Slowly progressive bronchiolitis obliterans. A case report with detailed pulmonary function studies.

A case of idiopathic bronchiolitis obliterans in a 40-year-old man is presented. The chest radiograph showed miliary nodules, which on histological examination were found to consist of granulation tissue in and around bronchioles causing narrowing or obliteration of the airway lumen. The pulmonary function tests indicated a milk degree of airway obstruction, ventilation/perfusion inequality, hypoxemia which increased during exercise, and a well-preserved diffusion capacity suggesting absence of significant damage to the interstitium of the lung. Radiospirometry suggested that the functional derangement was most prominent in the lower parts of the lungs. Even though the inflammatory component was prominent no improvement was observed during steroid therapy. A history of respiratory symptoms for 20 years and a slight deterioration of the respiratory function over a follow-up period of 4 years suggested an unusually slow rate of progression of the disease.