The nervous system governs our thoughts and behaviors and is therefore known as the “command” of the human body. Neurological infections are not uncommon clinically, but due to the lack of knowledge or awareness of the disease among the general public, diagnosis is often delayed, making treatment difficult and leaving undesirable sequelae or even death. Therefore, it is necessary to enhance the understanding of neuroinfectious diseases. What is neuroinfectious disease? Neuroinfectious disease is the abbreviation of neurological infectious disease, which is the inflammation of the nervous system caused by various pathogens, such as viruses, bacteria, fungi, spirochetes, rickettsiae, parasites, etc. Neuroinfectious diseases are common and frequent diseases in neurology, and their scope involves many disciplines such as internal, external, gynecological and pediatric. It includes infectious diseases of the central nervous system and infectious diseases of the peripheral nervous system. The former causes various encephalitis, meningitis, meningoencephalitis or myelitis, while the latter mainly causes various mononeuritis (such as facial neuritis, vestibular neuritis, inflammation of the motor nerve, etc.) and polyneuritis (such as Green-Barre syndrome, brachial plexus neuritis, etc.). Common symptoms of neuroinfectious diseases Infectious diseases of the central nervous system have complex etiology and highly variable clinical symptoms. Common symptoms include fever, headache, vomiting, seizures (epileptic seizures), mental abnormalities, neck resistance sensation, and in severe cases, coma or paralysis. The main symptoms of infectious diseases of the peripheral nervous system are numbness, pain, weakness or paralysis, and muscle atrophy. Cranial nerve damage may also include diplopia, facial palsy (crooked mouth), vertigo, or difficulty swallowing. How to diagnose neuroinfectious disease early Neuroinfectious disease, especially central nervous system infectious disease with fever, headache, vomiting, seizures, mental abnormalities, coma, neck resistance or limb paralysis, and cerebrospinal fluid changes are not difficult to diagnose. However, some patients have atypical clinical manifestations and are often misdiagnosed as colds and gastritis. Raising awareness, early examination, timely lumbar puncture for cerebrospinal fluid, combined with electroencephalography, can improve the early diagnosis rate. Those who have recently developed headache, vomiting, seizure, mental abnormality, coma or paralysis, those who have “cold” with vomiting or acute fever with frequent vomiting, and those who have epilepsy after “cold or diarrhea” should go to the neurology department in time to get a clear diagnosis as soon as possible to avoid The diagnosis should be clarified as soon as possible to avoid delaying treatment. Neurological infections can be caused by viruses, bacteria, fungi, spirochetes, rickettsiae, parasites and other pathogens. The manifestations of neuroinfectious diseases caused by various pathogens are similar, but their treatment and prognosis vary greatly, and the changes in their cerebrospinal fluid vary. The diagnosis can be established early by lumbar puncture and laboratory examination of the cerebrospinal fluid. In some patients, the cerebrospinal fluid changes are atypical, so two or more lumbar punctures are needed to make a definite diagnosis and to dynamically observe the changes in the cerebrospinal fluid. In some patients, lumbar puncture for cerebrospinal fluid replacement or intrathecal drug injection is required to improve the therapeutic effect. What other tests should be performed in patients with neuroinfectious diseases? Patients with encephalitis often have abnormalities in the EEG and therefore require an EEG examination. Some meningitis (e.g., septic meningitis, tuberculous meningitis, etc.) can be complicated by hydrocephalus, etc., which can be demonstrated on a brain CT or MRI scan. Peripheral neuropathy should be studied by electromyography to understand the extent of neuropathy, etc. Blood count and sedimentation are also important for the diagnosis of neuroinfectious diseases.