Overview of Acute Viral Hepatitis

BySonal Kumar, MD, MPH, Weill Cornell Medical College
Reviewed/Revised Aug 2022 | Modified Aug 2023

Acute viral hepatitis is inflammation of the liver, generally meaning inflammation 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 in the upper right part of the abdomen, and jaundice.

  • Doctors do blood tests to diagnose hepatitis and identify its cause.

  • Vaccines can prevent hepatitis A, B, and E (the hepatitis E vaccine is available only in China).

  • Usually, specific treatment is not needed.

(See also Overview of Hepatitis.)

Acute viral hepatitis is common throughout the world. Most cases of acute viral hepatitis resolve on their own, but some persist and progress to chronic hepatitis.

Causes of Acute Viral Hepatitis

Acute viral hepatitis can be caused by five major hepatitis viruses (see table The Hepatitis Viruses):

The hepatitis A virus is the most common cause of acute hepatitis, followed by the hepatitis B virus.

Other viruses can also cause acute viral hepatitis. These viruses include the Epstein-Barr virus (EBV), which is the virus that causes infectious mononucleosis (mono).

Engaging in certain activities, such as getting a tattoo or body piercing, sharing needles to inject drugs, or having multiple sex partners, increases the risk of developing hepatitis.

Symptoms of Acute Viral Hepatitis

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. Infection with both hepatitis B and D (called coinfection) may make the symptoms of hepatitis B even more severe.

Symptoms of acute viral hepatitis usually begin suddenly. They include

  • A poor appetite

  • A general feeling of illness (malaise)

  • Nausea and vomiting

  • Fever

  • Pain in the upper right part of the abdomen (where the liver is located)

In people who smoke, a distaste for cigarettes is a typical symptom. Occasionally, especially with hepatitis B, infected people develop joint pains and itchy red hives on the skin (wheals or urticaria).

Appetite usually returns about a week after symptoms begin.

Sometimes, after 3 to 10 days, the urine becomes dark, and stool becomes pale. Jaundice (a yellowish discoloration of the skin and whites of the eyes) may develop. It is sometimes accompanied by itching. These symptoms occur because the damaged liver cannot remove bilirubin from the blood as it normally does. Bilirubin is a yellow pigment produced when hemoglobin (the part of red blood cells that carries oxygen) is broken down as part of the normal process of recycling old or damaged red blood cells. Bilirubin then builds up in the blood and is deposited in the skin (making it look yellow and causing itching) and the whites of the eyes (making them look yellow). Bilirubin is normally secreted into the intestine as a component of bile (the greenish-yellow digestive fluid produced by the liver) and excreted in stool, giving stool its typical brown color. In people with hepatitis, stools are pale because bilirubin does not enter the intestine to be eliminated in stool. Instead bilirubin is eliminated in urine, making the urine dark.

The liver may be enlarged and tender.

Most of the initial symptoms (poor appetite, nausea, vomiting, and fever) usually disappear within a week, 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. But it can sometimes take much longer to resolve completely.

Rarely, fulminant hepatitis develops. Fulminant hepatitis is severe hepatitis with signs of liver failure. Fulminant hepatitis can occur in people with hepatitis A, but it is more likely to develop in people with hepatitis B, particularly if they also have hepatitis D. It can also occur in people taking drugs that can damage the liverheavy drinking. Fulminant hepatitis can progress very quickly, usually within days or weeks. The liver can no longer synthesize enough of the proteins that help blood clot. However, even though blood does not clot normally, people are not more likely to bruise or to bleed easily or without cause. The liver cannot remove toxic substances as it normally does. So these toxic substances build up in the blood and reach the brain, causing mental function to deteriorate quickly—called hepatic (portosystemic) encephalopathy. People may lapse into a coma within days to weeks. Fulminant hepatitis may be fatal, especially in adults. Sometimes liver transplantation must be done immediately to save the person's life.

People with acute viral hepatitis usually recover in 4 to 8 weeks, even without treatment. However, some people infected with hepatitis B or C develop chronic infections.

Diagnosis of Acute Viral Hepatitis

  • Blood tests

Doctors suspect acute viral hepatitis based on 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.

Doctors suspect fulminant hepatitis if

  • People are very ill and develop jaundice very quickly.

  • Mental function quickly deteriorates.

  • Blood tests to determine how quickly blood clots—prothrombin time or international normalized ratio (INR)—are abnormal.

  • People who have liver disease start worsening rapidly.

Testing for acute viral hepatitis usually begins with blood tests to determine how well the liver is functioning and whether it is damaged (liver tests). Liver tests involve measuring the levels of liver enzymes and other substances produced by the liver. These tests can indicate whether the liver is inflamed and often help doctors distinguish hepatitis due to alcohol abuse from that due to a virus.

To diagnose fulminant hepatitis, doctors do liver tests to determine how quickly blood clots (because if people have fulminant hepatitis, blood does not clot normally).

If acute viral hepatitis seems likely, the cause is identified if possible. To help identify the cause, doctors usually do the following:

  • Ask about activities that can increase the risk of getting viral hepatitis (see table The Hepatitis Viruses).

  • Do blood tests to help them identify which hepatitis virus is causing the infection.

These blood tests can detect parts of specific viruses or specific antibodies produced by the body to fight the viruses. (​Antibodies​ are proteins produced by the immune system to help defend the body against attack by viruses and other foreign invaders.)

Occasionally, if the diagnosis is unclear, a liver biopsy is done: A sample of liver tissue is removed with a needle and examined.

Prevention of Acute Viral Hepatitis

Because treatments for viral hepatitis are only partially effective, preventing viral hepatitis is very important.

Vaccines and immune globulin

Vaccines to prevent hepatitis A and hepatitis B are available in the United States. A vaccine for hepatitis E is currently available only in China. 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. Hepatitis vaccines are given by injection into muscle.

Routine vaccination with the hepatitis A vaccine and hepatitis B vaccine is recommended in the United States for all children (see figure Routine Vaccinations for Infants, Children, and Adolescents) and for adults at high risk of getting hepatitis (see table The Hepatitis Viruses).

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.

If people who have not been vaccinated are exposed to hepatitis A virus, they are given a single dose of hepatitis A vaccine or an injection of standard immune globulin, depending on their age and health. Standard immune globulin contains antibodies obtained from blood collected from a large group of people who have a normal immune system. Immune globulin prevents infection or decreases its severity. However, the amount of protection it provides varies, and the protection is only temporary.

Other preventive measures

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 of Acute Viral Hepatitis

  • Supportive care

  • Antiviral drugs for acute hepatitis C

For most people with acute viral hepatitis, special treatment is not necessary. However, people with severe acute hepatitis may require hospitalization so that symptoms can be treated. If doctors suspect that fulminant hepatitis is developing, the person is hospitalized so that mental status can be monitored, liver tests can be done, and doctors can determine whether liver transplantation is needed.

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 test results are not quite normal.

People with hepatitis should not drink alcohol until they have fully recovered.

If hepatitis B causes fulminant hepatitis, people are usually treated in an intensive care unit. Antiviral drugs may help. However, liver transplantation is the most effective treatment and is the best hope of survival, particularly for adults.

People with acute hepatitis C infection should be treated with antiviral drugs to decrease the risk of transmission of the infection to others and to decrease the risk of hepatitis becoming chronic.

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