A common cause of hepatitis is an infection with a virus. The five viruses primarily associated with hepatitis are named in the order of their discovery: A, B, C, D, and E. In some countries or areas, acute viral hepatitis is most commonly caused by hepatitis A (HAV), hepatitis B (HBV), and hepatitis C (HCV), while only HBV and HCV cause chronic hepatitis.

Essentials for Diagnosis 
(1) It is clinically manifested as general debility, poor appetite, nausea, vomiting, fullness in the epigastriurn, and dull pain in the hepatic region.

(2) Various degrees of jaundice may be found in the skin and sclera. The liver becomes slightly enlarged with tenderness and percussion pain. Hepatic face, vascular spiders, liver palms and hepatosplenomegaly with slightly hard texture may be present in chronic active hepatitis.

(3) An increase of direct bilirubin in blood, gradual deepening color of urine and an apparent rise of serum aminotransferase may occur.

(4) Hepatitis virus or antigen can be detected in etiological examination; and specific antibody of hepatitis virus in serological examination.

(5) Rapid deepening of jaundice, frequent vomiting, abdominal distension, anorexia, hiccup, extreme fatigue, an inclination of bleeding, or mental disturbance occur, and progressive shrinking of the liver with impaired function of the liver is manifested in severe cases. Prothrombin time is prolonged and cholinesterase activity is reduced.