CNS Infection Flashcards
(45 cards)
what age group is most likely to get meningitis
young children
if someone was to get meningitis, who are the most likely to die from it
the elderly
what is aseptic meningitis
bacterial meningitis that is culture negative + and meningitis caused by things other than bacteria
what are the three bacteria that are the commonest causes of meningitis and what is THE most common
H. influenza N. Meningitidis - most common S. pneumoniae
Which type of meningitis is the most prevalent throughout the world
A
why do certain bacteria over others tend to cause meningitis
because they are encapsulated and therefore can avoid complement fixation and phagocytosis by the immune system
which additional bacteria are neonates exposed to that can cause meningitis
E coli and other gram negatives (group B strep and Listeria)
what is the likely source of the bacteria causing menigitis
commensals of the nasopharynx
what is the typical clinical presentation of an child/adult with meningitis
fever, vomiting/nausea, headache, stiff neck, photophobia, seizures
what is the typical clinical presentation of a baby with meningitis
fever, nausea/vomiting, irritable, refusing to feed, altered mental state, bulging fontanelle
when do you get the non-blanching rash associated with meningitis
when you have meningococcal septicaemia
what is the defining sign for meningitis
abnormal CSF
what are the differences between CSF in viral and bacterial meningitis
viral - 100s of LYMPHOCYTES, with negative grain stain, lower amount of protein and higher glucose bacterial - 1000s of NEUTROPHILS, with gram stain positive, higher protein and lower glucose
major contraindications for lumbar puncture
raised ICP shock extensive purpura convolutions coagulation abnormalities
why is it important for CSF analysis to occur quickly after the sample has been taken
because the WBCs start to lyse as they are in hypotonic solution
what is the empiric antibiotic treatment for meningitis in infants, children and adults
intravenous 3rd generation cephalosporin
what is the empiric antibiotic treatment for meningitis in neonates
E coli and other gram negatives - 3rd generation cephalosporin group B streptococcus and Listeria = intravenous penicillin and gentomycin
what is the most common sequalae of bacterial meningitis
hearing loss
what is the most common cause of encephalitis
viral: HSV
what is the fundamental difference in the clinical presentation of meningitis and encephalitis
encephalitis - you have altered conscious state
what are the normal values of CSF
pressure less than 150mmH20 protein less than 0.4g/l WBC less than 5x10^6 no RBC gram stain negative glucose more than 60% blood
difference between neurotropic and neuroinvasive virus
neurotropic - able to replicate in nerve cells neuroinvasive - capable of entering or infecting the CNS
main causes of viral encephalitis
HSV 1 and 2 rabies virus arboviruses enteroviruses
what do we think postinfectious encephalomyelitis is caused buy
autoimmunity - parts of the virus look like parts of the myelin sheath of nerves and therefore the immune system starts to degrade myelin sheath of nerves after a viral infection
