Causes of hepatitis B

Hepatitis B

Hepatitis B is the most common liver infection in the world and is caused by the hepatitis B virus. The hepatitis B virus enters the body and travels through the blood to the liver. In the liver, it attaches to the liver cells and multiplies. Although the patient may not have any problems at this phase, multiplication of the virus triggers a response from the body’s immune system.

Hepatitis B infection can lead to cirrhosis (scarring of the liver), liver failure or even liver cancer unless diagnosed and managed early.
There are probably 350 - 400 million people with chronic (lifelong) hepatitis B infection worldwide.

Hepatitis B infection is considered to be ’acute‘ in the first 6 months after infection. If hepatitis B virus tests (HBsAg) are positive after 6 months, this is now a ‘chronic’ (long term) hepatitis B infection, which may last a lifetime.

Symptoms of acute hepatitis B

Symptoms resulting from acute hepatitis B infection are common, with jaundice occurring approximately 12 weeks after initial infection.
The symptoms of acute hepatitis B include:

• Loss of appetite
• Nausea and vomiting
• Tiredness
• Abdominal pain
• Muscle and joint pain
• Jaundice
  

Many people with acute hepatitis B have no symptoms and never realize they had the infection. A small number of those with acute hepatitis B become very sick in a short period of time. This happens if there is massive damage to the liver and it stops working. This is called acute liver failure.

Symptoms of chronic hepatitis B

Most people with chronic hepatitis B do not have any symptoms of infection so that they feel healthy and may not be aware they are infected. However, other s may experience symptoms, which are similar to those experienced with other forms of viral hepatitis. These can include:

• Tiredness, depression and irritability
• Pain in the liver (upper, right side of abdomen)
• Nausea and vomiting
• Loss of appetite
• Joint aches and pains.
  

People with chronic hepatitis B have a significantly increased risk of developing liver cancer.

Disease course

 The main predictor of disease course is the duration of infection:

• Infants infected with hepatitis B rarely experience symptoms of acute infection, but 90% will develop chronic or lifelong infection

• Children infected with hepatitis B rarely experience symptoms of acute infection, but 30% will develop chronic or lifelong infection

• Adults or adolescents infected with hepatitis B commonly experience symptoms of acute infection, however less than 5% develop chronic or lifelong infection

Transmission of the virus

Hepatitis B is found in blood and body fluids (saliva, semen, vaginal secretions and breast milk). The most common routes of spreading include:

• Sexual contact
• Sharing of needles / syringes
• Needle stick injuries among healthcare workers
• Reuse of inadequately sterilized needles
• Child-to-child transmission through household contact such as biting
• Sharing personal items such as razors, toothbrushes or nail clippers

Hepatitis B is NOT spread by contaminated food or water, and cannot be spread through casual social contact such as kissing, sneezing, coughing, hugging or eating food prepared by a person with hepatitis B.

Tests for Hepatitis B

To understand the tests, it is important to understand two basic terms:

• Antigen— a foreign substance in the body, such as the hepatitis B virus; and

• Antibody— a protein that the immune system makes in responses to a foreign substance. Antibodies can be produced in response to a vaccine or a natural infection.

 

Test	Abbreviation	What it shows
Hepatitis B surface antigen	HBsAg	Shows that the person is infected with hepatitis B. It can be detected during acute and chronic infection.
Hepatitis B surface antibody	HBsAb or Anti-HBs	Shows that the person has developed immunity to hepatitis B. It can be detected in people who have    recovered from hepatitis B or been vaccinated against hepatitis B.
Hepatitis B e antigen	HBeAg	Shows that hepatitis B virus is multiplying.
Hepatitis B e antibody	HBeAb or Anti-HBe	Shows that the person’s immune system has responded    against hepatitis B and the virus is not actively replicating.
Hepatitis B core antibody	HBcAb or Anti-HBc	Shows that a person has been infected with hepatitis    B but does not provide any protection against infection.
Hepatitis B virus DNA	HBV DNA	Measures the amount of hepatitis B virus in the    blood and indicates how actively the virus is multiplying.

Other tests are used to check how the liver is working and whether the virus has damaged it. :

Liver Function Tests (LFTs):  are a group of blood tests that show how well the liver is working. One important test is the AlanineAminotransferase (ALT). The ALT is released from liver cells into the bloodstream when the liver is injured. An ALT level above normal may indicate liver damage. ALT levels are included in the regular monitoring of all chronic hepatitis B patients; this test can also be useful in deciding whether a patient would benefit from treatment, or for evaluating how well a current treatment is working;

• Liver biopsy: involves the removal of a small piece of tissue from the liver using a fine needle. The tissue is examined under a microscope to look for inflammation or liver damage; and

• AFP: is a blood test which can sometimes detect liver cancer

Treatment

Those who have immunity and normal LFTs do not need treatment. People who are chronically infected but do not have any liver damage also do not need treatment but need close monitoring. However, if a person has liver damage they should consider having treatment for hepatitis B. The decision on when to start treatment is complex and should be made in consultation with a gastroenterologist / hepatologist.
The most common are anti-viral medications taken as tablets each day for a year or longer:

• Lamivudine

There are almost no side effects to Lamivudine, however a significant concern is the possible development of hepatitis B virus mutations and antiviral drug resistance after long-term use.

• Adefovir

There are almost no side effects except for the possibility of developing virus mutations and antiviral drug resistance.

• Entecavir (Baraclude)

Entevavir has potent activity against chronic hepatitis B. There are almost no side effects except for the possibility of developing virus mutations and antiviral drug resistance.

• Tenofovir (Viread)

Tenofovir has potent activity against chronic hepatitis B. It is particularly useful in patients who have developed drug resistance to other medications.

Treatment aims are to stop the hepatitis B virus from multiplying, or to reduce the rate of multiplication as much as possible. This decreases the risk of serious liver disease developing later in life and makes it possible for the liver to repair some of the damage and to work better. However, it is very rare that any of these medications will cure hepatitis B infection.

The main side effect of the antiviral tablets is sometimes the hepatitis B virus mutates (changes) during the course of treatment, which means the antiviral tablets are not as effective against the new form of the virus. This is called antiviral resistance.

During treatment, the patient’s blood tests are monitored very carefully to look for signs of antiviral resistance. If there are signs of resistance such as elevated liver enzymes and high levels of hepatitis B virus in the blood, the antivirals may be changed.

Lifestyle advice for people with chronic hepatitis B

There are a number of things people with chronic hepatitis B can do to stay healthy, including:

• Limit or avoid alcohol

• Do not smoke

• Eat a healthy, well-balanced diet

Prevention

• Consider being vaccinated

• Practice safe sex (use a condom)

• Wash hands after touching blood or body fluids

• Wear disposable gloves if giving someone first aid, or cleaning up blood or body fluids

• Avoid sharing toothbrushes, razors, needles, syringes, personal hygiene items or any object that may come into contact with blood or body fluids

• Use new and sterile needles / syringes for each injection

• Cover all cuts and open sores with a band aid or bandage

• Wipe up any blood spills and then clean the area with bleaching powder

• Throw away personal items such as tissues, menstrual pads, and bandages in a sealed plastic bag.

Those who have been exposed to the hepatitis B virus and who have not been vaccinated should receive hepatitis B immunoglobulin (HBIG) within 72 hours of exposure, and a dose of hepatitis B vaccine as soon as possible or within 7 days.

Vaccine

Hepatitis B can be prevented with a safe and effective vaccine that has been available since 1982. It is now recommended that all babies and adolescents be vaccinated against hepatitis B. All healthcare workers should also be vaccinated.