RESUMEN
To investigate the association of idiopathic pulmonary fibrosis [IFF] and rheumatological disorders in patients with chronic hepatitis C virus [HCV] infection via clinical laboratory and radiological studies. Fifty one patients, 36 males and 15 females, with documented HCV and 25 healthy subjects, 18 males and 7 females, were enrolled in the study. Clinical examination, laboratory investigations [biochemical, virological and immunological] and plain chest X-ray [CXR], high resolution computed tomography [HRCT] and pulmonary function tests [PFT] were performed in all subjects. The presence of arthralgia, myalgia, fibromyalgia, polymyositis [PM], type II mixed cryoglobulinaemia [MC], purpura, and Raynaud's phenomenon and pulmonary fibrosis, were observed in 8/51, 10/51, 4/51, 5/51, 9/51, 2/51, 1/51 and 9/51 of HCV-positive patients, respectively. The presence of high serum creatinine kinase [CK], RF, ANA, complement-4 [C4] reduction and Anti-Jo-1 antibodies were observed in 5/51,5/51, 2/51, 3/51 and 3/51 of HCV-positive patients, respectively. There was a significant difference between controls and patients with HCV for the presence of arthralgia, myalgia, polymyositis, type II MC and IFF on HRCT [p<0.01, <0.01, <0.05, <0.01 and <0.01 respectively]. Pulmonary fibrosis was found in 3/5 and 5/9 patients with polymyositis and type II MC respectively. HRCT findings of IFF consisted of nodular areas of high attenuation, ground-glass attenuation, consolidation, septal lines, non-septal lines, and honeycombing in 6/51, 2/51, 1/51, 2/51, 4/51, and 1/51 patients with HCV, respectively. Our nine patients with interstitial pulmonary involvement had HRCT scores consistent with mild parenchymal abnormalities in 3, moderate in 5 and severe in one patient. Only one case in the controls [1/25] had ground-glass attenuation on HRCT. PFT abnormalities were present in only 13 patients [-26%]. PFT measurements revealed that VC, FVC, FEV1, and FEF25-75 were below 80% of the predicted value in 10/51, 11/51, 8/51 and 16/51 patients with HCV, respectively. DLCO was decreased in 21/51 patients. However, there was no significant difference between controls and patients with HCV infection in mean PFT parameters. No correlation was found among HRCT features and PFT abnormalities. The results of this study suggest that chronic HCV infection appears to be involved in the pathogenesis of rheumatic diseases and pulmonary fibrosis. An association between interstitial lung disease [ILD] and polymyositis and/or type II mixed cryoglobulinemia seems to occur frequently in patients with chronic HCV infection. HRCT provides a sensitive and noninvasive technique than PFTs for detecting pulmonary involvement in HCV despite absence of symptoms, normal chest radiograph, and normal pulmonary function testing