MEDICAL CONDITIONS
Viral Hepatitis
What is hepatitis?
Hepatitis is an inflammation of the liver. Many illnesses and conditions can cause liver inflammation, such as viral infections, bacterial infections, drugs, alcohol, chemicals, and autoimmune diseases . When medical professionals speak of hepatitis, they are usually referring to liver inflammation caused by viruses. These specific hepatitis viruses have been labeled A, B, C, D, E, F (not confirmed), and G. As our knowledge of new viruses grows, it is likely this alphabetical list will become more lengthy. While some viruses, such as mononucleosis and cytomegalovirus, can also cause liver inflammation, they do not primarily attack the liver. This review centers on viruses that primarily infect the liver, particularly viral hepatitis types A, B, and C.
The liver is located in the upper right hand side of the abdomen, mostly behind or beneath the rib cage. The liver of an adult normally weighs close to three pounds. The liver performs the following vital functions for the body: - The liver helps purify the blood by changing harmful chemicals into harmless substances. The source of these chemicals can be external, such as medications or alcohol, or internal, such as ammonia or bilirubin . Typically, these harmful substances are broken down into smaller substances that are excreted from the body into the urine or stool.
- The liver produces many important compounds, especially proteins, that are necessary for health. It produces albumin , the building block protein of the body, as well as the proteins that help blood to clot properly.
- The liver stores many of the sugars, fats and vitamins until they are needed elsewhere in the body.
- The liver transforms smaller building block type substances into larger more complicated compounds needed elsewhere in the body. One of these types of functions is the building up and breaking down of cholesterol . When the liver is inflamed, it does not perform these functions for the body as efficiently, which brings about many of the symptoms associated with hepatitis.
What are the types of viral hepatitis?
TYPE A HEPATITIS
At one time, type A hepatitis was referred to as "infectious hepatitis" because of how the illness was transmitted. Infection with hepatitis A virus (HAV) can be spread through food, water, and stool, especially where unsanitary conditions allow water or food to be contaminated by human sewage (the fecal-oral mode of transmission). It can typically be spread among household members and friends through the passage of oral secretions (intimate kissing) or stool (poor hand washing). It is likewise common to have cases spread through restaurants and day care centers if hand washing and sanitary precautions are not observed. Type A hepatitis accounts for about 150,000 of the 500,000-600,000 new cases of viral hepatitis that occur each year in the United States. Household or family contacts of infected individuals are at risk for developing hepatitis A. Hepatitis A is an acute illness that never develops into a chronic form of liver infection.
TYPE B HEPATITIS
Type B hepatitis was at one time referred to as "serum hepatitis," because it was thought that the only way hepatitis B virus (HBV) could spread was through blood or serum contamination. It is now known that it can spread by close family contact, especially sexual contact, and the transfer of blood or serum through needle sticks, blood transfusions, hemodialysis , and childbirth. The infection can also be spread by tattooing, body piercing, and sharing razors and toothbrushes. There are 200,000-300,000 new cases of hepatitis B viral infection each year in the United States. About 6-10% of these patients develop chronic hepatitis B infection (infection lasting more than six months). Patients with chronic hepatitis B can infect other individuals. It is estimated that there are 1.2 million people in the United States and 200-300 million people world wide who suffer with chronic hepatitis B.
TYPE C HEPATITIS
Type C hepatitis was previously referred to as "non-A, non-B hepatitis," because the causative virus had not been identified. However, it was known to be neither hepatitis A nor B. Usually, the hepatitis C virus (HCV) is believed to be spread by blood transfusion , hemodialysis, and needle sticks. Approximately 90% of transfusion-associated hepatitis is caused by hepatitis C. Transmission of the virus by sexual contact has been reported, but is considered rare. There are about 150,000 new cases of hepatitis C each year. An estimated 50-70% of these patients develop chronic hepatitis C infection. Patients with chronic hepatitis C infection can continue to infect others. It is estimated that there are about 3.5 million people with chronic hepatitis C in the United States.
TYPES D,E,F, and G HEPATITIS
There are also viral hepatitis types D, E, F (not confirmed), and G. The most significant of these at present seem to be type D (the delta agent), which only causes disease in the presence of the hepatitis B virus and type E .
Who is at risk for hepatitis?
People who are at risk for developing hepatitis are workers in the health care professions, people with multiple sexual partners, intravenous drug users, and hemophiliacs. Hepatitis is generally thought to be as much as ten times more common in the lower socioeconomic and poorly educated groups. About one third of all cases of hepatitis come from an unknown or unidentifiable source. This means that you don't have to be in a high risk group in order to be infected with the hepatitis virus.
What are the symptoms and signs of hepatitis?
