The liver is the largest organ in the body, occupying the entire upper right quadrant of the abdomen. It performs over 500 vital functions. It processes all of the nutrients the body requires, including proteins, glucose, vitamins, and fats. The liver manufactures bile, the greenish fluid stored in the gall bladder that helps digest fats. One of the liver's major contributions to life is to render harmless potentially toxic substances, including alcohol, ammonia, nicotine, drugs, and harmful by-products of digestion. Old red blood cells are removed from the blood by the liver and spleen, and the iron is cycled to the bone marrow to make new ones. Damage to the liver can impair these and many other processes. Hepatitis is a disorder in which viruses or other mechanisms produce inflammation in liver cells, resulting in their injury or destruction. In most cases this inflammatory process is triggered when the immune system fights off infections caused by viruses. It can also be caused, however, by an overactive immune system that attacks its own liver cells. Inflammation of the liver can also occur from medical problems, drugs, alcoholism, chemicals, and environmental toxins. Hepatitis varies in severity from a self-limited condition with total recovery to a life-threatening or life-long disease.

Experts define hepatitis as short-term (acute hepatitis) or prolonged (chronic hepatitis). 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 having either condition can experience varying degrees of severity.

Acute hepatitis can begin suddenly or gradually, but it has a limited course and rarely lasts beyond one or two months. Usually there are only spotty liver cell damage and evidence of immune system activity, but on rare occasions, acute hepatitis can cause severe -- even life-threatening -- liver damage.

The chronic forms of hepatitis persist for prolonged periods. Experts usually categorize chronic hepatitis as either (1) chronic persistent or (2) chronic active hepatitis.

Chronic persistent hepatitis is usually mild and nonprogressive or slowly progressive, causing limited damage to the liver. Cell injury in such cases is usually limited to the region of portal tracts, which contains vessels that carry blood to the liver from the digestive tract. In some cases, however, more extensive liver damage can occur over long periods of time and progress to chronic active hepatitis.

If damage to the liver is extensive and cell injury occurs beyond the portal tract, chronic active hepatitis can develop. Significant liver damage has usually occurred by this time. Liver cells are destroyed between the portal tract and the central veins in the liver, and progressive cell damage can build a layer of scar tissue over the liver, resulting in the condition known as cirrhosis. In such cases, the entire liver is threatened with malfunction and failure.

Most cases of hepatitis are caused by viruses that attack the liver; most are named with the letters A through G. It should be noted that the cause of hepatitis is sometimes unexplained, indicating that additional viruses have not yet been discovered.

Hepatitis A, formerly called infectious hepatitis, is always acute and never becomes chronic. The virus is excreted in feces and transmitted in contaminated food and water. Eating shellfish taken from sewage-contaminated water is a common means of contracting hepatitis A. It can also be acquired by close contact with individuals infected with the virus. The hepatitis A virus does not directly kill liver cells, and experts do not yet know how the virus actually injures the liver.

The virus for hepatitis B, formerly called serum hepatitis, is found in semen, blood, and saliva. It is usually spread by blood transfusions, contaminated needles, and sexual contact. Blood screening as reduced the risk from transfusions. The virus does not kill cells directly, but seems to activate cells in the immune system, which cause inflammation and damage in the liver. Hepatitis D virus can replicate only by attaching to hepatitis B and therefore cannot exist without the B virus being present. Between 1% and 10% of hepatitis B patients go on to develop chronic hepatitis and hepatitis B can become chronic without an acute stage.

Hepatitis C was the major cause of all cases of hepatitis resulting from transfusions and most resulting from intravenous drug use. Because of blood screening, the risk from transfusions is now 1 in 10,000. It can also be transmitted through injuries in the skin. It may also be transmitted sexually. About 10% to 60% of acute hepatitis C patients develop the chronic form, which can also occur without a preceding acute stage.

Hepatitis E is similar to hepatitis A and is transmitted by contact with contaminated food or water. It was thought to be rare, but experts now estimate that up to 20% of people in the US may be infected, even those who haven't traveled.

Hepatitis G accounts for about 9% of cases that cannot be diagnosed as hepatitis A through E. It also occurs in about 25% of patients with of hepatitis A, 32% of those with hepatitis B, and 20% of patients with hepatitis C. Hepatitis G appears always to be chronic, but to date indications are that it is mild and does not even increase the severity of any accompanying hepatitis virus.

