PULMONARY INVOLVEMENT IN POLYMYOSITIS AND IN DERMATOMYOSITIS

Objective. To assess prevalence, characteristics, and predictive facto rs of pulmonary involvement in polymyositis (PM) and dermatomyositis ( DM). Methods. The medical records of 55 consecutive patients with PM a nd DM between 1983 and 1996 were reviewed. The criteria for diagnosis of PM and DM were based upon Bohan and Peter criteria. Results. Twenty -two patients (40%) developed lung impairment with a mean of 17 months after onset of PM and DM. The 3 main types of pulmonary disorders wer e interstitial lung disease (41%), ventilatory insufficiency with bron chopneumonia (22.8%), and alveolitis (with pulmonary function tests re vealing restrictive pattern, low diffusing capacity, and normal comput erized tomography) (36.2%). Both morbidity and mortality rates were as high as 40 and 27%, respectively, in PM and DM patients with lung inv olvement. Moreover for the group with pulmonary diseases, serum GOT an d ferritin levels were higher (p = 0.01 and p = 0.02) and the presence of anti-Jo-l antibody and characteristic microangiopathy were more fr equent (p < 0.05 and p = 0.0002). Conclusion. This series reveals both high prevalence (40%) and severity of pulmonary involvement in PM and DM. Our findings also suggest that high serum GOT and ferritin levels , presence of anti-Jo-l antibody and characteristic microangiopathy ma y have predictive value and should encourage the search for pulmonary dysfunction and interstitial lung disease in patients with PM and DM.