How many types of hepatitis are there?

B.E.

Hepatitis simply refers to inflammation and/or injury of the liver. There are many causes of hepatitis -- too many to list here. The most common causes of hepatitis include infections (viral being the most common, but also bacterial and fungal), alcohol abuse, medications (certain over-the-counter and prescription medications can lead to liver injury), autoimmune disorders and fatty deposits in the liver, such as those that may form in diabetic patients.

When most people refer to hepatitis, they are probably talking about viral hepatitis, which is classified into several types. Hepatitis A, which is very common in underdeveloped countries, is acquired from water or food sources. This type of hepatitis is usually mild and may sometimes be discovered only by blood testing. Hepatitis A never leads to chronic liver disease.

The hepatitis B virus is most often contracted via blood contact -- such as with IV drug abusers sharing needles or health care workers who are stuck by tainted needles. It can also be spread via sexual contact and from mother to baby during childbirth. Hepatitis B can lead to chronic liver disease and the complications that result from it.

Hepatitis C is spread via blood and body-fluid contact (as with Hepatitis B). Hepatitis C used to be the most common type of hepatitis acquired via blood transfusions until a test for it became available in the 1980s. Hepatitis C commonly leads to chronic hepatitis and over many years can lead to chronic liver disease manifested by cirrhosis.

Other much less common types of viral hepatitis include hepatitis D (which is seen most commonly in IV drug abusers and which requires co-infection with hepatitis B), hepatitis E (seen in pregnant women and spread in a similar fashion to hepatitis A) and hepatitis G (commonly seen in patients who are undergoing hemodialysis). It is speculated that other types of viral hepatitis have yet to be identified.