If a child presents with fever, headache, nausea, vomiting, or even convulsions and seizures, it is necessary to be vigilant about the possibility of encephalitis. It is advised to seek medical attention in pediatrics or neurology to conduct a thorough examination. First, an MRI of the brain should be carried out to observe if there are any abnormal signals in the meninges or any damage within the brain substance. Second, cerebrospinal fluid analysis via lumbar puncture is essential for diagnosing encephalitis, as encephalitis patients often show significant abnormalities in cell count and biochemistry of the cerebrospinal fluid, allowing for the identification of different types of infections. Third, an electroencephalogram (EEG) is conducted. While EEG specificity is not high, an affected cerebral cortex in encephalitis patients will show abnormal slow waves. Fourth, routine tests such as a complete blood count should be performed; an elevated blood count can indirectly indicate a potential infection in the patient.