Pulmonary function tests

Systemic sclerosis-associated interstitial lung disease (SSc-ILD) is the leading cause of morbidity and mortality in SSc patients. In autopsy studies, up to 70 of the SSc patients show histological evidence of lung involvement. In surgical lung biopsies from SSc-ILD patients, a pattern of non-specific interstitial pneumonia is present in a majority, while usual interstitial pneumonia is found in a more variable proportion of patients. Up to 90 of the SSc patients have lung function abnormalities, especially with respect to gas transfer. Pulmonary function testing, therefore, is a major tool of investigation of lung involvement in SSc.