Autoimmune hepatitis (AIH) is a disease characterized by irresolving inflammation of the liver, a predominant pen portal. Hepatitis which generally involves young women who are well nourished with moon facies, acne, amenorrhea hirsuties, pigmentation and abdominal striae.
Onset is insidious and patient may be asymptomatic for number of years. Patient is mildly jaundiced with hepatosplenomegaly. Signs of chronic liver disease in the form of cirrhosis may appear.
Since Autoimmune hepatitis is autoimmune disease, episodes of fever with polyarthritis of rheumatid type appear. The cause of the disease is not known but a complex interaction between triggering factors, auto antigen, genetic predisposition and immune regulatory networks is operative.
Because of deranged immuno regulation auto antibodies against hepatocytes, surface antigens are produced. A genetic predisposition is an absolute prerequisite. It is associated with HLA-AI, HLA-B8, HLA-DR3 and HLA DR4. Predisposition only is inherited and not the disease which must be triggered by an antigen.
Humoral disturbances are present characterized by hypergammaglobulinemia mainly of IgG and rise in anti nuclear antibodies (ANA) and anti-smooth muscle antibodies (ASMA). Suppressor T cell function is impaired and it plays important role in the pathogenesis of the disease.
Other auto immune diseases may co-exist. Hepatitis C virus infection has also been incriminated in the pathogenesis of disease. The disease has been divided into three types: Type I is present in elderly women; Type II, the most common, is seen in young women; and type III is present in children.
Diagnosis of the diseases is made by clinical picture of chronic liver disease, presence of hypergammaglobulinaemia, auto antibodies (ANA, ASMA) and absent HBs Ag. Enzyme levels (AST/ ALT) are elevated.
Treatment for Autoimmune hepatitis
Prednisolone is the drug of choice and is given in the dose of 1-1.5 mg/kg body weight /day in divided doses. This produces improvement in the form of decrease in jaundice, fall in serum globulins, auto antibodies levels and decrease in size of spleen. Patient soon gets a feeling of well being.
Treatment of Autoimmune hepatitis has to be continued for a long period spread over months to years. Prednisolone needs to be tapered off slowly and the patient may even require a maintenance dose.
Azathioprine in the dose of 50-100 mg/day is used along with prednisolone. Its main benefit is to act as a steroid sparing drug whose dosage can be reduced.