Hepatitis basically means inflammation of the liver. The word hepatitis simply means “inflammation of the liver and a diagnosis of hepatitis means nothing more than that the liver cells have become irritated or swollen; this condition results in an inflammation of the liver. it does not imply anything about the cause of the inflammation.

The five basic signs of inflammation include redness, warmth, swelling, tenderness, and loss of function. But while the inflammation of a joint is quite apparent, an individual may have hepatitis without being aware of it.

When most people think of hepatitis, they think of viral hepatitis, a liver disease caused by various viruses. In addition to viruses, however, there are many other causes of hepatitis:

• autoimmunity (autoimmune hepatitis )• metabolic disorders, such as alpha 1-antitrypsin deficiency• bacteria, fungi, or protozoa• exposure to toxic agents (toadstool poisoning, for example)• herbs, alcohol, or drugs (drug-induced hepatitis)• chemical poisons

Congenital defects, parasitic infections, metabolic disorders, and neoplasms may also result in hepatitis.

There are two main modes of transmission, blood borne and fecal oral routes. a blood-borne infection is spread by contact with contaminated blood; a fecal oral route occurs when infection laden stool from one person finds its way into the mouth of another. hepatitis a (HAV) and hepatitis e (HAE) are also known as fecal borne hepatitis, for example, because of their mode of transmission.

Symptoms and Diagnostic Path

Because it performs so many functions, and because it plays a major role as a detoxifying agent, the liver is subject to a variety of environmental insults and toxins. it is one of the most frequently injured organs in the body.

Injury to the liver can cause a wide range of impairment to the liver’s vital functions, yet in many instances of viral hepatitis, there are no symptoms. many cases go undiagnosed because the symptoms suggest a flu-like illness, or they may be very mild or absent. And because the liver is so resilient, it gives little or no warning of its pathology until the damage is advanced. The liver generally continues to carry on its duties despite a significant amount of damage, but eventually the damage will lead to various types of dysfunction. When the liver suffers from inflammation, regardless of its specific cause, it leads to clinical manifestations that are often similar. Those classic symptoms include malaise, fatigue, mild fever, nausea, vomiting, anorexia (weight loss), vague abdominal pain (especially discomfort in the right upper quadrant above the liver), and sometimes diarrhea. There may also be muscle or joint aches and itching of the skin.

Hepatitis occurs in two general forms: acute and chronic.

Acute hepatitis Acute hepatitis is defined as hepatitis lasting fewer than six months. Acute hepatitis can be caused by bacterial, viral, and amebic infections, as well as by medicines and toxins. The condition usually comes on rapidly, with symptoms that may be severe, but it runs a short course. Autoimmune hepatitis, in which some liver cells (hepatocytes) are destroyed by the body’s own immune system, can also occur as acute hepatitis. Hepatitis a, B, C, D, and E can all cause acute hepatitis.

In the early stages, the symptoms of acute hepatitis include the following:

• aching muscles and joints• change in taste perception• enlarged liver• fatigue• fever• general malaise• headache• loss of appetite• nausea• skin rash

In later stages, symptoms include:

• dark urine• jaundice (yellowing of the skin and whites of the eyes)• light colored stools

Acute hepatitis generally resolves on its own, but occasionally it can result in massive tissue destruction of the liver, leading to liver failure, or fulminant hepatitis.

Acute infectious viral hepatitis usually improves on its own. fewer than one in 300 patients develops liver failure and, with it, the risk of death. Hepatitis caused by mononucleosis always improves on its own; acute hepatitis caused by medicines or alcohol usually improves once the patient stops taking the offending medicine or abstains from alcohol.

Chronic hepatitis Chronic hepatitis lasts longer than six months. a chronic condition usually comes on slowly and has a long course. The causes of chronic hepatitis are similar to that of acute hepatitis, but not all cases of viral hepatitis develop into chronic conditions. Contagious viral hepatitis such as hepatitis B, C, and D can cause chronic hepatitis. In addition, inborn metabolic disorders, such as Wilson’s disease (a disorder of copper metabolism) and hemochromatosis (a disorder of iron metabolism) can lead to chronic hepatitis. Repeated exposure to toxins, such as alcohol and drugs, can also cause chronic hepatitis. Chronic inflammation, whatever the cause, may lead to advanced and irreversible scarring of the liver tissue known as cirrhosis.

