What is autoimmune hepatitis?
Autoimmune hepatitis, often referred to as AIH, is one cause of chronic hepatitis and can be, if untreated, one of the most severe forms.
For a long time AIH was known as chronic active hepatitis. AIH is just one of the causes of chronic active hepatitis but it is now recognised as a specific disease.
What causes AIH is not well understood. It is believed the cells that do the damage are circulating blood cells known as lymphocytes. They behave as though the hepatocytes (the liver cells) are foreign and start to destroy them.
Fortunately AIH is relatively uncommon although it occurs in both males and females.Between the ages of 15 and 25, it is women who are mostly affected. Around the ages of 45 and 55, both men and women are affected.
Common symptoms of AIH are:
- general feeling of ill-health
- lack of energy
- tendency to tire easily
- inability to finish a full days work
- the need to have more sleep
- joint pains (arthralgia) which are an indirect effect of chronic hepatitis and are usually mild and intermittent, noted mostly in the mornings.
Less common symptoms may be:
- decreased appetite
- weight loss
- abdominal pain or bloating
- abnormal blood vessels on the skin on the face, arms and chest
If the disease is very active or advanced, jaundice (yellowing of the skin and whites of the eyes and darkening of the urine) may occur.
If cirrhosis develops as a result of chronic AIH there may be muscle wasting, weight loss, ascites (swelling of the abdomen with fluid) and vomiting blood. In many cases the condition develops almost secretly, with no factor pointing to the liver as a cause of ill-health.
This is usually made by taking a careful medical history, performing a physical examination, arranging of blood tests and a liver biopsy.
People with AIH may have other autoimmune diseases at the time of diagnosis of AIH, before the diagnosis is made or after. Some of the conditions associated with autoimmune hepatitis include:
- thyroid disease (either over or under active)
- pernicious anaemia (a deficiency of vitamin B12)
- vitiligo (pale patches on the skin).
Liver function tests (LFTs) are blood tests that measure substances in the bloodstream that indicate that the liver is damaged.
Other blood tests used in AIH include those that identify immunoglobulins and autoantibodies.These are antibodies in the blood that react with the body’s own cells and include antinuclear antibodies (ANA) or smooth muscle antibodies (SMA). To assess the amount of liver damage, confirm the diagnosis and to exclude other causes of liver disease, a liver biopsy is usually done. In this procedure a fine hollow needle is passed throught the skin to the liver and a small sample of liver tissue is withdrawn.
This is usually done under local anaesthetic and may mean an overnight stay in hospital.
The cause of AIH as yet remains unknown. You will not develop AIH by exposure to someone else with the disease. It is not thought to be due to a virus and has nothing to do with alcohol. Although there is a genetic link to AIH, at the present time there is nothing that can be done to prevent the condition occurring.
Once the diagnosis has been made, treatment is almost always required.
The treatment used is called immunosuppression. This therapy uses a type of steroids, known as corticosteroids, to reduce (suppress) the ability of your immune system to fight infection.
It is usual to start treatment with a relatively high dose of steroids, usually prednisone or prednislone. When the inflammation is brought under control, the dose can be reduced. Usually other drugs are added to allow for a lower dose of steroids.
Another immunosuppressant, azathioprine, is most commonly used in combination with steroids. This drug is slower acting and has fewer side effects than steroids.
If AIH is well controlled, steroids may be withdrawn completely so that you are maintained on azathiopine only, although this is not always possible.
Autoimmune hepatitis appears more often to be a controllable rather then a curable disease, therefore most patients need long-term maintenance therapy. It may be possible to completely withdraw the immunosuppression but this is not without risk as relapse can occur months, or even years after withdrawal.
Other drugs such as cyclosporin, tacrolimus, mycophenolate and D-penicillamine may also be considered.
You should not stop taking any of these drugs without first consulting your doctor or specialist.