Hepatitis GB has been discovered as a new distinct form, but it is not known yet whether it causes a serious condition. A number of other common viruses, including herpes simplex, can sometimes injure the liver, although they rarely cause severe hepatitis. Cytomegaloviruses are harmless in most people but can injure the livers in infants and people with impaired immune systems, such as those with AIDS.

Chronic hepatitis may develop when the body's immune system attacks cells in the liver, a condition called autoimmune chronic hepatitis. Autoimmune chronic hepatitis accounts for about 20% of all chronic hepatitis cases. Like other autoimmune disorders, this condition develops because a genetically defective immune system attacks the body's own cells and organs -- in this case, the liver -- after being triggered by an environmental agent, probably a virus. This agent may be a virus; suspects include the measles virus, a hepatitis virus, or the Epstein-Barr virus, which causes mononucleosis. In about 30% of cases, autoimmune hepatitis is associated with autoimmune disorders that attack other parts of the body, but the relationship between these conditions is unclear.

Over time, alcohol abuse leads to increased demands for oxygen by the liver and, at the same time, fat accumulates and impairs the liver's ability to absorb oxygen. Cells in the liver become damaged and may die, possibly leading to cirrhosis, a dangerous and life-threatening condition.

Because the liver plays such a major role in metabolizing drugs, hundreds of medications can cause reactions that are similar to those of acute viral hepatitis. Symptoms can appear anywhere from two weeks to six months after starting drug treatment. In most cases, they disappear when the drug is withdrawn, but, in rare circumstances, they may progress to serious liver disease. Among the drugs most prominently cited for liver interactions are halothane, isoniazid, methyldopa, phenytoin, valproic acid, and the sulfonamide drugs. Notably, very high doses of acetaminophen (Tylenol) have been known to cause severe liver damage and even death, particularly when used with alcohol.

About one third of the US population has antibodies to hepatitis A, indicating previous infection by the virus. It infects 180,000 Americans every year. Feces-contaminated water and food are the major sources of infection, and infected people can transmit it to others if they do not take strict sanitary precautions. Of the various strains of hepatitis, hepatitis A is the one people are most likely to encounter in the course of international travel. Outbreaks have occurred in day care centers, but a recent study of child care workers found that incidence of hepatitis A and B among this group was actually lower than in the general population. Risk is low if good hygienic precautions are used, particularly when changing babies and handling diapers. The disease has also been transmitted sexually among homosexual men and it often occurs in intravenous drug users.

About 350 million people carry hepatitis B worldwide; it is very common in southern Africa, Asia, and the Mediterranean. It is carried through body fluids. In the U.S., there are about 128,000 new cases every year and about 1 to 1.35 million people with chronic hepatitis B. It can infect children and adults; up to 90% of hepatitis B patients are men. Blood screening and vaccinations have significantly reduced the rate of infection, but drug users who share needles are at considerable risk. Hepatitis B may also be transmitted through sexual activity. Pregnant women with hepatitis B can transmit the virus to their babies. Even if they are not infected at birth, unvaccinated children of infected mothers run a 60% risk of developing it before age five. Children are more likely than adults to become chronic carriers. The virus can be passed from cuts, scrapes, and other breaks in the skin. Also at risk are hospital workers exposed to blood products, staff members of institutions for mentally impaired people, prisoners, and emigrants from areas where the disease rate is high. Contaminated medical instruments, including fingerstick devices used for more than one individual, have been known to transmit the virus.

Hepatitis D occurs only in people with hepatitis B. It is not common in the U.S. except in intravenous drug abusers and people who require multiple transfusions. Those who have the antibody for hepatitis B are immune to further infection from both hepatitis B and D viruses.

About 28,000 people acquire hepatitis C every year and as many as 3.9 million Americans are chronic carriers of the virus. Its primary mode of transmission has been through transfusions. Because of blood screening this risk has been dramatically reduced to 1 in 10,000 since 1990. Hepatitis C can exist for decades, however, without symptoms, and nearly 300,000 people who had transfusions before 1990 may have contracted the virus. Experts urge anyone who had transfusions before 1990 be tested, even though treatments for the virus are limited. People who are still at high risk for hepatitis C include intravenous drug users, intranasal cocaine users, people who have had body-piercing, and organ transplant recipients. Transmission of the virus through contaminated medical devices used in invasive procedures, such as colonoscopy, has been reported. Either sexual promiscuity or a long-term sexual relationship with an infected partner appears to increase the risk. The risk in long-term relationships is about 1% per year. The risk increases with frequency of sexual activity and intimate behavior, such as sharing toothbrushes. Although most health care providers are at low risk, the chance of infection in hospital workers who are accidentally stuck with a needle is high, ranging from 4% to 10%. Unless her own infection is severe, a pregnant woman with this virus is unlikely to pass it on to her infant. Even given these risk factors, it is still not known how 40% of patients acquire this form of hepatitis.

