CAN INTERSTITIAL PNEUMONIA AS THE SOLE PRESENTATION OF COLLAGEN VASCULAR DISEASES BE DIFFERENTIATED FROM IDIOPATHIC INTERSTITIAL PNEUMONIA

We prospectively followed 68 patients diagnosed as idiopathic intersti tial pneumonia (IIP) over a period of 1-11 years. Thirteen patients (1 9%) subsequently developed systemic manifestations of collagen vascula r diseases (CVD) and were diagnosed as having had interstitial pneumon ia as the sole presentation of CVD (CVD-IP). Compared with the 55 IIP patients, the 13 CVD-IP patients were relatively younger, predominantl y female, and had a lower incidence of dust inhalation in their histor y. They also had a higher erythrocyte sedimentation rate, higher incid ence of the x-ray finding of discoid atelectasis in the lower lung fie lds, and a better prognosis than the IIP patients. However, these feat ures did not clearly distinguish the two groups. We conclude that the patients clinically and/or histologically defined as suffering from II P cannot be distinguished from CVD-IP patients before systemic signs o f CVD appear in the latter group.