Drug-induced lung disease: Keys to diagnosis and management

Drug-induced lung disease is often a difficult diagnostic challenge for the clinician because of its diverse presentations and the increasing number of causative agents. Common clinical presentations include interstitial pneumonitis/fibrosis, hypersensitivity pneumonitis, noncardiogenic pulmonary edema, and airways dysfunction. The chest radiograph may not detect early drug-induced lung disease, and radiographic changes in more advanced disease are not specific. Pulmonary function studies, including measurement of diffusing capacity, are more sensitive in detecting early drug-induced lung disease; however, specificity is low. Additional chest imaging techniques, including high-resolution CT scans and gallium scans, can increase diagnostic accuracy. Bronchoscopy has limited diagnostic utility for these disorders, although it can exclude other possible diagnoses such as infection or alveolar hemorrhage. Thoracoscopic lung biopsy is a promising alternative to standard open lung biopsy. Therapy must be individualized and includes discontinuation of the offending drug, supportive care, and use of corticosteroids in patients with severe symptoms or lung dysfunction.