Autoimmune hepatitis

December 31, 2014

Synonyms

Overview

Autoimmune hepatitis is a chronic, autoimmune disease of the liver that occurs when the body's immune system attacks liver cells causing the liver to be inflamed. Common initial symptoms include fatigue or muscle aches or signs of acute liver inflammation including fever, jaundice, and right upper quadrant abdominal pain. Individuals with autoimmune hepatitis often have no initial symptoms and the disease is detected by abnormal liver function tests.

Anomalous presentation of human leukocyte antigen (HLA) class II on the surface of liver cells, possibly due to genetic predisposition or acute liver infection, causes a cell-mediated immune response against the body's own liver, resulting in autoimmune hepatitis. This abnormal immune response results in inflammation of the liver, which can lead to further symptoms and complications such as fatigue and cirrhosis. The disease may occur in any ethnic group and at any age, but is most often diagnosed in patients between age 40 and 50.

Symptoms

Though there is a strong female predominance, men are also at risk for the disease. Patients may present with signs of chronic liver disease (abnormal liver function tests, fatigue, aches) or acute hepatitis (fever, jaundice, right upper quadrant abdominal pain).

"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 distinct entities.[citation needed] 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, polyserositis 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.

Causes

Although the exact cause of autoimmune hepatitis is unknown, evidence suggests that liver injury in a patient with autoimmune hepatitis is the result of a cell-mediated immunologic attack. This autoimmune attack may be triggered by genetic factors, viral infections, or chemical agents. Autoimmune hepatitis sometimes occurs in relatives of people with autoimmune diseases, further suggesting a genetic cause. 60% of patients have chronic hepatitis that may mimic viral hepatitis, but without serologic evidence of a viral infection. The disease usually affects women and is strongly associated with anti-smooth muscle autoantibodies.

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 diseases).

A number of specific antibodies found in the blood (antinuclear antibody (ANA), anti-smooth muscle antibody (SMA), liver/kidney microsomal antibody (LKM-1, LKM-2, LKM-3), anti soluble liver antigen and liver–pancreas antigen (SLA/LP) and anti-mitochondrial antibody (AMA)) are of use, as is finding an increased Immunoglobulin G level. However, the diagnosis of autoimmune hepatitis always requires a liver biopsy.

Expert opinion has been summarized by the International Autoimmune Hepatitis Group, which has published criteria which utilize clinical and laboratory data that can be used to help determine if a patient has autoimmune hepatitis. A calculator based on those criteria is available online.

Overlapping presentation with primary biliary cirrhosis and primary sclerosing cholangitis has been observed.

Prognosis

Autoimmune hepatitis is not a benign disease. Despite a good initial response to immunosuppression, recent studies suggest that the life expectancy of patients with autoimmune hepatitis is lower than that of the general population. Additionally, presentation and response to therapy appears to differ according to race. For instance, African Americans appear to present with a more aggressive disease that is associated with worse outcomes.

Treatment

Treatment may involve the prescription of immunosuppressive glucocorticoids, with or without azathioprine, and remission can be achieved in up to 60–80% of cases, although many will eventually experience a relapse. Budesonide has been shown to be more effective in inducing remission than prednisone, and result in fewer adverse effects. Those with autoimmune hepatitis who do not respond to glucocorticoids and azathioprine may be given other immunosuppressives like mycophenolate, cyclosporin, tacrolimus, methotrexate, etc. Liver transplantation may be required if patients do not respond to drug therapy or when patients present with fulminant liver failure.