Encephalitis

Acute inflammation of the brain parenchyma

Aetiology

  • Usually viral - usually HSV, VZV and other herpes group viruses, HHV-6, 7, enteroviruses and adenovirus
  • Limbic encephalitis is a form of antibody-mediated encephalitis
    • May be associated with underlying malignancy or autoimmune

Clinical presentation

  • Fever (90%)
  • Meningism
  • Personality and behavioural change, which progresses to a reduced level of consciousness and even coma
  • Seizures (focal and generalised)
  • Focal neurological deficits, such as speech disturbance

Investigations

  • MRI - bilateral medial temporal lobe involvement
  • EEG
  • CSF
    • Viral - elevated lymphocytes, viral detection by CSF PCR
    • Limbic - antibodies may be identifiable

Management

  • Suspected HSV and VZV encephalitis is treated immediately with intravenous aciclovir, even before investigation results are available - significantly improves outcomes
  • Management of limbic encephalitis depends on cause - treat tumour, immunosuppressive treatment