Pathologic mechanisms of drug-induced lung disorders

The pathology of drug-induced lung disease is approached on the basis of patterns of tissue reaction in this review. The entities described include various pathologic lesions, from diffuse alveolar damage to interstitial pneumonias and angiopathies. Because the histopathologic manifestations of drug injury are variable and nonspecific, pathogenetic mechanisms are emphasized. Drugs may cause injury by direct toxicity or by triggering immunologic responses, but often this neat distinction is blurred by the combined effects of preexisting lung injury and the concurrent administration of several drugs. Thus the identification of drug-induced lung disease requires thorough knowledge of the clinical history and rigorous analysis of histopathologic features.