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Acute viral encephalitis in children: Pathogenesis, incidence, and etiology

Hordur S Hardarson, MD
Section Editor
Morven S Edwards, MD
Deputy Editor
Carrie Armsby, MD, MPH


Viral infection of the central nervous system most often leads to meningitis, meningoencephalitis, or encephalitis, in descending order of frequency [1]. Encephalitis implies inflammation of the brain and strictly speaking is a pathological diagnosis. However, in practice, most patients with encephalitis are diagnosed based on clinical manifestations of brain dysfunction and laboratory or imaging evidence of inflammation (ie, white blood cells in the cerebrospinal fluid and/or inflammation on brain imaging).

Encephalitis is an acute, life-threatening emergency, requiring prompt intervention. Although discussed separately, the assessment and management often are performed simultaneously (table 1).

The pathogenesis, epidemiology, and etiology of viral encephalitis in children and adolescents will be discussed here. The clinical manifestations, differential diagnosis, evaluation, treatment, and prevention of viral encephalitis in children and adolescents and viral encephalitis in adults are discussed separately. (See "Acute viral encephalitis in children: Clinical manifestations and diagnosis" and "Acute viral encephalitis in children: Treatment and prevention" and "Viral encephalitis in adults".)


Central nervous system (CNS) infections are described according to the site of infection:

Encephalitis – Encephalitis is inflammation of the brain parenchyma and is associated with neurologic dysfunction. Characteristic clinical features include altered mental status (decreased level of consciousness, lethargy, personality change, unusual behavior), seizures, and/or focal neurologic signs, often accompanied by fever, headache, nausea, and vomiting [2]. (See "Acute viral encephalitis in children: Clinical manifestations and diagnosis", section on 'Clinical features'.)

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Literature review current through: Oct 2017. | This topic last updated: Oct 06, 2016.
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