Medical Health Encyclopedia

Hepatitis - Introduction




Introduction


Hepatitis means "inflammation of the liver." It is a disorder in which viruses or other mechanisms produce inflammation in liver cells, resulting in their injury or destruction. The liver is the largest internal organ in the body, occupying the upper right area of the abdomen. It performs over 500 vital functions. Some key roles are:

  • The liver processes all of the nutrients the body requires, including proteins, glucose, vitamins, and fats.
  • The liver manufactures bile, the greenish fluid stored in the gallbladder that helps digest fats.
  • One of the liver's major contributions is to render harmless potentially toxic substances, including alcohol, ammonia, nicotine, drugs, and harmful by-products of digestion.



Digestive system
The esophagus, stomach, large and small intestine -- aided by the liver, gallbladder, and pancreas -- convert the nutritive components of food into energy and break down the non-nutritive components into waste to be excreted.

Damage to the liver can impair these and many other processes. Hepatitis varies in severity from a self-limited condition with total recovery to a life-threatening or life-long disease. It can occur from many different causes:

  • In the most common hepatitis cases (viral hepatitis), specific viruses injure liver cells and activate the immune system to fight off the infection. Certain immune factors that cause injury become overproduced.
  • Hepatitis can also result from an autoimmune condition, in which abnormally targeted immune factors attack the body's own liver cells.
  • Inflammation of the liver can also occur from medical problems, drugs, alcoholism, chemicals, and environmental toxins.

All hepatitis viruses can cause an acute (short term) form of liver disease. Some specific hepatitis viruses (B, C, and D), and some non-viral forms of hepatitis, can cause chronic (long term) liver disease. (Hepatitis A and E viruses do not cause chronic disease.) In some cases, acute hepatitis develops into a chronic condition, but chronic hepatitis can also occur on its own. Although chronic hepatitis is generally the more serious condition, patients with either condition can have varying degrees of severity.

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