CNS Infections Flashcards
tumbling motility at room temp (37)
Listeria
grows at 4 degrees C
listeria
high risk patients for listeria
neonates
pregnant women (20 fold increase)
patients with defective or cell mediated immunity
refrigeration is not sufficient to kill
listeria
how is early onset listeria acquired in neonates?
transplacentally
**80 mortality
disseminated abscesses and granulomas in multiple organs
granulomatosis infanticeptica
how is late onset listeria acquired?
at birth or soon after
late onset listeria presents 2-3 weeks after birth with
meningoencephalitis septicemia
**70% mortality
in immunocompromised adults, listeria can present as
meningitis
bacteremia
**50% mortality in immunocompromised
facultative intracellular, replicates in macrophages
listeria
listeria’s internalins help mediate
forced phagocytosis
listeriolysin
pore forming hemolysin
activated by acidic pH
how is listeria motile?
actin polymerization (ActA protein)
listerias phospholipases do what?
destabilize vacuolar membrane
not sensitive for CSF
listeria
umbrella like growth in mobility agar
listeria
how has listeria acquired antibiotic resistance
conjugated plasmids from enterococci
DOC listeria
ampicillin or TMP-SMX
**IV for meningitis
listeria prevention
avoid eating at risk foods
is GBS encapsulated
yes
colonizes GI and GU tracts
GBS
pregnant women are at high risk of transmission of GBS, what is done to screen these patients?
culture at 35-37 weeks
GBS is part of normal vaginal flora in
25% of women
in non-pregnant adults, GBS can cause
endocarditis
in neonates, GBS can cause
pneumonia
meningitis
sepsis
risk factors for neonatal GBS infection
maternal colonization
PROM
diagnostic factor for GBS
CAMP factor
DOC for GBS meningitis/bacteremia in adults
pen G
DOC for GBS endocarditis
Pen G and gent
DOC for GBS infections in neonates
ampicillin + gent
prevention of GBS
prenatal screen cultures
two major causes of neonatal meningitis
E coli
GBS
portal of entry for E coli in neonates
nasopharynx and GI tracts
Hib is covered by what vaccine
2nd gen PRP conjugate
what age is the Hib vaccine given?
2-15 months
non-encapulated strains of Hib cause
otitis media, sinusitis, geriatric pneumonia
DOC invasive H. flu
cephalosporin
common cause of community acquired meningitis
N. meningitidis
what capsule serogroups of N. meningitidis are relevant to the US
B, C, Y
is N. meningitidis considered normal flora
no
transmitted through exchange of respiratory and throat secretions
N. meningitidis
diagnostic triad: N. meningitidis
nuchal rigidity
sudden high fever
altered mental status
3-7 days after exposure
starts with severe headache
N. meningitidis
20% of N. meningitidis cases develop
meningococcemia
progression of meningococcemia
petechial lesions –> hemorrhagic bullae –> gangrene
DOC N. meningitidis
ceftriaxone, cefotaxime
N. meningitidis prophylaxis
rifampin
ceftriaxone
diagnosis N. meningitidis
lumbar puncture and gram/stain culture of CSF
what age group is the Hib-MenCY vaccine for
[N. meningitidis]
6-18 months
what age group is the MenACWY vaccine for
[N. meningitidis]
2-55 years
quadrivalent
infection of the leptomeninges-including arachnoid mater and the CSF in both the subarachnoid space and cerebral ventricles
meningitis
infection of brain parenchyma; AMS >24 hrs, focal neuro deficit, seizure, CSF pleocytosis, abnormal imaging
encephalitis
cross over between infection of the arachnoid CSF and brain parenchyma with combine clinical features
meningoencephalitis
rare inflammatory demyelinating disease of the CNS though to be an autoimmune process triggered by an environmental stimulus in susceptible individuals
acute disseminated encephalomyelitis
HA
stiff neck
retained cerebral function
meningitis
no stiff neck
AMS
encephalitis
no fever
normal CSF
MRI unremarkable
encephalopathy
ADEM occurs
post infection/vaccination
MRI focal hyperinstensity in gray matter
viral encephalitis
MRI focal hyperintensity in white matter
ADEM
most common fatal sporadi viral encephalitis worldwide
HSV
treatment HSV/VZV meningitis
IV acyclovir
temporal lobe changes
HSV meningitis
Diagnosis HSV meningitis
HSV PCR of CSF
diagnosis VZV meningitis
CSF VZV PCR
maybe IgM
leading recognizable cause of aseptic meningitis accounting for 85-95% of all cases
enterovirus
summer/fall seasonality
enterovirus
fecal oral spread, houseflies, wastewater [virus]
enterovirus
diagnosis EV meningitis
CSF EV PCR
treatment EV meningitis
supportive care
treatment CMV meningitis
ganciclovir, foscarnet
is EBV meningitis common?
