Hepatitis A
ساعت ۱۱:٢٦ ‎ب.ظ روز یکشنبه ٩ اسفند ۱۳۸۸  کلمات کلیدی:

Hepatitis A


Hepatitis A Overview

Hepatitis is a general term that means inflammation of the liver. Inflammation of the liver can result from infection, from exposure to alcohol, certain medications, chemicals, or poisons, or from a disorder of the immune system.

Hepatitis A refers to liver inflammation caused by infection with the hepatitis A virus (HAV). HAV is one of several viruses that can cause hepatitis and is one of the 3 most common hepatitis viruses in the United States. The other 2 are hepatitis Band hepatitis C.

Unlike hepatitis B and hepatitis C, hepatitis A does not cause chronic (ongoing, long-term) disease. Although the liver does become inflamed and swollen, it heals completely in most people without any long-term damage. Once you have had hepatitis A, you develop lifelong immunity and cannot get the disease again.

Because of the way it is spread, the hepatitis A virus tends to occur in epidemics and outbreaks. As many as 1 in 3 people in the United States have antibody to HAV, meaning they have been exposed to the virus, but most do not become ill. The number of cases of hepatitis A in the United States varies among different communities and has not been affected significantly by the introduction of thehepatitis A vaccine since the early 1990s.

Hepatitis A Causes

  • The hepatitis A virus is found in the stools (feces) of people with hepatitis A. It is transmitted when a person puts something in his or her mouth that has been contaminated with the feces of an affected person. This is referred to as fecal-oral transmission. 

    • If food or drinking water becomes contaminated with stool from an infected person (usually because of inadequate hand washing or poor sanitary conditions), the virus can quickly spread to anyone who drinks or swallows the contaminated food or water. 
    • The virus can also be spread by eating raw or undercooked shellfish collected from water that has been contaminated by sewage. 
    • The hepatitis A virus can be transmitted through blood transfusions, although this is extremely rare.
  • People who are infected can start spreading the infection about 1 week after their own exposure. People who do not have symptoms can still spread the virus. Infection with HAV is known to occur throughout the world. 

    • The risk of infection is greatest in developing countries with poor sanitation or poor personal hygiene standards. 
    • Infection rates are also higher in areas where direct fecal-oral transmission is likely to occur, such as daycare centers, prisons, and mental institutions. 
  • People at increased risk for hepatitis A infection 

    • Household contacts of people infected with HAV 
    • Sexual partners of people infected with HAV 
    • International travelers, especially to developing countries 
    • Military personnel stationed abroad, especially in developing countries  
    • Men who have sex with other men 
    • Users of illegal drugs (injected or non-injected) 
    • People who may come into contact with HAV at work
  • Workers in professions such as health care, food preparation, and sewage and waste water management are not at greater risk of infection than the general public. 
  • People who live or work in close quarters, such as dormitories, prisons, and residential facilities, or work in or attend daycare facilities are at increased risk only if strict personal hygiene measures are not observed.

 

Hepatitis A Symptoms

Many people with HAV infection have no symptoms at all. Sometimes symptoms are so mild that they go unnoticed. Older people are more likely to have symptoms than children. People who do not have symptoms can still spread the virus.

 

  • Symptoms of hepatitis A usually develop between 2 and 6 weeks after infection. The symptoms are usually not too severe and go away on their own, over time. The most common symptoms are as follows:

     

    • Nausea
    • Vomiting
    • Diarrhea, especially in children
    • Low-grade fever
    • Loss of appetite
    • Rash
    • Tirednessfatigue
    • Jaundice - A yellow discoloration of the skin and the whites of the eyes
    • Urine is dark brownish in color, like cola or strong tea.
    • Pain in area of liver - On the right side of the abdomen, just under the rib cage

 

  • If the vomiting is severe, dehydration may occur. The symptoms of dehydration include the following:

     

    • Feeling weak, tired, or "blah"
    • Feeling confused or unable to concentrate
    • Rapid heartbeat
    • Headache
    • Urinating less frequently than usual
    • Irritability

 

  • Symptoms usually last less than two months, although they may last as long as nine months. About 15% of people infected with hepatitis A have symptoms that come and go for 6-9 months.

 

  • Hepatitis does not occur simply from being near someone who has the disease at work or at school.

 

When to Seek Medical Care

The health care provider should be called if any of the following symptoms occur:

 

  • Nausea and vomiting that does not improve within 1-2 days
  • Yellow skin or eyes
  • Dark colored urine
  • Pain in the belly (abdomen)
The following situations also warrant a call to the health care provider:

 

  • You have symptoms and think that you might have been exposed to someone with hepatitis.
  • You have other medical problems and think that you might have hepatitis.
  • You have had close contact with someone diagnosed with hepatitis.
If you cannot reach your health care provider, or if you have any of the following, go to theemergency department.

 

  • Vomiting and inability to keep down any liquids
  • Severe pain or high fever
  • Confusion, delirium, or difficulty awakening

 

Exams and Tests

Your health care provider will ask you questions about your illness. You will be asked about your symptoms and about any possible exposures to hepatitis.

If your health care provider determines that you may be at risk for contracting hepatitis, you will have blood drawn.

 

  • The blood will be tested to determine how well your liver is functioning.
  • A test will be done for antibody to hepatitis A. The test will show whether you have been exposed recently to HAV.
  • Your blood probably will be tested for the hepatitis B and hepatitis C viruses as well.

