CNS Infections Flashcards
untreated CNS infection can cause
brain herniation
cord compression and necrosis
paralysis
when the brain parenchyma is inflamed it is called…
encephalitis
viral meningitis is an example of __ meningitis
aseptic
a brain abscess means there is…
acute, focal pus-forming area of the brain that is infected
a brain abscess will present with what kinds of symptoms
focal, stroke-like symptoms
meningitis from pus forming cells is called…
pyogenic meningitis
what does pyogenic meningitis look like microscopically?
neutrophils in SA space
where is the pus in pyogenic meningitis?
layer over the leptomeninges on the surface of the brain
main bacterial causes of meningitis
pneumococcus
meningococcus
listeria rarely
who could get listeria meningitis?
> 60s
immunosuppressed people
Tx of CABM (community acquired)
ceftriaxone iV + dexamethasone IV
gram +ve diplococci in a suspected meningitis patient…
strep pneumoniae
gram +ve bacillus in an old person with suspected meningitis…
listeria monocytogenes
what viruses are the main cause of viral meningitis?
enteroviruses
Hx questions for viral meningitis
recent travel
onset of symptoms (late summer/autumn)
Ix for viral meningitis
stool culture
throat swab
CSF PCR
Tx for viral meningitis
supportive
main symptom difference between encephalitis and meningitis?
in encephalitis you get very confused as you have cerebral cortex disturbance
insidious onset of symptoms, stupor, coma, severe confusion and partial paralysis…..
encephalitis
Ix for encephalitis
lumbar puncture
EEG
MRI
what virus is the most likely cause in a patient with encephalitis?
herpes simplex
Tx of viral encephalitis
ACICLOVIR IV
Hx q’s for suspected enceph?
recent flu-like illness new seizures altered behaviour/cognition? rash? family ill? travel? immunocompromised?
main symptoms of CABM
headache
fever
neck stiffness
mental state change
commonest CABM bacteria in teens
neisseria
commonest CABM bacteria in neonates
listeria, group B strep, e. coli
commonest CABM bacteria in adults
strep pneumoniae
risk factors for CABM
immunocompromisation
head trauma/neurosurgery
complications of CABM
purulence
verebral oedema
hydrocephalus
pathophysiology of CABM
nasopharyngeal colonisation or
extension of bacteria via sinuses/fractures/blood or
from far away infection eg UTI
WCC is usually over ___ in CABM
2000
what white cells are most present in CAB
neutrophils
protein should be __ and glucose should be __ in CAB
high
low (bacteria eating it)
in viral meningitis glucose is ___
normal
do PCR to check for what viruses in a suspected encephalitis?
HSV1 + 2
enteroviruses
VZV
non blanching purpura is a sign of…
meningococcal septicaemia
NOT MENINGITIS
most common type of meningitis in kids under 4
HiB
what co-morbs are associated with strep pneumo meningitis?
alcohol addiction
diabetes
skull fractures
how is listeria spread?
via blood
antibiotic for listeria monocytogenes?
IV ampicillin/amoxicillin
NOT CEFTRIAXONE
if you have a risk factor for listeria but have strep pneumoniae meningitis what should be given
ceftriaxone AND amoxicillin to cover potential listeria
HIV patient with a CD4+ level under 100 who has meningitis could have what bacteria?
cryptococcus
low glucose, high protein and high neutrophils always means CABM T or F
F, can be a false-positive
non-infectious causes of aseptic meningitis?
sarcoid
migraine
vasculitis
drugs eg co-trimoxaole, NSAIDs
if a patient has strep pneumo what drug should you give along with an antibiotic and why
steroid eg dexamethasone as it calms down the immune response
pen allergic antibiotic for CABM?
chloramphenicol IV
1st steps in treatment for bacterial meningitis (ABCDE is fine)
blood cultures and coag screen
give treatment
take a throat and skin (if applicable) swab
main Ix for meningitis
lumbar puncture!!
do CT first if seizures/signs of SOL/immunocompromised
dose and freq for ceftriaxone?
2g bd
dose and freq for amoxicillin
2g qds
in viral meningitis the main white cells are..
lymphocytes
