Acute septic meningitis has a rapid onset and starts early with severe pain in the whole head, which is persistent and gradually worsens, and sometimes there are explosive and intense headache attacks on top of the persistent headache. In addition to headache, there are also systemic symptoms of acute infection, such as high fever, generalized muscle aches, nausea, vomiting, with jet vomiting as the characteristic symptom. Almost all patients have psychiatric abnormalities, manifested as excitement, confusion, delirium. 10% of patients have coma, 25% of patients may have limited or generalized seizures, 5% to 20% of patients have cranial nerve palsy and focal signs of the nervous system, and 80% of patients have signs of meningeal irritation. The onset of tuberculous meningitis is mostly slow, mostly in children and young adults, and is often preceded by symptoms of tuberculosis toxicity lasting 2 to 3 weeks, including low fever, night sweats, loss of appetite, weight loss, and poor sleep. The headache may be severe, accompanied by nausea and vomiting, or it may be dull or distended and last for a long time. Children often have convulsive attacks with depression, apathy, delirium, and in severe cases, coma and diaphoresis. Early signs are not obvious, but in late stages, typical signs of meningeal irritation and neurological localization appear, such as abducens and motoneuropathy, monoplegia or hemiplegia. The clinical manifestations of viral meningitis are acute or subacute in onset. The clinical symptoms of viral meningitis are similar in all causes, with severe headache and continuous throbbing pain throughout the head, accompanied by fever, neck strength, nausea, vomiting, lethargy, dizziness, and neck and back pain, and the older the person, the more severe the symptoms. Physical examination is rarely positive, and meningeal irritation is the only neurological sign. However, regardless of the type of encephalitis, it is best to confirm it based on the clinical symptoms and cerebrospinal fluid results, as well as the ancillary tests, to make a comprehensive analysis in order to treat the condition.