Rarely, rash or unexplained fever may appear. In women, the absence of menstruation (amenorrhoea) is a frequent feature. Physical examination may be normal, but it may also reveal signs and symptoms of chronic liver disease. Many people have only laboratory abnormalities as their initial presentation, as unexplained increase in transaminases and are diagnosed during an evaluation for other reasons. Others have already developed cirrhosis at diagnosis. Of note, alkaline phosphatase and bilirubin are usually normal. Autoimmune hepatitis may overlap with other autoimmune conditions, mainly type 1 diabetes mellitus, ulcerative colitis, lupus, celiac disease, vasculitis, and autoimmune thyroiditis. Cause
The prevailing theory for the development of autoimmune hepatitis is thought to be the interplay of genetic predisposition, an environmental trigger (virus, drugs, herbs, immunizations), and failure of the native immune system resulting in chronic inflammation of hepatocytes and subsequent fibrosis of the liver.There is no specific evidence of the cause. Sixty percent of patients have findings associated with chronic hepatitis but without serologic evidence of a viral infection. The disease is strongly associated with anti-smooth muscle autoantibodies.The exact genes and triggers responsible remain undefined, but studies show association of early-onset, severe disease with the HLA-DR3 serotype and late-onset disease with the HLA-DR4 serotype. Diagnosis
The diagnosis of autoimmune hepatitis is best achieved with a combination of clinical, laboratory, and histological findings after excluding other etiological factors (e.g. viral, hereditary, metabolic, cholestatic, and drug-induced liver diseases). The requirement for histological examination necessitates a liver biopsy, typically performed with a needle by the percutaneous route, to provide liver tissue.
Epidemiology
Autoimmune hepatitis can develop in people of any race or age but occurs most frequently in women. Eighty percent of cases are the type 1 subtype with women being affected 4 times more often than men; for the type 2 subtype, women are affected 10 times more often than men.European studies suggest a disease incidence of 1 to 2 people affected per 100,000 population with a prevalence of 10 to 25 people per 100,000 population.The disease has a bimodal peak occurring between the ages of 10 to 20 and then later in life between the ages of 40 to 50. History
Autoimmune hepatitis was previously called "lupoid" hepatitis due to people having an associated autoimmune disease like system lupus erythematosus at time of diagnosis, which was believed to be its cause. It was originally described in the early 1950s. References


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