Hepatitis B is one of the most widespread human infections. About 400 million people around the world are infected, and it causes about a million deaths each year. The hepatitis B virus is the second most common known cause of human cancer, after tobacco smoke. Apart from liver cancer, it also causes acute hepatitis, chronic hepatitis, liver cirrhosis, and liver failure.
In the USA and other developed countries, hepatitis B is usually acquired by sexual transmission or intravenous drug use. Shared needles, whether used medically, or for drug addiction or tattooing, are a major risk factor for this infection. Unlike the HIV (AIDS) virus, the hepatitis B virus is hardy, and can survive outside the body for a long time.
In developing countries, most infections occur at time of birth from an infected mother. Infections acquired at this young age are usually long lasting. Hepatitis B is also transmitted by blood transfusion and blood products, though this is very rare now. Other rare routes of Hepatitis B infection in childhood are organ transplantation and sexual abuse.
The Hepatitis B virus has an affinity for the liver, and reaches the liver cells, regardless of how it enters the body. Reproduction of the virus causes death of these cells. Death of a large number of liver cells in a short period can cause acute fulminant hepatitis, with deep jaundice, poor appetite, and sometimes bleeding. If the liver failure progresses, the child may develop seizures, become unconscious, and might even die.
In most children, however, this acute picture is not seen. In most infected children, the virus multiplies slowly and persists in the body, causing slow liver damage. The infected person has the virus in the liver and blood, but no signs of disease, and is infectious to others. This state is known as the chronic carrier state.
Most children who acquire the infection at birth or soon after become chronic carriers. In contrast, adults who get the infection have an acute illness, followed by clearance of the virus. Thus protection of children by vaccination is important.
As the virus multiplies, the liver cells are destroyed, causing loss of liver function. This leads to jaundice, bleeding, fluid accumulation, etc. This is known as chronic hepatitis.
Long term Hepatitis B infection can also be accompanied by liver cirrhosis. As liver cells are destroyed, they are replaced by fibrous tissue. The liver is shrunken, and poorly functional. About 12% of people with chronic hepatitis B infection will develop cirrhosis each year.
Liver cell cancer is another life threatening complication of long term hepatitis B virus infection. The hepatitis B virus is the second most common cause of cancer in humans, after tobacco smoke. Liver cancer usually occurs 25 to 30 years after the infection first occurs. Most hepatitis B deaths are by cancer or chronic liver disease; it rarely causes acute severe disease.
Last Revision: February 16, 2016
The aims of treatment are to stop multiplication of the virus and prevent the liver disease from progressing. Treatment for hepatitis b infection is only given if there is evidence of active liver disease on laboratory tests or liver biopsy.
Two types of treatment are available -- interferon and anti viral drugs. Interferon is a product of the body's immune system that destroys viruses. It has now been synthesized in the laboratory, and has been used for the treatment of chronic hepatitis. Treatment with interferon is prolonged and expensive. Interferon cannot be given to people who have developed cirrhosis of the liver and liver failure.
Among the antiviral drugs, lamivudine has given fairly good results. Another drug being tried is Adefovir. These drugs have also been used in combination with each other, and with interferon. If these measures fail, or if cancer develops, one option is liver transplantation.
None of these drugs or combinations are curative. The best that can be hoped for is to prevent viral multiplication, and to slow down liver damage. Preventive measures against hepatitis B are therefore very important.
Dr. Parang Mehta,
Opposite Putli, Sagrampura,
Surat, India. Tel: +91 9429486624.
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