Chronic Nonbacterial Osteomyelitis of the Sternocostoclavicular Region in Adults: A Single‐Center Dutch Cohort Study

Abstract

Sternocostoclavicular hyperostosis (SCCH) is a rare autoinflammatory bone disorder caused by chronic nonbacterial osteomyelitis (CNO), which is associated with sclerosis and hyperostosis primarily affecting the sternum, the medial end of the clavicles, and the first ribs. Other areas of the axial skeleton may also be affected. The more severe synovitis–acne–pustulosis–hyperostosis–osteitis (SAPHO) syndrome is additionally associated with dermatoses and joint manifestations. This Dutch retrospective cross‐sectional single‐center cohort study characterizes the spectrum of clinical features in adult CNO/SCCH patients at the time of diagnosis. The only inclusion criteria was the availability of complete sets of clinical and imaging data systematically collected over three decades using in‐house protocols. Data from 213 predominantly female patients (88%) with a median age of 36 years at presentation were studied. The mean diagnostic delay was 5 ± 5 years. The main symptoms were chronic pain (92%), bony swelling (61%), and restricted shoulder girdle function (46%); 32% had palmoplantar pustulosis and 22% had autoimmune disease. The majority (73%) had isolated SCCH; 59 (27%) had additional localizations in vertebrae (19%), the mandible (9%), or both (2%); 4 had SAPHO. The prevalence of current or past smoking was high (58%), particularly for patients with palmoplantar pustulosis (76%). There was a significant relationship between delay in diagnosis and both the extent of affected skeletal sites (p = 0.036) and erythrocyte sedimentation rate levels (p = 0.023). Adult‐onset CNO is characterized by distinctive clinical and radiological features, but diverse aspects of its spectrum are currently not fully captured by a comprehensive classification. Delayed diagnosis is still common and potentially associated with irreversible structural changes and debilitating chronic symptoms, increasing the burden of illness and negatively impacting on quality of life. It is hoped that findings from this study will dispel confusion about nomenclature and classification of adult‐onset CNO and increase awareness of its distinctive clinical and radiological features, and thus facilitate early diagnosis and referral for treatment, which should positively impact prognosis by preventing disease progression, although this remains to be established. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Comment on: The neglected and untreated pains of CRMO and SAPHO syndrome

“…CNO/SCCH is specifically characterized by sclerosis, hyperostosis, erosions and ankylosis of the sternocostoclavicular region, accompanied by strongly increased isotope uptake on nuclear imaging. Similar to what the authors describe for CRMO/SAPHO, CNO/SCCH is poorly recognized and is associated with severe diagnostic delay (5 years median [ 4 ]). We therefore fully concur that all CNO patient populations are ill-served, facing excessive (and expensive) diagnostic trajectories during which irreversible tissue damage may manifest due to delay of potentially adequate treatment.…”

“…We would like to add that another distinguished CNO subtype is localized in the sternum, clavicles and upper ribs, and is also descriptively referred to as sternocostoclavicular hyperostosis (SCCH: ORPHA 178311). CNO/SCCH contrasts with CRMO in its localization in the axial skeleton and adult onset (whereas CRMO is mostly a paediatric and peripheral disease), and differentiates from full SAPHO due to frequent absence of synovitis and dermatologic manifestations [ 3 , 4 ].…”

“…We therefore fully concur that all CNO patient populations are ill-served, facing excessive (and expensive) diagnostic trajectories during which irreversible tissue damage may manifest due to delay of potentially adequate treatment. We deliberately state ‘potentially’, as CNO/SCCH deals with a similar mayhem of off-label, physician-dependent, non-trialled treatment options that the authors describe for CRMO/SAPHO [ 3 , 4 ].…”

Determinants of Quality of Life in Adult Patients with Chronic Non-Bacterial Osteomyelitis (CNO) of the Sternocostoclavicular Region (SCCH): A Dutch Single Center Study

“…Seeking social support was also more frequently reported by patients with CNO/SCCH than in those with chronic pain of unknown etiology, possibly indicating that establishment of a diagnosis of CNO/SCCH as the source of the chronic pain may be associated with a greater sense of social acceptance and greater tendency to ask family and friends for help. More palliative coping, defined as seeking distraction with other occupations, such as smoking or drinking alcohol, was also more prevalent in CNO/SCCH patients, which is of particular relevance as smoking is a known trigger for an auto-inflammatory reaction, which may exacerbate disease activity, thus potentially inducing higher levels of pain and more limitations in shoulder girdle function [ 1 ].…”

“…The skeletal lesions are associated with the characteristic dermatosis palmoplantar pustulosis (PPP) in about 30% of cases. The disorder most commonly presents in young adulthood, predominantly in women, with lesions most commonly isolated to the sternocostoclavicular region [ 1 ]. The natural history of CNO/SCCH is characterized by episodes of remissions and exacerbations, followed by a chronic state associated with potentially debilitating symptoms due to irreversible structural changes in affected bones, secondary arthritis in adjacent joints, and limitations in shoulder girdle function.…”