ABSTRACT
Encephalitis is commonly caused by viruses. But beyond viruses there are so many causes of encephalitis. Encephalitis is the inflammation of the brain parenchyma due to any reason. As there are so many causes of encephalitis presentations are also variable. So to diagnose encephalitis a set of clinical, laboratory, electroencephalographic and neuroimaging criteria is used. Any children attend medical facility with sudden onset altered mental status along with any of the following features like fever, seizure, focal neurological signs should be evaluated as encephalitis. Viruses are the common cause of encephalitis. Along with infectious etiologies a vast group of noninfectious like autoimmune causes encephalitis also established. When children presented with above mentioned features along with behavior problem and or movement disorder there is a high suspicion of autoimmune etiology. Any suspected case of encephalitis should initiated treatment with antiviral along with supportive treatment; then step wise evaluation should be done to reach an etiological diagnosis. If infectious etiology could not be established or no significant improvement is found with antiviral therapy; immunomodulating therapy should be considered along. In all cases CSF analysis including biochemistry, cytology, viral PCR along with MRI and EEG should do; further investigations depend upon initial reports and clinical and epidemiological background. Dose and duration of antiviral depends on patient's age and response to treatment and comorbidity. Acyclovir 500mg/m²/BSA per dose 3 times daily for 21 days are adequate for HSV encephalitis. Monitoring of renal function is the essential. Adjuvant treatment with steroid and or manitol for cerebral edema and antiseizure drugs for convulsion is used where necessary. Meticulous fluid and nutritional support as well good general care improve outcome. In spite of adequate treatment of encephalitis mortality and morbidity was found a significant number of cases; among the morbidity behavior problem, seizure focal deficit are common.
