[The subclinical involvement of the lung in rheumatoid arthritis: evaluation by high-resolution computed tomography]

Pulmonary involvement is one of the most frequent extra-articular manifestations of rheumatoid arthritis (RA) and represents a serious complication, being the second cause of death after infection. High-resolution computed tomography (HRCT), owing to its increased sensitivity and diagnostic accuracy respect to the conventional chest radiograph (CXR), allows to detect pulmonary abnormalities in RA patients more frequently than CXR. The aim of this study was to assess pulmonary involvement by HRCT in lifelong non-smoking RA patients without symptoms and clinical signs of pulmonary disease. Seventy-two patients (54 women and 18 men) with a mean age of 56.8+/-10.4 years (range, 40-77 years) and mean duration of disease of 6.9+/-4.7 years (range, 2-12 years) entered the study. 52/72 (72%) were positive for rheumatoid factor (> 20 UI/ml). Standard CXR and HRCT were carried out in each patient. CXR showed a mild interstitial fibrosis in 7 patients (9.7%), whereas HRCT demonstrated pulmonary abnormalities in an higher number of them (22/72 = 30.5%). The most frequent abnormal findings on HRCT were irregular pleural margins (13.8%) and septal/subpleural lines (18%), both compatible with pulmonary fibrosis. Ground-glass opacities were found in 8.3% of the patients. Pulmonary nodules (diameter, range 0,5-2 cm) predominantly located in the subpleural portions of the lung, were demonstrated in the same percentage (8.3%) of patients. Small airway involvement, represented by bronchiectasis/bronchioloectasis, was shown in 15.2% of patients. Subpleural cysts were present in two cases (2.8%). No patient had evidence of honeycombing on HRCT. In conclusion, HRCT is an accurate, non-invasive and safe method of diagnosing lung abnormalities in RA patients without signs and clinical symptoms of pulmonary disease.