There may or may not be any symptoms. many patients have no symptoms at first. When symptoms do develop, they include:

• abdominal pain• aching muscles and joints• enlarged liver• fatigue• increased need for sleep• jaundice (yellowing of skin and eyes)

Viral hepatitis Worldwide, viral hepatitis remains one of the leading causes of chronic liver disease, and is an area of active medical research. at least five distinct human hepatitis viruses have been identified, and they are responsible for the vast majority of cases of acute and chronic hepatitis. they have been named alphabetically in the order of their discovery: hepatitis a (HAV), B (HBV), C (HCV), D (HDV), and E (HEV). Two other possible hepatitis viruses, hepatitis F (HFV) and G (HGV), have been named, but they do not play a significant role in infection, and not all researchers agree that they even exist.

The primary target of a hepatitis virus is the hepatocyte, the major liver cell. it is there that the virus replicates, causing hepatocellular injury. Cell damage occurs either as a direct result of viral replication or as an immune mediated response. (In an immune-mediated response, the body’s attempts to eliminate the virus cause the inflammation of the liver and the problems associated with it.)

Many other viruses also affect the liver and cause inflammation, including infectious mononucleosis, yellow fever, herpes simplex, cytomegalovirus, Epstein-Barr, HIV (human immunodeficiency virus), and Ebola virus, which causes hemorrhagic fever. However, these viruses do not primarily target the hepatocyte. The vast majority of cases of viral hepatitis are caused by one of the hepatitis viruses (A, B, C, D, and E). Regardless of the cause, however, all instances of liver inflammation are classified as hepatitis. The patient may experience many of the same symptoms, though the duration and severity of the illnesses may differ.

The human hepatitis viruses are very different from one another. they cause different types of liver disease, and there are several possible ways to classify them. The common factor is that they are all viral in origin, meaning that the patient is infected by a virus.

Most people recover from hepatitis a and E. There may be mild flare-ups during the process of recovery, but a relapse does not necessarily preclude complete recovery. Hepatitis B, C, and D, on the other hand, can linger, becoming a chronic, possibly lifelong, infection. (An individual cannot become infected by hepatitis D unless he or she has already been infected by hepatitis B, or contracts hepatitis B and D at the same time.) Chronic hepatitis can lead to cirrhosis and liver cancer. Even those who are otherwise healthy may be able to infect others.

Hepatitis A Hepatitis a (HAV) is most commonly seen in children in developing countries, but its incidence has been increasing in the developed world. There are sometimes outbreaks of hepatitis a in restaurants or institutions where contaminated food has been served. People most often become infected by consuming contaminated food or water, by eating raw shellfish, or by using cooking utensils that have been contaminated. The incubation period is normally two to six weeks after exposure to the virus. Hepatitis a is an acute condition; it never turns chronic. Hepatitis a used to be called infectious hepatitis.

Hepatitis B hepatitis b (HBV) is a blood-borne disease, meaning that it is spread through exposure to an infected person’s blood. it can also be transmitted through sexual contact. Hepatitis B can also be transmitted vertically, which means that it can be spread from an infected mother to her infant at birth. The incubation period is anywhere from four to 25 weeks.

About 10 percent of hepatitis B cases turn chronic; the rest are acute, and the patient recovers. When an individual is infected at birth or at a very young age, it is more likely to turn chronic.

Hepatitis C hepatitis c (HCV) used to be called non-A, non-B hepatitis before the virus was isolated. it is a blood-borne infection, primarily transmitted through direct blood contact. it is less commonly transmitted through sexual contact or vertical transmission from an infected mother to her child at birth. The incubation period is usually five to 10 weeks. The majority of hepatitis C cases are chronic; only about 25 percent of cases are considered acute. Symptoms may be nonexistent or may develop only later.

Hepatitis D hepatitis d (HDV) can infect only people who are already carriers of the hepatitis B virus. The incubation period is about two to eight weeks. it is found mainly in intravenous drug users, and can cause both acute and chronic conditions.

Hepatitis E hepatitis e (HEV) used to be known as enteric or epidemic non-A, non-B hepatitis. it is considered to be an acute condition.