no, exceedingly rare
**don’t go looking for it
in AIDS and POTs, consider EBV causing _______ in the CNS
B cell lymphoma
seasonality July-September
West Nile
transmitted from Culex mosquito
West Nile
fever
rash
flaccid paralysis
West Nile
diagnosis WNV meningits
IgM in CSF
treatment WNV meningitis
supportive
encapulated yeast
cryptococcal meningoencephalitis
risk for cryptococcal meningoencephalitis increases in HIV patients when
CD4 is below 100
treatment cryptococcal meningoencephalitis
ampho B + flucytosine
diagnosis cryptococcal meningoencephalitis
CSF cryptococcal antigen
main protozoan causing primary amebic meningoencephalitis
N. fowleri
primarily children/young adults freshwater swimming
N. fowleri
July-Sept seasonality
N. fowleri
timing to onset is 5-8 days but could be as short as 24 hrs
N. fowleri
bifrontal or fitemporal headaches unresponsive to analgesics w/high fevers
N. fowleri
alteration in taste/smell
N. fowleri
treatment: N. fowleri
miltefosine
but most people die
illness script: encephalitis
fever, confusion, no meningismus, fluctuating level of consciousness
illness script: acute meningitis
acute onset headache with fever and meningismus
what two signs can be used to indicate meningismus?
Kernig’s
Brudzinkski’s
why would you get a head CT prior to lumbar puncture?
immunocompromised
altered consciousness
new seizure
known CNS disease
papilledema
focal neuro defect
neutrophils predominate CSF, think….
bacterial
monocytes predominate CSF, think….
TB, crypto
lymphocytes predominate CSF, think….
viral
eosinophils predominate CSF, think…..
parasite
WBC 1000-5000 in CSF
bacterial
WBC 50-300
TB
WBC 50-500
cryptococcal
WBC 50-1000
viral
WBC 150-200
parasite
glucose normal
viral, parasite
glucose >45
bacteria
glucose <40
bacterial
glucose <45
TB
clear CSF
viral
protein 100-500
bacterial
protein 50-300
TB
protein >45
cryptococcal
protein <200
viral
protein >45
parasitic
high risk for S. pneumo meningitis
non vaccinated
asplenic
treatment S. pneumo meningitis
ceftriaxone
high risk of N. meningitidis
complement deficiency
treatment N. meningitidis meningits
ceftriaxone
high risk of listeria meningitis
low cell-mediated immunity
extremes of age
treatment listeria meningitis
ampicillin
high risk of H. flu meningitis
asplenic
treatment H. flu meningitis
ceftriaxone
empiric antimicrobial therapy for bacterial meningitis
ceftriaxone and vanc
**add amp if concern for listeria
if S. pneumo is suspected, what should be added to chemotherapy
dexamethasone
**discontinue if cultures come back negative for S. pneumo
illness script brain abscess
subacute onset headache with fever and focal neurodefecit
brain abscesses are caused by what pathogens
bacterial (frequently anaerobes)
protozoan
fungal
brain abscess associated with cranial trauma, post neurosurgery, endocarditis
S. aureus
Toxoplasmosis can cause brain abscesses after
reactivation a long time after initial exposure in AIDS patients
gram positive diplococci
S. pneumo
gram positive rod
listeria
gram negative rod/coccobacilli
H. flu
gram negative cocci
N. meningitidis
otitis media + CNS infection
S. pneumo
pregnant + CNS infection
listeria
asplenia + CNS
encapsulated
encephalitis with orchitis or parotitis
mumps
subacute meningoencephalitis in HIV+
cryptococcus
asymmetric flaccid paralysis
west nile
MRI temporal lobe enhancement
HSV-1 encephalitis
