Inflammatory brain tissue infections are mainly caused by pathogens that cross the blood-brain barrier to reach the local brain tissue and infect the brain cells. The underlying cause is mainly due to the body’s own immune system, such as people who stay up late, are nervous, smoke, drink, and suffer from cold, insomnia, and malnutrition are more likely to develop encephalitis. In addition, people with diabetes, chronic heart failure, chronic obstructive pulmonary disease, chronic tumors, AIDS, long-term hormone use, as well as the elderly and children, are also susceptible to encephalitis, which is caused by low immune function, resulting in infection by viruses, bacteria, tuberculosis, fungi and other pathogens invading brain tissue. There are also non-infectious encephalitis, such as autoimmune encephalitis mediated by autoimmunity, which is also a common type of encephalitis in clinical practice.