Encephalitis

Question 1

What is encephalitis?

Answer 1

Inflammation of the brain which can be due to infective and non-infective causes

Question 2

What are the causes of encephalitis?

Answer 2

Viral (most common cause)

• HSV-1/2
• CMV
• EBV
• VZV
• measles
• mumps
• rabies

Bacterial:

• bacterial meningitis
• TB
• malaria
• listeria

AI
-antibodies targeting brain tissue

Question 3

How might someone with encephalitis present?

Answer 3

Altered consciousness 
Altered cognition 
Decreased GCS
Seizures 
Unusual behaviour 
Acute onset of focal neurological symptoms 
Headache 

Consider in any of these when preceded by infectious prodrome:

• raised temp/fever
• rash
• lymphadenopathy
• cold sores
• conjunctivitis
• meningisms (photophobia/stiff neck etc)

Question 4

What investigations are done when encephalitis is suspected?

Answer 4

Blood cultures

Throat swabs for PCR

Lumbar puncture
-viral PCR of CSF

Contrast CT ( can be use when LP CI)
-focal bilateral temporal lobe involvment = suggestive of HSV encephalitis 

MRI scan= after LP for better visualisation of brain

EEG
-might show diffuse abnormalities -> not routinely required

HIV testing

Question 5

What are the CI for LP?

Answer 5

GCS< 9

Haemodynamically unstable

Active seizures

Post-ictal

Question 6

What is the managment of encephalitis?

Answer 6

(Treatment started before confirmation to minimise the complications associated with encephalitis)

Aciclovir-> HSV and VZV
Ganciclovir -> CMV
NOTE: need to repeat the LP after treatment to see if treatment has been successful

Question 7

What are the possible complications of encephalitis?

Answer 7

Lasting fatigue

Prolonged recovery

Change in personality or mood

Learning disability

Headaches

Chronic pain

Movement disorders

Sensory disturbance

Seizures

Hormonal imbalance