CNS infections Flashcards
what are the non-infectious etiologies for CNS infections?
neoplasia
collagen vascular disease
medications
CSF : serum glucose ratio of less than 0.6 indicates what type of infection?
bacterial meningitis
what does protein concentration tell you?
if there is an infectious process going on
when is the opening pressure value important?
elevated intracranial pressure (cryptococcal meningitis)
definition: xanthochromia
yellowish supernatant of CSF that is the result of RBC lysis, indicating presence of oxyHb, metHb, and bilirubin (will not change after spinning CSF)
CSF protein concentrations above what value is abnormal?
50 mg/dL
what has become the preferred modality of choice in neuroimaging a patient with suspected CNS infection?
MRI
what criteria are critical for bacteria against CNS infections (eg acute meningitis)?
- penetration of CNS
- rapid bactericidal activity
entry into CSF is enhanced by what factors (4)?
- low MW
- low degree of ionization
- high lipid solubility
- low degree of protein binding
which organisms account for about 80% of acute bacterial meningitis cases?
s. pneumo
n. meningitidis
what are the main drugs used against bacterial meningitis?
vancomycin
cephalosporin
beta lactam
why should coagulase negative staph be considered in a neurosurgical process that leads to an infection?
one of the normal skin flora (more common)
neurosurgical process that leads to an infection - what organism should be considered? which drug should be used?
coagulase negative staph
vancomycin + 3rd generation cephalosporin
treatment of early lyme disease
doxycycline or amoxicillin
treatment for cryptococcal meningitis
amphotericin B or fluconazole
what is the preferred imaging test for meningitis?
MRI with contrast
initial approach to patient with brain abscess
- contrast CT or MRI
- single or multiple ring enhancing lesions - surgery
- start empirical abx when abscess material is obtained for micro and histo
- steroids for pts with edema, mass effect, hernitation
