Inflammation of the liver. Hepatitis can be caused by infections with various organisms, including bacteria, viruses (Hepatitis A, B, C, etc.), or parasites. Chemical toxins such as alcohol, drugs, or poisonous mushrooms can also damage the liver and cause it to become inflamed.
A rare but extremely dangerous cause of hepatitis results from overdose of acetaminophen (Tylenol), which can be deadly. In addition, immune cells in the body may attack the liver and cause autoimmune hepatitis. Hepatitis may resolve quickly (acute hepatitis), or cause long-term disease (chronic hepatitis).
In some instances, progressive liver damage or liver failure may result. The incidence and severity of hepatitis vary depending on many factors, including the cause of the liver damage and any underlying illnesses in a patient.
Common risk factors include intravenous drug use, Tylenol overdose (the dose needed to cause damage is quite close to the effective dose so be sure to be careful to take Tylenol only as directed).