[Imaging features of drug-induced lung diseases]

Drug-induced lung diseases are an increasingly frequent cause of morbidity. Over 350 drugs are now recognized as being implicated in drug-induced lung diseases. Early diagnosis is critical. Discontinuing the drug may result in regression of the adverse effect. Diagnosis is based on a history of drug exposure with a temporal relationship between the introduction of the drug and the onset of symptoms, histologic evidence of lung damage and exclusion of other causes of lung injury. Unfortunately there is no specific test available. Histologic and radiologic findings are often non specific and diagnosis can be difficult. Drugs can cause a constellation of distinct patterns of respiratory involvement and all anatomic compartments of the lungs may be involved. The most common patterns are: non specific interstitial pneumonia and fibrosis, pulmonary eosinophilia, hypersensitivity pneumonitis, pulmonary edema with or without diffuse alveolar damage, bronchiolitis obliterans organizing pneumonia, pulmonary hemorrhage and vasculitis. It is important to be familiar with their common radiologic appearances.