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hepatitis A Images (Click to view larger image)
Alternative Names
hepatovirus infection
Definition
Hepatitis A is an infection and inflammation of the liver caused by the hepatitis A virus. It is one of several types of hepatitis.
What is going on in the body?
The liver is an important organ located in the upper right quadrant of the abdomen. It is responsible for: - filtering the blood
- making bile, a substance that aids in digestion and helps rid the body of harmful substances
- processing fats and sugars, helping the body store energy for later use
- making important proteins, such as those involved in blood clotting
- metabolising many medications, such as barbiturates, sedatives, and amphetamines
- storing vitamins A, B12, D, and several of the B-complex vitamins. The liver also stores iron and copper.
The liver is susceptible to hepatitis viruses. A hepatitis virus can cause sudden, severe inflammation of the liver cells. Infection can occur at any age. Classic yellowing of the eyes and skin, called jaundice, is usually the first sign of a problem. Hepatitis A does not cause problems or disease in other parts of the body, as other hepatitis viruses can.
After exposure to the virus, the hepatitis usually occurs within 2 to 4 weeks. In industrialised countries, hepatitis A usually occurs in an epidemic setting. This is a cluster of cases in a population that has previously been unexposed. These cases in an epidemic can have a common source of exposure.
Some parts of the world have persistent, ongoing cases in a large part of the population. This hepatitis, called endemic hepatitis A, occurs in non-industrialised countries.
What are the signs and symptoms of the infection?
Symptoms can range from mild to moderate and include: The symptoms gradually improve. Children with hepatitis A often do not have symptoms.
Rarely, acute fulminant hepatitis, which involves severe liver cell destruction and loss of liver function, occurs. It can be fatal. Symptoms include: - an enlarged, painful liver
- enlarged spleen
- severe jaundice
- susceptibility to bleeding
- encephalopathy, a disorder in the functioning of the brain
- aplastic anaemia in rare cases. Aplastic anaemia is a condition in which the bone marrow cannot make enough red and white blood cells.
What are the causes and risks of the infection?
Hepatitis A is generally spread by food and water that is contaminated with the virus from an infected person. Rarely, it is spread when a person is exposed to the blood of another person with acute hepatitis. The following groups have a higher risk for this disease: - military personnel
- homosexual males
- travellers to Third World countries
What can be done to prevent the infection?
To prevent the infection, a person should: - eat only properly prepared food and drink clean water
- wash hands well after using the toilet
- have an injection of serum immunoglobulin if exposed to the virus
- have the hepatitis A vaccine if he or she is in a high-risk group. The vaccine is usually given in 2 injections that are 6 to 12 months apart. Both immunoglobulin and hepatitis A vaccine can safely be given together.
Anyone exposed to hepatitis A is immune for life.
How is the infection diagnosed?
The doctor may suspect hepatitis A after doing a physical examination and checking liver function tests. Another blood test, often drawn at the same time as the liver function tests, can confirm that hepatitis A is the cause of the symptoms.
Hepatitis A recurs in about 10% of people. This results in symptoms that come and go, along with abnormal liver function tests over several weeks to a few months.
What are the long-term effects of the infection?
For most people, hepatitis A clears up and there are no long-term problems. Rarely, there are long-term problems such as: - acute fulminant liver failure, a serious complication that can be lethal or can require a liver transplant
- aplastic anaemia, which is a bone marrow failure problem. It results in low blood cells including red cells, platelets, and white blood cells.
What are the risks to others?
Anyone who comes into contact with a person with hepatitis A is at risk for the disease. It is most important that no one is exposed to the stool or urine of the infected person. Other bodily secretions are not likely to cause an infection.
Finding the source and preventing additional exposure to that source also is very important. People with active hepatitis A need to wash their hands well after using the toilet. Infected people may need to take 1 to 4 weeks of time off from work. They also may need to report to their local health department.
What are the treatments for the infection?
Treatment of hepatitis A includes: Antiviral and anti-inflammatory medications are not helpful for the treatment of hepatitis A.
Acute fulminant hepatitis can cause life-threatening liver failure. This requires a hospital stay and treatment for the bleeding disorder, as well as for neurological and nutritional problems. Sometimes, the only effective treatment is a liver transplant.
What are the side effects of the treatments?
The side effects of treatment for routine hepatitis A are minimal. Problems associated with the hepatitis A vaccine are minimal, as well. A person who has been exposed to the virus and is injected with serum immunoglobulin as a precaution may feel some pain at the injection site or have a mild, brief flu-like illness.
A liver transplant for acute fulminant hepatitis can cause many problems, including failure or rejection of the new liver. After a liver transplant, a person will need to take powerful anti-rejection medications for the rest of his or her life. Side effects of these medications increase the risk for infections, certain cancers, and other problems.
What happens after treatment for the infection?
After the hepatitis A is resolved, the person will no longer need medications. He or she can return to normal activities, even if some jaundice remains.
How is the infection monitored?
The doctor will often repeat the liver function tests to assure that they are normal. Other tests, like liver ultrasound or CT scan, are not needed.
Author: Thomas Fisher, MD
Reviewer: HealthAnswers Australia Medical Review Panel
Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia
Last Updated: 1/10/2001
Contributors
Potential conflict of interest information for reviewers available on request |
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