Semin Respir Crit Care Med. 2020 Apr;41(2):184-201. doi: 10.1055/s-0040-1708499. Epub 2020 Apr 12.
Nonspecific interstitial pneumonia (NSIP) is a complex disorder commonly associated with other conditions such as connective tissue diseases (CTDs) and environmental exposures. Although idiopathic NSIP has been recognized as a separate clinical entity, recent studies have suggested that a proportion of these cases have autoimmune features suggestive of underlying CTDs. The diagnosis of NSIP usually carries a better prognosis compared with idiopathic pulmonary fibrosis but has an unpredictable natural history. Its pathogenesis is thought to be an inflammatory-driven process involving multiple pathways, including a genetic predisposition. The lack of specific clinical features often makes the diagnosis of NSIP difficult. The huge variability of radiological and histological features seen in NSIP adds to the complexity of achieving an accurate diagnosis of NSIP and a multidisciplinary approach is often required. There is a lack of consensus on the optimal management strategy of NSIP. Early clarification of the goals of therapy and close monitoring for the progression of disease is important across the spectrum of NSIP irrespective of its etiology. Although immunosuppressive and immunomodulatory agents are commonly used for severe and progressive disease, the therapeutic landscape of NSIP is constantly evolving as the role of newer agents such as antifibrotic therapies is being explored.