[Respiratory disorders in Sjögren's syndrome: its comparison with scleroderma and normal state]

The respiratory system was evaluated in 40 patients with primary Sjogren's syndrome (pSS) and its involvement was compared with that of 26 patients with secondary Sjogren's syndrome (sSS), 40 with rheumatoid arthritis (RA), 30 with scleroderma and 100 matched healthy controls using questionnaire, physical examination and functional criteria (spirometry, flow/volume curve, total lung capacity, diffusion). The commonest clinical manifestation in pSS patients was dry cough either alone (xerotrachea) or in combination with dyspnea (indicative of diffuse interstitial lung disease). Functional analysis revealed that 38% of pSS patients had impaired diffusion and 25% impaired flow/volume curve (indicative of small airways disease). Interstitial lung involvement was more common in extraglandular pSS (52% versus 21% in glandular). However no pSS patient was incapacitated from pulmonary disease and when pulmonary function was compared with that of scleroderma and healthy controls it was shown that the dysfunction in primary Sjogren's syndrome was much less serious than in scleroderma and not much different from that of healthy controls. The respiratory involvement in sSS differed since it was more suggestive of obstructive lung disease (19%) in a way very similar to that of rheumatoid arthritis. The results indicate that pulmonary involvement in pSS although frequent is not clinically important. They also suggest that sSS does not add pulmonary manifestations to RA. The differences in pulmonary involvement between pSS and sSS further support the thesis that they are different disease entities.