Hepatitis G is detected in between 1.5% and 3.2% of blood donors and is believed to be more common than hepatitis C. From what is known of hepatitis G, its risk factors are probably similar to those of hepatitis C, although incidence among patients with multiple blood transfusions is much lower than with hepatitis C.

Autoimmune chronic hepatitis may occur in women between the ages of 20 and 40 who have other diseases of the immune system, including systemic lupus erythematosus, rheumatoid arthritis, Sjoulmgren's syndrome, inflammatory bowel disease, glomerulonephritis, and hemolytic anemia. About 30% of patients are men, however, and in both genders there is often no relationship to another autoimmune disease. In general, no major risk factors have been discovered for this condition.

Symptoms of acute viral hepatitis may begin suddenly or develop gradually. They may be so mild that patients mistake the disease for the flu. Nearly all patients experience some fatigue and often have mild fever. Gastrointestinal problems are very common, including nausea and vomiting and a general feeling of discomfort in the abdomen or sharper pain that may be localized in the upper right quadrant. This pain tends to increase during jerking movements, such as climbing stairs or riding on a bumpy road. GI problems can lead to loss of appetite, weight loss, and dehydration. After about two weeks, dark urine and jaundice -- a yellowish color in the skin and whites of the eyes -- develops in some, but not all, patients. Children tend not to develop jaundice. About half of all hepatitis patients have light colored stools, muscle pain, drowsiness, irritability, and itching -- usually mild. Diarrhea and joint aches occur in about a quarter of patients. The liver may be tender and enlarged and most people have mild anemia. In about 10% of patients, the spleen is enlarged.

In very rare cases, within two months of onset, a very serious condition known as fulminant hepatitis develops. Symptoms may include a large swollen abdomen (known as ascites) and a peculiar hand-flapping tremor (called asterixis). These symptoms may be followed by stomach and intestinal bleeding and mental confusion, stupor, or coma caused by brain injury (encephalopathy).

Symptoms of hepatitis A are usually mild, especially in children. They generally appear between two and six weeks after exposure to the virus. Adult patients are more likely to have fever, jaundice, and itching that can last one to several months.

Hepatitis B symptoms appear long after the initial infection -- usually four to 24 weeks. Many patients may not even experience symptoms, or they may be mild and flu-like. About 10% to 20% of patients have a fever and rash. Nausea is not common. Hepatitis B patients may experience general aching in the joints, but sometimes the pain can resemble arthritis, affecting specific joints and accompanied by redness and swelling.

If they appear at all, symptoms develop about a month or two after a person is infected with hepatitis C. These are usually milder than those of hepatitis B. About 75% of patients show no signs of jaundice, and many do not experience any symptoms.

Symptoms of Chronic Hepatitis B and C. Both hepatitis B and C can progress to chronic hepatitis usually with no early acute symptoms. Symptoms of progressive chronic viral hepatitis may be very subtle and no more than a mild persistence of acute symptoms for six or more months. In fact, chronic hepatitis C can be present for as long as 20 years without presenting any obvious problems. Some patients develop pain in small joints in the body (such as the hand) that may be nearly indistinguishable from symptoms of rheumatoid arthritis, fibromyalgia, or carpal tunnel syndrome. In other patients, chronic hepatitis B or C can lead to long term disability or liver failure before they experience any symptoms at all.

The symptoms of chronic autoimmune hepatitis range from minimal to severe, including fatigue, jaundice, fever, and weight loss. The liver and spleen are often enlarged. In addition, patients with this condition may experience skin disorders, including palmar erythema (red palms) and spider angioma (a blood-red spot, the size of a pin head, from which tiny blood vessels radiate like spider legs). Itching is not common, however. The abdomen or legs may be swollen due to the accumulation of fluid.

