Flashcards in CNS infections - Cellular Pathogens Deck (18):
what is the typical cause of non-bacterial meningitis?
viral pathogen. typically enteroviruses
what is cause of aseptic meningitis?
anything non-bacterial cause (ie virus, inflammatory conditions, etc)
3 most pathogenic causes behind meningitis (infants/ children/adults? typical origin?
haemophilius influenzae (type B)
All of these come from nasopharynx.
3 most common pathogenic causes of meningitis in neonates? origin?
E. coli (and other gram neg bacilli),
Group B streptococcus
All of these come from the birth canal (ie from the gut)
how might meningitis infections develop?
pathogen colonizes nasophrynx.
invasion of blood stream and multiplication.
invasion of meninges and CNS
increased permeability of BBB
pleocytosis and increased ICP
release of pro-inflammatory compounds
what are the symptoms/signs of a neonate/toddle suffering from meningitis?
fever, vomiting/nausea, irritable/unsettled, refusing food/drink
altered mental state
what is characteristic sign of nisseria meningitis infection?
meningococcaemia produces a petechial or purpuric rash
what are normal csf values for WBC, RBC, pressure, protein and glucose?
Pressure 2.5 mmol/L (>60% blood)
what might a csf analysis of viral meningitis show?
normal clear appearance,
lots of lymphocytes (100s)
what might a csf analysis of bacterial meningitis show?
1000s of N,
gram stain positive,
what might a csf analysis of TB meningitis show?
100's of lymphocytes,
ziehl-neelsen stain positive
very high protein
glucose very low
when should a lumbar puncture not be performed in children/young adults with suspected meningitis
-signs of raised ICP (fluctuating levels of conciousness, relative bradycardia, focal neurological signs, poorly responsive pupils)-->will cause herniation of brain stem through foramen magnum
-after convulsions (until stabilized)
what are the dangers of delaying analysis of a csf sample?
cells lyse in hypotonic fluid, white cell count decreases, causing a false negative
what are treatment priorities for meningitis?
-Steroids at least 15 min prior to 1st Abx dose or within 1hr of 1st abx dose.
what Abx would you use to empirically treat infant/children/adults with suspected bacterial meningitis?
IV dose 3rd gen cephalosporin (cefotaxime or ceftriaxone)
...against usual pathogens of nisseria, haemophilius influenzae type B or strep pneumoniae.
what Abx would you use to empirically treat neonates with suspected bacterial meningitis?
Group B Strep or Listeria can be treated with IV penicillin or gentamicin.
E. coli can be treated with IV dose 3rd gen cephalosporin (cefotaxime or ceftriaxone)
most common neuronal injury following meningitis?