Hepatitis B

Hepatitis is an inflammation of the liver. Hepatitis B (HBV, a specific type of hepatitis) is a serious viral infection of the liver that can become chronic, leading to progressive liver disease. People who have the virus but no symptoms are known as carriers.


Anatomy
Your liver is found behind your lower ribs on the right side of your abdomen. It's normally the size of a football. The liver fights infection and controls bleeding. It also produces bile, which assists with food digestion, stores energy, and removes drugs and other harmful products from your blood. The liver is essential for life.

Causes/associated factors
Generally, hepatitis can be caused or aggravated by a variety of factors, including medications, alcohol, toxins, parasites, bacteria and viruses. Specifically, hepatitis B is caused by the hepatitis B virus, which infects cells of the liver and is found in the blood and other body fluids of infected persons. In the United States, acute hepatitis B is most common in people ages 15 to 39. Thanks to vaccination programs, overall incidence of hepatitis B has dropped.
Most adults who have acute hepatitis B recover completely within six months. People who do not fully recover can become chronic carriers of HBV and infect others with the disease, as well as develop serious complications, as described below. In the United States, there are more than 1 million chronic carriers of HBV. Five to 10 percent of adults, 30 percent of children and up to 90 percent of infants with hepatitis B become chronic carriers.

Infants born to mothers who are infected with hepatitis B are at risk for the infection. You are also at higher risk for hepatitis B if you:

are a homosexual or bisexual man
have multiple sexual partners
have household or sexual contact with someone who is infected with hepatitis B
have a sexually transmitted disease
inject illegal drugs
live or work in a prison or other crowded institutional setting
receive clotting factors for a blood clotting disorder
receive hemodialysis (an external method of removing unwanted material from your blood, which is normally a function of the kidneys)
are routinely exposed to blood, blood products or human bites (such as health care workers, members of the police force, firefighters and military personnel)
live in, travel to or emigrated from a region of the world where hepatitis B is prevalent (including infants and children of immigrants from areas where hepatitis B is prevalent)
Testing donated blood has dramatically reduced the spread of hepatitis B through blood transfusions.


Transmission
The hepatitis B virus circulates in your blood. The infection spreads through exposure to infected blood or body fluids (such as semen and saliva). It can spread from an infected mother to her baby, most commonly during birth. An infected person's blood, either fresh or dried, is highly contagious during the one to two months before and after symptoms appear. People who develop antibodies (compounds that help neutralize or destroy foreign substances in the blood) and recover completely from the disease will not remain contagious. However, those who develop chronic hepatitis B have the potential to spread the virus indefinitely.
The incubation period (time from exposure until symptoms develop) is six weeks to six months. The average is 120 days.


Signs/symptoms
Most children and about half of all adults who have acute hepatitis B have no symptoms. When symptoms are present, they usually develop slowly. In some cases, symptoms may be severe, especially if you also have hepatitis D at the same time. Symptoms may include:
jaundice (yellowing of the skin and whites of the eyes)
fatigue and weakness
loss of appetite
nausea and vomiting
low-grade fever
tea-colored urine
abdominal discomfort or pain
sometimes, joint pain, rash or kidney problems

Diagnosis
The doctor will review your medical history, including potential exposure to hepatitis, medication use, blood transfusions and sexual history. Your doctor will also do a physical exam, and you'll need blood tests to detect hepatitis B antigens (foreign substances in the body) and antibodies (compounds that neutralize or destroy the foreign substances). These blood tests can help the doctor determine how far the infection has progressed and how best to treat your condition. Liver function studies can help the doctor determine the severity of liver inflammation.
There are several blood tests used to help diagnose HBV and determine if the infection is active, cured or chronic.

The hepatitis B surface antigen (HbsAg) is the outer covering of the hepatitis virus. This antigen can be detected in your blood during the incubation period, as early as one or two weeks after exposure to the virus, and during the early weeks of symptoms. You are considered to be a chronic hepatitis carrier if this antigen is still present after the illness is over.

The hepatitis B surface antibody (HbsAb) is one of your body's defenses against the hepatitis B virus. The antibody can be detected in your blood about four weeks after the hepatitis B surface antigen disappears. The antibody's presence indicates the infection is over and your body is protected against any future contact with the hepatitis B virus -- you are immune. The antibody is also present after you've been vaccinated against HBV.

Hepatitis B core antibody (HBcAb) is produced as a defense against the hepatitis B core antigen, which is found inside the virus. This antibody is present during the infection and usually persists afterward. It's the only hepatitis indicator found in your blood between the disappearance of the hepatitis B surface antigen and the appearance of the hepatitis B surface antibody.

Treatment
There is no specific treatment or cure for acute hepatitis B. General treatment measures may include the following:
Get plenty of rest. Your doctor may also recommend that you limit your physical activity (especially during the acute phase of the disease).

Eat well.

Do not drink alcohol. Because alcohol is metabolized in the liver, drinking puts added strain on the organ.

Discuss the use of any prescription or over-the-counter drugs and herbal medications with your doctor before use, and only take medications that have been recommended by your doctor. Breaking down certain medications can add strain to the liver.
Your doctor may prescribe medication if you have severe nausea and vomiting or you're too ill to eat well. In severe cases, hospitalization may be necessary. A liver transplant may be recommended if you develop acute liver failure.

Once the infection clears up, follow-up blood tests to monitor your liver function will be done periodically for several months. Blood testing for certain types of hepatitis B antigens is recommended for six to nine months after an acute infection to determine whether you've developed chronic hepatitis B. If you have chronic hepatitis B, you may be treated with alpha interferon, which boosts your body's immune response to the virus, or the antiviral medication lamivudine.


