Viral hepatitis, a group of systemic infectious diseases caused by a variety of hepatitis viruses, mainly liver damage. Classification of hepatitis viruses 1, Hepatophilic viruses: there are five known hepatophilic viruses – HAV (A), HBV (B), HCV (C), HDV (D) and HEV (E). 2, non-hepatophilic viruses: all secondary liver damage: EBV (EBV) cytomegalovirus (CMV) yellow fever virus (YFV) herpes simplex virus (HSV) rubella virus (RV) Viral hepatitis, in general, refers specifically to hepatitis caused by hepatophilic virus infection. Clinical classification of viral hepatitis 1, acute viral hepatitis: divided into acute jaundice-free and acute jaundice, the latter is more serious. 2.Chronic viral hepatitis: after hepatitis virus infection, the symptoms are delayed or recurrent, and the duration of the disease is more than 6 months (many patients with chronic hepatitis as the first manifestation). It is mainly seen in HBV, HCV and HDV infection. According to the degree of liver function damage, clinically viral hepatitis can be divided into mild, moderate and severe. 3.Severe hepatitis (also known as liver failure): clinically divided into: (1) Acute severe hepatitis: start with acute yellow liver, extreme fatigue within 2 weeks, rapid and dangerous, and the natural course of the patient’s death is mostly within 2 weeks. (2) Subacute severe liver: the disease starts with acute yellow liver, extreme fatigue appears after 2 weeks, the progress is slower, and the natural course of the disease is mostly in several weeks to several months. (3) Chronic severe liver: with history of chronic hepatitis, cirrhosis, HBsAg carrier or other underlying chronic liver diseases, the clinical manifestations are the same as that of subacute severe liver, but the duration of the disease is longer and there is a tendency of recurrent fluctuation, which is often prolonged for several months. Prognosis of severe hepatitis: the total morbidity and mortality rate is still 30%~50%; the morbidity and mortality rate is more than 90% in those who have hepatorenal syndrome or hepatic encephalopathy above stage III. 4.Silent hepatitis: it can be seen in various types of hepatitis virus infection. The onset of the disease is similar to acute jaundice hepatitis, but the symptoms are lighter and the jaundice is heavier; itching of skin and light color of stool can occur. 5.Hepatitis cirrhosis: clinically divided into: (1) compensated cirrhosis: early cirrhosis, no obvious manifestation of liver failure, no ascites, hepatic encephalopathy, esophagogastric fundic varices caused by upper gastrointestinal bleeding. (2) decompensated cirrhosis: middle and late cirrhosis, with obvious liver function abnormality and signs of decompensation, ascites, hepatic encephalopathy, obvious varices of esophagogastric fundus vein or upper gastrointestinal bleeding. Clinical manifestations: different degrees of fatigue, poor appetite, anorexia, abdominal distension, yellow urine, yellow body and eyes, low urine and other symptoms, some of which are similar to colds and gastric diseases, and some of which are easy to be ignored because of the lack of obvious symptoms. Laboratory tests 1, liver function: alanine aminotransferase (glutamic acid aminotransferase ALT), menthyl aminotransferase (glutamic acid aminotransferase AST), bilirubin (TBIL), γ-glutamyltransferase (GGT), and other abnormalities of varying degrees can occur. 2.Coagulation function: abnormality of prothrombin time (PT) may occur. 3.Pathogenetics: Hepatitis A antibody, hepatitis B virus marker (commonly known as hepatitis B two halves) and hepatitis B DNA, hepatitis C antibody and hepatitis C RNA, hepatitis D antibody and hepatitis D RNA, and hepatitis E antibody can be detected. 4.Imaging tests such as liver and gallbladder ultrasound, CT, MRI, etc. 5.Hepatocentesis histopathology biopsy. Treatment Viral hepatitis currently lacks effective treatment, and should be treated differently according to different pathogens, different clinical types and histologic damage. Prevention 1, Hepatitis A and E patients should take digestive tract isolation; Hepatitis B, C and D patients should take blood/body fluid isolation to cut off the corresponding transmission pathway. 2.For susceptible people, hepatitis A vaccine and hepatitis B vaccine can be injected, while hepatitis C, hepatitis D and hepatitis E still lack vaccine with exact efficacy. For those who have accidental contact with the infectious source, they can be injected with human hepatitis B high potency immunoglobulin or human C globulin for passive immunization.