What causes hepatitis B?
Hepatitis B is caused by none other than the hepatitis B virus. Hepatitis B infection occurs worldwide but is most common in Asia, Africa, southern Europe and Latin America. Approximately 2 billion people have been infected with hepatitis B and there are about 350 million people with chronic hepatitis B infection. Chronic infection in children occurs most commonly in those who are born to infected mothers (about half of chronic hepatitis B cases occur this way). Adults and older children who develop hepatitis B infection often will clear the infection without treatment. Some children with an acute infection will not clear the virus and will develop chronic hepatitis B. These children have a higher risk of long-term complications (i.e., cirrhosis and liver cancer) when compared to hepatitis B acquired in adulthood.
What are the phases of hepatitis B infection?
Immune-tolerant phase - This phase of chronic hepatitis B infection is mainly seen in children infected at birth. The virus reproduces aggressively but causes little inflammation. The body has not yet been triggered to fight the virus actively. This phase may last into adulthood.
Immune-active phase - For unknown reasons, the body realizes it is infected with a foreign virus and mounts a raging defense. Unfortunately, this aggressive response to the virus leads to inflammation that can damage the liver. Most children will enter the inactive state but some will retain active inflammation. The children "stuck" in this phase of hepatitis B infection are the most likely to develop liver damage or liver cancer.
Inactive hepatitis B phase - Most children with active inflammation have gradual reduction in liver inflammation and enter the inactive phase. This phase is a chronic carrier state in which ongoing liver damage is minimal but these children can still spread the virus to others through contact with blood.
What are the symptoms of acute hepatitis B?
- Young children may have NO symptoms!
- Decreased appetitite
- Abdominal pain
What are the symptoms of chronic hepatitis B?
Children typically have no symptoms until cirrhosis develops. This usually does not occur until adulthood. The symptoms of chronic hepatitis B infection with cirrhosis are those of liver dysfunction.
How is hepatitis B diagnosed?
The presence of certain hepatitis B proteins in the blood (antigens) and the bodies immune response proteins (antibodies) can make the diagnosis and also provide clues as to whether the infection is chronic.
The amount of viral particles in the blood can be estimated by checking a blood hepatitis B DNA PCR test.
Other blood tests can determine if there is active inflammation and tissue damage in the liver (ALT, AST).
Other tests of liver function may also be determined (INR, bilirubin, albumin).
How is hepatitis B treated?
There is no specific treatment for an acute hepatitis B infection. Chronic infection can be treated (and occasionally can be cured) with antiviral medicines such as: entecavir, adefovir, peginterferon alfa-2a, and telbivudine. Treatment goals are to suppress virus production and lower the risk of long-term complications such as liver cirrhosis and liver cancer (hepatocellular carcinoma). Treatment is often not effective for children with chronic smoldering hepatitis B. The treatments are often difficult and long-term. The decision to treat chronic hepatitis B should be made after the parents are well-informed about the potential risks and benefits of treatment.
How can hepatitis B infection be prevented?
The hepatitis B vaccine is recommended for all infants in 3 doses given before disharge from the newborn nursery, at 1-2 months old, and at 6-18 months old. Infants born to mothers known to have hepatitis B infection should receive the vaccine and hepatitis B immunoglobulin within 12 hours of birth.
All blood products in the United States should be screened for hepatitis B.
All pregnant mothers should be checked for hepatitis B before delivery of the infant. If the mother is positive for the virus (or if the mother's status is not known), the infant should receive the vaccine and hepatitis B immunoglobulin within 12 hours after birth.
Can a mother with chronic hepatitis B breastfeed?
Yes. The risk of transmitting the hepatitis B virus from mother to infant is not increased by breastfeeding.Click here for the CDC recommended vaccine schedule.
Photo - TEM micrograph of en:hepatitis B virions, also known as Dane particles. Obtained from the CDC Public Health Image Library. Image credit: CDC/Dr. Erskine Palmer (PHIL #270), 1981. Used with permission.
Last Updated (Monday, 06 September 2010 14:20)