[Clinical picture and evolution of hepatitis C].
Hepatitis C is becoming the main cause of cirrhosis and primary liver carcinoma. Infection by hepatitis C virus (HCV) generally induces an asymptomatic acute hepatitis. HCV infection becomes chronic in about 80% of cases. In a minority of the subjects, chronic HCV infection is asymptomatic with persistent viremia and normal liver tests. These asymptomatic subjects have minimal liver histologic lesions and a good prognosis. In a majority of the subjects, chronic HCV infection is associated with chronic hepatitis with increased serum transaminases levels. Among the patients with chronic hepatitis, the majority have a mild liver disease with a moderate increase in serum transaminases levels and, at liver histology, minimal lesions; a minority (about 20%) have a more severe liver disease and will develop cirrhosis after 5 to 20 years. In patients with HCV related cirrhosis, the incidence of hepatocellular carcinoma is high (around 5% per year). The factors influencing the evolution of HCV infection are not known. Alcohol is certainly an important factor which increases the risk of development of fibrosis then cirrhosis. Virus related factors, such as genotype and level of replication, might also be important. Autoimmune diseases have been reported in association with hepatitis C. HCV infection is a major cause of mixed cryoglobulinemia associated with vasculitis or glomerulonephritis. A relationship between HCV and auto-immune diseases such as thyroiditis or Gougerot syndrome has been suggested but not demonstrated. HCV infection is frequent in patients with porphyria cutanea tarda; in these patients, HCV related liver disease might trigger the expression of the metabolic disease.