Adult Medical Emergency Handbook - Scottish Intensive Care Society

ENCEPHALITIS
VIRAL ENCEPHALITIS
Viral encephalitis is inflammation of the brain due to viral infection.
Herpes simplex is the most destructive but potentially treatable
causative agent. Currently, Herpes simplex encephalitis is estimated
to occur in approximately 1 in 250,000 to 500,000 individuals a year.
It occurs throughout the year and in patients of all ages, 1 / 3 in those
aged less than 20 years and approximately one half in those aged over
50 years. In pre aciclovir (acyclovir) days, the mortality was over 70%.
Other viral causes of acute encephalitis include:
• Enterovirus, mumps, influenza, EBV, VZV, CMV.
• In patients with travel history: arboviruses, rabies.
Presentation
• Signs of meningeal inflammation: e.g. fever, headache, neck
stiffness.
• Altered mentation/personality change.
• Decreasing conscious level.
• Focal neurology.
• Seizures
INITIAL MANAGEMENT
• Careful clinical examination including full neurological examination
and Glasgow Coma Score.
• ABCDE as Chapter 2.
• Ask for travel history.
• If patient needs a CT head scan, do not delay antibiotics (see
Meningitis chapter) and aciclovir (10mg/kg tds IV).
• Ensure the patient is stable enough for transfer to CT scan.
INVESTIGATIONS
• FBC, U+E’s, glucose, LFT, Ca, clotting screen.
• Blood cultures X3.
• Blood for serology.
• Throat swabs in viral transport medium.
• Stool for Virology
• Parotid duct swab (for mumps) in viral transport medium.
• Swab any lesion suggestive of Herpes simplex.
adult medical emergencies handbook | NHS LOTHIAN: UNIVERSITY HOSPITALS DIVISION | 2009/11
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