What is encephalitis? How does it happen?

Encephalitis refers to inflammatory diseases of brain parenchyma, including infectious inflammation and non-infectious inflammation. Infectious inflammation is caused by the invasion of pathogenic microorganisms into the central nervous system, including viruses, bacteria, fungi, spirochetes, prion proteins, parasites, etc. The most common is viral encephalitis, most common in herpes simplex encephalitis; bacterial encephalitis is most common in purulent bacteria, meningococcus, etc., and also includes special bacteria, Mycobacterium tuberculosis; Treponema pallidum is the most common form of spirochete. Noninfectious encephalitis is caused by immune abnormalities, represented by autoimmune encephalitis, multiple sclerosis (MS), optic neuromylitis, etc., and can also involve white matter in the brain.