Meningitis Flashcards
risk factors for meningitis
neonates advanced age pregnancy nasopharyngeal colonization with n.meningitis, spneumoniae, h.influenzae prior URTI choclear implants cranial anatomical defects trauma fracture neruosurgery prosthesis drains IC
pathogenesis of meningitis
bug originates in nasopharyngeal cavity
adheres to cells and gets into bloodstream
have capsules to protect from bloodstream IS
cross the BB and gets into CSF where theres no IS
massive inflammatory response, bacteria lysis, release of exotoxins
most likely pathogens of meningitis
strep pneumo 50% = gram positive diplococci
niesseria menigitis = gram negative cocci
h.influenzae found in unimmunized
listeria monocytogenes 5% gram positive bacilli
most common pathogens in neonates
s. agalactiae
ecoli
most common pathogens in children
n. meningitidis
s. pneumoniae
most common pathogens in adults
s.pneumoniae
n.meningitidis (younger adults)
l.monocytogenes - pregnancy, >60, IC
s.aureus
gram negative bacilli - IC, health care associated
3 most common clinical signs of meningitis
fever >40 (90%)
nuchal rigidity or neck stiffness
CNS: headache, photophobia, confusion, siezures
clinical signs in infants
non specific symptoms
fever, seizure, resp distress, septic shock
what sign is highly suggestive of meningococcal infection
rash thats hemorrhagic
also disseminated - septic shock
3 complications of meningitis
herniation - diffuse swelling, hydrocephalus
infarcts - inflammatory occlusion of basal arteries
seizures - cortical inflammation
what is the prognosis affected by
pathogen
patient age
health status
treatment
mortality rates for
- penumoniae
- meningitidis
- monocytogenes
- 10-30%
- 10-40%
- 15%
3 fundamentals for AM therapy
- early prompt initiation
- CSF penetration
- rapid sterilization
what factors determine CSF penetrations
antibiotic size lipophilicity ionization protein binding barrier inflammation
describe the blood/CSF barrier
tight junctions
thick wall
can pump out solutes
depend on the inflammation for drugs to get through
which drugs can achieve therapeutic concentrations with or without inflammation
chloramphenicol ( dont use toxic to blood cells)
metronidazole
rifampin
which drugs can acheive therapeutic concentrations in the CSF with inflammation
penicillins 3rdGC and cefuroxime daptomycin fluoroquinolones linezolid meropenem tmp-smx vanco
which drugs is a therapeutic CSF concentration not achieved
aminoglycosides
other cephalosporins
empirical therapy for children under 1 month
cefotax
ampicillin
+/- gent (to make amp more cidal)
empirical therapy for 1mon to 17 years
cefotax/ceftriax +vanco
vanco added initially to cover penicilllin resistant strep pneumo with reduced susceptibility to ceph until susceptibility determined
empirical treatment for 18-50 years
cefotax/ceftriax +vanco
empirical therapy for >50
cefotax/ceftriax + vanco + amp (risk of listeria)
why must you treat empirically
if miss the bug the patient dies
cefotax menigitis dose
2g q4hr
ceftriax dose
2g q12hr
ampicillin dose
2g q4hr
vanco dose
15-20mg/kg q8hr
nero dose
2g q8hr
pen G dose
4MU q4h (upper limit of normal dosing)
rifampin dose
600mg q24hr (same as normal dosing)
lab results in meningitis
increase WBC, mostly PMNs
protein elevated bc increased permeability
glucose in CSF low becuase bacteria using it as food, normally its 50% of what is in the serum
peak incidence of meningococcal meningitis
children and young adults
natural immunity usually by 20 yoa
treatment for n.meningitidis penicillin susceptible
pen G or amp 5-7days
cipro alternative
treatment for n.meningitidis penicillin resistant
cefotax/ceftriax
alternative chloram?
how has the conjugate vaccination affected streptococcal meningitis
declining incidence but increased incidence on non included serotypes
directed therapy for s.pneumoniae if penicillin sensitive
penG or amp
cipro alternative
5-7 days
directed therapy for penicillin resistant streptococcal
cefotac/ceftriax 10-14 days
alternative levo/moxi +/- vanco chloram, linezolid??
directed therapy for strep pneumoniae with 3rdGC MIC >1
cefotax/ceftriax + vance
dont just do vanco bc not sure how much penetrates CSF
directed therapy for strep pneumoniae with 3rdGC MIC >2
cefotax/ceftriax + vanco + rifampin
directed therapy for l.monocytogenes
pen G or amp + gent 21 days
for synergy may not pass into CSF but only need a little amount for synergy to occurs
alternatives: TMP-SMX, linezolid
recommended guidelines for using adjunctive dexamethasone therapy
immunocompetent adults with suspected or proen pneumococcal meningitis
infants or children with h.influenzae
dose of adjuvant dexamethasone
0.15mg/kg q 6hr x 2-4 days
initiated 10-20min before or with 1st antibiotic dose bc when antibiotic kills the bacteria it explodes and thats when inflammation occurs
when should fever resolve
24-48 hours
when should neck stiffness resolve
48-72 hours
when should CSF values resolve
culture negative within 24 hours
normal glucose by 3 days and protein by 7-10 days
when should rash resolve
over 7 days
vaccines that reduce the incidence of meningitis
h.influenzae
pneumococcal conjugate 13 valent
meningococcal c conjugate
penumococcal polysaccharide
meningococal infection should treat close contacts within 60 days prophylactically with what
cipro 500 1 dose oral children 10mg/kg
rifampin 600mg q12 hour x 4 doses oral, children 10mg/kg
ceftriaxone 250 im 1 dose, children 125
