Nonspecific interstitial pneumonia (NSIP) describes a histopathologic pattern that can be seen in patients with immunodeficiency, drug or environmental exposures, and connective tissue diseases. The clinical diagnosis of NSIP, however, should be reserved for idiopathic cases in which no causative factor is identified. Patients typically present with cough, dyspnea, restrictive pulmonary physiology with decreased gas transfer, and ground-glass infiltrates on high-resolution computed tomography (HRCT). Response to immunosuppressive therapy is often successful; however, patients with progressive disease are at increased risk of subsequent mortality and should be considered for alternative treatment strategies such as lung transplantation.
