An Update on Nonspecific Interstitial Pneumonia

Abstract

In Brief Nonspecific interstitial pneumonia (NSIP) is a histologic and radiographic pattern that can be observed in a variety of clinical circumstances. It is most commonly seen in the context of underlying connective tissue disease. The NSIP pattern may also be found in patients with drug hypersensitivity, environmental or occupational exposures, and in immunodeficiency. When no underlying cause is found, the term “idiopathic NSIP” is used. A recent report from the American Thoracic Society working group commissioned to study NSIP confirms the importance of distinguishing this entity from the other idiopathic interstitial pneumonias. Clinical history and radiographic findings may be suggestive but histology is a necessary adjunct; all factors must be considered in formulating a final diagnosis. Arriving at the correct diagnosis is vital since the prognosis of NSIP differs significantly from that of other idiopathic interstitial pneumonias, in particular idiopathic pulmonary fibrosis. In addition, the treatment of NSIP may focus on immunosuppressive therapy, which typically is not used for idiopathic pulmonary fibrosis. Much has been learned about NSIP in the 15 years since the first description of this entity, but additional study is necessary to help define its biology and optimal therapy. Nonspecific interstitial pneumonia is a histological pattern of lung disease that is found in patients with connective tissue disease, drug hypersensitivity, environmental or occupational exposures, and immunodeficiency. It is important to distinguish nonspecific interstitial pneumonia from other forms of interstitial lung disease because of differences in prognosis and treatment.