Hepatitis - Hepatitis B and D

Acute Form. Acute hepatitis B is generally mild, but it can be lethal in about 1% of patients. Patients who are coinfected with hepatitis D or C are at risk for serious complications. In patients whose immune systems are severely compromised, such as in AIDS, there is risk of a rapidly progressive form of HBV called fibrosing cholestatic hepatitis. Even patients with mild symptoms can remain chronically infected with the virus.

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Chronic Form. About 70% of patients infected with hepatitis B will eventually eliminate the virus without any treatment. The rest will progress to chronic hepatitis. Hepatitis B can also become chronic without an acute stage. The risk for developing a chronic form of hepatitis D is the same as for hepatitis B alone.

The great majority of people with hepatitis B have a good long-term outlook, especially children infected with the virus. Still, about 5% to 10% eventually develop cirrhosis, and worldwide, approximately two million people die each year from hepatitis B, globally making it the ninth leading cause of death. Co-infection with hepatitis D or C increases the risk for cirrhosis. HBV also poses a risk for liver cancer. In Asia about 15% of people who have chronic hepatitis B develop liver cancer, but this high rate is not seen in other parts of the world. Diet may play a role in a higher or lower risk for liver cancer.

Specific Tests for Identifying Hepatitis B

A diagnosis of hepatitis B relies on measuring the liver enzymes aspartate (AST) and alanine (ALT), are released when the liver is damaged, assays to identify the viral DNA, and a liver biopsy.

Physicians then must determine if the condition is chronic but inactive or whether it is more aggressive. This is suggested by identifying a specific antigen called HBsAg, which is a protein that is found in the blood in early stages of hepatitis B and suggests the presence viral replication. Most people develop antibodies to this antigen during convalescence. Their condition is referred to as HBeAG negative or anti-HBe and suggests that infection is on the wane. About 5% to 10% of people do not clear the infection but become carriers of the antigen (called HBsAG-positive). Evidence of its persistence for more than six months suggests that the condition is chronic.

Tests have been developed that can identify specific genetic types of hepatitis B virus (designated A to G). It is not clear how significant they are in treating patients with HBV.

It is important to remember, however, that viral levels are not an accurate measure of actual liver damage. Only a biopsy can determine this.