[Functional disturbances in patients with interstitial lung diseases without signs of restriction]

Restriction is a typical functional abnormality in interstitial lung diseases (ILD) patients but not all of them represent this pattern. The aim of this study was to evaluate 164 patients with ILD in whom normal lung volumes (FVC and TLC > 80% predicted) were found. There were 111 patients with sarcoidosis (phase I--9, II--77, III--25 patients), 25 patients with pulmonary fibrosis, 12 patients with allergic alveolitis and 16 patients with disseminated radiological changes in the lungs of different etiology. Some patients (40%), mostly with fibrosis and allergic alveolitis, were treated with corticosteroids. Measured parameters included static compliance (Cst), transfer factor for CO (TLco and Kco) and maxima expiratory flow-volume curves (MEF50). 33% of patients had all examined functional parameters in normal range, 50% had decreased maximal expiratory flows (particularly in the sarcoidosis group), 46% decreased Cst and 24% decreased transfer factor. Decreased Cst was found in 31% of patients with sarcoidosis, in 67% of patients with allergic alveolitis and in 96% of patients with lung fibrosis. Decreased TLco or Kco was found only in 11% of patients with sarcoidosis, in 42% of patients with allergic alveolitis and in 60% of patients with pulmonary fibrosis. It seems that, these discussed tests are very helpful in detecting functional abnormalities in patients with ILD without signs of restriction. Increased lung elasticity and decreased transfer factor for CO indicate the existence of early or presisting functional disturbances (despite treatment) in patients with ILD and normal lung volumes.