CNS Infections Flashcards
what is another name for bacterial meningitis?
pyogenic
what can be seen microscopically in the subarachnoid space if bacterial meningitis?
neutrophils
what are the methods of infection in bacterial meningitis?
nasopharyngeal colonisation
direct extension of bacteria
remote foci of infection e.g. endocarditis, pneumonia, UTI
what are the clinical signs of bacterial meningitis?
fever
stiff neck
alteration in cosciousness
what are the symptoms of bacterial meningitis?
headache
N&V
photophobia
lethargy
rash
what is the likely causitive organism of bacterial meningitis in
1) neonates
2) children
3) 10-21yrs
4) >21yrs
5) >65yrs
neonates = listeria, Group B strep, E.coli
children = H. influenza
10-21yrs = neisseria (meningococcus)
>21yrs = streptococcus > neisseria
>65yrs = streptococcus > listeria
Neisseria is also known as?
meningococcal
where is neisseria found in healthy carriers?
fund in throats
(proabably gains access to meninges through bloodstream)
why do symtposm occur in neisseria?
due to endotoxin produced
what vaccine is given to cover children/teens from neisseria?
MenACWY vaccine
what does H. influenza look like on microscopy?
small gram -ve rods
what is the most common type of H. influenza in children under 4yrs old?
type b
what does H. influenza require for growth?
blood
is there a vaccine against H. infulenza?
yes- conjugated vaccine directed against the capsular polysaccharide antigen
where is strep pneumoniae commonyl found?
nasopharynx
who is most susceptible to strep pneumococcus (pneuomococcal) meningitis?
diabetics
alcoholics
young children
pts w CSF skull fractures
what gram stain is listeria monocytogenes?
gram +ve bacilli
who is commonly affected by listeria monocytogenes?
neonates
>55yrs
immune suppressed
what should be done on arrival in patient w suspected meningitis?
blood culture and coag screen
throat swab
disrupt and swab/aspirate any skin lesion for miscroscopy andn culture
all adult patients with suspected meningitis undergo LP- why would LP not be performed?
contraindicated
confident clinical diagnosis of meningococcal infection w meningococcal rash
who would require a CT prior to LP in suspected meningitis?
immunocomprised state
history of CNS disease- mass lesion/stroke
new onset seizure- within 1 week of presentation
focal neurological deficit
abnormal level of consciousness
what is generally seen in CSF if bacterial meningitis?
high white cell count
neutrophilia
high protein
low glucose
what is the initial therapy given in bacterial menigngitis?
ceftriaxone IV + dexamethasone IV
if >60yrs add in amoxicillin
vancomycin if pen allergic
if allergic to penicillin/cephalosporns what should be given as initial therapy for bacterial meningitis?
chloramphenicol + dexamethasone
add in co-trimoxazole if >60yrs