If you have had a large amount of vomiting or have not been able to take in liquids, your bloodelectrolytes may be out of balance. Your blood chemistry may be tested to check this.

Hepatitis A Treatment

There are no specific medicines to cure infection with hepatitis A. Most people require no treatment except to relieve symptoms.

If you have been exposed to someone who is infected with HAV, there is a treatment that may prevent you from becoming infected. It is called immune globulin and is more likely to be effective when given within 2 weeks of exposure.

Self-Care at Home

The following measures can help you feel better while you are having symptoms.

 

  • Take it easy; curtail your normal activities and spend time resting at home.
  • Drink plenty of clear fluids to prevent dehydration.
  • Avoid medicines and substances that can cause harm to the liver such asacetaminophen (Tylenol) and preparations that contain acetaminophen.
  • Avoid alcoholic beverages, as these can worsen the effects of HAV on the liver.
  • Avoid prolonged, vigorous exercise until symptoms start to improve.
Call your health care provider if symptoms worsen or a new symptom appears.

Be very careful about personal hygiene to avoid fecal-oral transmission to other members of the household.

 

Medical Treatment

  • If you are dehydrated, your doctor may prescribe IV fluid to help you feel better. 
  • If you are experiencing significant nausea and vomiting, you will receive medicines to control these symptoms. 
  • People whose symptoms are well controlled can be cared for at home. 
  • If dehydration or other symptoms are severe or if you are extremely confused or difficult to arouse, then you may need to stay in the hospital.

 

Next Steps

Follow-up

Follow the recommendations of your health care provider.

 

  • Take it easy; get plenty of rest.
  • Drink plenty of clear fluids.
  • Avoid alcoholic beverages.
  • Avoid medicines such as acetaminophen (Tylenol) that can be harmful to the liver.
  • Avoid prolonged or vigorous physical exercise until your symptoms improve.
  • Call your health care provider if symptoms worsen or a new symptom appears.

 

Prevention

If you have hepatitis A, strict personal hygiene and hand washing help prevent transmission of HAV to others.

  • Wash your hands thoroughly every time you use the bathroom, before touching or preparing food, and before touching others. Wash carefully with soap and warm water and dry thoroughly. 
  • Contaminated surfaces should be cleaned with household bleach to kill the virus. 
  • Heat food or water to 185°F or 85°C to kill the virus.
If you are not infected with HAV, you can protect yourself from becoming infected. 

  • Wash your hands carefully with soap and warm water several times a day, including every time you use the bathroom, every time you change a diaper, and before preparing food. 
  • Do not eat raw or undercooked seafood or shellfish such as oysters from areas of questionable sanitation (just about everywhere). 
  • Travelers to developing countries should not drink untreated water or beverages with ice in them. Fruits and vegetables should not be eaten unless cooked or peeled.
There are vaccines that work to prevent infection with HAV. 

  • The vaccines, Havrix and VAQTA, contain no live virus and are very safe. No serious adverse effects have been reported. Some people have some soreness at the injection site for a few days. 
  • The vaccines are given in a series of 2 shots. The second is given 6-18 months after the first. The shots can be given at the same time as other vaccines. 
  • Your protection starts about 2-4 weeks after the first shot. The second dose is necessary to ensure long-term protection. 
  • The vaccines are thought to protect from infection for at least 20 years. 
  • The vaccines must be given before exposure to the virus. They do not work after exposure.
Not everyone needs to have the hepatitis A vaccines. However, the vaccines are recommended for the following groups: 

  • All children older than 2 years who live in communities where the number of HAV infections is unusually high or where there are periodic outbreaks of hepatitis A (The vaccines are not recommended for children younger than 2 years because they are not as effective.) 
  • People who are likely to be exposed to HAV at work - The only group of workers shown to be at higher risk than the general population is people who work in research laboratories where HAV is stored and handled. Routinevaccination is not recommended for health care workers, food service workers, daycare personnel, and sewage and waste-water workers. 
  • Travelers to developing countries (it must be given at least 4 weeks before travel) 
  • Men who have sex with men 
  • People who use illegal drugs - This group has higher-than-average rates of HAV infection. 
  • People who are likely to become seriously ill if they are infected with HAV - This includes people with impaired immune systems or chronic liver disease
  • People with blood-clotting disorders who receive clotting factors
If you have never had hepatitis A and are exposed to the virus, call your health care provider immediately. There is a treatment that may prevent you from becoming infected. It is called hepatitis B immune globulin (BayHep B, Nabi-HB). 

  • Immune globulin is a preparation of antibodies that can fight the virus in the body. 
  • It is given as a one-time shot (injection). 
  • It must be given within 2 weeks after exposure for maximum protection. 
  • Immune globulin can be safely given to children younger than 2 years. 
  • Immune globulin can be given during pregnancy and breastfeeding
  • Immune globulin can provide short-term protection against infection if given before exposure. This protection lasts no longer than 3 months.

If you have had hepatitis A confirmed by a blood test, you cannot get it again. You should continue to practice preventive measures, however, to prevent transmission of other infections.

Outlook

Hepatitis A symptoms are usually mild and go away on their own.

 

  • Rarely will you develop complications such as relapsing hepatitis or liver failure.
  • With relapsing hepatitis, symptoms improve, but then return.
  • Death from hepatitis A is rare.
  • The elderly, the very young, and people with advanced chronic liver diseases such as from hepatitis C are at greatest risk for complications from hepatitis A.