Infectious Disease: Encephalitis

Question 1

Defintion

Answer 1

Inflammation of the brain. This can be a result of a infective or non-infective causes.

Question 2

Non infective causes of encephalitis

Answer 2

Autoimmune

Question 3

Infective causes

Answer 3

Viral (MC)
- Herpes simplex virus (HSV) (MC viral cause)
= in children MC is HSV-1 from cold sores
= In neonates MC is HSV-2 from genital herpes, contracted during birth
- Varicella Zoster Virus (VZV) = associated with chickenpox
- Cytomegalovirus = associated with immunodeficiency
- Epstein-Barr Virus = associated with infectious mononucleosis, enterovirus, adenovirus, and influenza virus
- Important to ask about vaccinations as polio, mumps, rubella and measles viruses

Question 4

Signs and symptoms

Answer 4

Altered consciousness
Altered cognition
Unusual behaviour
Acute onset of focal neurological symptoms
Acute onset of focal seizures
Fever

Question 5

Diagnosis

Answer 5

GOLD STANDARD = Lumbar puncture = sending CSF for viral PCR testing
(CT head + neck if LP Contraindicated)
- MRI after LP
- EEG recording for mild or ambitious symptoms but is not always routinely required
- Swabs of throat and vesicle swabs to establish causative organism
- HIV testing recommended in all Px with encephalitis

Question 6

Contraindications of doing an LP

Answer 6

GCS below 9
Haemodynamically unstable
Active seizures
Post-ictal

Question 7

Treatment

Answer 7

IV antiviral medications used to treat the suspected or confirmed underlying cause:
- ACICLOVIR = HSV or VZV
- GANCICLOVIR = cytomegalovirus

Repeat lumbar puncture is usually performed to ensure successful treatment prior to stopping antivirals

Aciclovir = started empirically is suspected encephalitis until results are available. Other viral causes have no effective treatment and management is supportive

Follow-up, support and rehabilitation is required after encephalitis with help managing the complications

Question 8

Complications of encephalitis

Answer 8

• Lasting fatigue and prolonged recovery
• Change in personality or mood
• Changes to memory and cognition
• Learning disability
• Headaches
• Chronic pain
• Movement disorders
• Sensory disturbance
• Seizures
• Hormonal imbalance