ABSTRACT
In encephalitis, a degree of leptomeningeal inflammation is invariably present and the clinical symptoms reflect both diffuse and focal cerebral pathology as well as meningitis (fever, headache, and signs of meningism). The degree of altered consciousness is a measure of the severity of acute encephalitis and may range from drowsiness to coma. Seizures, both focal and generalised, are common. In contrast to aseptic viral meningitis, neuropsychiatric symptoms often predominate in encephalitis, for example, anomia, hallucinations, psychosis, personality changes, and agitation. Acute encephalitis constitutes a neurological emergency and it is imperative that appropriate treatment is started as soon as possible based on the likely clinical diagnosis (see Box 9.1).
