Infective Encephalitis

Overview

Overview Encephalitis, inflammation of the brain parenchyma, can be caused by either an infection or autoimmune process. Clinical features of encephalitis include fever, altered mental status, neurological deficit and seizures. Definitive diagnosis rests on a lumbar puncture with CSF examination. Encephalitis can be difficult to distinguish from meningitis. Young, old and especially those who are immunocompromised are susceptible to developing encephalitis.

	Encephalitis	Meningitis

Signs and symptoms

• Meninges involvement
  • Neck stiffness
  • Photophobia
• Altered level of consciousness
• Hallucination
• Personality changes
• Seizures
• Focal neurological disturbance
  • aphasia
  • ataxia
  • upper motor neuron weakness
  • lower motor neuron weakness
  • cranial nerve palsy

Differential Diagnosis

Investigations

• FBC
• EUC
• LFT
• CMP
• VBG
• Blood cultures
• Urinalysis
• Electroencephalogram
• CT brain
• MRI brain
• Lumbar puncture with CSF examination

 

Aetiology

Herpesviruses

• Herpes Simplex Virus
• Ebstein Barr Virus
• Varicella Zoster Virus

Arthropod-bourne viruses

• Japanese encephalitis
• West Nile Virus

Enteroviruses

Pathophysiology

Complications and Prognosis

Complications

 

Prognosis

80% of patients will have severe neurologic sequelae