Hepatitis B is inflammation (irritation and swelling) of the liver due to the hepatitis B virus (HBV).

Other types of hepatitis include:

• Hepatitis A
• Hepatitis C
• Hepatitis D

See also:

• Autoimmune hepatitis
• Chronic persistent hepatitis
• Drug-induced hepatitis

The hepatitis B virus spreads through blood, semen, vaginal fluids, and other body fluids. Infection can occur if you have:

• Blood transfusions
• Contact with blood in health care settings
• Had direct contact with the blood of an infected person by touching an open wound or been stuck with a needle
• Had unsafe sex with an infected person
• Received a tattoo or acupuncture with contaminated instruments
• Shared needles during drug use
• Shared personal items (such as toothbrushes, razors, and nail clippers) with an infected person

The hepatitis B virus can be passed to an infant during childbirth if the mother is infected.

The risk of becoming chronically infected depends on your age at the time of infection. Most newborns and about 50% of children infected with hepatitis B develop chronic hepatitis. Only a few adults infected with HBV develop the chronic condition.

Most of the damage from the hepatitis B virus is due to the body's response to the infection. When the body's immune system detects the infection, it sends out special cells to fight it off. However, these disease-fighting cells can lead to liver inflammation.

The liver damage also interferes with the body's ability to get rid of bilirubin, a breakdown product of old red blood cells. This leads to jaundice (yellow discoloration of the eyes and body) and dark urine.

It takes about 1-6 months from the time of infection until symptoms of acute hepatitis appear. Early symptoms may include:

• Appetite loss
• Fatigue
• Low-grade fever
• Muscle and joint aches
• Nausea and vomiting
• Yellow skin and dark urine due to jaundice

People with chronic hepatitis may have no symptoms, or they may have symptoms similar to those of acute hepatitis.

The following tests are done to identify and monitor liver damage from hepatitis B:

• Albumin level
• Liver function tests
• Prothrombin time

The following tests are done to help diagnose hepatitis B:

• Antibody to hepatitis B core antigen (Anti-HBc)
• Antibody to HBsAg (Anti-HBs)
• Hepatitis B surface antigen (HBsAg)
• Hepatitis E surface antigen (HBcAg)

Patients with chronic hepatitis may receive ongoing blood tests.

Acute hepatitis needs no treatment other than careful monitoring of liver function, which involves blood tests. In the rare case that you develop liver failure, you should be monitored in a hospital until you recover or you need a liver transplant. A liver transplant is the only cure in some cases of liver failure.

Liver damage makes it harder for the liver to break down proteins, so limit your protein intake. You will take medications to limit protein production by bacteria in your body.

Patients with chronic hepatitis are treated with antiviral medications. Hepatitis B cannot be cured, but these medications may help lessen the infection. Liver transplantation is used to treat end-stage chronic hepatitis B liver disease.

For more information on treatment, see liver disease.

See: Liver disease support group

The acute illness usually goes away after 2 - 3 weeks. The liver usually returns to normal within 4 - 6 months in almost all patients who are infected.

Some people develop chronic hepatitis. People who have chronic hepatitis B stay infectious. They are considered carriers of the disease, even if they do not have any symptoms.

Hepatitis B is deadly in approximately 1% of cases.

There is a higher rate of hepatocellular carcinoma in those who have had hepatitis B than in the general population.

Other complications may include:

• Chronic persistent hepatitis
• Cirrhosis

Call your health care provider if:

• You develop symptoms of hepatitis B
• Hepatitis B symptoms do not go away in 2 or 3 weeks, or new symptoms develop
• You belong to a high-risk group for hepatitis B and have not yet received the HBV vaccine.

All children should receive their first dose of the hepatitis B vaccine at birth, and complete their vaccination series by age 6 - 18 months. Children younger than age 19 who have not been vaccinated should receive "catch-up" doses.

People who are at high risk, including health care workers and those who live with someone with hepatitis B, should get the hepatitis B vaccine.

Infants born to mothers who either currently have acute hepatitis B or who have had the infection receive a special vaccination that includes hepatitis B immune globulin and a hepatitis B immunization within 12 hours of birth.

Screening of all donated blood has reduced the chance of getting hepatitis B from a blood transfusion. Mandatory reporting of the disease allows state health care workers to track people who have been exposed to the virus. The vaccine is given to those who have not yet developed the disease.

Avoid sexual contact with a person who has acute or chronic hepatitis B. Using condoms consistently and properly may also reduce your risk of developing this condition.

Dienstag JL. Hepatitis B virus infection. N Engl J Med. 2008;359:1486-1500.

Jou JH, Muir AJ. In the clinic. Hepatitis C. Ann Intern Med. 2008;148:ITC6-1-ITC6-16.