AUTOIMMUNE HEPATITIS DEFINITION
Autoimmune hepatitis is liver inflammation that occurs when your body’s immune system turns against liver cells. The exact cause of autoimmune hepatitis is unclear, but genetic and environmental factors appear to interact over time in triggering the disease.
Untreated autoimmune hepatitis can lead to scarring of the liver (cirrhosis) and eventually to liver failure. When diagnosed and treated early, however, autoimmune hepatitis often can be controlled with drugs that suppress the immune system.
A liver transplant may be an option when autoimmune hepatitis doesn’t respond to drug treatments or when liver disease is advanced.
AUTOIMMUNE HEPATITIS CAUSES
The exact mechanism whereby the body’s own immune system attacks the liver is not yet known. It appears that certain types of white blood cells (the type of blood cell that usually fights infection), in addition to attacking foreign substances (e.g. germs and viruses) misread liver cells as foreign substances and start attacking these cells. The type of damage that follows is known as chronic hepatitis. A number of other conditions can cause identical patterns of liver damage. These include viruses such as hepatitis B and hepatitis C, certain types of drugs, and overload of certain metals such as copper and iron in the liver. There are also much rarer causes of chronic active hepatitis.
AUTOIMMUNE HEPATITIS PATHOPHYSIOLOGY
One theory for the pathogenesis of AIH suggests that the disease is caused by an environmental trigger in a genetically predisposed individual. The exact relationships between the genes and the autoimmune process remain largely undefined, but at the molecular level, they are thought to involve the antigen, the major histocompatibility complex (MHC), and the T cell receptor (TCR). These form a ternary complex in which short segments called complementary determining regions (CDR) identify and contact the antigen-MHC complex. Viruses, drugs, herbs, and immunizations have been suggested as triggering agents but the nature of relevant antigens is still undefined, and in most instances, no specific inducer of autoimmunity can be identified.
AUTOIMMUNE HEPATITIS SYMPTOMS
Symptoms of AIH range from mild to severe. In the early stages, you may have no symptoms, but in later stages, symptoms can appear suddenly. They may also slowly develop over time.
AIH symptoms include:
- enlarged liver (hepatomegaly)
- abnormal blood vessels on the skin (spider angiomas)
- abdominal distention (swelling)
- dark urine
- pale-colored stools
AUTOIMMUNE HEPATITIS DIAGNOSIS
No single test is diagnostic for AIH. The diagnosis of AIH is based on a combination of characteristic clinical features and typical laboratory abnormalities. Other causes of chronic hepatitis should be excluded, including alcohol induced hepatitis, drug-induced hepatitis, and viral hepatitis.
In the majority of cases. When patients do not meet all the criteria or have atypical features, the diagnosis of AIH becomes less certain and they should be referred to a gastroenterologist or hepatologist.
AUTOIMMUNE HEPATITIS TREATMENT
Drugs and Medication
Immunosuppressant drugs can be used to stop the immune system’s attack. Such drugs include 6-mercaptopurine and azathioprine. Taking immunosuppressant drugs may compromise your body’s ability to fight other infections.
Corticosteroids, usually in the form of prednisone, can directly treat liver inflammation. They can also serve as immunosuppressants. You will likely need to take prednisone for a minimum of 18-24 months. Some patients must continue taking the drug for life to prevent AIH from recurring. Prednisone may cause serious side effects, including diabetes, osteoporosis, high blood pressure, and weight gain.
A liver transplant (replacing your liver with a donor organ) can treat AIH. However, the disease can sometimes recur even after a transplant. According to the National Digestive Diseases Information Clearinghouse (NDDIC), there is a 90 percent one-year survival rate for patients who have a transplant. The five-year survival rate is 70 to 80 percent.