From the time that an individual is exposed to hepatitis until the onset of the illness is called the incubation period. The incubation period varies, depending on the specific virus. Hepatitis A has an incubation period of about 15-45 days, while hepatitis B is from 45-160 days and hepatitis C is 2 weeks to 6 months. Many patients infected with these three hepatitis viruses have few or no symptoms of being ill. In fact, most individuals who contract hepatitis B and C have no symptoms. For those who do develop symptoms, the most common are typical flu- like symptoms including loss of appetite, nausea, vomiting, fever, weakness, tiredness, and aching in the abdomen. Less common symptoms include dark urine, light-colored stools, fever, and jaundice (a yellow appearance to the skin and white portion of the eyes). Symptoms of fatigue, poor appetite, and nausea can last several weeks to several months. While many patients recover from viral hepatitis without any specific treatment, some patients with hepatitis B and C develop chronic hepatitis (hepatitis lasting over six months). Patients with hepatitis A do not develop chronic infections. Those patients who develop chronic hepatitis B or C can be infected for many years and have a lifelong increased risk of developing liver cirrhosis and/or liver cancer . Fifty percent of patients with chronic hepatitis B will die of cirrhosis or liver cancer. Liver failure from chronic hepatitis C is the most common reason (indication) for liver transplantation in the United States.
How is hepatitis diagnosed?
Hepatitis is usually first diagnosed during the active illness, based on the symptoms and an examination of the patient. It is confirmed by blood tests for liver function, which include bilirubin (the pigment that causes jaundice) and liver enzymes (released into the blood by damaged liver cells). When abnormal liver function tests suggest the diagnosis of hepatitis, specific blood tests are now available to determine which hepatitis viruses are involved. Please read the Liver Blood Enzymes article.
Patients with chronic hepatitis B or C may have few or no symptoms. In these patients, chronic hepatitis may be discovered only when random screening lab tests are performed for reasons other than suspicion of hepatitis. Persistent mildly abnormal liver enzymes will alert the physician to perform further tests to specifically diagnose the presence of hepatitis B or C.
Obstruction of the bile ducts, from either gallstones or cancer , can occasionally mimic acute viral hepatitis. Ultrasound testing can be used to exclude the possibility of gallstones or cancer. For more information, please read the Ultrasound article.
How is hepatitis treated?
In patients with acute symptoms of hepatitis, the initial treatment consists of relieving the symptoms of nausea, vomiting, and generalized discomfort. Careful attention should be given to medications which can have adverse effects in patients with abnormal liver function. Only those medications which are considered a necessity should be administered. The patient must abstain from all alcohol intake. Sedatives or tranquilizer types of medications are avoided. It is occasionally necessary to provide intravenous (I.V.) fluids to prevent dehydration caused by vomiting. Patients with severe nausea and/or vomiting may need to be hospitalized. Once the type of hepatitis has been identified, treatment of chronic hepatitis B (with interferon or lamivudine) and C (with interferon-ribavivin combinations) can be initiated. (See the articles on hepatitis B and Hepatitis C.) There is active research in the area of developing more effective treatments for viral hepatitis.
A vaccine is now available to prevent hepatitis A. Children receive a series of three injections, the first and second at one month intervals, and a booster 6-12 months later. Adults receive only two shots, about 6-12 months apart. Immune serum globulin (ISG) can be administered to prevent infection in individuals who are known to have short term exposure to hepatitis A. ISG may be given either before potentially being exposed (travelers) or for people who have been in close contact with someone with active hepatitis A infection.
A vaccine is also now available to prevent hepatitis B. It is currently recommended by the American Academy of Pediatrics that all newborn babies in the United States be given immunizations for the hepatitis B virus as a routine part of their basic immunizations. If an infant is born to a mother with hepatitis B, the infant should be given HBIG . HBIG is Hepatitis B Immune Globulin, which is similar to the immune serum globulin given to patients with exposure to type A hepatitis, except that HBIG is specific for the hepatitis B virus. It is strongly recommended that older children and adults in high risk groups be vaccinated to prevent hepatitis B infection. If an individual is accidentally exposed to hepatitis B infection at any age, HBIG can be given at the same time immunization for hepatitis B begins.
There is currently no vaccine available to prevent hepatitis C virus infection. The best form of prevention is the ongoing careful screening of the blood used for transfusions. Likewise, banking your own blood prior to any major surgery can provide a safe source of blood should blood transfusion be necessary during or after surgery. Blood banking also prevents potential exposure to the AIDS virus (HIV).
Prevention of hepatitis, like any other illness, is preferable to reliance upon treatment. Taking precautions to prevent exposure to another individual's blood (through transfusion or exposure to dirty needles), semen (unprotected sex), and other bodily waste (stool) will help prevent the spread of these viruses.
Conclusions
Viral hepatitis is a common, widespread problem, which may not cause symptoms or result in only minor short-term symptoms. However, it can cause prolonged severe illness leading to liver failure, liver transplantation, cirrhosis of the liver , and/or liver cancer. Those persons who suspect that they have been exposed to, or are infected with hepatitis, should contact their personal physicians to discuss the need for further evaluation and possible treatment. - Many illnesses and conditions can cause liver inflammation (hepatitis).
- Viruses that primarily affect the liver are called viral hepatitis types A, B, C, D, E, F (not confirmed), and G.
- Viral hepatitis types B and C can cause chronic disease.
- Symptoms of viral hepatitis include fatigue, flu-like symptoms, dark urine, light-colored stools, fever, and jaundice.
For more information about viral hepatitis, please visit this site: The Health Gazette: Hepatitis B Immunization (http://www.freenet.scri.fsu.edu/HealthGazette/hep2.html)
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