Disease: Hepatitis A

What Is Hepatitis A?

Generally acquired through contaminated food, hepatitis A is an acute, viral-borne inflammation of the liver.

Hepatitis is an inflammation of the liver, an organ with several important functions.

Your liver converts dietary nutrients into useful substances and breaks down toxins and chemicals.

Hepatitis A is a type of hepatitis caused by the hepatitis A virus (HAV).

Numerous other types of viral and non-viral hepatitis also exist, including hepatitis B, hepatitis C, and alcohol-related hepatitis.

Causes and Transmission of Hepatitis A

You can get hepatitis A if HAV, which is present in feces and blood, gets into your body through your mouth.

The virus is passed between people through the "fecal-oral route," which can occur:

  • When an infected person touches objects or food after going to the bathroom and failing to wash his or her hands properly
  • When someone doesn't wash properly after handling diapers or cleaning up the stool of an infected person
  • During sex with an infected person, particularly if it involves direct or indirect anal-oral contact, or anal sex in which sanitary measures aren't taken afterwards

You can also get hepatitis A by ingesting food or water contaminated with feces containing HAV.

Common sources of HAV transmission include fruits, vegetables, shellfish, ice, and water.

This mode of transmission is far less common in the United States and other developed countries, which have better sanitation measures in place, such as treating the water supply with chlorine or chloramine.

You cannot get HAV through casual contact with an infected person, such as through hugging or even being coughed or sneezed on.

And babies cannot get HAV from breast milk.

Risk Factors for Hepatitis A

You are at an increased risk for hepatitis A if you:

  • Live in or travel to a developing country where hepatitis A is common
  • Live with someone who has hepatitis A
  • Have oral-anal sexual contact with someone who is infected
  • Are a man who has sex with men
  • Use illegal drugs, including those that aren't injected
  • Have hemophilia or other disorders that affect blood clotting
  • Work in the health care, food, or sewage industries

Hepatitis A Prevalence

Hepatitis A is one of the most common causes of foodborne illness, according to the World Health Organization (WHO).

Each year, there are about 1.5 million reported cases of hepatitis A around the world, according to a 2012 report in the World Journal of Hepatology.

However, the actual rate of infection is likely up to 10 times higher because many cases go unreported, the article notes.

In 2012, there were 1,562 reported cases of hepatitis A in the United States, according to the CDC, which adds that the actual number is likely closer to 3,050 cases, if asymptomatic infections and under-reporting are taken into consideration.

What's more, about half of all infections in the United States are actually acquired outside of the country, according to the CDC.

Sources:

  • How does the liver work?; U.S. Library of Medicine
  • Hepatitis; MedlinePlus/NIH
  • Surveillance for Viral Hepatitis – United States, 2012; CDC
  • What I need to know about Hepatitis A; National Institute of Diabetes and Digestive and Kidney Diseases
  • Hepatitis A; World Health Organization
  • Hepatitis A FAQs for the Public; CDC
  • Franco et al. (2012). "Hepatitis A: Epidemiology and prevention in developing countries." World Journal of Hepatology

Hepatitis A Symptoms

Most adults who get symptomatic hepatitis A show signs of jaundice, a yellowing of the skin and eyes.

Hepatitis A is an inflammation of the liver caused by the hepatitis A virus, or HAV.

The disease is fairly common, and may affect up to 15 million people worldwide each year, according to a 2012 report in the World Journal of Hepatology.

You can get hepatitis A if you ingest the virus, typically through eating or drinking something contaminated with HAV.

Symptoms of Hepatitis A

After contracting HAV, symptoms don't appear right away.

The virus has an incubation period of 2 to 7 weeks before any symptoms occur, according to the Centers for Disease Control (CDC), with the average incubation period lasting 28 days.

However, some people, especially young children, may catch the virus without even knowing it because symptoms never develop.

In fact, about 70 percent of hepatitis A cases in children under six years old are asymptomatic, according to the CDC.

Symptoms that do develop are generally mild and may include:

  • Low-grade fever
  • Fatigue
  • Loss of appetite
  • Nausea and vomiting
  • Diarrhea
  • Abdominal pain
  • Upset stomach
  • Pruritus (itching)
  • Dark-yellow urine and light- or clay-colored stools
  • Muscle aches and joint pain

Additionally, jaundice, or the yellowing of the skin and eyes, occurs in more than 70 percent of hepatitis A cases in older children and adults, according to the World Health Organization (WHO).

