Autoimmune Hepatitis

Autoimmune hepatitis is a disease in which the body's immune system attacks liver cells. This causes the liver to become inflamed (hepatitis). Researchers think a genetic factor may predispose some people to autoimmune diseases. About 70 percent of those with autoimmune hepatitis are women, most between the ages of 15 and 40.

The disease is usually quite serious and, if not treated, gets worse over time. It's usually chronic, meaning it can last for years, and can lead to cirrhosis (scarring and hardening) of the liver and eventually liver failure.

Autoimmune hepatitis is classified as either type I or II. Type I is the most common form in North America. It occurs at any age and is more common among women than men. About half of those with type I have other autoimmune disorders, such as type 1 diabetes, proliferative glomerulonephritis, thyroiditis, Graves' disease, Sjögren's syndrome, autoimmune anemia, and ulcerative colitis. Type II autoimmune hepatitis is less common, typically affecting girls ages 2 to 14, although adults can have it too.

Symptoms

Fatigue is probably the most common symptom of autoimmune hepatitis. Other symptoms include

People in advanced stages of the disease are more likely to have symptoms such as fluid in the abdomen (ascites) or mental confusion. Women may stop having menstrual periods.

Symptoms of autoimmune hepatitis range from mild to severe. Because severe viral hepatitis or hepatitis caused by a drug—for example, certain antibiotics—has the same symptoms, tests may be needed for an exact diagnosis. Your doctor should also review and rule out all your medicines before diagnosing autoimmune hepatitis.

Diagnosis

The doctor will make a diagnosis based on symptoms, blood tests, and liver biopsy.

• Blood tests. A routine blood test for liver enzymes can help reveal a pattern typical of hepatitis, but further tests, especially for autoantibodies, are needed to diagnose autoimmune hepatitis. Antibodies are proteins made by the immune system to fight off bacteria and viruses. In autoimmune hepatitis, the immune system makes antinuclear antibodies (ANA), antibodies against smooth muscle cells (SMA), or liver and kidney microsomes (anti-LKM). The pattern and level of these antibodies help define the type of autoimmune hepatitis (type I or type II).
  
  Blood tests also help distinguish autoimmune hepatitis from viral hepatitis (such as hepatitis B or C) or a metabolic disease (such as Wilson's disease).
  
  
• Liver biopsy. A tiny sample of your liver tissue, examined under a microscope, can help your doctor accurately diagnose autoimmune hepatitis and tell how serious it is. You will go to a hospital or outpatient surgical facility for this procedure.

Causes

One job of the immune system is to protect the body from viruses, bacteria, and other living organisms. Usually, the immune system does not react against the body's own cells. However, sometimes it mistakenly attacks the cells it is supposed to protect. This response is called autoimmunity. Researchers speculate that certain bacteria, viruses, toxins, and drugs trigger an autoimmune response in people who are genetically susceptible to developing an autoimmune disorder.

Reference:

National Digestive Diseases Information Clearinghouse, USA.