In most cases of acute viral hepatitis, recovery is complete and the liver returns to normal within two to eight weeks. In a small number of cases of hepatitis B or C, the condition can be prolonged and recovery may not occur for a year. About 5% to 10% of these patients will experience flare-up of symptoms in a milder form before full recovery. A few of these patients may go on to develop chronic hepatitis. In the rare event that fulminant hepatitis develops, the liver fails and gastrointestinal hemorrhage and brain damage (encephalopathy) occur, resulting in mental confusion, or even coma. Without liver transplantation, death occurs in up to 80% of these cases. Pregnant women with acute hepatitis B, C, or E are at higher risk for these complications. Other serious, and also rare, consequences of acute viral hepatitis are aplastic anemia (which can be fatal), hypoglycemia, and polyarteritis -- a serious inflammation of blood vessels. People who have been infected with a hepatitis virus continue to produce antibodies to that specific virus. This means that they cannot be reinfected with the same hepatitis virus again. Unfortunately, they are not protected from other types.

Hepatitis A is the least serious hepatitis virus; it never becomes chronic. Fulminant hepatitis is the major concern, but even if this condition develops, it is less dangerous than with other viral types; only one in a thousand patients are at risk for death from this complication. Similarly hepatitis E is acute and not serious, except in pregnant women, when it can be life-threatening.

Acute hepatitis B is lethal in only 1% of patients, but even patients with mild symptoms can remain chronically infected with the virus. Between 5% and 15% of hepatitis B patients carry the virus throughout their lives, and about 25% of these carriers progress to chronic hepatitis. People most at risk for carrying the virus are children infected before they are five and newborns, most of whom become carriers. People most at risk for progression to chronic hepatitis are those infected in early childhood and people with damaged immune systems, such as AIDS patients.

If a patient with hepatitis B becomes co-infected with hepatitis D, the consequences can be very serious. There is an increased risk for fulminant hepatitis, a life-threatening condition. The risk for developing a chronic form of hepatitis D is the same as for hepatitis B alone.

The mortality rate for acute hepatitis C is well below 1%, but people infected with hepatitis C tend to become life-long carriers of the virus. Between 40% and 60% of these patients develop chronic hepatitis within four years. It is currently not possible to predict which patients will develop the chronic form of hepatitis C.

Patients with chronic persistent hepatitis who have few, if any, symptoms generally have a favorable outlook, with only a small risk for developing cirrhosis. In chronic active hepatitis, however, liver biopsies often reveal scarring indicative of cirrhosis and damage to the liver cells that bridge the portal and central veins of the liver. Nearly every bodily process is affected by a damaged liver, including digestive, hormonal, and circulatory systems. Without treatment, encephalopathy, stomach and intestinal bleeding, or kidney failure may eventually develop, with life-threatening consequences. The degree of severity in people with hepatitis caused by viruses B and C usually depends on the degree to which the virus can replicate itself. Viruses that replicate quickly usually cause a more severe form of chronic hepatitis.

The great majority of people with chronic persistent hepatitis B have a good long-term outlook, but between 5% and 10% become carriers of the virus and 5% to 10% eventually develop cirrhosis. The addition of hepatitis D is a particular danger and increases the risk for cirrhosis. Hepatitis B is a primary cause of liver cancer. In Asia about 15% of people who have chronic hepatitis B develop liver cancer, but this high rate is not seen in other parts of the world. (One Italian study which followed a group of hepatitis B patients for 11 years found no development of liver cancer over that period of time.) Vaccinations for hepatitis B is proving to significantly reduce this risk.

A recent study reported that from the time of diagnosis, the 10-year risk for the patients in the study developing cirrhosis was 29% and for liver cancer was 14%. It should be noted that these patients had had hepatitis for many years before being diagnosed, so these time frames are not based on when a patient first gets hepatitis. One large study has identified people at highest and lowest risk for developing cirrhosis: people who contracted hepatitis after exposure in a hospital setting, blood transfusion, and when the cause is unknown have a 20% to 30% chance for cirrhosis; those who developed hepatitis C from drug abuse, sexual activity, and occupational exposure have a lower risk -- around 10%. Another study found that drinking alcohol also significantly increased the risk. A study reporting a high rate of hepatitis C in diabetics has led some experts to theorize that the virus may have effects on the immune system or pancreas that could cause this disorder in some people.

Although only recently identified, experts believe that hepatitis G usually has a mild chronic course and the likelihood of liver damage is low.

