Hepatitis - Viral
The term "hepatitis" means inflammation of the liver, from whatever cause. This inflammation is associated with damage to liver cells (hepatocytes). Cellular damage, leading to cell death or necrosis, destroys the function of hepatocytes and releases enzymes and other molecules which can be detected in the blood. Inflammation and damage are diagnosed by microscopic examination of liver tissue, usually obtained by liver biopsy.
Cause of Hepatitis - Viral
Viral hepatitis is inflammation and damage to the liver caused by one of several possible viruses. Such viruses are usually widespread in the body, including the blood, liver and other organs.
There are many different viruses that can affect the liver. In Australia, the well-known ones are hepatitis A virus, hepatitis B virus, and hepatitis C virus. Of these, only hepatitis B and C can become chronic. In patients with acute hepatitis other viral infections need to be considered such as Epstein Barr virus and cytomegalovirus. In patients with chronic hepatitis, hepatitis D virus should also be considered (this occurs in conjunction with hepatitis B).
There are several possible outcomes for viral infections that affect the liver:
1. The virus may be dormant, causing no symptoms or damage at all, and can either remain in the body for a long time or clear from the body without the person being aware.
2. The virus may cause an acute (short-lived) illness which resolves over a period of weeks or months. There are usually symptoms of hepatitis (loss of appetite, tiredness, nausea, jaundice (yellowing of the whites of the eyes and skin), itch, and dark urine.
3. The virus may remain in the body for a long time. This is called chronic hepatitis and lasts for more than 6 months (see Hepatitis - chronic). Damage occurs to the liver - sometimes rapidly, but in other patients the damage is low-grade and continues for many years. The symptoms of chronic hepatitis may be mild, for instance lethargy and nausea, or there may be no symptoms. While symptoms are always of concern to the patient and doctor, the presence of only mild symptoms does not mean that serious liver damage will not occur. Blood tests and a liver biopsy are usually required to assess the severity of liver damage.
4. If the damage is severe or goes on for a long time, scarring of the liver (cirrhosis) results. This scar tissue eventually prevents the liver from working properly and causes complications (see Cirrhosis of the liver).