CNS infections

Question 1

meningitis is what

Answer 1

inflammation of the meninges

Question 2

encephalitis is inflammation of what

Answer 2

the brain - can be with/without meningitis

Question 3

most common CNS aetiology

Answer 3

blood borne
nasopharynx -> blood -> CSF

less common:
direct spread eg. paranasal sinuses, middle ear

anatomical defect eg. in dura mater causing recurrent meningitis

Question 4

which part of meningitis pathophysiology causes neck stiffness/photophobia

Answer 4

subarachnoid inflammation

–> BBB breakdown –> emigration of neutrophils

Question 5

what is kernig and burdzinski’s signs

Answer 5

kernig: pain on flexion of hip and knee
brudzinski: life neck causes pain and knee flexion

Question 6

features of normal CSF on LP

Answer 6

10-20cm opening pressure 
clear 
<5 cells 
glucose 50-66% 
protein <0.45

Question 7

features of bacterial infected CSF on LP

Answer 7

opening pressure high 
cloudy 
very high cells 100-5k
neutrophils 
low glucose 
high protein >1

Question 8

features of viral infected CSF on LP

Answer 8

normal/high OP
gin clear 
slightly increased cells 5-100 
very low glucose 
very high protein 1-5.0

Question 9

CI to LP

Answer 9

cardioresp instability
signs of raised ICP (coma, high BP, low HR, pailloedema)
coagulopathy
thrombocytopenia

Question 10

empirical treatment of meningitis

Answer 10

cefotaxime iv 2g asap
ceftriaxone iv asap

dexamethosome 0.15mg/kg 6hrly

if over 55, (may have listerial) - ampicillin or amoxicillin

Question 11

treating meningiococcal meningitis

Answer 11

benzylpenicillin iv
or cefotaxime

PLUS dexamethosone for 4 days

Question 12

common causes of meningitis in neonates

Answer 12

Group B step
E coli
listeria

Question 13

common causes of meningitis in 1mon-6y

Answer 13

Neisseria meningitiis strep pneumoniae

Haemophilus influenzae

Question 14

common causes of meningitis >6y

Answer 14

Neisseria meningitis

stept pneumoniae

Question 15

children younger than 3 months treatment ?bacterial meningitis

Answer 15

iv cefotaxime + amixicillin/ampicillin

Question 16

commonest causes of intracerebral abscess

Answer 16

direct/indirect spread from infection in paranasal air sinuses, middle ear, teeth

Question 17

treating cerebral abscess

Answer 17

cefotaxime or ceftriaxone
PLUS metronidazole

might need to drain by needle or burr hole

Question 18

how to diagnose herpes simplex encephalitis

Answer 18

1. demonstrate temporal lobe 2. oedema on imaging
   HSV DNA in CSF by PCR
2. EEG changes in temporal cortex
3. demonstrate rising HSV IGM/G in serum