Encephalitis *****

Question 1

what is the etiology of encephalitis

Answer 1

IT IS USALLY viral - and almost never identified

• Viral: HSV-1 & 2,
 arboviruses, 
CMV, EBV, 
VZV (varicella-zoster virus), 
HIV (seroconversion), 
 mumps, 

• Non-viral: any bacterial meningitis, 
TB,
 malaria, 
listeria, Lyme disease, 
legionella,
typhus

leptospirosis, aspergillosis, cryptococcus, schistosomiasis,

Question 2

what are the clinical manifestations of encephalitis ?

Answer 2

whenever odd behaviour, consciousness, focal neurology or seizure is preceded by an infectious prodrome

Bizarre encephalopathic behaviour or confusion
low GCS or coma
Fever
Headache
Focal neurological signs
Seizures

Question 3

what are the clinical manifestations of a infectious prodrome to encephalitis

Answer 3

increase in temp
lymphadenopathy
cold sores
conjuctivitis

Question 4

what is the diagnosis of encephalitis ?

Answer 4

• Bloods: 
blood cultures
 serum for viral PCR (also throat swab and MSU midstream urine); 
toxoplasma IgM titre; 
malaria film

Contrast-enhanced CT
focal bilateral temporal lobe involvement suggestive of
HSV encephalitis
Meningeal enhancement suggests -meningoencephalitis

LP - always AFTER NEUROINAGING

increase in CSF protein and lymphocytes,
decrease in glucose
CSF for viral PCR including HSV

Question 5

what is the management for enecephalitis ?

Answer 5

treatment is started before diagnosis
Mortality in untreated viral encephalitis is ~70%. Aim to start aciclovir within 30min
for 14 days as empirical treatment for HSV

Symptomatic treatment: eg phenytoin for seizures

ask for History of travel or animal bite.