Tuesday, September 24, 2013

Testing for chronic hepatitis B

An infectious inflammatory illness of the liver caused by the hepatitis B virus, HBV can be either acute or chronic.

Transmission is usually the result of contact with infectious blood or body fluids containing blood and in Asia, where the prevalence of HBV is high, it is often passed from person to person through sexual contact, re-use of contaminated needles and syringes in drugs users as well as through blood transfusions.

Vaccination against hepatitis B is now part of the overall immunisation programme for children and while the number of cases has dropped, the disease is still prevalent among those who have not been immunised. Acute HBV often resolves itself but the chronic disease in many cases leads to cirrhosis or hepatocellular carcinoma.

Screening the blood for the HBsAg surface antigen is the most common approach for diagnosing chronic HBV and yields prompt results. If a patient's blood tests are positive for hepatitis B, and the HBsAg is persistently positive for over six months, the patient has chronic hepatitis B. If such a case, the patient needs to undergo an additional test to determine whether the virus B has split and mutated, as well as to ascertain how much of the virus is in the body. The measurements for assessing hepatitis B viral activity are HBeAg, HBeAb, and HBV DNA.

If it is found that the hepatitis B virus has active viral replication, the doctor will perform a blood test to see if there is any inflammation in the liver by checking the level of enzymes in the blood (AST, ALT). If the AST and ATL are unusually high with no known causes, the patient is suffering from chronic hepatitis B. In this case, a test also needs to be conducted to evaluate the function of the liver by checking the levels of albumin and bilirubin in the blood - the Prothrombin time (PT) test.

An ultrasound examination can be conducted to see whether a patient with Hepatitis B has developed cirrhosis. The ultrasound examination can also detect tumours in the liver or liver cancer. Patients with high risk of liver cancer such as men aged over 40, women aged above 50 years old, patients with cirrhosis or with history of liver cancer in their family will have an ultrasound examination of the liver and a blood test to check the level of alpha tetoprotein (AFP) every six months in order to monitor occurrence of liver cancer.

In some patients, liver tissues can confirm the presence of hepatitis B and evaluate the severity of the inflammation of the liver and fibrosis in the liver. A tissue test is not an operation. It can be conducted by using a needle to penetrate into the skin to remove tissues from the liver for examination. The side effects from this method are very minor.

The possibility of significant bleeding or the need for an operation occurs in just 3 out of every 1,000 cases. Recently, many additional ways have been developed for assessing fibrosis stage in the liver, including Fibroscan, which can reduce the need for a tissue test by 60 per cent.

After evaluating the severity and stage of liver disease, the doctor will consider every indicator to decide on the best treatment approach and treatment strategy. Most importantly, the patient needs to be examined every 3-6 months because there is a possibility that the disease will develop in the future. The next step will be the treatment and care of the hepatitis B patient.


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