The persistent form is usually benign and causes little trouble, although there is a very small risk that chronic persistent hepatitis can evolve to the active form. A recent study found that the overall outlook for treated patients with autoimmune hepatitis and no indication of hepatitis viruses was very favorable. In this study, the 10-year survival rate was 95% -- similar to the same age-group in the general population. The five-year survival rate for chronic active form of this hepatitis is only 50% if the disease is not treated. (This rate may be higher in people with milder symptoms and less liver damage.) During the early years, patients are most at risk for liver failure and bleeding in the stomach and esophagus. This risk diminishes over time but is replaced by an increase in liver cancer rates and bleeding in the stomach and intestines. The risk for liver cancer is not has high, however, as with chronic viral hepatitis.

In people suspected of having or carrying viral hepatitis, physicians will measure certain substances in the blood. One of the most important factors indicative of hepatitis is bilirubin, a red-yellow pigment that is normally metabolized in the liver and then excreted in the urine. In patients with hepatitis, the liver cannot process bilirubin, and blood levels of this substance rise, sometimes causing jaundice. Physicians will also look for elevated blood levels of enzymes known as aminotransferases, which are released when the liver is damaged. Aminotransferase levels tend to rise before jaundice develops and to drop after it occurs. High levels do not necessarily mean the condition is very severe, but levels below 500 IU/L generally indicate mild disease.

To identify the particular virus causing hepatitis, blood tests called radioimmunoassays are performed. Some of these tests can pin-point hepatitis antigens, which are proteins that are unique to the specific viruses. More commonly, radioimmunoassays identify particular antibodies, which are molecules in the immune system that attack specific antigens. Antibodies may not appear for up to weeks or months after hepatitis develops, so if the tests are performed too early, they may not detect antibodies even if the patient is infected. Antibodies also persist after patients recover, so a positive antibody test can indicate a previous infection but cannot necessarily determine if the infection is active.

The first antibodies produced to fight the hepatitis A virus are IgM antibodies. They appear early in the course of the disease and usually can be identified using radioimmunoassays as soon as symptoms appear. IgM antibodies disappear during recovery, but IgG antibodies persist, indicating previous infection.

A radioimmunoassay for hepatitis B must be done promptly to identify the antigen, HBsAg, which is found in the blood in early stages but disappears within four months unless the patient becomes a long-term carrier. Antibodies to the antigen appear during convalescence and may be identified then, even if the antigen itself was missed early on. To diagnose hepatitis D using an antibody test, hepatitis B must also have been identified.

A number of tests, particularly one known as enzyme-linked immunosorbent assay (ELISA), are available for identifying the antibody to the hepatitis C virus. The antibody for hepatitis C may not show up for three to six months after the onset of the disease, so the absence of the antibody is not necessarily an indication of a healthy liver. If the physician still firmly believes the virus is present, another test, polymerase chain reaction (PCR), may be performed. A PCR is able to make multiple copies of the genetic material (the RNA) of the virus to the point where it is detectable. It is also the only test available to identify hepatitis G but is very expensive (about $200) and not recommended for what seems to be, so far, a mild disorder.

Blood tests for chronic hepatitis include measurements of aminotransferase levels, bilirubin levels, and detection of blood clotting problems. Immunoassays to detect antibodies to hepatitis viruses are also performed. If a patient experiences symptoms of chronic active hepatitis for six months or more and a virus cannot be identified, then autoimmune hepatitis is usually suspected. To help confirm this condition, test results may show high levels of immune factors called serum globulins or certain antibodies to liver proteins. In some cases, a successful trial of steroid drugs may be the only way to diagnose autoimmune hepatitis. A liver biopsy may be performed for acute viral hepatitis caught in a late stage or for severe cases of chronic hepatitis. Some experts are now recommending biopsies for all chronic hepatitis C patients, regardless of severity, because of the risk for liver damage even in patients without symptoms. A biopsy helps determine treatment possibilities, the extent of damage, and the long-term outlook.

For mild cases of acute viral hepatitis, no drug therapy or other treatment is either available or necessary. Hospitalization is needed only for people at high risk for complications, such as pregnant women, elderly people, patients with other serious conditions, or those who have severe nausea and vomiting and need to have fluids administered intravenously. The primary goals for managing acute viral hepatitis are to provide adequate nutrition, to prevent additional damage to the liver, and to prevent transmission to others.

No vitamins or special diets have been proven to be particularly beneficial. Eating many small snacks during the day, with larger ones in the morning, may help prevent weight loss while reducing the severity of nausea. Patients might be able to tolerate high-caloric drinks to supplement the regular diet.

