Hepatitis is Inflammation of the Liver from Any Cause.
Hepatitis commonly results from a virus, particularly one of five hepatitis viruses-A, B, C, D, or E. Less commonly, hepatitis results from other viral infections, such as infectious mononucleosis, yellow fever, andcytomegalovirus infection. The major nonviral causes of hepatitis are alcohol and drugs. Hepatitis can be acute (lasting less than 6 months) or chronic; it occurs commonly throughout the world.
Hepatitis A virus spreads primarily from the stool of one person to the mouth of another. Such transmission is usually the result of poor hygiene. Waterborne and foodborne epidemics are common, especially in developing countries. Eating contaminated raw shellfish is sometimes responsible. Isolated cases, usually arising from person-to-person contact, are also common. Most Hepatitis A infections cause no symptoms and go unrecognized.
Hepatitis B virus is less easily transmitted than hepatitis A virus. One way it can be transmitted is through contaminated blood or blood products. However, because of precautions taken to ensure a safe blood supply, blood transfusions rarely are responsible for the transmission of the Hepatitis B virus in the advanced countries. But this is not so in developing countries. Transmission commonly occurs among injecting drug users who share needles, as well as between sexual partners, both heterosexual and male homosexual. A pregnant woman infected with Hepatitis B can transmit the virus to her baby during birth.
The risk of exposure to the Hepatitis B virus is increased for patients undergoing kidney dialysis or in cancer units and for hospital personnel who have contact with blood. Also at risk are people in closed environments (such as prisons and institutions for the mentally retarded), where close personal contact exists.
Hepatitis B can be transmitted by healthy people who are chronic carriers of the virus. Whether insect bites can transmit this virus isn't clear. Many cases of Hepatitis B have no known source. In areas of the world such as the Far East and parts of Africa, Hepatitis B virus is responsible for many cases of chronic hepatitis, cirrhosis, and liver cancer.
Hepatitis C virus causes at least 80 per cent of the hepatitis cases arising from blood transfusions, plus many scattered cases of acute hepatitis. It is most commonly transmitted by injecting drug users who share needles. Sexual transmission is uncommon. Hepatitis C virus is responsible for many cases of chronic Hepatitis and some cases of cirrhosis and liver cancer. For unknown reasons, people with alcoholic liver disease often have hepatitis C as well; the combination of diseases sometimes produces a greater loss of liver function than would result from either disease alone. A small proportion of Healthy people appear to be chronic carriers of the hepatitis C virus.
Hepatitis D virus occurs only as a co-infection with Hepatitis B virus, and it makes the Hepatitis B infection more severe. Drug addicts are at relatively high risk.
Hepatitis E virus causes occasional epidemics similar to those caused by Hepatitis A virus. So far, these epidemics have occurred only in under-developed countries.
Acute Viral Hepatitis
Acute viral hepatitis is inflammation of the liver caused by infection with one of the five hepatitis viruses; for most people the inflammation begins suddenly and lasts only a few weeks.
Symptoms and Diagnosis
Symptoms of acute viral hepatitis usually begin suddenly. They include a poor appetite, a feeling of being ill, nausea, vomiting, and often a fever. In people who smoke, a distaste for cigarettes is a typical symptom. Occasionally especially with Hepatitis B infection, the person develops joint pains and wheals (itchy red hives on the skin).
After a few days, the urine becomes dark, and jaundice may develop. Most symptoms typically disappear at this point and the person feels better even though the jaundice is getting worse. Symptoms of cholestasis (a stoppage or reduction of bile flow)—such as pale stools and general itching-may develop. The jaundice usually peaks in 1 to 2 weeks, then fades over 2 to 4 weeks.
Acute viral hepatitis is diagnosed on the basis of the person's symptoms and the results of blood tests that evaluate liver function. In about half the people with this disease, a doctor will find the liver to be tender and somewhat enlarged.
Acute viral hepatitis must be distinguished from several other conditions that cause similar symptoms. For instance, the flulike symptoms early in the disease can mimic those of other viral diseases, such as influenza and infectious mono-nucleosis. Fever and jaundice are also symptoms of alcoholic hepatitis, which occurs in people who regularly drink significant amounts of alcohol. The specific diagnosis of acute viral hepatitis can be made if blood tests reveal viral proteins or antibodies against hepatitis viruses.
Acute viral hepatitis can produce anything from a minor flulike illness to fatal liver failure. In general, Hepatitis B is more serious than Hepatitis A and is occasionally fatal, especially in elderly people. The course of Hepatitis C is somewhat unpredictable: The acute illness is usually mild, but liver function may improve and then worsen repeatedly for several months.
A person with acute viral hepatitis usually re-covers after 4 to 8 weeks, even without treatment. Hepatitis A rarely if ever becomes chronic. Hepatitis B becomes chronic in 5 to 10 per cent of the infected people and can be mild or full-blown. Hepatitis C has the greatest likelihood of becoming chronic- about a 75 per cent chance. Though usually mild and often without symptoms, Hepatitis C is a serious problem because about 20 per cent of the affected people eventually develop cirrhosis.
A person with acute viral hepatitis can become a chronic carrier of the virus. In the carrier state, the person has no symptoms but is still infected. This situation occurs only with hepatitis B and C viruses, not Hepatitis A virus. A chronic carrier may eventually develop liver cancer.
People with unusually severe acute hepatitis may require hospitalisation, but in most cases treatment is not necessary. After the first several days, appetite usually returns and the person does 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 function test results aren't quite normal.
