Autoimmune hepatitis (previously known as chronic active hepatitis) is characterized by chronic inflammation of the liver associated with circulating autoantibodies and elevated serum globulins. 

The etiology of this disease is not known. The International Autoimmune Hepatitis Group has published diagnostic criteria for autoimmune hepatitis that combines liver histology with serum laboratory studies. Other causes of chronic liver disease should be excluded.

The clinical manifestations of this disease vary widely. A subset of patients may be asymptomatic and may be identified by abnormal liver transaminases. Other patients will present with signs and symptoms of liver disease or cirrhosis. Patients may have fatigue, pruritus, nausea, or abdominal pain. Patients may have arthralgia involving the small joints. Hepatosplenomegaly and jaundice may or may not be present. 

This disease is more common in women. Some population differences in presentation have been noted, but are not present in all cases. Individuals of African descent are more likely to present with cirrhosis. Patients of Asian descent are more likely to have mild disease. South American pediatric patients often have severe liver inflammation on presentation.

Other autoimmune conditions may be present concomitantly including thyroiditis, ulcerative colitis, type 1 diabetes mellitus, rheumatoid arthritis, and celiac disease.

In addition to elevated transaminases, laboratory evaluation may show increased bilirubin and alkaline phosphatase. Serum globulins (usually IgG) are usually elevated. Some combination of autoantibodies (eg, antinuclear antibodies [ANA], antismooth muscle antibodies [ASMA], anti-liver kidney microsomal antibodies [anti-LKM-1], or anti-liver cytosol antibodies [anti-LC1]) are present. 

Type 1, or "classical," autoimmune hepatitis is characterized by +ANA and +ASMA antibodies. 

Type 2 autoimmune hepatitis is characterized by +anti-LKM-1 or +anti-LC1 antibodies.