Objectives: The clinical characteristics, pathogens, and outcome were analyzed to investigate the etiology of acute pediatric encephalitis in 2 tertiary pediatric medical centers in Israel.
Methods: A retrospective study among children aged 1 month to 18 years hospitalized with the diagnosis of acute encephalitis between January 1999 and December 2009. Data on presenting symptoms, clinical findings, microbiological, virologic, electroencephalographic and neuroimaging studies, laboratory results, and hospital course were retrieved from the medical records and the computerized microbiology database.
Results: Forty-four children were included. An etiologic agent was identified in 11 (25%): Mycoplasma pneumoniae (n = 2), enterovirus (n = 3), herpes simplex virus (HSV) (n = 1), Epstein-Barr virus (n = 2), human herpes virus 6 (n = 1), influenza virus type A (n = 1), and varicella zoster virus (n = 1). Presenting features included fever (90% of patients), seizures (39%), focal neurological signs (18%), and decreased consciousness (67%). Diagnostic findings included pleocytosis in the cerebrospinal fluid (76% of patients), electroencephalographic abnormalities (78%), and neuroimaging abnormalities (34%). All patients were treated with acyclovir until negative result for HSV polymerase chain reaction was received from cerebrospinal fluid, the child with HSV encephalitis was treated with intravenous acyclovir for 3 weeks. The outcomes at the time of discharge were: normal (66%), motor difficulties (14%), global neurological deficits (7%), visual defects (2%), and hearing impairment (2%) and no deaths.
Conclusions: The etiology of acute encephalitis remains unknown in the majority of cases. There was no correlation between adverse outcome and a specific etiologic agent. The high morbidity rate may suggest that current therapeutic modalities may not be sufficient.