Hepatitis F hepatitis f (HFV) may or may not exist. if the virus does exist, it appears to be transmitted by the oral-fecal route.

Hepatitis G hepatitis g (HGV) resembles hepatitis C but appears to be more benign. it is transmitted through blood and blood products.

Nonviral hepatitis There are two main types of nonviral hepatitis, alcoholic hepatitis and drug-induced hepatitis (also known as toxic hepatitis). a third type, autoimmune hepatitis, is also nonvi-ral but is uncommon.

Granulomatous hepatitis is sometimes mentioned as a nonviral hepatitis, but strictly speaking it is not a true hepatitis. In granulomatous hepatitis, white blood cells collect in the liver. The condition does not always cause liver inflammation, nor does it always cause fibrosis. Hepatic granulomas (a mass of granulated tissue usually associated with infections, particularly ulcerated infections) are found in about 3 to 10 percent of liver biopsies. usually they indicate a systemic disorder rather than primary liver disease. There may be many causes, but the usual culprit is an infectious disease. The list of possible infections is long, and includes bacterial infections, such as tuberculosis and other mycobacterial infections; fungal infections, such as histoplasmosis and cryptococcosis; parasitic infections such as schistosomiasis the most common worldwide and toxoplasmosis; and, less commonly, viral infections, such as infectious mononucleosis. Other possible causes include Q fever, syphilis, and cat-scratch fever.

Autoimmune hepatitis In autoimmune hepatitis, liver inflammation is caused by the patient’s own immune system. The condition is sometimes known as autoimmune chronic active hepatitis (CAH), idiopathic chronic active hepatitis, or lupoid hepatitis. Most patients with autoimmune hepatitis about 70 percent are women between the ages of 15 and 40.

Autoimmune hepatitis is a chronic and progressive condition, but the patient often shows symptoms of acute hepatitis, including jaundice, fever, and signs of severe liver dysfunction.

The reason for the immune system’s attack is unknown, but researchers believe that genetic factors predispose some people to autoimmune hepatitis, as well as to other autoimmune conditions. Autoimmune hepatitis is often associated with the production of specific antibodies that can be detected by blood tests.

Autoimmune hepatitis is quite serious. The immediate result is liver inflammation. if untreated, it can result in long term liver cell death, cirrhosis, and liver failure.

Alcoholic hepatitis Alcoholic hepatitis, a result of excessive alcohol intake, is the most common precursor of cirrhosis in the United States. usually alcoholic hepatitis develops only after years, often decades, of alcohol abuse. That is not always the case, however. some patients can develop hepatitis within a very short time of the onset of alcohol abuse, often within only a year.

Toxic hepatitis Toxic, or drug-induced, hepatitis is caused by inhaling or ingesting a toxic chemical. The symptoms are similar to viral hepatitis, but the damage to the liver tends to be more extensive.

Industrial chemicals toxic to the liver include carbon tetrachloride, vinyl chloride, and a variety of heavy metals. Toxic hepatitis can also be caused by poisonous mushrooms. The list of medications that can be toxic to the liver includes isoniazid (used to treat tuberculosis), methyldopa (a treatment for high blood pressure), acetaminophen (the pain reliever), oral contraceptives, and anabolic steroids.

Because of the similarity between viral hepatitis and toxic hepatitis, it is important for the physician and the patient to be wary. In any apparent case of viral hepatitis that does not conform to the usual demographic profile, or that does not respond to standard treatment, the possibility of toxic exposure should be investigated. The primary tools in that investigation include a history of exposure to hepatotoxic chemicals, medications, and other agents.

Neonatal hepatitis This uncommon form of hepatitis occurs only in newborns. neonatal hepatitis develops usually within two months of birth, and the cause can be difficult to determine. it may clear up within six months or cause permanent liver damage, depending on the cause and nature of the condition.

Signs and symptoms do not show the whole picture; the doctor therefore uses a variety of blood tests to determine the type of hepatitis the patient may be suffering from. The doctor may consider another possible diagnosis, such as syphilis, bacterial sepsis, leptospirosis (a type of bacterial infection), or schistosomiasis (a parasite infection).

