Hepatitis B Virus (HBV) Symptoms & Causes

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We understand that you may have a lot of questions when your child is diagnosed with hepatitis B, such as:

  • What exactly is it?
  • What is the cause of hepatitis B?
  • What are potential complications in my child’s case?
  • What are the treatments?
  • What are possible side effects from treatment?
  • How will it affect my child long term?

We’ve tried to provide some answers to those questions here, and when you meet with our experts, they can explain your child’s condition and treatment options fully.

What is the liver, and what does it do?

The liver is the body’s second largest organ, located in the right side of the abdominal cavity below the diaphragm and above the right kidney and intestines. The liver helps the body in hundreds of ways:

  • All of the blood coming from the stomach and intestines passes through the liver through a large vein called the portal vein. The liver turns nutrients from the food we eat and chemicals from the medicines we take into forms that the rest of our bodies can use.

  • The liver helps clean the bloodstream of harmful substances and poisons.

  • The liver makes bile, which contains chemicals to help us digest the food we eat.

  • The liver helps control blood sugar and cholesterol levels.

  • The liver makes the proteins that allow blood to clot normally.

What is hepatitis B?

Hepatitis B is a liver disease caused by the hepatitis B virus (HBV), and the most common serious liver infection in the world. It ranges in severity from a mild illness that lasts a few weeks and clears on its own to a serious, long-term illness that requires lifelong care.

Children and adults who are not able to clear an HBV infection within six months (the infection's acute stage) go on to develop chronic hepatitis B, a serious illness that can cause long-term health problems and requires long-term care. The risk that a child with acute hepatitis B will develop the chronic form goes down with age, so for instance an infant with acute hepatitis B has about a 90 percent chance of having the infection become chronic; the risk in children under five years old is about 30 percent, while that of an adult is between two and six percent.

Over the course of decades, chronic hepatitis B progresses through four stages – immune tolerance, immune clearance, inactive carrier, and reactivated – based on the behavior of the virus and how your child’s immune system responds against it. The inactive carrier phase, in particular, can last for years, often until well into adulthood.

What happens to the liver in hepatitis B?

In acute symptomatic hepatitis B, the liver can become swollen and inflamed, but the infection may be silent, particularly in infants. Should the infection become chronic and enter reactivated stage, the virus can cause inflammation that in turn causes the healthy, soft tissues in the liver to harden and scar, typically over the course of decades. If not stopped, this hardening can lead to serious liver diseases such as cirrhosis or liver cancer. This happens in upwards of a quarter of people with chronic hepatitis B.

Causes

What causes hepatitis B?

Hepatitis B is caused by the hepatitis B virus (HBV). The virus is passed from person to person through contact with blood infected with HBV, sexual intercourse, or intravenous drug use. Mothers infected with HBV can pass the virus on to their children during childbirth, though doctors can reduce that risk by giving newborns both the hepatitis B vaccine and a medication called hepatitis B immune globulin (or HBIG) within about 12 hours of birth.

While the number of new cases of hepatitis B in the United States has dropped dramatically in the last two decades – thanks to widespread (and now universal) childhood vaccination – there are still about 1.2 million people in the U.S. with the infection. Most cases in the U.S. now are in people who have immigrated or children adopted from countries in the Far East, Western Africa, or Eastern Europe, where hepatitis B is still widespread. Because chronic hepatitis B causes few or no symptoms, many do not even realize they are infected.

Signs and symptoms

What are the symptoms of hepatitis B?

The majority of infants with acute hepatitis B have no symptoms; they also have no idea they are infected. Over time, as the virus causes increasing damage to the liver, patients can experience symptoms like fatigue, nausea, dark urine, muscle soreness, vomiting, loss of appetite, stomach pain and jaundice.

How is hepatitis B diagnosed?

If your child’s doctor suspects that your child may have been infected with HBV, he or she may test their blood to see if it contains a portion of the virus called the surface antigen. If the test comes back positive, your child’s doctor may run additional tests for the other portions of the virus that can provide more information.

Children and adults with HBV surface antigen in their blood for more than six months – meaning that they now have chronic hepatitis B – typically undergo periodic tests to monitor their liver function and look for signs of serious liver disease. If such tests show that the virus is starting to damage your child’s liver, then a biopsy may be ordered as well to determine whether the time is right to start treatment.

Because in the U.S. HBV is most often passed from mother to child, your doctor will also want to know whether there is any history of liver disease, and in particular liver cancer, in your family. It is not uncommon for multiple members within a family to be infected, and knowledge of your family’s history could help your doctor predict how the virus will behave within your child.

How do you treat hepatitis B?

Acute and chronic hepatitis B are treated very differently. In prescribing treatment for hepatitis B, doctors in our Center for Childhood Liver Disease aim to inactivate the virus, reduce the amount of virus in the blood, and prevent the progressive liver damage that could lead to cirrhosis or liver cancer.

If your child has acute hepatitis B, our doctors will recommend rest, healthy eating, and drinking plenty of fluids. If we determine that the infection has lasted more than six months – that is, that your child has chronic hepatitis B – and that the virus is starting to damage the liver, then we may start treatment with one of a variety of medications. Your doctor will discuss pros and cons of each medication with you.

In additions, new medications have become available over the last few years to treat hepatitis B in adults, and are currently being evaluated for the treatment of children. Your child’s doctor may discuss clinical trials (research studies) of these medications in which your child may be able to participate.

While the hepatitis B vaccine is not effective in people who are already infected with the virus, we do recommend that all children and adults with hepatitis B receive the vaccine against hepatitis A in order to prevent additional liver inflammation and injury.

How can hepatitis B affect my child in the long term?

First off, you should know that children with chronic hepatitis B can lead completely normal lives, and can attend school and play sports without any special arrangements, just like any other child.

However, if your child has chronic HBV infection he or she could very well be infected with it for life. Over the decades, the virus can cause progressive damage to the liver and lead to such complications as cirrhosis and liver cancer.

When they become older, children with hepatitis B should avoid drinking alcohol, as it can make the disease progress more quickly. Once they become or if they are sexually active, they should practice safe sex so as to not pass the virus on to others.

We are grateful to have been ranked #1 on U.S. News & World Report's list of the best children's hospitals in the nation for the third year in a row, an honor we could not have achieved without the patients and families who inspire us to do our very best for them. Thanks to you, Boston Children's is a place where we can write the greatest children's stories ever told.”
- Sandra L. Fenwick, President and CEO

Boston Children's Hospital 300 Longwood Avenue, Boston, MA 02115 617-355-6000 | 800-355-7944

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