Symptoms usually persist for less than two months, but some people may be sick for up to six months, according to the CDC.

Complications of Hepatitis A

Unlike other types of viral hepatitis, hepatitis A doesn't become chronic and generally doesn't cause long-term liver damage. But it can cause complications.

Some people with hepatitis A experience a relapse, during which their infection returns and they experience symptoms again.

This usually happens about 2 to 3 months after the initial infection, and it occurs in 3 to 20 percent of children who get hepatitis A, according to a 2000 article in the journal Vaccine.

Cholestasis, or cholestatic hepatitis, is another potential complication of hepatitis A. It is the result of bile buildup, and it causes persistent jaundice and intense pruritus.

In rare cases, people with hepatitis A may suffer from fulminant and subfulminant hepatitis, which can rapidly cause liver failure.

This typically affects people with a pre-existing liver disease or a weakened immune system, according to the UK's National Health Services.

Symptoms of liver failure include:

  • Hepatitis-like symptoms, including jaundice, nausea, and vomiting
  • Bruising and bleeding easily
  • Edema, the buildup of fluid in the extremities, and ascites, the buildup of fluid in the abdomen
  • Hair loss
  • Disorientation or confusion, also called hepatic encephalopathy
  • Sleepiness

The fatality rate of fulminant hepatitis is about 80 percent, according to the Vaccine report.

Diagnosis of Hepatitis A

To diagnose hepatitis A, your doctor will first get your medical history and ask about your recent symptoms.

Next, your doctor will likely conduct a physical exam to see if your liver is enlarged and tender.

Finally, your doctor will take your blood to be analyzed.

You have hepatitis A if the blood tests reveal elevated levels of:

  • IgM and IgG antibodies specific to the hepatitis A virus
  • Liver enzymes, particularly the enzyme alanine aminotransaminase (ALT)

Sources:

  • Ciocca, Mirta (2000). "Clinical course and consequences of hepatitis A infection." Vaccine
  • Hepatitis A FAQs for Health Professionals; CDC
  • Hepatitis A; MedlinePlus/NIH
  • Hepatitis A; World Health Organization
  • Hepatitis A - Complications; NHS

Hepatitis A Treatments

Lots of rest, proper nutrition, and adequate fluid intake are recommended if you have hepatitis A.

Once in your body, the hepatitis A virus (HAV) incubates for 2 to 7 weeks before causing any symptoms.

Symptoms of hepatitis A can include jaundice (yellowing of the eyes and skin), abdominal pain, pruritus (itching), and gastrointestinal issues — though not everyone experiences symptoms.

The best way to prevent contracting hepatitis A is to get two doses of the hepatitis A vaccine, which can make you immune to the virus.

Postexposure Protection

If you aren't immune to HAV and you contract it, the hepatitis A vaccine can still be helpful and provide postexposure protection.

That is, the vaccine can help prevent a full-blown hepatitis A infection if it's taken within two weeks of exposure to HAV.

The Centers for Disease Control and Prevention (CDC) recommends that healthy people between 1 and 40 years of age get the hepatitis A vaccine (at the age-appropriate dose) for postexposure protection.

People over 40 years old should instead receive a dose of immune globin (IG) antibodies to protect against hepatitis A infection.

It's unknown how well the vaccine works in this age group, but it can be used in place of IG if the antibodies aren't available, the CDC notes.

Additionally, IG should be used in place of the vaccine for postexposure protection in people who are:

  • Younger than one year old
  • Allergic to the vaccine or its components
  • Have a severely weakened immune system
  • Have chronic liver disease

Medications for Hepatitis A

If you have a hepatitis A infection, your body will clear the infection on its own, typically within six months.

There are no specific medications or treatments to help cure an infection, though some prescription or over-the-counter medications may be used for symptomatic relief.

Mild pain relievers, such as ibuprofen (Advil), may help relieve abdominal pain. However, these medications should be used sparingly to protect your liver.

Alcohol and medications that may damage the liver, including acetaminophen (Tylenol) and aspirin, should be avoided.

If you're suffering from pruritus (itchy skin), antihistamines may help.

And antiemetic drugs, such as the prescription medication metoclopramide (Reglan), may help ease nausea and vomiting.

Discuss all of the medications you plan to take with your doctor first.

At-Home Therapies

If you have hepatitis A, doctors recommend plenty of rest, proper nutrition, and adequate fluid intake, according to the CDC.

During periods where your symptoms are severe, avoid strenuous activities, including work or school, if possible.