The liver processes many types of medications, so as soon as hepatitis is diagnosed, the patient should stop taking all drugs, including over-the-counter medications, except those a physician specifically prescribes or recommends. In some cases, the physician may prescribe drugs that have minimal impact on the liver to alleviate the symptoms of hepatitis, such as nausea or severe itching. All patients should abstain from alcohol and sexual contact during the acute phase. Moderate drinking (one or two drinks per evening) after recovery is not harmful for most people. Everyone, however, should avoid taking acetaminophen (Tylenol) with alcohol, which carries a risk for liver damage, even in people without hepatitis.

Although most patients with hepatitis experience fatigue and require more rest than usual, they can be as physically active as they want without affecting recovery. In fact, patients should be encouraged to be as active as they can. Depression is common, particularly in people used to an active life. Patients should be reassured that in the great a majority of hepatitis cases, recovery is complete.

At the onset of acute hepatitis, periodic visits to the physician for repeat blood tests are necessary, the frequency of which depends on how well the patient feels. If symptoms still occur after three months and laboratory tests still indicate active presence of the virus, the patient should be evaluated every month. If symptoms persist beyond 6 months, a liver biopsy may be required to determine any liver damage.

For those who develop fulminant hepatitis and liver failure, treatment is aimed at the affected organs and systems. No medications, including corticosteroids, has any effect against the condition itself. Liver transplantation is currently the only life-saving treatment for fulminant acute hepatitis and has survival rates of up to 60%. Without liver transplantation, the chance of survival is only 20%.

The goals for treating all forms of chronic hepatitis are to relieve symptoms, prevent the development of cirrhosis, reduce viral levels, and improve survival. The medical therapy of chronic viral hepatitis is very different from the treatment of chronic autoimmune hepatitis, so a correct diagnosis is essential.

Patients with autoimmune hepatitis who have mild symptoms and slight inflammation of the liver do not require any treatment except to alleviate symptoms. They should be monitored, however, for any signs of disease progression. Severe autoimmune hepatitis is a life-threatening condition and requires intensive therapy. Because this hepatitis is caused by an overactive immune system attacking the body's own cells, it is most successfully treated with the steroid drugs prednisone and prednisolone. Steroids suppress the immune system and reduce inflammation, producing remission of symptoms in about 80% of patients. Azathioprine (Imuran) is often prescribed along with steroids to help reduce severe side effects caused by using steroids alone. Azathioprine also suppresses the immune system and helps prevent relapse, but the drug will not induce remission by itself. About half of patients relapse within six months, and only about 20% of patients achieve remission (are disease-free) for more than five years. Readministering prednisone therapy after relapse achieves another remission in 80% of patients. In one promising study, patients who continued to use azathioprine after prednisolone was withdrawn had no relapses for at least a year. Unfortunately, long-term use of azathioprine may increase the risk for cancer, although studies indicate that this risk is very low.

For most patients, steroids reduce symptoms within three months, improve liver function within six months, and restore liver health within two years. Between 10% and 20% of patients continue to deteriorate despite steroid treatment, although higher doses may help some of these people. Treatment usually needs to continue about two years before the disease is in complete remission, but it rarely lasts more than three years. Side effects can be very distressing and sometimes serious; they include weight gain, skin problems, moon-shaped face, high blood pressure, diabetes, cataracts, mental disturbances, infections, and osteoporosis. Usually, steroids are stopped when disease symptoms have disappeared, when blood tests show that aminotransferase levels are less than two times normal, and liver biopsies reveal no active cell damage. Steroid medications must be withdrawn very slowly. Patients who are very elderly or who have advanced cirrhosis are not good candidates for this treatment. It should also be noted that about 85% of people with chronic active autoimmune hepatitis do not have severe symptoms; in these cases, physicians often must weigh the risk for progression to a more serious condition against the long-term adverse effects of steroid treatment. If all therapies fail and the disease becomes life-threatening, liver transplantation may be performed. Because of all of these effective treatment options and in spite the high rate of relapse, long-term survival rates in patients with autoimmune hepatitis are excellent. (Steroids are generally not useful for chronic hepatitis B or C and, in fact, suppressing the immune system in these patients can encourage the viruses to replicate more quickly.)

Drug treatments for chronic hepatitis B, D and C are aimed at reducing or preventing liver damage and boosting or modifying the immune system to promote its attack on the viruses. Treatment outcomes are assessed by testing levels of aminotransferase to determine liver damage and using polymerase chain reaction (PCR) tests to detect the amount of virus left. After treatment, however, some patients may have low levels of virus and high indicators of liver damage while others display opposite results. It is not yet clear how to weigh these criteria in evaluating the overall health of the patient.