Good hygiene helps prevent the spread of Hepatitis A virus. Because the stool of people with Hepatitis A is infectious, stool samples must be handled with special care by health practitioners. The same is true for the blood of people with any type of acute hepatitis. On the other hand, infected people don't require isolation-it does little to prevent the transmission of Hepatitis A, and it won't prevent the transmission of Hepatitis B or C.
Medical personnel reduce the chance of infection from blood transfusions by avoiding unnecessary transfusions, using blood donated by volunteers rather than paid donors, and screening all blood donors for Hepatitis B and C. Because of screening, the number of cases of Hepatitis B and C transmitted through a blood transfusion has been greatly reduced, though not eliminated.
Vaccination against Hepatitis B stimulates the body's immune defenses and protects most people well. However, dialysis patients, people with cirrhosis, and people with an impaired immune system derive less protection from vaccination. Vaccination is especially important for people at risk of contracting Hepatitis B, though it isn't effective once the disease is established. For these various reasons, universal vaccination of all people against Hepatitis B is being increasingly recommended.
Hepatitis A vaccines are given to people at high risk of acquiring the infection, such as travellers to parts of the world where the disease is wide-spread. No vaccines are available against Hepatitis C, D, and E viruses.
People who haven't been vaccinated and who are exposed to hepatitis may receive an antibody preparation (immune serum globulin) for protection. Antibodies are intended to give immediate protection against viral hepatitis, but the amount of protection varies greatly with different situations. For people who have been exposed-per-haps by an accidental needle stick-to blood infected with Hepatitis B virus, Hepatitis B immune globulin provides better protection than ordinary immune serum globulin. Infants born to mothers with Hepatitis B are given Hepatitis B immune globulin and are vaccinated. This combination prevents chronic Hepatitis B in about 70 per cent of those infants.
Chronic hepatitis is inflammation of the liver that lasts at least 6 months.
Chronic hepatitis, though much less common than acute hepatitis, can persist for years, even decades. It is usually quite mild and does not produce any symptoms or significant liver damage. In some cases, though, continued inflammation slowly damages the liver, eventually producing cirrhosis and liver failure.
Hepatitis C virus is a common cause of chronic hepatitis; about 75 per cent of acute Hepatitis C cases become chronic. Hepatitis B virus, some-times with Hepatitis D virus, causes a smaller percentage of chronic infections. Hepatitis A and E viruses do not cause chronic hepatitis. Drugs such as methyldopa, isoniazid, nitrofurantoln, and possibly acetaminophen can also cause chronic hepatitis, particularly when they are taken for prolonged periods. Wilson's disease, a rare hereditary disease involving abnormal copper retention, may cause chronic hepatitis in children and young adults.
No one knows exactly why the same viruses and drugs will cause chronic hepatitis in some people but not in others, or why the degree of severity varies. One possible explanation is that in people who develop chronic hepatitis, the immune system overreacts to the viral infection or drug.
In many people with chronic hepatitis no obvious cause can be found. In some of these people, there appears to be an overactive immune system reaction that is responsible for the chronic inflammation. This condition, called autoimmune hepatitis, is more common among women than men.
Symptoms and Diagnosis
About a third of chronic hepatitis cases develop after a bout of acute viral hepatitis. The remainder develop gradually without any obvious previous illness.
Many people with chronic hepatitis have no symptoms at all. For those who do, the symptoms often include a feeling of illness, poor appetite, and fatigue. Sometimes the person also has a low fever and some upper abdominal discomfort. Jaundice may or may not develop. Features of chronic liver disease may eventually develop. These can include an enlarged spleen, spider like blood vessels in the skin and fluid retention. Other features may occur especially in young women with autoimmune hepatitis. These can involve virtually any body system and include acne, cessation of menstrual periods. Joint pain, lung scarring, inflammation of the thyroid gland and kidneys, and anemia.
Although the person's symptoms and liver function test results provide helpful diagnostic information, a liver biopsy (removal of a tissue sample for examination under a microscope) is essential for a definite diagnosis. Examining liver tissue under a microscope allows a doctor to determine the severity of the inflammation and whether any scarring or cirrhosis has developed. The biopsy may also reveal the underlying cause of the hepatitis.
Prognosis and Treatment
Many people have chronic hepatitis for years without developing progressive liver damage. For others, the disease gradually worsens. When this happens and the disease is the result of viral hepatitis B or C infection, the antiviral agent inter-feron-alpha may stop the inflammation. However, the drug is expensive, adverse effects are common, and hepatitis tends to recur once treatment is stopped. Therefore such treatment is reserved for selected people with the infection.
Autoimmune hepatitis is usually treated with corticosteroids, sometimes together with azathioprine. These druos suppress the inflammation, resolve the symptoms, and improve long term survival. Nevertheless, scarring (fibross) in the liver may gradually worsen. Discontinuing therapy usually leads to a recurrence, so most people have to take the drugs indefinitely. Over a period of years, about 50 per cent of the people with autoimmune hepatitis develop cirrhosis, liver failure, or both.
If a drug is suspected to cause the hepatitis, the person should stop taking it. Doing so may make the chronic hepatitis disappear.
Regardless of the cause or type of chronic hepatitis, any complications - such as ascites (fluid in the abdominal cavity) or encephalopathy (abnormal brain function) - require treatment.
The author is a gastro-interelogist and endoscopy specialist.
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