Hepatitis B: Description:
Hepatitis B 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 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.
Hepatitis B virus can cause an acute illness with symptoms that last several weeks, including yellowing of the skin and eyes (jaundice), dark urine, extreme fatigue, nausea
, vomiting and abdominal pain
. People can take several months to a year to recover from the symptoms. HBV can also cause a chronic liver infection that can later develop into cirrhosis of the liver or liver cancer.
Causes and Risk factors:
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.
Hepatitis B is diagnosed from the results of specific HBV blood tests (serologies) that reflect the various components of the HBV. The diagnosis is made on the basis of a blood sample which will demonstrate antibodies against hepatitis B, or hepatitis B components in the patient's blood. The blood sample can demonstrate the presence of several different viral components. All patients with chronic infections have the viral component called HBsAg. When HBsAg is present, the infectiousness of the disease is at its highest and in the long run, those patients are at increased risk of developing complications. A blood test for liver function can determine the severity of the disease - the extent to which the liver is affected by the virus. In cases of chronic type B hepatitis, the severity of the disease can be determined by a tissue sample from the liver.
There are three standard blood tests for HBV:
1. Hepatitis B surface antigen (HBsAg): Hepatitis B surface antigen is the outer surface of the virus. Testing positive for this antigen means you can easily pass the virus to others. A negative test means you're not currently infected.
2. Antibody to hepatitis B surface antigen (anti-HBs): A positive result on this test means you have antibodies to HBV. This may be due to a prior HBV infection from which you've recovered or you may already have been vaccinated. In either case, you can't infect others or become infected yourself because you're protected by the vaccine or your own natural immunity.
3. Antibody to hepatitis B core antigen (anti-HBc): Although this test identifies people who have a chronic infection, the results can sometimes be ambiguous. If you test positive for hepatitis B core antibodies, you may have a chronic infection that you can transmit to others. But you also may be recovering from an acute infection or have a slight immunity to HBV that can't otherwise be detected. How this test is interpreted often depends on the results of the other two tests. When the results are uncertain, you may need to repeat all three tests.
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.
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.
Medicine and medications:
Approved Hepatitis B Drugs in the United States:
Interferon Alpha (Intron A) is given by injection several times a week for six months to a year, or sometimes longer. The drug can cause side effects such as flu-like symptoms, depression, and headaches.
Pegylated Interferon (Pegasys) is given by injection once a week usually for six months to a year. The drug can cause side effects such as flu-like symptoms and depression.
Lamivudine (Epivir-HBV, Zeffix, or Heptodin) is a pill that is taken once a day, with few side effects, for at least one year or longer. Approved 1998 and available for both children and adults.
Adefovir Dipivoxil (Hepsera) is a pill taken once a day, with few side effects, for at least one year or longer.
Entecavir (Baraclude) is a pill taken once a day, with few side effects, for at least one year or longer.
Telbivudine (Tyzeka, Sebivo) is a pill taken once a day, with few side effects, for at least one year or longer.
Tenofovir (Viread) is a pill taken once a day, with few side effects, for at least one year or longer.
Although the FDA has approved these seven drugs for chronic hepatitis B, they do not provide a complete cure, except in rare cases (a "cure" generally means that a person loses the hepatitis B virus and develops protective surface antibodies).
The drugs, however, significantly decrease the risk of liver damage from the hepatitis B virus by slowing down or stopping the virus from reproducing. As with HIV, it appears that combination therapy will probably be the most effective method of combating chronic hepatitis B infections.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.