Interferons act directly against the virus. The standard drug currently used for chronic viral hepatitis B, D, and C is interferon alpha-2b (Roferon-A, Intron A). Other interferons are being tested, including recombinant type-I interferon (Infergen) and interferon beta, which is benefiting many children with hepatitis B who do not respond to interferon-alpha. In those who respond to interferon, studies are showing improved symptoms, a normal long-term survival rate, and, in some, no return of the disease. The percentage of patients who benefit over the long-term, however, is small. Not all patients are candidates; among others, the treatment is inappropriate for patients with advanced hepatitis, fluid in the abdomen, or any serious medical or psychiatric problems. Even when the drug is effective, the disease recurs half the time and requires additional treatment.

Patients with hepatitis B should be given interferon if they show signs of liver damage; it is not recommended for those with normal aminotransferase levels. The drug has eliminated the virus and sustained significant remission in 25% to 40% of patients with chronic hepatitis B. The drug is usually taken by injection every day for 16 weeks.

In patients with hepatitis C taking interferon for six months there is an even lower average rate of sustained response -- about 15%. (Although studies indicate this rate can be boosted to 24% with treatment of a year or longer.) Early eradication of the virus is the most important factor for success In one study, over 75% of patients whose viral count was eliminated in the first week had a sustained response. However, only 35% of those whose count was down by week two and 12.5% of those whose count was down by the fourth week had a sustained response. In some cases, a very short course of corticosteroids may be used initially to boost the effect of interferon. (In such cases, the steroids do no harm.) Effects of the drug may be enhanced before treatment in certain patients by reducing iron levels through a series of blood-drawings. Combinations with other drugs, including ribavirin, thymosin alpha, or ursodeoxycholic acid, are showing promise (for more information on these drugs, see discussions below).

Common side effects are flu-like symptoms that usually occur within six hours and last for 12. More chronic effects include depression, irritability, weight loss, vomiting, and general weakness. Interferon often causes a drop in platelet and white blood cell counts, increasing susceptibility to bacterial infections. It may also trigger an autoimmune response, possibly causing anemia, diabetes, lupus-like symptoms, thyroid abnormalities, or even autoimmune hepatitis.

Among the drugs showing promise for patients who do not respond to interferon are nucleoside analogues, which directly affect viral replication. Such drugs include ribavirin, lamivudine (Epivir), famciclovir (Famvir), and adefovir. Lamivudine has reduced hepatitis B to undetectable levels after four weeks. Unfortunately, the virus recurs in almost all cases, although this recurring mutation may be weaker than the original strain. Administering the drug for longer periods may produce sustained remission in more patients while still being safe. A study using adefovir, also called GS840, reported a drop in hepatitis B virus levels of 97% in 20 patients. For hepatitis C patients, the most promising treatment is a combination of ribavirin and interferon alpha (Rebetol), which has produced sustained improvement in 40% to 77% of hepatitis C patients. This treatment may not be effective, however, in people with severe or late-stage disease.

Immunomodulators are drugs that modify or regulate part of the immune system. One of these, thymosin is a synthetic version of a peptide derived from the thymus gland and is a promising therapy when used alone or in combination with interferon for hepatitis B or when used in combination with interferon for hepatitis C. Vaccines, including Hepagene, are being investigated for treating and preventing hepatitis B.

Amantadine (Symmetrel) is a drug commonly used for Parkinson's disease but which may have some antiviral effects. In hepatitis C patients who had failed interferon, the drug produced normal aminotransferase levels in 27% and it reduced the viral load to undetectable levels while producing a sustained response in 18% of these patients. Ursodiol, or ursodeoxycholic acid, a drug ordinarily used for gallstones, improves aminotransferase levels, although it has no effect against the virus. For hepatitis C patients it may prove useful in combination with interferon but it is not useful alone.

If treatment fails for any type of severe hepatitis, liver transplantation may be tried, although hepatitis B patients have a success rate of only 50% to 60% because of recurrence. (The success rate is higher in those who have hepatitis D.) Experiments using monthly infusions of hepatitis B immune globulin (HBIg) after transplantation show great promise in preventing recurrence in these patients. This may need to be administered life long. One study reported that lamivudine may be helpful in preventing recurrence of hepatitis B after liver transplantation. Hepatitis C also commonly returns in transplanted livers, progressing to cirrhosis within an average of 51 months in 8% of patients. Autoimmune hepatitis may also recur after liver transplantation, but only after several years. Unfortunately, there are only about half the number of available livers as there are candidates. New regulations controlling liver transplantation now give priority to patients with the best chance of long-term survival -- such as a young person with severe mushroom poisoning as opposed to an elderly person with alcoholic cirrhosis.

