[Chronic hepatitis--diagnosis and differential diagnosis].

Since the first classification of chronic hepatitis (CHH) more than 25 years have elapsed. Since then conditions for assessment of the etiology, pathogenesis and therapy of the disease have improved. These findings must be applied in the contemporary diagnosis of CHH. The first task is to assess the correct etiology of the disease because it is decisive for treatment, development and prognosis of the disease. The most important cause of CHH is viral hepatitis. Hepatitis B and C are frequently occurring diseases and may develop into CHH and cirrhosis of the liver. New therapeutic procedures, using interferons, can prevent this. Idiopathic autoimmune hepatitis is a serious form where interferon therapy is contraindicated, while the condition usually responds very well to treatment with corticoids and immunosuppressive substances. It is important to take into consideration also possible liver damage by drugs and the fact that the clinical picture is associated with a certain stage of metabolically conditioned changes, in particular Wilson's disease. It is important to examine carefully the histological finding and laboratory results, as it is possible to evaluate from them the severity of the disease. We should also attempt to evaluate these changes quantitatively.