Viral hepatitis



Last Review Date: April 14, 2016


Overview

Hepatitis is inflammation of the liver. It is most commonly caused by a viral infection, but may be due to chemicals, alcohol or drugs and inherited diseases or autoimmune disease. The following information is concerned with those caused by viruses.

The liver performs many functions in the body, including processing the body’s nutrients, manufacturing bile to help digest fats and breaking down potentially toxic (harmful) substances into harmless ones that the body can use or excrete. When the liver is damaged, these functions are impaired to some extent and the potentially toxic substances accumulate. The hepatitis virus reaches the liver through the blood stream, multiplies in the liver cells and is released into the bloodstream, the bile duct, and faeces. In this way, it can be spread to other people. Screening donated blood for the presence of blood-borne hepatitis viruses and other communicable diseases has greatly reduced the transmission of infections in people receiving blood transfusions.

The table below summarises the three most common strains of hepatitis: Hepatitis A, Hepatitis B and Hepatitis C.
 

Virus Hepatitis A Hepatitis B Hepatitis C
Transmission route Faecal-oral Infected needle or blood, sexual contact Infected needle or blood, sexual contact
Incubation time (acute infection) 15-50 days 45-160 days 14-180 days
Onset Sudden Either sudden or slow, unnoticed Usually slow, unnoticed
Severity Mild Occasionally severe Usually slow-developing and symptoms not specific or strong
Chronic form? No Yes Yes
Associated with other diseases? None Liver cancer, cirrhosis Liver cancer, cirrhosis
Testing to diagnose acute infection HAV-Ab, IgM HBsAg, Anti-HBc, IgM, HBeAg Anti-HCV, HCV RNA (note - may have same results as in chronic hepatitis)
Testing to diagnose chronic infection or to monitor treatment N/A HBsAg, HBV DNA, Anti-HBe Anti-HCV (once), HCV RNA or viral load, HCV genotype (once)
Tests that detect previous infection HAV-Ab, IgG Anti-HBs, Anti-HBc total Anti-HCV
Vaccine available? Yes Yes No
Common treatment None Chronic form - entecavir, tenofovir, lamivudine, adefovir, pegylated interferon Chronic form - pegylated interferon and ribavirin, sofosbuvir, daclatasvir, sofosbuvir+ledipasvir


Abbreviations defined:

HAV-Ab = Hepatitis A Antibody 
Anti-HBs = Hepatitis B surface antibody 
HBsAg = Hepatitis B surface antigen 
HBeAg = Hepatitis B e-antigen 
Anti-HBe = Hepatitis B e-antibody 
Anti-HBc = Anti-hepatitis B core antigen 
HBV DNA = Hepatitis B Virus (test for virus genetic material) 
Anti-HCV = Hepatitis C Antibody 
HCV RNA = Hepatitis C Virus (test for virus genetic material) 
HCV Viral Load = A detection and/or count of the amount of virus in the blood 
HCV Genotype = Determines the type of Hepatitis C present (1 of 6 types)


Acute & Chronic

Hepatitis may start rapidly (acute) or more slowly (chronic).

Acute hepatitis typically makes the affected person feel sick - as if they have the flu - often with loss of appetite and sometimes diarrhoea and vomiting. In many cases, it causes a brown discolouration of urine, loss of colour in the stools and a yellow colour of the skin and eyes (jaundice). Most affected people eventually recover completely. The acute form may last from a few days or weeks to several months.

Chronic hepatitis usually causes no symptoms or mild non-specific symptoms such as loss of energy and tiredness - most people don’t know that they have it. In some people, chronic hepatitis can gradually damage the liver and after many years, cause it to fail. The chronic form may last from six months to many years after infection. Since the liver also produces blood clotting factors, some people with chronic hepatitis develop bleeding problems.


Testing

There are a number of blood tests that may be used to diagnose hepatitis. A liver function test (LFT) is a group of tests that include those for a number of enzymes produced by the liver. Persistent elevation of the liver enzymes ALT and GGT can indicate damage to liver cells, decreasing the ability of the liver to perform its many functions. There are tests for antibodies against each type of virus that causes hepatitis. Elevated bilirubin levels appear most obviously as yellowing of the skin and whites of the eyes, indicating breakdown of liver cells and an inability to process bile.

A liver biopsy, in which a needle is inserted into the liver to withdraw a small amount of liver tissue that is then examined under a microscope by a pathologist, is the definitive way to assess the extent of liver damage. This is an invasive procedure requiring skill on the part of the physician performing the biopsy. Liver biopsy is used when a diagnosis or measurement of liver damage cannot be made by other means. A non-invasive test called the Fibroscan that uses a form of ultrasound to measure liver stiffness and hence the degree of fibrosis may sometimes be used and there are also several blood tests with combinations of markers that can be used to estimate the amount of liver fibrosis.

For people with chronic hepatitis regular check-ups (see fact sheet) are essential.

This video from Hepatitis Australia - Liver Check-Up explains what occurs at one clinic in Sydney. Clinics elsewhere may use different testing techniques and new drugs becoming available may also change the way people with chronic hepatitis are followed up.


 


Related pages

On this site
Tests: Liver Function Tests, hepatitis A, hepatitis B, hepatitis C
Conditions: Liver disease, sexually transmitted diseases

Elsewhere on the web
Hepatitis Australia