Severe brain inflammation. The disease is an infectious disease of the central nervous system, usually caused mostly by viral infections, commonly known as herpes simplex virus encephalitis. Patients may present with headache and fever, as well as physical signs and symptoms, which may manifest as sensory disturbances in the lateral extremities, motor disturbances and possibly hemianopia, and speech dysfunction in the case of left-sided lesions. Some patients may present with seizures and may also present with psychiatric symptoms. Some patients with encephalitis may be clinically cured with aggressive and correct treatment, while others may have some residual symptoms. In severe cases, the patient may develop impaired consciousness, including drowsiness, lethargy, and coma, as well as a decerebrate or vegetative state, among others. After the onset of the disease, proper treatment should be given in a timely manner, mainly antiviral therapy, which is commonly used clinically, including acyclovir and ganciclovir. When the intracranial pressure is increased, the cranial pressure should be lowered, and the commonly used drugs are mannitol and glycerol fructose. If there is a disorder of consciousness, the treatment is usually applied to wake up the brain and compound musk to wake up the brain.