Hepatitis

Acute Viral Hepatitis

Acute viral hepatitis is inflammation of the liver caused by infection with one of the five hepatitis viruses. In most people, the inflammation begins suddenly and lasts only a few weeks.

•    Symptoms range from none to very severe.
•    Affected people may have a poor appetite, nausea, vomiting, fever, pain the upper right abdomen, and jaundice.
•    Doctors do a physical examination and take blood samples to analyze.
•    Vaccines can prevent hepatitis A, B, and E.
•    Usually, specific treatment is not needed.

Acute viral hepatitis can be caused by many different viruses.  Hepatitis A is the most common cause, followed by hepatitis B.

Symptoms

Acute viral hepatitis can cause anything from a minor flu-like illness to fatal liver failure. Sometimes there are no symptoms. The severity of symptoms and speed of recovery vary considerably, depending on the particular virus and on the person's response to the infection. Hepatitis A and C often cause very mild symptoms or none at all and may be unnoticed. Hepatitis B and E are more likely to produce severe symptoms. Co-infection with hepatitis B and D may make the symptoms even more severe.

Symptoms usually begin suddenly. They include a poor appetite, nausea, vomiting, and often a fever and pain in the upper right of the abdomen (where the liver is located). Occasionally, especially with hepatitis B, infected people develop joint pains and itchy red hives on the skin (wheals or urticaria).

Typically, after a few days, the urine becomes dark, and jaundice (a yellowish discoloration of the skin and whites of the eyes) develops. Both of these symptoms occur because bilirubin builds up in the blood. Bilirubin is the main pigment in bile, the greenish yellow digestive fluid produced by the liver. Most symptoms usually disappear at this point, and people feel better even though the jaundice may worsen. The jaundice usually peaks in 1 to 2 weeks, then fades over 2 to 4 weeks. Symptoms of cholestasis (a reduction or stoppage of bile flow)—such as pale stools and overall itchiness—may develop, particularly in people with hepatitis A.

Rarely, particularly with hepatitis B, symptoms become extremely severe (fulminant). Liver failure may occur and may be fatal, especially in adults.

Diagnosis

Doctors suspect acute viral hepatitis on the basis of symptoms. During the physical examination, a doctor presses on the abdomen above the liver, which is tender and somewhat enlarged in about half of the people with acute viral hepatitis. Blood tests to evaluate liver function are done. They can indicate whether the liver is inflamed and often help doctors distinguish hepatitis due to alcohol abuse from that due to a virus. Blood tests help doctors identify which hepatitis virus is causing the infection. These tests can detect parts of the viruses or specific antibodies produced by the body to fight the viruses. Occasionally, if the diagnosis is unclear, a biopsy is done: A sample of liver tissue is removed with a needle and examined.

Prevention

Vaccines, given by injection into muscle, are available to prevent hepatitis A, B, and E infections. The hepatitis A vaccine is recommended for all children and for adults likely to be exposed to the virus. Hepatitis B vaccine is recommended for everyone. Hepatitis E vaccine, a new vaccine, will most likely be used in endemic areas. As with most vaccines, protection requires allowing a number of weeks for the vaccine to reach its full effect as the immune system gradually creates antibodies against the particular virus. People who have not been vaccinated and who are exposed to hepatitis A virus can obtain protection with an injection of an antibody preparation called standard immune globulin. It prevents infection or decreases its severity. However, the amount of protection varies, and the protection is only temporary.

If people who have not been vaccinated are exposed to hepatitis B virus, they are given hepatitis B immune globulin and are vaccinated. Hepatitis B immune globulin contains antibodies to hepatitis B, which help the body fight the infection. This preparation prevents symptoms or decreases their severity, although it is unlikely to prevent infection. Some people need a booster dose of the vaccine.
No vaccines against hepatitis C or D virus are available. However, vaccination against hepatitis B virus also reduces the risk of infection with hepatitis D virus.

Other preventive measures against infection with the hepatitis viruses can be taken:
•    Washing hands thoroughly before handling food
•    Not sharing needles to inject drugs
•    Not sharing toothbrushes, razors, or other items that could get blood on them
•    Practicing safe sex—for example, using barrier protection such as a condom
•    Limiting the number of sex partners

Donated blood is unlikely to be contaminated because it is screened. Nonetheless, doctors help reduce the risk of hepatitis by ordering blood transfusions only when essential. Before surgery, people can also sometimes prevent the need for transfusion of blood from an unknown donor by donating their own blood weeks before the operation.

Treatment and Prognosis

In most people, special treatment is not necessary, although people with unusually severe acute hepatitis may require hospitalization. After the first several days, appetite usually returns and people do not need to stay in bed. Severe restrictions of diet or activity are unnecessary, and vitamin supplements are not required. Most people can safely return to work after the jaundice clears, even if their liver function test results are not quite normal.

People with hepatitis should not drink alcohol until they have fully recovered. A doctor may need to stop a drug or reduce the dosage of a drug that could accumulate to harmful levels in the body because the infected liver cannot process (metabolize) them. Thus, people should tell their doctor all the drugs they are taking (both prescription and nonprescription, including any medicinal herbs), so that the dosage can be adjusted if necessary.

People with acute viral hepatitis usually recover in 4 to 8 weeks, even without treatment. However, people infected with hepatitis C and, to a lesser extent, those infected with hepatitis B may become carriers of the virus. Carriers have no symptoms but are still infected and can transmit the virus to others. Carriers may develop chronic hepatitis even though the disease is not apparent. Carriers may eventually develop cirrhosis (severe scarring of the liver or liver cancer. Carriers of hepatitis B are also more likely than other people to develop liver cancer.



http://www.merck.com/mmhe/sec10/ch137/ch137b.html