Pulmonary function in patients with systemic sclerosis.

Abstract

The lungs are frequently affected in systemic sclerosis (SSc), a generalized connective tissue disorder. We evaluated the prevalence of respiratory functional abnormalities and their correlation with symptoms and radiograph features in a group of 34 patients who fulfilled the American Rheumatism Association criteria for the diagnosis of systemic sclerosis. Patients were submitted to a specific respiratory questionnaire and to lung function tests. Measurements were performed according to the European Coal and Steel Community (ECSC) recommendations and results expressed as a SD score, an accurate method that, taking into account the dispersion of the parameters in the reference population, allows precise definition of pathological subjects. Of the patients examined, 38% reported dyspnoea at rest or on exertion. No other respiratory symptoms were reported. Fifty percent had a normal chest radiograph. This study documents the high prevalence of respiratory functional abnormalities in patients with SSc. A restrictive pattern was found in 41% and an isolated diffusion impairment in 18%. No significant relationship was found between the isolated impairment of transfer factor of the lungs for carbon monoxide (TL,CO) and the mean duration of the scleroderma: thus, it does not seem to represent an early sign of severe restrictive disease. No bronchial or bronchiolar obstructive patterns were observed: it can be stated that small airways dysfunction is not a characteristic manifestation of SSc as considered previously. A significant association was found between the group of subjects with chest radiographic abnormalities and that with a restrictive pattern or isolated TL,CO alteration (p = 0.018). Chest radiographic abnormalities were also found in 29% and dyspnoea in 35% of the patients with normal respiratory function. The mean duration of scleroderma was not significantly different between the groups with and without abnormalities on chest radiography, between the groups with and without a restrictive pattern or isolated diffusion impairment, and between the groups of patients with and without dyspnoea. In conclusion, an accurate evaluation of respiratory function is recommended in the assessment of patients with systemic sclerosis, since the functional involvement of the lung cannot be predicted on the basis of the chest radiograph and the respiratory symptoms.