Hepatitis B

Hepatitis B
• Definition of Hepatitis B
• Description of Hepatitis B
• Causes and Risk Factors of Hepatitis B
• Symptoms of Hepatitis B
• Diagnosis of Hepatitis B
• Treatment of Hepatitis B
• What Questions To Ask Your Doctor About Hepatitis B
• Prevention of Hepatitis B

Definition of Hepatitis B

Article updated and reviewed by Sreeni Jonnalagadda, MD, Associate Professor of Medicine, Interventional and Pancreatobiliary Endoscopy, Washington University School of Medicine on June 6, 2005.

Hepatitis B is a viral infection of the liver caused by the Hepatitis B virus (HBV).




Description of Hepatitis B

Hepatitis literally refers to any inflammation of the liver. In fact, there are five forms of acute viral hepatitis that are often clinically indistinguishable from one another. These diseases are unrelated to each other except by the fact that they all cause liver damage.

It is important not to confuse hepatitis B with with any other viral hepatitis. Each has its own mode of transmission and associated risk factors. Hepatitis A, for example, is transmitted by the fecal-oral route, whereas hepatitis B is often transmitted through sexual contact or IV drug abuse.

HBV is a known threat to health care workers. Each year in the U.S., an estimated 12,000 health care workers contact Hepatitis B from their patients. About 300 people die each year of this illness or its long-term consequences. This is in contrast to the observation that only seven health care workers have developed AIDS as a result of occupational exposure. The ease of the transmission of the virus is one of the many challenges facing public health professionals.

Hepatitis B infection may result in a range of health outcomes. After a two- to six-month incubation period, HBV can lead to acute hepatitis. Most individuals are able to recover completely from an acute infection. However, if the body is unable to mount an effective immune response, a patient may become a "chronic carrier" of hepatitis B virus.

Chronic carriers are at increased risk of developing cirrhosis of the liver and hepatocellular carcinoma (HCC), a serious liver cancer. In fact, HBV is regarded by many scientists to be second only to tobacco as a known human carcinogen. CDC estimates that approximately 25 percent of carriers suffer chronic symptoms, and those people are at the greatest risk of cirrhosis.

All carriers, whether or not they have active symptoms, have a 12 to 300 times greater risk of developing primary liver cancer than non-carriers.

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Causes and Risk Factors of Hepatitis B

Hepatitis B follows a similar mode of transmission as the human immunodeficiency virus (HIV), the agent responsible for AIDS. Both are transmitted through exposure to infected blood or blood products, sexual contact and from mothers to infants primarily at birth.

However, hepatitis B appears to be far more infectious than HIV. According to the Centers for Disease Control and Prevention, approximately 30 to 40 percent of acute HBV infections in the U.S. occur in individuals with no known risk factors. In comparison, only 4 percent of AIDS cases have occurred in individuals with no known risk factors.

Hepatitis B is threatening for a variety of other reasons. In addition to the ways in which HIV is spread, hepatitis B appears to be spread by casual contact. It can be acquired by close contact within families, or from person to person through contact with open skin lesions. The virus may possibly be spread by exposure of mucous membranes to saliva, but you cannot get it from food or water, sneezing or coughing, breastfeeding, handshakes, hugs or casual contact.

Another important fact is that hepatitis B can remain stable outside the body for days or weeks, even when dry.




Symptoms of Hepatitis B

Symptoms and signs of hepatitis B can range from none to minimal in the early stages of the illness, to jaundice (yellowing of the skin), nausea, abdominal pain, fever, and malaise in the acute phase. Appetite loss, fatigue, itching, dark urine and pale stools are some common symptoms.

After the initial infection, carriers of hepatitis B usually have few symptoms.




Diagnosis of Hepatitis B

Diagnosis of hepatitis B is based upon examination of the blood for characteristic antigens and antibodies associated with the disease.




