Encephalitis

Question 1

A 6 year old boy was brought in by his mum with a 3 day history of fever up to 39.5 degrees and headache. She was also worried that he has become very confused this morning, unable to recall his name and where he was. He also had episodes of nausea and vomiting this morning. Upon examination, you find that his gait is abnormal.

Answer 1

Impression
This child present as unwell, and demands immediate emergency assessment for further work up. Given the fevers, vomiting and unsteady gait, I am concerned about encephalitis (?HSV - bacterial vs viral), and the potential for elevated intracranial pressure given new onset neurological signs. A major differential to rule out is meningitis This requires urgent treatment to prevent significant morbidity and mortality. Significant complications include Waterhouse-Friederichson syndrome.

DDx to consider
- infective: other causes of meningitis/encephalitis, cerebral abscess, toxins
- SOL
- Causes of ataxia; GBS, seizure disorder
- vascular
- metabolic: hypoglycaemia

Goals
- call for senior help and emergently manage patient to reduce risk of complications and mortality
- targeted assessment to determine underlying aetiology

Question 2

Encephalitis - Assessment

Answer 2

Assessment
- call for senior help, begin A to E assessment and emergent management

A - as per
B - A per
C - IVC access, HR/BP monitoring, initial bloods (VBG, FBC, UEC, cultures, LFT, CRP/ESR, coagulation studies. Administer fluids and emipircal ABx for encephalitis (?bacterial)
D - GCS, consider neuroimaging esp if diagnostic uncertainty, CXR (As part of septic work-up) esp, neuro exam
E - LP - send for MCS

Question 3

Encephalitis - Acute management

Answer 3

Management
Acute
- Fluids
- Empirical antibiotics (refer to local guidelines), should not be delayed for more than 30 minutes after decision to treat
o Meningitis: IV Ceftriaxone 50mg/kg +/- Vancomycin and Steroids
o Encephalitis: IV aciclovir +/- azithromycin

• Steroids: IV dexamethasone at or before ABx administration. not to be administered beyond 12 hrs of initial ABx administration
• CTB/MRI-Brain once stable: MRI is more sensitive for encephalitis

Other considerations
- treat all seizures in setting of meningitis immediately
- NETS retrieval, PICU admission

Ongoing
- chemoprophylaxis for contacts
- audiology assessment after 4-8 weeks post infection
- ongoing review for neurodevelopmental delay
- PHU reporting of HiB and N meningitides if causative pathogens.

Question 4

Encephalitis - History

Answer 4

History
- sx: nausea, vomiting, lethargy, malaise, headache, irritability, poor feeding, (severe) fever, focal neurology, purpuric rash, seizures
- HPI: preceding illness,
- PMHx, meds, allergies, immunisation history!

Question 5

Encephalitis - Examination

Answer 5

Examination
- General obs + vitals: lethargy, floppy, loc, etc
- Neuro: focal neurology, neck stiffness, positive Kernigs/Brudzinski’s, abnormal gait, photophobia
- systems review: purpuric/vesiscular skin rash