Hepatitis B

Hepatitis B is a serious liver infection caused by the hepatitis B virus (HBV). For some people, hepatitis B infection becomes chronic, meaning it lasts more than six months. Having chronic hepatitis B increases your risk of developing liver failure, liver cancer or cirrhosis — a condition that causes permanent scarring of the liver.

Most people infected with hepatitis B as adults recover fully, even if their signs and symptoms are severe. Infants and children are more likely to develop a chronic hepatitis B infection. A vaccine can prevent hepatitis B, but there's no cure if you have it. If you're infected, taking certain precautions can help prevent spreading HBV to others

Signs and symptoms

.Signs and symptoms of hepatitis B, ranging from mild to severe, usually appear about one to four months after you've been infected. Signs and symptoms of hepatitis B may include:

• Abdominal pain
• Dark urine
• Fever
• Joint pain
• Loss of appetite
• Nausea and vomiting
• Weakness and fatigue
• Yellowing of your skin and the whites of your eyes (jaundice)

When to see a doctor

If you know you've been exposed to hepatitis B, contact your doctor immediately. A preventive treatment may reduce your risk of infection if you receive the treatment within 24 hours of exposure to the virus.

If you think you have signs or symptoms of hepatitis B, contact your doctor.

Causes

Hepatitis B infection is caused by the hepatitis B virus (HBV). The virus is passed from person to person through blood, semen or other body fluids.

Common ways HBV is transmitted include:

• Sexual contact. You may become infected if you have unprotected sex with an infected partner whose blood, saliva, semen or vaginal secretions enter your body.
• Sharing of needles. HBV is easily transmitted through needles and syringes contaminated with infected blood. Sharing intravenous (IV) drug paraphernalia puts you at high risk of hepatitis B.
• Accidental needle sticks. Hepatitis B is a concern for health care workers and anyone else who comes in contact with human blood.
• Mother to child. Pregnant women infected with HBV can pass the virus to their babies during childbirth. However, the newborn can be vaccinated to avoid getting infected in almost all cases. Talk to your doctor about being tested for hepatitis B if you are pregnant or want to become pregnant.

Acute vs. chronic hepatitis B

Hepatitis B infection may be either short-lived (acute) or long lasting (chronic).

• Acute hepatitis B infection lasts less than six months. Your immune system likely can clear acute hepatitis B from your body, and you should recover completely within a few months. Most people who acquire hepatitis B as adults have an acute infection, but it can lead to chronic infection.
• Chronic hepatitis B infection lasts six months or longer. When your immune system can't fight off the acute infection, hepatitis B infection may last a lifetime, possibly leading to serious illnesses such as cirrhosis and liver cancer.

The younger you are when you get hepatitis B — particularly newborns or children younger than 5 — the higher your risk the infection becoming chronic. Chronic infection may go undetected for decades until a person becomes seriously ill from liver disease.

Risk factors

Hepatitis B spreads through contact with blood, semen or other body fluids from an infected person. Your risk of hepatitis B infection increases if you:

• Have unprotected sex with multiple sex partners or with someone who's infected with HBV
• Share needles during intravenous (IV) drug use
• Are a man who has sex with other men
• Live with someone who has a chronic HBV infection
• Are an infant born to an infected mother
• Have a job that exposes you to human blood
• Travel to regions with high infection rates of HBV, such as Africa, Central and Southeast Asia, and Eastern Europe.

Complications

Having a chronic HBV infection can lead to serious complications, such as:

• Scarring of the liver (cirrhosis). The inflammation associated with a hepatitis B infection can lead to extensive liver scarring (cirrhosis), which may impair the liver's ability to function.
• Liver cancer. People with chronic hepatitis B infection have an increased risk of liver cancer.
• Liver failure. Acute liver failure is a condition in which the vital functions of the liver shut down. When that occurs, a liver transplant is necessary to sustain life.
• Other conditions. People with chronic hepatitis B may have kidney disease, inflammation of blood vessels or anemia.

Tests and diagnosis

If your doctor suspects you have hepatitis B, he or she will examine you and likely order blood tests. Blood tests can determine if you have the virus in your system and whether it's acute or chronic. Your doctor might also want to remove a small sample of your liver for testing (liver biopsy) to determine whether you have liver damage. During this test, your doctor inserts a thin needle through your skin and into your liver and removes a tissue sample for laboratory analysis.

Screening healthy people for hepatitis B

Doctors sometimes test certain healthy people for hepatitis B infection because the virus can damage the liver before causing signs and symptoms. Talk to your doctor about screening for hepatitis B infection if you:

• Live with someone who has hepatitis B
• Have had sex with someone who has hepatitis B
• Have a liver enzyme test with unexplained abnormal results
• Have HIV or hepatitis C
• Are an immigrant from, have parents from or have adopted children from places where hepatitis B is common, including Asia, the Pacific Islands, Africa and Eastern Europe
• Inject illegal drugs
• Are an inmate
• Are a man who has sex with men
• Receive kidney dialysis
• Take medications that suppress the immune system, such as anti-rejection medications used after an organ transplant
• Are pregnant.

Treatments and drugs

Treatment to prevent hepatitis B infection after exposure

If you know you've been exposed to the hepatitis B virus, call your doctor immediately. If you haven't been vaccinated or aren't sure whether you've been vaccinated or whether you responded to the vaccination, receiving an injection of hepatitis B immune globulin within 12 hours of coming in contact with the virus may help protect you from developing hepatitis B. You should be vaccinated at the same time.

Treatment for acute hepatitis B infection

If your doctor determines your hepatitis B infection is acute — meaning it is short-lived and will go away on its own — you may not need treatment. Instead, your doctor might recommend rest and adequate nutrition and fluids while your body fights the infection.

Treatment for chronic hepatitis B infection

If you've been diagnosed with chronic hepatitis B infection, you may have treatment to reduce the risk of liver disease and prevent you from passing the infection to others. Treatments include:

• Antiviral medications. Several antiviral medications — including lamivudine (Epivir), adefovir (Hepsera), telbivudine (Tyzeka) and entecavir (Baraclude) — can help fight the virus and slow its ability to damage your liver. Talk to your doctor about which medication might be right for you.
• Interferon alfa-2b (Intron A). This synthetic version of a substance produced by the body to fight infection is used mainly for young people with hepatitis B who don't want to undergo long-term treatment or who might want to get pregnant within a few years. It's given by injection. Side effects may include depression, difficulty breathing and chest tightness.
• Liver transplant. If your liver has been severely damaged, a liver transplant may be an option. During a liver transplant, the surgeon removes your damaged liver and replaces it with a healthy liver. Most transplanted livers come from deceased donors, though a small number come from living donors who donate a portion of their livers.

Other drugs to treat hepatitis B are being developed.

Source : 

http://www.mayoclinic.org/