Chronic Active Hepatitis and Related Disorders

Chronic hepatitis in children should be suspected if clinical features and abnormal liver function tests persist for over one month following an episode of acute hepatitis, in children who present with relapsing hepatitis, or those presenting coincidentally with features of chronic liver disease. Specific investigation must be undertaken to define aetiology. For example, hepatitis B, Wilson's disease and α₁-antitrypsin deficiency must be excluded. Early histological diagnosis by an experienced histopathologist is mandatory.

Chronic persistent hepatitis requires no therapy, but careful follow-up is desirable, especially for hepatitis B-positive cases. If the histological appearances are those of chronic active hepatitis, distinction between HBVassociated and autoimmune varieties is necessary. Autoimmune CAH in children differs from that in adults in that the onset is often acute, response to immunosuppressants usually favourable, and withdrawal of therapy may be successful, especially if diagnosis is established early before serious liver damage occurs. Evidence is presented to suggest that autoimmune CAH is associated with a genetic predisposition to autoimmune disease, characterized by both antigen-specific and antigen-independent T suppressor cell defects. An antibody-dependent non-T cell cytotoxicity operates against liver cell surface antigens. HBV CAH, on the other hand, may respond poorly to immunosuppressants and appropriate therapeutic regimens are not defined.

There is some evidence to suggest that early diagnosis and institution of therapy in autoimmune CAH may lessen the incidence of cirrhosis on follow-up. Further studies to understand the interaction between hepatocytes, inflammatory cells and non-parenchymal cells in the process of hepatic fibrosis may provide the means of active intervention in this area in the future.