[Clinical features and morbidity of group B diffuse interstitial pneumonia, atypical subtype, compared with group A, typical idiopathic subtype].

Diffuse interstitial pneumonia of unknown etiology has been subclassified into two groups on the patho-histological basis by the study group under the sponsorship of the Japanese Ministry of Health and Welfare. One is Group A, typical idiopathic subtype, fundamentally corresponding to UIP (usual interstitial pneumonia, Liebow) and the other is Group B, closely similar to Group A but possibly modified by respiratory infection. As the clinical features of Group B have not been clarified so far, we investigated them in 8 cases of Group B (M:F = 7:1, 56.7 years at first visit) and 5 cases of Group A (M:F = 4:1, 54.4 years), all of which were pathologically diagnosed by open lung biopsy and/or autopsy. Only in Group B, there were 3 cases with occupations related to dust exposure, and 7 cases with intermittent but persistent mucus expectoration. The duration of symptoms before the first presentation to hospital was longer in Group B than in Group A (1.6 years vs. 0.6 years). Clubbed fingers were more frequently observed in Group B (n = 6 vs. n = 1), but induration in the tuberculin test was less frequent in Group B (n = 1 vs. n = 5). In the chest X-ray findings, pleural thickening was frequent in Group B (n = 6 vs. n = 0), but elevation of the diaphragm was unusual in Group B (n = 2 vs. n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)