Treatment of Hepatitis B

There are four medications currently approved by the Food and Drug Administration (FDA) for treatment of active hepatitis B infection.
•Alfa Interferon (Brand names: INTRON A, INFERGEN, ROFERON): Interferon is an antiviral agent with antiproliferative and immunomodulatory agent that is administered by subcutaneous injection daily or three times per week, for 12-16 weeks or longer. With adequate teaching, the injections can easily be administered at home by patients. High pretreatment ALT and lower levels of HBV DNA are the most important predictors of response to alfa interferon therapy. Virologic response to alfa interferon occurs in less than 10 percent of patients with normal ALT. A sustained response can be seen in 15 - 30 percent of patients with HBeAg-negative chronic hepatitis B and less than half of the responders show sustained clearance of HBsAg.
Side Effects: Depression – this is more commonly seen in patients with a prior history of depression. Muscle aches, fatigue, and low grade fevers are common and may be minimized by taking Tylenol (acetaminophen). Occasionally, patients may develop low white blood cell count, headaches, irritability, and thyroid dysfunction. Underlying autoimmune disorders may also be unmasked.

•b) Lamivudine (Epivir-HBV, 3TC): inhibits hepatitis B viral DNA synthesis. It should be taken orally, once daily. It is approved for use in adults and children and is usually tolerated well. Occasionally, it may cause a rise in the liver enzyme ALT. Pretreatment ALT is an important predictor of response, with HBeAg conversion occurring in over a third of patients when the ALT is greater than five times normal. While Lamivudine benefits patients with HBeAg-negative chronic hepatitis B, the vast majority of patients relapse once treatment is stopped.
•Adefovir dipivoxil (Hepsera): inhibits DNA polymerase activity and reverse transcriptase. This drug is administered orally on a daily basis and is typically well tolerated. It can be associated with kidney dysfunction, particularly if used in high doses. The optimal duration of therapy is not yet clear. About 50 - 60 percent of HBeAg positive and negative hepatitis B patients respond to this medication; data regarding the durability of response is awaited.
•Baraclude (Entecavir): is the latest drug approved by the FDA for treatment of chronic hepatitis B. It works by inhibiting the function of Hepatitis B virus polymerase. Side effects include headache, fatigue, dizziness, nausea, and transient elevation in liver enzymes. This drug is taken orally, once daily and the optimal duration of therapy is not yet established.

In patients with severe liver dysfunction, a liver transplant may be required.




What Questions To Ask Your Doctor About Hepatitis B

Who is at risk of contracting hepatitis B?

What treatment is available for hepatitis B?

Based on my laboratory data, what is the likelihood of durable response to treatment?

Is cirrhosis of the liver or liver cancer likely to develop?

What preventive measures can be taken?

What if I become pregnant?

Editorial review provided by VeriMed Healthcare Network.



Prevention of Hepatitis B

Current public health efforts to prevent the disease have focused on vaccinating people in high-risk groups and, increasingly, vaccinating all children and adolescents.

Those at greatest risk are: intravenous drug abusers; heterosexuals with multiple partners; homosexual men; health care workers; and children born to immigrants from China, Southeast Asia, and other areas where hepatitis B is very common.

Two companies have a hepatitis B vaccine license for use in the U.S. and both are produced by recombinant DNA technology. As part of a national effort to eliminate hepatitis B transmission, the Advisory Committee on Immunization Practices, with the concurrence of the American Academy of Pediatrics and the American Academy of Family Physicians, has recommended that all infants receive hepatitis B vaccine as part of their childhood immunization schedule.

Three doses of vaccine are required to achieve effective immunization and will induce adequate antibody in 80 - 95 percent of persons who get three doses. The vaccination schedule most often used is three intramuscular injections, with the second and third doses administered at one to six months after the first.

The first dose of hepatitis B vaccine is given soon after birth before the infant is discharged from the hospital or in the first two months of life. The second dose is given between one and two months after the first and the third at six to 18 months of age. Since 1999, two-dose vaccines are available and required in some states for adolescents age 11 to 15 years.

Infants born to mothers infected with hepatitis B virus should be treated with hepatitis B immune globulin and hepatitis B vaccine within 12 hours of birth, with the second and third doses of vaccine given at one and six months of age.

Adults and older children should receive the injections in the deltoid. Infants should receive the injections in the thigh. Buttock injection should never be used.

Other means of prevention include:
•(if carrier) Cover open wounds, don't share razors or manicure tools.
•Practice safe sex
•Don't share needles, razors, toothbrushes, manicure tools or other items that could bear contaminated blood.
•Don't allow yourself to be pierced or tattooed with non-sterile equipment.
•Limit alcohol intake.