Blood tests for detecting specific antigens and antibodies are necessary to demonstrate the agent responsible for viral hepatitis. Specific antigens test for viral proteins. The body’s primary response to viral infection is to produce antibodies and T cells. at least three classes of antibodies are produced: immunoglobulin G (IgG), immunoglobulin M (IgM), and immunoglobulin a (IgA).

Viruses are very simple, and there is some debate as to whether they are truly life forms. unlike most life forms, viruses do not have an independent metabolism and are unable to reproduce themselves. they must commandeer their host cells and can reproduce themselves only within their host cells by using the host’s energy sources, chemical compounds, and protein synthesis machinery. In that sense, viruses may be likened to parasites.

One sign of virus is that it reproduces and randomly changes its genetic material. By doing so, a virus can evade the host’s immune system.

Viruses are so tiny that they are measured in terms of nanometers. a nanometer is one billionth of a meter. The human red blood cell, one of the smallest cells in the body, is about thirty times the size of the largest virus. Viruses range in size from about 15 nanometers to 250 nanometers. Because viruses are so small, they cannot be seen under a regular microscope. they can be seen only with an electron microscope, an instrument that can produce enlarged images of tiny objects through a beam of electrons.

Viruses contain either ribonucleic acid (RNA) or deoxyribonucleic acid (DNA) as their genetic material. Animals and plants have only DNA as their genetic material. Most viruses have a core protein around which winds the viral RNA or DNA. some viruses may be enveloped in a fatty (lipid) outer layer that contains specific viral proteins. Apart from the protein that is part of their structure, most viruses produce proteins to perform the biochemical functions necessary for them to reproduce.

Another characteristic of a virus is a property called cellular tropism. Tropism is an involuntary movement of an organism or one of its parts in response to an external stimulus. Tropism involves turning or curving toward or away from the stimulus. In the case of viruses, cellular tropism results in the virus preferentially infecting certain host cells. for example, the human immunodeficiency virus (HIV) has a preference for certain cells of the immune system. Viruses that cause hepatitis preferentially infect hepatocytes, the major cells of the liver, and are therefore referred to as primarily hepatotropic.

What makes viruses so lethal is their ability to mutate. Because they can reproduce rapidly, their mutation rates are high. That makes it difficult for the body to eliminate the virus from its system. Experts believe that mutation may be an important way that the hepatitis C virus escapes detection by the immune system. Mutation also makes it difficult to create vaccines or to design drugs, as the viruses can change the viral proteins that are normally the targets for drugs.

Another important characteristic of viruses that makes them lethal is a property called latency. Viruses may integrate their DNA, or a DNA copy of their RNA, into the DNA of the host cell. When they do so, the viruses propagate when the host cell divides. The viruses are not replicating, or are replicating only at a very low level, the viral particles that the host’s immune system usually targets to kill. Consequently, the viruses remain in the body. These latent viruses can later be activated and begin to replicate again, making viral particles that are highly infectious. for instance, in hepatitis B, the virus can integrate into the host cell’s DNA.

Furthermore, viruses commandeer the machinery of the cells they infect, using the host cell’s energy and chemical compounds. That characteristic makes it extremely difficult to design drugs that can kill viruses. In the case of bacteria, antibiotics usually target the bacterial proteins that the bacteria uses to synthesize its proteins or for energy metabolism. But since a virus uses the host’s protein synthesis machinery, drugs cannot be directed against the proteins to inhibit viral replication, because that would also kill the host cells.

All those characteristics can make viral causes of hepatitis difficult to detect and difficult to expel from the body. The long-term consequences of viral hepatitis may include cirrhosis, which involves permanent damage to the liver structure and function, and liver cancer.

Treatment Options and Outlook

The management of hepatitis primarily involves removing the patient from exposure to its cause, to the extent possible. Any drugs or substances known to be toxic, such as alcohol, should be immediately discontinued. Nonessential medication may be stopped; for other medications, the physician should determine a course of action on a case by case basis.

The patient may receive supportive care and rest as needed. General measures include a well-balanced diet. The doctor should evaluate any herbs or other substances the patient is taking, and weigh carefully the risk versus benefit of any medication or herbal product, especially if the patient has acute hepatitis.

Sedatives should not be given, especially if the patient shows signs of mental confusion or other altered mental status (encephalopathy). Sedatives can mask signs of fulminant hepatitis or even trigger it.

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