Hepatitis is a gastroenterological disease, featuring inflammation of the liver. The clinical signs and prognosis, as well as the therapy, depend on the cause.

Most cases of acute hepatitis are due to viral infections:

* Hepatitis A
* Hepatitis B
* Hepatitis C
* D-agent (requires presence of the hepatitis B virus)
* Hepatitis E
* Hepatitis F (discredited)
* Hepatitis G
* In addition to the hepatitis viruses, some other viruses can cause hepatitis, including cytomegalovirus, Epstein-Barr virus, yellow fever, etc.

Hepatitis A:

Hepatitis A or infectious jaundice is an enterovirus transmitted by the orofecal route, transmitted to humans through methods such as contaminated

food. It causes an acute form of hepatitis and does not have a chronic stage. The patient’s immune system makes antibodies against hepatitis A

that confer immunity against future infection. People with hepatitis A are advised to rest, stay hydrated and avoid alcohol. A vaccine is available

that will prevent infection from hepatitis A for life. It can be spread through personal contact, consumption of raw sea food or drinking contaminated

water. Hepatitis A is primarily spread in third world countries, and can also be more often found in southern Europe than in northern and western

Europe. Hepatitis A is transmitted fecal-orally, generally by ingesting contaminated water or food. Strict personal hygiene and the avoidance of raw

and unpeeled foods can help prevent an infection. Infected persons already begin excreting the hepatitis A virus with their stool two weeks after the

appearance of the first symptoms. The time between the infection and the start of the illness can run from 15 to 45 days, and approximately 15% of

sufferers may experience relapsing symptoms from six months to a year following initial diagnosis.

Hepatitis B:

Hepatitis B causes both acute and chronic hepatitis in some patients who are unable to eliminate the virus. Identified methods of transmission

include blood (blood transfusion, now rare), tattoos (both amateur and professionally done), horizontally (sexually or through contact with blood or

bodily fluids), or vertically (from mother to her unborn child). However, in about half of cases the source of infection cannot be determined. Blood

contact can occur by sharing syringes in intravenous drug use, shaving accessories such as razor blades, or touching wounds on infected persons.

Needle-exchange programmes have been created in many countries as a form of prevention. In the United States, 95% of patients clear their

infection and develop antibodies against hepatitis B virus. 5% of patients do not clear the infection and develop chronic infection; only these people

are at risk of long term complications of hepatitis B.

Hepatitis C:

Hepatitis C (originally “non-A non-B hepatitis”) can be transmitted through contact with blood (including through sexual contact). Hepatitis C may

lead to a chronic form of hepatitis, culminating in cirrhosis. It can remain asymptomatic for 10-20 years. No vaccine is available for hepatitis C.

Patients with hepatitis C are prone to severe hepatitis if they contract either hepatitis A or B, so all hepatitis C patients should be immunized against

hepatitis A and hepatitis B if they are not already immune. However, hepatitis C itself is a very lethal virus and can cause cirrhosis of the liver. The

virus, if detected early on can be treated by a combination of interferon and the antiviral drug ribavirin. The genotype of the virus determines the

rate of response to this treatment regimen.

Hepatitis D:

Hepatitis D is a virus like substance that has been called the delta agent. It is the closest thing to a viroid that infects a human being. Some

scientist class it as a viroid. It cannot proliferate without the presence of hepatitis B virus, because its genome lacks certain essential genes.

Hepatitis E:

Hepatitis E produces symptoms similar to hepatitis A, although it can take a fulminant course in some patients, particularly pregnant women; it is

more prevalent in the Indian subcontinent.

Hepatitis G:

Another type of hepatitis, hepatitis G, has been identified.

Other viruses can cause infectious hepatitis:

* Mumps virus
* Rubella virus
* Cytomegalovirus
* Epstein-Barr virus
* Other herpes viruses

Alcoholic hepatitis:

Ethanol, mostly in alcoholic beverages, is an important cause of hepatitis. Usually alcoholic hepatitis comes after a period of increased alcohol

consumption. Alcoholic hepatitis is characterized by a variable constellation of symptoms, which may include feeling unwell, enlargement of the liver,

development of fluid in the abdomen ascites, and modest elevation of liver blood tests. Alcoholic hepatitis can vary from mild with only liver test

elevation to severe liver inflammation with development of jaundice, prolonged prothrombin time, and liver failure. Severe cases are characterized by

either obtundation (dulled consciousness) or the combination of elevated bilirubin levels and prolonged prothrombin time; the mortality rate in both

categories is 50% within 30 days of onset.

Drug induced hepatitis:

A large number of drugs can cause hepatitis. The anti-diabetic drug troglitazone was withdrawn in 2000 for causing hepatitis. Other drugs associated with hepatitis.