Hepatitis A is infectious for two to four weeks before symptoms develop and for a few days afterward. People with hepatitis B or C may become carriers of the virus after recovery, even if chronic disease does not develop and symptoms are not present.

Patients with viral hepatitis should abstain from sexual activity or take strict precautions if they cannot. Sterilizing utensils or clothing is not necessary with any type of hepatitis, but hot water and thorough cleanings are necessary for items used by patients with hepatitis E and A. Utensils used by the patient for eating and cooking should be kept separate from those used by others. Because hepatitis A and E are usually passed through contaminated food, people with these viruses should not prepare food for others; unfortunately these viruses are most contagious before symptoms appear. Restrictions on food preparation are not necessary for other types of hepatitis. All objects contaminated by blood from patients with hepatitis B or C must be handled with special care.

Travelers should be vaccinated against hepatitis A if they are traveling for long periods of time to countries where epidemics occur. They should peel and wash all fresh fruits and vegetables themselves and avoid raw or undercooked meat and fish. Even ice cubes can cause infection, and only carbonated bottled water should be used for brushing teeth and drinking. If carbonated water is not available, tap water should be boiled for ten minutes.

The standard preventive measure against hepatitis A has been immune globulin (formerly gamma globulin) injections. A vaccine, Havrix, is now available and is very safe and effective. It can be given along with immune globulin and other vaccines. Although not yet routinely given to children under two, the vaccine is proving to be safe for infants. People who should receive Havrix include those in communities where outbreaks occur, sexually active homosexual men, people with chronic liver disease, health care workers exposed to the virus, and travelers to developing countries. Travelers should also receive immune globulin if they are visiting high risk areas within four weeks of the vaccination. There are few side effects although allergic responses can occur. Hair loss has been reported in a very few people after a second administration.

All transfused blood is now tested for both hepatitis B and C, significantly reducing the risk from this source. Several vaccines, including Recombivax HB, GenHevac B, Hepagene, and Engerix-B, can prevent hepatitis B and are effective and safe, including for infants and children. Vaccination programs are also proving to reduce the risk for liver cancer. Because the incidence of hepatitis B is rising in the U.S., experts recommend immunization against hepatitis B in all infants and children older than eleven and those under eleven who live in areas populated by immigrants from countries with a high incidence of the disease. Others who should be vaccinated are people who have had sexual contact with infected individuals, health care workers who may come in contact with contaminated blood or body fluids, and people who travel frequently or stay for prolonged periods in countries with high prevalence of this disease. Three doses given over six months are usually required for adults; a recent study reported that older adults would benefit from a fourth dose without incurring serious side effects. People with alcoholism, who often have a lower response, may be protected with high doses. A small percentage of people do not develop immunity even after a vaccine has been given repeatedly. A more potent vaccine is proving to be effective in many people who do not respond to a standard vaccine. The vaccine loses its effect after five years in about a third of those who had it, but the value of a booster shot is uncertain. Preventing hepatitis B also prevents hepatitis D. Screening pregnant women for hepatitis B and then treating the infants of infected mothers as soon as they are born appear to be very effective prevention strategies for newborns. Treatment is with immune globulin and a series of vaccinations at birth, one month, and six months.

Although transfused blood has been tested for both hepatitis B and C since 1990, those with previous transfusions -- even those performed decades ago -- may be at risk. Such individuals are urged to be tested. Immune globulin helps protect against developing hepatitis C after transfusions. Periodic doses of immune globulin in sexual partners of infected people also appear to confer protection. Avoiding exposure or preventing transmission is, however, still very important for hepatitis carriers and for those in contact with them. Infected patients should use condoms and contraceptives that prevent passage of the virus, possibly even in relationships that last for years. Sexual partners, no matter what the duration of the relationship, should avoid sharing personal items, such as razors or toothbrushes, and abstain from sexual activity during menstruation or infections that cause bleeding in the genital or urinary areas. Community needle exchange programs should be encouraged. Studies are finding that these programs reduce the incidence of both hepatitis and AIDS significantly without encouraging drug abuse.