CNS Infections Flashcards
what is encephalitis
infection of the brain parenchyma
what is meningitis
infection of the meninges around the brain
what is acute aseptic meningitis
a meningitis infection where the cause is not bacterial (pyogenic) usually viral instead
how does pyogenic meningitis present
exudate in basal and convexity surface
list the early features of meningitis
headache fever leg pains cold feet abnormal skin colour
list the late features of meningitis
neck stiffness, photophobia - meningism
reduced GCS
seizures and focal CNS signs
shock - prolonged cap refill
list the 2 most common causative organisms for meningitis
strep pneumonia
neisseria meningitidis
gram positive and gram negative respectively
immunocompromised, older patients and alcoholics are more likely to develop meningitis from which organisms
listeria monocytogenes
haemophilus influenzae
what is the treatment for a common community acquired bacterial meningitis
ceftriaxone IV 2g BD
dexamethasone IV 10mg QDS
why is dexamethasone prescribed in meningitis
has an anti-inflammatory effect, reduces swelling in the brain which prevents secondary complications such as oedema and raised ICP
what antibiotic is given first line for meningitis if someone is penicillin allergic
chloramphenicol
what viruses are most likely to cause viral meningitis
ECHO virus
what is the treatment for viral meningitis
supportive treatment as condition is usually self-limiting
describe the symptoms of encephalitis
changes to mental state confusion focal neurological signs meningism fever psychosis
if a neonate develops meningitis what bacterium are most likely to cause it
listeria
group B strep
E. Coli
if a child develops meningitis what bacterium are most likely to cause it
haemophilus influenzae - usually eradicated by vaccine
most likely causative organism for meningitis in adults
strep pneumoniae
most likely causative organism for meningitis in patient with head trauma
staph
gram -ve bacilli
list the main complications of meningitis
exudate forming around cranial nerves III and VI
oedema
ventriculitis
hydrocephalus
list the most likely routes of entry for bacterial meningitis
nasopharyngeal colonisation
direct extension from bacterial infection eg sinusitis or mastoiditis
remote foci and spread through blood - endocarditis §
when is a lumbar puncture contraindicated in patient with meningitis
when there is risk of raised ICP
elderly patient also
list signs of raised ICP
vomiting and nausea papilloedema headache confusion pupils do no dilate hypertension
list the components of the 4 samples that are sent off containing CSF
1 - haematology cell count, differential
2 - microbiology, gram stain, cultures
3 - chemistry, protein and glucose
4 - haematology, cell count, differential
list the components of CSF in bacterial meningitis
WCC raised predominately neutrophils
appears cloudy and turbid
glucose low
protein elevated
list the CSF findings of a normal sample
WBC 0-5 (primarily lymphocytes, no neutrophils)
RBC 0-10
protein <1% serum
glucose >60% plasma glucose concentration
list the components of CSF in aseptic meningitis
WBC slightly elevated predominately lymphocytes
glucose normal
protein slightly elevated
sample appears clear
what is the treatment for aseptic meningitis that is HSV positive
IV aciclovir
list the occasions where CT is the first investigation before lumbar puncture in the event of suspected meningitis
immunocompromised patient history of CNS disease new onset seizure papilloedema focal neurological deficit eg non-reactive pupil, abnormal visual field
all adults with suspected meningitis should receive a lumbar puncture in hospital true/false
false - all should get in unless a clear contraindication or confident enough based off of meningococcal rash
what antibiotic is added into the prophylaxis if an elderly person has suspected meningitis
amoxicillin - to cover for listeria