Complications
Hepatitis B may lead to:
chronic infection
chronic liver disease
cirrhosis (a chronic liver disease that may result in liver failure)
liver failure
liver cancer
For carriers, complications may occur years later. In some cases, hepatitis B may be fatal.


Pregnancy-specific information
Hepatitis B can pass from mother to child. If this happens, the baby is at high risk of developing chronic infection or liver disease. Routine testing for the presence of the hepatitis B surface antigen is recommended during pregnancy. If you don't receive this test during pregnancy or you're at increased risk of developing the infection after your prenatal testing, get tested before delivery. If the test is positive, your baby faces the risk of infection.
The hepatitis B vaccine can be given during pregnancy, preferably as soon as possible. Be sure to consult your doctor.


Senior-specific information
Aging may alter the effectiveness of your immune system, leaving you vulnerable to hepatitis B and other types of infections. Your overall health and nutritional status are key factors in your susceptibility. Hepatitis B vaccination is recommended for anyone in a high-risk group.

Prevention
Prevention is crucial because there is no cure for hepatitis B. Learn how hepatitis B spreads and modify any high-risk behaviors.
To protect yourself from hepatitis B, as well as other infections that spread through body fluids (such as HIV and hepatitis C), it's important to:

Avoid using illegal drugs. If you inject drugs, stop. Try to get into a substance abuse treatment program. If you cannot stop injecting drugs, never reuse or share injection equipment.
Avoid sharing personal care items, such as toothbrushes and razors, that could have blood on them.
Avoid touching anyone else's blood. If this is unavoidable, wear protective gloves.
Only have body piercing and tattooing done under sterile conditions.
Avoid having sex with an infected person. Unless you're in a monogamous relationship with an uninfected partner, use a condom each time you have sex.
To avoid the risk of occupational exposure, always follow universal precautions if you work in health care or public safety.
Hepatitis B immunization
The hepatitis B vaccine has been used in the United States since 1981. It is highly effective in preventing this disease -- after three injections, 80 to 100 percent of those vaccinated are protected from infection. Immunization was originally recommended for those at high risk of developing the illness. However, this approach had little effect on the number of new cases that continued to develop each year. In 1991, the recommendations were revised to include routine immunization of all infants, children and young adults who have never been immunized and adults who are at high risk.

The first dose of hepatitis B vaccine is typically given at birth, the second dose at ages 1 to 4 months and the third between ages 6 and 18 months. This schedule will vary, depending on your child's risk of developing the infection.

It's recommended that all pregnant women be tested for hepatitis B during pregnancy. For babies born to mothers who test negative for hepatitis B, the above schedule is appropriate. Premature infants born to negative mothers are usually vaccinated just before they are discharged from the hospital or when they are 2 months old. They should weigh at least 2 kilograms.

For babies born to mothers who have hepatitis B or are carriers of the hepatitis B virus, the first dose of the vaccine series should be given within 12 hours of birth. At the same time, these babies also receive a hepatitis B immune globulin (HBIG) injection. This medication provides immediate protection until the vaccine stimulates the body to produce its own protective antibodies. The second dose of the hepatitis B vaccine should be given at age 1 month, and the third dose at age 6 months.

Babies whose mothers have not been tested for hepatitis B should also receive the first dose of the vaccine series within 12 hours of birth. At the same time, the mother will be tested for hepatitis B. If she is positive, the baby will receive a hepatitis B immune globulin injection as soon as possible (no later than one week of age). The second and third doses will be given as described above, based on the mother's hepatitis B test.

If a child hasn't been immunized according to the recommended schedule, the series of shots can begin at a later date, with the second dose given one to two months after the first dose and the third four to six months after the first. All children should receive the vaccine by or before age 11 to 12. Adolescents age 11 to 15 can receive two higher doses of the vaccine instead of three with the second dose given four to six months after the first.

Adults who have not received the vaccine can begin the three-dose series at any time. This is especially important for those at high risk for contracting hepatitis B. The hepatitis B vaccine is given in three separate injections in the upper arm. The second dose is often given one to two months after the first, with the third dose given four to six months later. Your doctor may recommend another schedule, but the second dose should be given at least one month after the first, and the third dose should be given at least two months after the second and four months after the first.

For people over 18, a combined hepatitis A and hepatitis B vaccine is available. You'll need three doses, following the hepatitis B vaccine schedule.

If the interval between doses of hepatitis B vaccine is longer than recommended, the final antibody concentrations will not be affected. You will not have to start the series over or receive extra doses. However, if the interval between doses is less than recommended, the antibody response may be reduced. Any doses given without adequate time between injections should not be considered part of the primary series.

The vaccine is given in the front of the upper leg in infants and in the upper arm in older children and adults. Other immunizations may be given at the same time in other locations. It's unknown exactly how long immunization lasts, but current studies suggest a series of shots provides more than 15 years of protection. Booster shots are not currently recommended for healthy children or adults.

If you've been exposed or possibly exposed to hepatitis B, notify your doctor immediately. He or she may recommend an injection of hepatitis B immune globulin (HBIG; a protein that can act as an antibody, a compound that neutralizes or destroys foreign substances in the blood). HBIG should be given as soon as possible after exposure to the virus and be followed by a hepatitis B vaccination. HBIG provides protection until the vaccine can stimulate the body to produce its own protective antibodies.