Autoimmune Hepatitis

Autoimmune Hepatitis
By Howard J. Worman, M. D.

Autoimmune hepatitis is a condition in which the patient's own immune systems attacks the liver causing inflammation and liver cell death. The condition is chronic and progressive. Although the disease is chronic, many patients with autoimmune hepatitis present acutely ill with jaundice, fever and sometimes symptoms of severe hepatic dysfunction, a picture that resembles acute hepatitis.

Autoimmune hepatitis usually occurs in women (70 %) between the ages of 15 and 40. Although the term "lupoid" hepatitis was originally used to describe this disease, patients with systemic lupus erythematosus do not have an increased incidence of autoimmune hepatitis and the two diseases are distint entities. Patients usually present with evidence of moderate to severe hepatitis with elevated serum ALT and AST activities in the setting of normal to marginally elevated alkaline phosphatase and gamma-glutamyltranspeptidase activities. The patient will sometimes present with jaundice, fever and right upper quadrant pain and occasionally systemic symptoms such as arthralgias, myalgias, polyserositits and thrombocytopenia. Some patients will present with mild liver dysfunction and have only laboratory abnormalities as their initial presentation. Others will present with severe hepatic dysfunction.

Autoimmune hepatitis should be suspected in any young patient with hepatitis, especially those without risk factors for alcoholic, drug, metabolic or viral etiologies. Serum protein electrophoresis and testing for autoantibodies are of central importance in the diagnosis of autoimmune hepatitis. Patients with one subtype of autoimmune hepatitis have serum gamma-globulin concentrations more than twice normal and sometimes antinuclear antibodies and/or anti-smooth muscle (anti-actin) antibodies. Patients with another subtype may have normal or only slightly elevated serum gamma-globulin concentrations but will have antibodies against a particular cytochrome p450 isoenzyme that are called anti-LKM (liver kidney microsome).

Patients in whom a diagnosis of autoimmune hepatitis is suspected should have a liver biopsy. If the biopsy is consistent, treatment with steroids (prednisone or pednisolone) and azathioprine (Imuran) is begun immediately. These are tapered over the next 6 to 24 months depending upon the patient's course. If immediate liver biopsy is contraindicated because of a prolonged prothrombin time or thrombocytopenia, steroids and azathioprine should be started prior to biopsy if the diagnosis of autoimmune hepatitis is likely based on clinical criteria (e.g. a young woman with severe hepatitis, elevated serum gamma-globulin concentration, negative risk factors and serologies for viral hepatitis). The patient will often rapidly improve and biopsy should be performed to confirm the diagnosis as soon as the prothrombin time decreases and platelet count increases to within safe ranges.

About two thirds to three quarters of patients with autoimmune hepatitis respond to treatment based on the return of serum ALT and AST activities to normal and an improved biopsy after several months. Some patients relapse as steroids and azathioprine doses are tapered or stopped and need chronic maintenance medications. Over the long term, many patients develop cirrhosis despite having a response to treatment, and patients who do not respond to treatment will almost always progress to cirrhosis. If end-stage liver disease develops, orthotopic liver transplantation is an effective procedure.

For more information, you may want to see a recent review article by Edward L. Krawitt, M. D. at the University of Vermont College of Medicine: Krawitt, E. L. 1996. Autoimmune hepatitis. New England Journal of Medicine. 334:897-903.

Source: http://cpmcnet.columbia.edu/dept/gi/autoimmune.html

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