Lung involvement in "stable" undifferentiated connective tissue diseases: a rheumatology perspective.

Previous studies of the occurrence of interstitial lung disease (ILD) in undifferentiated connective tissue diseases (UCTD) were conducted in patients admitted to Respiratory Medicine Units. The aim of the present prospective study was to investigate lung involvement in UCTD patients admitted to a Rheumatology Unit. Eighty-one consecutive UCTD patients were enrolled in the study. Each patient underwent history and physical examination, routine laboratory investigations, antinuclear antibody (ANA) profiling, B-mode echocardiography, and lung function study according to previously reported methods. Lung high resolution computed tomography (HRCT) was performed in patients who provided informed consent. Six patients (7.4%) had a history of grade II dyspnea. Three of them had a DLCO ranging from 42 to 55% of the predicted value; and a HRCT-documented ILD with a non-specific interstitial pneumonia (NSIP) pattern. Symptoms in the other three patients were due to cardiac disease. None of the 75 asymptomatic patients, had relevant findings at physical examination, 26/75 had a DLCO <80% (<70% in 10 cases). Of these, 3 of the 30 patients who underwent lung HRCT were affected by NSIP-ILD. Six of the 81 enrolled were affected by ILD, which was symptomatic in three patients. A higher percentage of patients had a reduced DLCO. The latter finding may reflect a preradiographic ILD or a preechocardiographic pulmonary vascular disease.