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Causes, clinical manifestations, evaluation, and diagnosis of nonspecific interstitial pneumonia

Kevin R Flaherty, MD, MS
Section Editor
Talmadge E King, Jr, MD
Deputy Editor
Helen Hollingsworth, MD


Nonspecific interstitial pneumonia (NSIP) is one type of idiopathic interstitial pneumonia (IIP). The other IIPs include usual interstitial pneumonia (UIP)/idiopathic pulmonary fibrosis (IPF), desquamative interstitial pneumonia (DIP), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), acute interstitial pneumonia (AIP), lymphocytic interstitial pneumonia (LIP), and cryptogenic organizing pneumonia (COP) (table 1) [1].

NSIP can be idiopathic or can be seen in association with HIV infection, connective tissue diseases, a variety of drugs, and hypersensitivity pneumonitis. It can also present in combination with the other IIPs.

The etiology, pathogenesis, clinical manifestations, and diagnosis, NSIP will be reviewed here. The treatment and prognosis of NSIP, and the pathology, clinical manifestations, diagnosis, and treatment of the other IIPs are discussed separately. (See "Idiopathic interstitial pneumonias: Clinical manifestations and pathology" and "Clinical manifestations and diagnosis of idiopathic pulmonary fibrosis" and "Treatment of idiopathic pulmonary fibrosis" and "Respiratory bronchiolitis-associated interstitial lung disease" and "Cryptogenic organizing pneumonia" and "Acute interstitial pneumonia (Hamman-Rich syndrome)".)


NSIP is a chronic interstitial pneumonia that is characterized by a homogeneous appearance of dense or loose interstitial fibrosis with mild to moderate chronic interstitial inflammation (table 2).

It is "nonspecific" in that it lacks the histopathologic features that characterize usual interstitial pneumonia (UIP), desquamative interstitial pneumonia (DIP), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), or acute interstitial pneumonia (AIP), such as fibroblast foci, dense alveolar septal fibrosis, organizing pneumonia, granulomas, conspicuous infiltration of lymphocytes or eosinophils, and temporal heterogeneity.


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Literature review current through: Aug 2017. | This topic last updated: Aug 10, 2017.
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