Bronchiolitis obliterans with organizing pneumonia.

In 1955, Epler and Colby first described idiopathic bronchiolitis obliterans with organizing pneumonia. Davison and colleagues termed the entity cryptogenic organizing pneumonia. Clinically, the disease resembles a flu-like syndrome of acute or subacute onset. Other features include crackles, patchy infiltrates on chest radiograph, restrictive function, and decrease in diffusing capacity. Most cases of idiopathic bronchiolitis obliterans with organizing pneumonia (BOOP) respond dramatically to corticosteroids. However, some patients deteriorate rapidly. Differences between idiopathic or secondary BOOP and other interstitial lung diseases are vast. CT findings and bronchoalveolar lavage fluid lymphocytosis are helpful in differentiating BOOP from idiopathic pulmonary fibrosis.