RAPID PROGRESSIVE BRONCHIOLITIS OBLITERANS WITH ORGANIZING PNEUMONIA

Bronchiolitis obliterans with organizing pneumonia (BOOP) is a distinc t clinical pathologic syndrome. Most patients experience a good respon se to therapy, and death from progressive BOOP is uncommon. This repor t describes the clinical features, etiologic factors, pathologic findi ngs, and outcome of 10 patients with rapidly progressive BOOP that was characterized by severe respiratory failure. The major clinical manif estations were dyspnea, cough, fever, crackles on chest examination, a nd hypoxemia at rest. Underlying conditions or exposures included conn ective-tissue disease, exposure to birds, and chronic nitrofurantoin t herapy. All patients had the characteristic histopathologic findings o f BOOP. However, at autopsy in six patients, the predominant histologi c pattern was that of alveolar septal inflammation and fibrotic honeyc ombing. Seven patients died and three patients survived but had persis tent pulmonary dysfunction despite aggressive care. In two patients BO OP has progressed, with severe chronic respiratory decompensation. Thu s, there is a subset of patients with BOOP who present with a fulminan t course leading to death or chronic severe fibrosis and marked impair ment of lung function. In addition, the histologic picture of BOOP may be a manifestation of early lung injury that can resolve or progress rapidly to alveolar septal inflammation, endstage fibrosis, and honeyc ombing.