According to clinical manifestations and virus types, viral hepatitis is classified into five categories and seven types.
(1) According to clinical manifestations, viral hepatitis can be divided into five categories:
① Acute hepatitis: It can be divided into icteric hepatitis and non-icteric hepatitis, which can be distinguished by the increase of bilirubin.
② Chronic hepatitis: It can be divided into chronic persistent hepatitis and chronic active hepatitis. 20% ~ 70% of patients with chronic active hepatitis caused by hepatitis B virus can develop cirrhosis, and the probability of developing liver cancer is 200 times higher than that of healthy people. 20% caused by hepatitis C virus develops into liver cancer.
③ Severe hepatitis: It can be divided into three types: acute severe hepatitis (fulminant hepatitis), subacute severe hepatitis (subacute liver necrosis) and chronic severe hepatitis. The mortality rate is as high as 70%, and there are more severe hepatitis in the elderly and during pregnancy.
④ Cholestasis hepatitis: Patients with jaundice can last for more than 6 weeks, but the symptoms are mild. Hepatitis B cholestasis is more common in the elderly.
⑤ Posthepatitis cirrhosis: It can be divided into active cirrhosis and static cirrhosis. The condition is serious and requires regular observation and treatment by doctors.
(2) According to the type of virus, viral hepatitis can be divided into seven types: A, B, C, D, E, G and G, and the first five types are more common. Among them, hepatitis A and hepatitis E are only acute hepatitis. Hepatitis A, B, C, D, E and G viruses have been detected by some methods. Hepatitis B virus can't be detected yet, and the diagnosis can be made by excluding hepatitis A to hepatitis G clinically.
Hepatitis A virus is mainly excreted from the intestine and spread by mouth through daily contact.
Hepatitis B virus can be excreted through various body fluids, such as blood, semen, vaginal secretions, saliva, milk, menstruation, tears, urine, sweat and so on. In fact, HBsAg was found in all secretions of patients. Therefore, there are three main ways of transmission of hepatitis B: ① perinatal mother-to-child transmission: it is mainly caused by contact with maternal blood or amniotic fluid during delivery and close contact after delivery. (2) Iatrogenic transmission: transmission through blood transfusion, plasma, blood products or the use of syringe needles, acupuncture needles and blood collection instruments contaminated by viruses. ③ Close contact transmission: close contact transmission caused by sexual contact or skin and mucous membrane damage.
Hepatitis C virus is mainly caused by blood transfusion, accounting for more than 70% of hepatitis after blood transfusion.
The transmission route of hepatitis D is basically the same as that of hepatitis B. Intravenous drug users, gay men, prostitutes and patients who often use blood products or renal dialysis are the high-risk groups of this disease.
Hepatitis E is mainly infected by contaminated water and fecal-oral route.
Hepatitis B virus has not been successfully isolated so far, and its pathogen has not been determined and recognized. At present, there is neither a clear recognized object nor a specific diagnostic method for hepatitis B, and elimination is still the main method, and its transmission route is not very clear.
The transmission route of hepatitis G is basically the same as that of hepatitis B and hepatitis C, so hepatitis G virus can infect hepatitis C or hepatitis B virus at the same time.