Causes
Common causes of pleurisy include trauma, postcardiac injury, infection (i.e., viral, bacterial, or parasitic), respiratory illness, caustic exposure (i.e., drug-induced), autoimmune disease, and malignancy (Table 1). While viral infections tend to be one of the more common causes, the cause can also be idiopathic or nonspecific. Nonspecific pleuritis is found in 30% to 40% of patients who undergo pleural biopsy for diagnosis. Idiopathic pleuritis should be utilized as a diagnosis of exclusion after other causes have been ruled out through extensive diagnostic measures.[2,5]
A retrospective analysis by Branch and McNeil that involved adults aged 40 years or less sought to determine an approach for distinguishing patients with idiopathic or viral pleurisy from those with pulmonary embolism. Idiopathic or viral pleurisy was the most common type, accounting for 53% of cases. The presence of pleural effusion significantly increased the probability that pleurisy was secondary to pulmonary embolism. Of the 97 cases reviewed, 22 had pleural effusions; of these, pulmonary embolism was the primary cause in 12 (55%). Pulmonary embolism is severe, and distinguishing this condition from other causes is imperative, as the clinical features of pulmonary embolism and other causes may be quite similar.[6]
There are numerous case reports discussing drug-induced lung disorders, but little attention has been paid to drug-induced pleural diseases, including pleural effusion, pleuritis, and/or pleural thickening. As more drugs are introduced, it is imperative to understand the mechanisms by which reported agents have resulted in pleural disease (Table 2).[7,8] Morelock and Sahn conducted a review of the literature from 1966 to 1998 to identify drugs associated with pleural disease and to examine findings and response to therapy. Drug effect was contributory when exposure to the drug produced pleural disease, when the pleural response remitted upon drug discontinuation, and when drug-induced pleural disease recurred with re-exposure.[8] While many mechanisms for most drug-induced pleural diseases remain hypotheses, five mechanisms in which drug-induced pleural disease may occur have been identified: hypersensitivity or allergic reaction; direct toxic effect; increased oxygen free-radical production; suppression of antioxidant defenses; and chemical-induced inflammation.[7,9]
US Pharmacist © 2012 Jobson Publishing
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