(BOOP) a disease entity characterized clinically by a flulike illness with cough, fever, shortness of breath, and late inspiratory crackles; there are specific histological features and patchy infiltrates on X-ray. It is sometimes the result of a viral infection, but may follow medication with certain drugs or be associated with connective-tissue disease, such as rheumatoid arthritis. The condition usually responds to oral corticosteroids; however, if a drug is implicated, it must be withdrawn.... bronchiolitis obliterans organizing pneumonia