The interstitial lung diseases are a diverse collection of disorders characterized by impaired gas exchange, restricted physiology on lung function testing, and diffuse parenchymal lung infiltrates on radiography. Although the interstitial lung diseases are many, in routine clinical practice, the most commonly encountered in general internal medicine practice are sarcoidosis, idiopathic pulmonary fibrosis, and connective tissue disease-associated interstitial lung diseases. In immunocompromised patients, infection is the most common cause of diffuse lung infiltrates and must be ruled out before any attempt to treat with immune altering agents like corticosteroids. This review will focus on the more clinically significant recent advances in the broad field of interstitial lung disease research, with emphasis on the more common interstitial lung diseases occurring in immunocompetent hosts.peer-reviewe
