Effects of steroid therapy on pulmonary involvement in sarcoidosis.

In eleven patients with stage II-III pulmonary sarcoidosis as assessed by mediastinoscopy or open lung biopsy, we carried out a functional study by evaluating static and dynamic pulmonary volumes, diffusing lung properties (TLCO, KCO), and mechanical properties: resistance of the airway, flow-volume curve, pressure-volume curve, flow-pressure curve, and dynamic compliance. In 7 of 11 patients a clinical and functional follow-up during steroid treatment over a period of 5 months to 3 years was also performed. Before treatment diffusing properties were in the normal range in 6 of 11 subjects, reduced in 4, and increased in 1. Elastic properties studied in 8 patients were in the normal range, whereas peripheral airway involvement was noted in 4 nonsmokers. During the follow-up the changes noted in diffusing lung properties on the whole parallelled the clinical and radiologic improvement or relapses after cessation of therapy. In contrast, no changes in elastic properties or lung volume were noted. We concluded that steroid treatment seems to improve parenchymal lung involvement in most cases as shown by the increase in diffusing lung properties.