[Diagnosis and treatment of chronic nonbacterial osteitis (CNO) and SAPHO syndrome : Implications of the current consensus recommendations of an international commission of experts for German rheumatology].

Since the 1980s, various terms have been used to describe diseases with the primary finding of sterile bone inflammation (osteitis), which is attributed to the rheumatological spectrum. Various terms, such as SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome, SCCH (sternocostoclavicular hyperostosis), and ACW (anterior chest wall syndrome), are in use to describe overlapping clinical phenomena with the leading finding of sterile, nonbacterial osteitis that have not yet been classified as a uniform entity. Against this background, an international panel of experts developed statements and recommendations in 2023 and 2024 as part of a consensus process using a standardized procedure. These establish adult chronic nonbacterial osteitis (CNO) as the uniform name for the disease. In addition, 16 recommendations for diagnosis and therapy were formulated and discussed. On this basis, the clinical implementation of the consensus recommendations has the potential to significantly improve the quality of treatment for adult CNO. This is described in detail below. It is important to emphasize the independence of adult CNO as an entity, which is not a subgroup of axial spondyloarthritis (axSpA) or psoriasis arthritis (PsA), but nevertheless occurs as an overlapping disease in 20-30% of cases. Diagnosis focuses on clinical activity parameters for quantifying symptoms and targeted radiological imaging of osteitis in the affected region (preferably with magnetic resonance imaging). The consensus recommendations provide relatively specific treatment recommendations, starting with NSAIDs (for 4-12 weeks, depending on therapy response), alternatively or subsequently coxibs, then intravenous bisphosphonates (for 3-12 months, depending on therapy response), alternatively or subsequently TNFi (also for 3-12 months), whereas no specific recommendations are formulated for long-term therapies. There are specific features for the use of these therapeutic modalities in Germany that must be taken into account, particularly with regard to off-label use. Conventional DMARDs are not used for adult CNO, unless there is an indication for this in patients with overlapping PsA or axSpA.