Several causes of hepatitis.
I. Infection
1, viruses: viral hepatitis is the most common of hepatitis and is the most important in clinical practice. Usually what we call viral hepatitis refers to hepatitis caused by hepatitis viruses that mainly invade the liver. These viruses can be called hepatophilic viruses, which means they are particularly prone to damage to liver cells and cause lesions mainly in the liver. Depending on the virus, they can be classified as hepatitis A, B, C, D, and E viruses, as well as hepatitis G virus.
However, the viruses that can cause liver damage are by no means limited to these few, but other less common viruses, such as cytomegalovirus, EBV, and hantavirus (the causative agent of renal syndrome hemorrhagic fever), can also sometimes cause liver damage. Even measles virus, herpes simplex virus, and mumps virus have been reported to cause hepatitis. In addition, it is possible to see individual patients clinically with clinical manifestations of viral hepatitis, but no pathogen can be detected, which may be caused by viruses currently unknown to us humans.
2. Bacteria: Normally, bacterial infections occur in our organism and often do not cause liver damage. However, some bacteria, such as Escherichia coli, Staphylococcus aureus, Streptococcus, etc., enter the liver through the bile duct and blood flow pathways; or open damage occurs in the liver and bacteria invade directly; or for unknown reasons, etc.; making local septic changes in the liver and producing liver abscesses can also cause hepatitis. In addition, a more specific type of bacteria, namely Mycobacterium tuberculosis infection, enters the liver by different routes, resulting in liver tuberculosis, which can also cause hepatitis, and these patients often have manifestations of tuberculosis infection in other organs. There are many other bacteria that can cause liver damage, and because they are relatively rare, they are not repeated.
3, fungus: fungal infections of the liver are extremely rare and often occur in people with severe immunodeficiency, such as patients with AIDS and those receiving immunosuppressive therapy.
4, parasites: schistosomiasis is common, the eggs of schistosomes can enter the liver along the bloodstream, causing liver damage, especially in recent years, the incidence of schistosomes in some areas increased, should attract our attention. Liver abscess caused by a protozoan infection called amoeba is also an important cause of parasitic liver damage. Other things like liver fluke, malaria, black fever, and encapsulated worms can also cause liver inflammation.
5, other: spirochetes (such as syphilis spirochetes, leptospira), rickettsia (such as Q fever, parrot fever), chlamydia (such as Chlamydia trachomatis), etc., all have the potential to cause liver damage.
Second, alcohol.
With the improvement of people’s living standards and the increase of alcohol consumption, alcoholic liver damage is becoming more and more common in our lives, and can also cause cirrhosis and even liver cancer in serious cases. Alcohol has a direct damaging effect on liver cells, it is mainly through the excessive oxidation of lipid components on the surface of liver cell membranes, thus destroying the liver cell membranes, and further development, will cause damage to microtubules and mitochondria and other structures in liver cells, thus causing hepatitis.
Third, toxic substances and drugs.
As the saying goes, “medicine is three parts poisonous”, we apply a certain drug to cure the disease, so to speak, is the use of the drug some kind of “toxicity”, so in a sense, the drug is also a special kind of poison. As we introduced earlier, one of the important functions of the liver is biotransformation, which can make the toxicity of drugs entering the body reduced or eliminated, and some drugs have to pass through the liver biotransformation to become active and curative drugs. But during this process, the drug or toxin then has the potential to cause hepatitis through a variety of pathways.
With the rapid growth of the global pharmaceutical industry and the availability of new drugs, drug-related hepatitis is increasingly becoming a major worldwide problem. Now there are many drugs whose side effects can be detected by serology and other tests, but there are still many drugs that were originally considered safe, and their side effects continue to be discovered with the deepening of clinical applications, especially on the basis of the original liver disease, certain drugs are more likely to cause liver damage, which should attract our attention.
Fourth, autoimmune liver disease.
The immune system in the human body plays an important role in defending against the invasion of foreign substances, while the body’s own cells, tissues, organs, etc. can be protected from recognition and attack by the immune system, which is controlled by a series of precise regulatory mechanisms. However, sometimes, for various reasons, this balance of our body is disrupted, so that the immune system in the body begins to attack its own tissues, organs, etc. This causes autoimmune damage, and if this damage occurs in the liver, it is autoimmune liver disease, which includes autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis and their overlapping diseases. Especially in recent years, with the increased awareness of such diseases, their incidence has also been on the rise.
V. Genetic metabolic factors.
Due to genetic metabolic factors, the liver or the body to a certain substance metabolism disorders, such as hereditary hyperbilirubinemia to conjugated bilirubin or unconjugated bilirubin metabolism disorders, hepatomegaly to copper metabolism disorders, hemochromatosis to iron metabolism disorders, and α1 antitrypsin deficiency, porphyria, etc., can cause impaired liver function.
VI. Tumor factors.
Malignant tumors such as primary liver cancer, metastatic liver cancer and liver sarcoma can cause liver function damage because of rapid tumor growth and compression of surrounding normal liver tissues, while liver function is often normal in the early stage of these tumors, which can easily lead to missed diagnosis and misdiagnosis; benign liver tumors, such as cysts, hemangiomas and hepatocellular adenomas, often have no effect on liver function unless the tumor is too large to form compression around.
VII. Effects of systemic diseases on the liver.
Various organs and tissues of the human body are an organic whole that are widely connected and affect each other. Diseases of the cardiovascular system, respiratory system, digestive system, urinary system, hematological system, endocrine system, etc., may cause changes in liver function.