osteomyelitis or CRMO, which affects alternating (long) bones predominantly in children and early adults, but also the variant that mainly affects the sternocostoclavicular region in adults (sternocostoclavicular hyperostosis or SCCH). CNO/SCCH is a disease mainly seen in females (67%) at midlife (median age at presentation 38 years). CNO can occur in the context of the broader rheumatic spectrum of Synovitis, Acne, Pustolosis, Hyperostosis and Osteitis (SAPHO) syndrome. The clinical range and exact definitions remain unclear, which makes diagnosis of CNO challenging. In combination with the absence of evidence-based trialed therapeutics both patient and physicians lack clear guidelines, making CNO a disease with long diagnostic delay (average 5 years) and insecure prospects.
Obviously there is an unmet need to align nomenclature and therewith expand international scientific research projects, with the ultimate aim to unravel pathophysiology and find diagnostics, biomarkers and effective treatment. Ongoing research focusses on pathophysiology, diagnostics, disease burden, and one randomized controlled trial in the Netherlands (LUMC) studies the effectiveness of pamidronate in adults.
Last year, the first international CNO conference was hosted with presentations and discussions for physicians, researchers and patients organized by P. Ferguson, A. Theos and C. Hedrich, with support from the American patient CRMO Foundation. While the CRMO foundation is based in the USA and focusses on children, there is also an active patient association in the Netherlands that focusses on adults.
A consensus meeting on adult CNO is being scheduled for mid-2023 (Leiden) (please mail to bone@lumc.nl if you are interested to join), co-hosted by ECTS. The goal of this meeting is to formulate a disease definition, and associated diagnostic and therapeutic recommendations for adult CNO.