PULMONARY INVOLVEMENT IN SYSTEMIC SCLEROSIS: INTERSTITIAL LUNG DISEASE AND PULMONARY ARTERIAL HYPERTENSION
Keywords:
Systemic sclerosis, scleroderma, interstitial lung disease, pulmonary arterial hypertension, high-resolution CT, DETECT algorithm, right heart catheterization, nintedanib, endothelin receptor antagonist.Abstract
Background: Systemic sclerosis (SSc) is an immune-mediated connective tissue disease in which pulmonary involvement — chiefly interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH) — is now the leading cause of disease-related mortality, having overtaken scleroderma renal crisis as management of the latter has improved.
Methods: This narrative review synthesizes current evidence on the pathogenesis, screening, diagnosis, and treatment of SSc-ILD and SSc-PAH, drawing on the 2023 American College of Rheumatology (ACR)/CHEST guideline on ILD screening in systemic autoimmune rheumatic disease and the 2023 EULAR recommendations for the management of systemic sclerosis.
Results: ILD, present in roughly two-thirds of SSc patients, arises from fibroblast activation and progressive collagen deposition and is best detected by high-resolution CT and monitored with serial pulmonary function testing. PAH, affecting up to a quarter of patients, arises from a distinct obliterative pulmonary vasculopathy and is screened for with echocardiography or the DETECT algorithm before confirmation by right heart catheterization. Because early symptoms of both conditions are non-specific and often overlap with other manifestations of SSc, structured, lifelong screening protocols are essential, since treatment delay is strongly associated with worse survival. Antifibrotic and immunosuppressive agents (mycophenolate mofetil, nintedanib, tocilizumab) are the mainstay for ILD, while endothelin receptor antagonists, phosphodiesterase-5 inhibitors, and prostacyclin pathway agents, increasingly used as upfront combination therapy, are the mainstay for PAH.
Conclusion: Because SSc-ILD and SSc-PAH are pathobiologically distinct but clinically overlapping, systematic, protocol-driven screening and mechanism-specific rather than one-size-fits-all treatment are central to reducing pulmonary mortality in systemic sclerosis, including in resource-limited settings such as Uzbekistan, where structured pulmonary function testing and echocardiographic screening remain feasible even where advanced PAH therapies are not always accessible.
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