What Is Hepatitis?
Hepatitis is a general term that
means inflammation of the liver . It can be acute or chronic and has a
number of different causes. It can be caused by a group of viruses known
as the hepatitis viruses, including A, B, C, D and E. Other viruses may
also be the culprit, such as those that cause mononucleosis (the
Epstein-Barr virus) or chickenpox (the varicella virus).
Hepatitis also applies to
inflammation of the liver caused by drugs and alcohol abuse or toxins
in the environment. In addition, people also can develop hepatitis from
other factors, such as fat accumulation in the liver (called fatty
liver disease), trauma or an autoimmune process in which a person's body
makes antibodies that attack the liver.
Viral hepatitis is common.
Thousands of cases are reported to the CDC each year, but researchers
estimate that the true number of people in the United States who have
the disease (acute and chronic) is much higher than the number
reported.
Many hepatitis cases go undiagnosed because they are mistaken for the
flu. Hepatitis can be serious because it interferes with the liver's many functions. Among other things, the liver produces bile to aid digestion, regulates the chemical composition of the
blood, and screens potentially harmful substances from the bloodstream.
flu. Hepatitis can be serious because it interferes with the liver's many functions. Among other things, the liver produces bile to aid digestion, regulates the chemical composition of the
blood, and screens potentially harmful substances from the bloodstream.
The five hepatitis viruses can be
transmitted in different ways, but they all have one thing in common:
They infect the liver and cause it to become inflamed. Generally, the
acute phase of the disease lasts from two to three weeks; complete
recovery takes about nine weeks. Many patients recover with a lifelong
immunity to the disease, but a few hepatitis victims (less than 1%) die
in the acute phase. Hepatitis B and C may progress to chronic hepatitis,
in which the liver remains inflamed for more than six months. This
condition can lead to
cirrhosis and possibly death.
cirrhosis and possibly death.
What Causes It?
Although their effects on the
liver and the symptoms they produce can be similar, the various forms of
hepatitis are contracted in different ways. In the case of viral
hepatitis, the severity and duration of the disease are largely
determined by the organism that caused it.
Hepatitis A, which is
generally contracted orally through fecal contamination of food or
water, is considered the least dangerous form of the disease because it
almost always resolves on its own. Also, it does not lead to chronic
inflammation of the liver. The hepatitis A virus commonly spreads
through improper handling of food, contact with household members,
sharing toys at day-care centers, and eating raw shellfish taken from
polluted waters.
Hepatitis B can spread
through sexual contact, blood transfusions, and needle sharing by
intravenous drug
users. The virus can pass from mother to child at birth or soon
afterward; the virus can also travel between adults and children to
infect whole families. In over half of all hepatitis B cases the source
cannot be identified.
The majority of adults with
hepatitis B recover completely, but a small percentage of them can't
shake the disease and become carriers. Carriers can transmit the disease
to others even when their own symptoms have vanished. A smaller
percentage of patients who cannot fight off the virus will develop
chronic hepatitis B. Like carriers, those with chronic hepatitis B are
able to pass on the virus. Up to 25% of chronic hepatitis B patients die
prematurely from the disease as a result of cirrhosis or
liver cancer.
liver cancer.
Hepatitis C is usually
spread through contact with blood or contaminated needles -- including
tattoo needles. Although hepatitis C may cause only mild symptoms or
none at all, approximately 20% of those infected develop cirrhosis
within 20 years. The disease can be passed on through blood
transfusions, but screening, which started in the early '90s, has
greatly reduced the number of such cases. In a third of all hepatitis C
cases, the source of the
disease is unknown.
Hepatitis D occurs only in
people infected with hepatitis B and tends to magnify the severity of
that disease. It can be transmitted from mother to child and through
sexual contact. Although less common, hepatitis D is especially
dangerous because it involves two distinct viruses working at once.
Hepatitis E occurs mainly
in Asia, Mexico, India, and Africa; only a few cases are reported in the
United States, mostly among people who have returned from a country
where the disease is widespread. Like hepatitis A, this type is usually
spread through fecal contamination, and it does not lead to chronic
hepatitis. This form is considered slightly more dangerous than
hepatitis A. It can cause severe disease and death in
pregnant women.
pregnant women.
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