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)