meningitis W4 Flashcards
what is bacterial meningitis
bacterial infection of the meningeal space
pathophysiology of bacterial meningitis?
bacteria invade meningeal space, multiply. leads to inflammation, neutrophils form pus causing elevated ICP and inflammation and thrombosis in the arteries. can cause damage in cranial nerves
what can inflammation and thrombosis in arteries cause (in bacterial meningitis)
ischaemia/stroke
what can damage to cranial nerves cause?
deficits eg deafness
3 organisms that cause meningitis?
neisseria meningitidis (‘meningococcus’)
streptococcus pneumonia (‘pneumococcus’)
haemophilus influenza
infection pattern in bacterial meningitis due to neisseria meningitidis?
epidemic outbreaks
other cause of bacterial meningitis?
listeria monocytogenes
what groups is listeria monocytogenes cause of meningitis common in?
older adults
diabetic patients
pregnancy
example of meningitis where infection seeds from other sites?
eg staphylococcus aureas where infection comes through skin (skull fractures)
clinical features of meningitis?
acute headache (onset in hours)
meningism (neck stiffness, photophobia)
fever
non-blanching rash (meningococcus)
confusion
reduced consciousness/coma
seizures
clinical features of meningitis on examination?
stiff neck
kernings and brudzinskis tests (these lack sensitivity)
when should you consider meningitis? (generally)
think meningitis in anyone with fever and headache
diagnosis of meningitis - key test?
CSF sampling via LP
CSF tests?
microscopy, culture and sensitivity testing
glucose levels compared to serum, protein
additional tests for meningitis?
PCR
virology
other infections (TB)
when should a LP not be performed before a CT scan? why?
reduced consciousness
focal signs (look for mass lesion eg empyema, abscess)
if these are present then risk of brain herniation
pressure of CSF in:
bacterial meningitis
viral meningitis
TB
bacterial meningitis - high
viral meningitis - normal
TB - high
appearance of CSF in:
bacterial meningitis
viral meningitis
TB
bacterial meningitis - cloudy/turbid or pus
viral meningitis - clear
TB - sometimes cloudy
white cell count in CSF (x10^6 / L) in:
bacterial meningitis
viral meningitis
TB
bacterial meningitis - 1000-5000 polymorphs
viral meningitis - 10-2000 lymphocytes
TB - 50-5000 lymphocytes
glucose levels in CSF in:
bacterial meningitis
viral meningitis
TB
bacterial meningitis - low
viral meningitis - normal
TB - low
protein levels in CSF in:
bacterial meningitis
viral meningitis
TB
bacterial meningitis - high
viral meningitis - normal, sometimes high
TB - high
CSF microbiology in:
bacterial meningitis
viral meningitis
TBL
bacterial meningitis - bacteria on gram stain culture
viral meningitis - sometimes virus on PCR
TB - myobacteria on ZN stain and culture
management of bacterial meningitis?
antibiotics
supportive treatment
management of complications
meningococcus prophylaxis in contacts - give single dose ciprofloxacin
when should antibiotics ideally be taken? when are they often actually taken? (for bacterial meningitis)
ideally after LP and blood cultures
often started early to prevent delay
