Clinical Features

• Progression: acute (hours to days) or subacute (weeks to 3 months)

• Nonspecific prodromal symptoms (hours to weeks prior)

  • Fever

  • Headache

  • Nausea

• Neurological

• Psychiatric

  • Behavioral changes (e.g., hypersexuality, hypomania, agitation)

  • Hallucinations

  • Anxiety

  • Psychosis

Subacute onset of psychiatric symptoms in combination with seizures and/or focal neurological deficits should raise clinical suspicion for encephalitis.

• Altered mental status

• Memory loss

• Seizures (focal or generalized)

• Focal neurological deficit

  • Hemiparesis

  • Hyperreflexia

  • Cranial nerve palsies

  • Language dysfunction (e.g., aphasia, dysarthria)

  • Extrapyramidal symptoms

• Dysautonomia