If you're experiencing pruritus, try wearing loose clothing, staying in cool and ventilated environments, and avoiding hot baths or showers.

To cope with nausea, avoid eating fatty foods, which can worsen this symptom.

It may also be helpful to eat smaller, more frequent meals throughout the day.

Nausea and vomiting often go hand-in-hand.

If you're vomiting (or have diarrhea), it's important to keep your fluid and electrolyte levels up to avoid dehydration, which can cause other problems.

Sources:

  • Postexposure Prophylaxis for Hepatitis A; CDC
  • Treating hepatitis A; NHS
  • How is Hepatitis A treated?; CDC
  • Hepatitis A; MedlinePlus/NIH
  • Hepatitis A, Treatments and drugs; Mayo Clinic

Hepatitis A Vaccine

After getting two doses of the hepatitis A vaccine, nearly 100 percent of people develop antibodies that protect them from the disease.

Caused by the hepatitis A virus (HAV), hepatitis A is an inflammation of the liver.

People who get hepatitis A develop antibodies that prevent them from ever getting the disease again.

Similarly, the hepatitis A vaccine can prevent people from getting the disease by priming their immune system to develop these protective antibodies.

What Is the Hepatitis A Vaccine?

The hepatitis A vaccine consists of an inactivated version of HAV.

There are two hepatitis A vaccines available: HAVRIX and VAQTA, which are produced by GlaxoSmithKline and Merck, respectively.

The first dose of the vaccine causes more than 95 percent of adults and more than 97 percent of children to develop protective antibodies, according to the CDC.

Nearly 100 percent of people will develop the antibodies after a second dose of the vaccine (given about 6 months after the first dose).

Research suggests the two vaccines are similarly effective at protecting against clinical hepatitis A.

HAVRIX, which first became available in 1995, was 94 percent effective in preventing hepatitis A in a study of 40,000 Thai children between the ages 1 and 16 years who were living in villages with high HAV disease rates, according to the CDC.

Comparatively, VAQTA, which first became available in 1996, was 100 percent effective in preventing hepatitis A in a study of 1,000 New York City children between the ages of 2 and 16 years who were living in a community with a high HAV disease rate.

China and some areas of India use another type of hepatitis A vaccine that contains live, attenuated (weakened) strains of HAV.

This vaccine has also been shown to be safe and highly protective against hepatitis A, according to the World Health Organization (WHO).

Who Should Be Vaccinated?

Today, the CDC recommends that all children receive their first dose of the hepatitis A vaccine when they're between 1 and 2 years old, and a second dose of the vaccine 6 to 12 months later.

However, children who don't receive the first dose before reaching two years of age can still receive the vaccine at a later time.

Adults who didn't receive the vaccine as children should also get the vaccine if they're at a high risk of contracting HAV. This includes people who:

  • Live in a community with high hepatitis A rates
  • Use illegal drugs (including non-injected drugs)
  • Have long-term liver disease or a disorder that affects blood clotting, such as hemophilia
  • Are men who have sex with other men
  • Have an occupational risk of hepatitis A, such as from working with HAV in a research lab or with primates infected with HAV

People who travel to countries with high hepatitis A rates are also at an increased risk of getting the disease, and may need to get the vaccine.

The CDC recommends that older adults, people with weakened immune systems, and those with chronic liver disease or another chronic medical condition receive an initial dose of the vaccine and a dose of immune globin (IG) antibodies within two weeks of travelling to areas with high hepatitis A rates.

People who choose not to receive the vaccine, or cannot receive it because they're under 12 months of age or allergic to the vaccine's components, should receive a single dose of IG before travelling.

This can prevent a hepatitis A infection for up to three months.

TWINRIX, a combination vaccine that contains vaccines for both hepatitis A and hepatitis B, has also been available since 2001.

TWINRIX is typically administered in three doses over a period of six months.

Side Effects of the Vaccine

The hepatitis A vaccine may cause several symptoms that last for 1 to 2 days including:

  • Muscle soreness at the site of injection
  • Headache
  • Loss of appetite
  • Tiredness

In rare cases, people experience serious allergic reactions to the vaccine within a few hours of injection.

Sources:

  • Hepatitis A, Vaccine; WHO
  • Possible Side-effects from Vaccines, Hepatitis A; CDC
  • Hepatitis A, The Pink Book; CDC
  • Hepatitis A FAQs for the Public; National Institute for Allergy and Infectious Diseases
  • Hepatitis A FAQs for Health Professionals; CDC

Source: http://www.everydayhealth.com

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