Airway function in stage I and stage II pulmonary sarcoidosis

Airway function was studied in 39 patients with stage I sarcoidosis and in 20 patients with stage II sarcoidosis. All of our patients were nonsmokers. Characteristic functional changes of restrictive lung disease was observed in 4 patients with stage II sarcoidosis. Specific airway conductance and % FEV1 were abnormal in 3 patients with stage II sarcoidosis. Abnormal small airway function was demonstrated in several patients with stage I and stage II sarcoidosis, always by multiple tests. Frequency dependence of dynamic compliance was demonstrated in 40% of stage I and 50% of stage II sarcoidosis. Maximal flow (Vmax50, Vmax25) was decreased respectively in 36 and 30% of patients of stage I sarcoidosis and in 56 and 62% of patients with stage II sarcoidosis. The ratio of closing volume to vital capacity was increased above corrected predictions in 30% of stage I and 44% of stage II sarcoidosis. delta Vmax25 decreased and Visov/VC (%) increased in more than 50% of patients. Upstream airway resistance was abnormally increased in 50% of patients with stage I and in 73% with stage II sarcoidosis. These results suggest that small airway dysfunction is common in early sarcoidosis without restrictive defect.