Infections of CNS Flashcards
List 4-6 bacteria that can commonly cause meningitis? (full genus + sp. names)
- Neisseria meningitidis: all ages
- Strep. pneumoniae: all ages
- Haemophilus influenzae: <5 y.o.
- Strep. agalactiae: Neonates
- E.coli: neonates
- Listeria monocytogenes: neonates & immunocompromised
a) What is meant by GNIDC?
b) What presumptive organism ID and disease could you report if you identified such a feature in a CSF?
a) GNIDC: Gram Neg. Intracellular Diplococci
b) Neisseria meningitidis => meningicoccal meningitidis
What is the significance of an elevated RBC count in tube 1 and tube 3?
(sub-arachnoid) haemorrhage
What is the significance of an elevated RBC count in tube 1 only & not in tube 3?
Bloody tap: needle hit a blood vessel as inserted in spine
What is xanthochromasia and what clinical condition is it associated with? What colour would CSF have?
xanthochromasia = pale yellow CSF = indicates past haemorrhage
What colour is normal CSF?
clear like water
What is the name of the causative organism of amoebic meningitis which is often associated with exposure to warm bodies of water?
Naegleria fowleri (death <1 week)
What is the significance of
a) high protein concentration in CSF?
b) low glucose concentration in CSF
a) hi [protein] = due to bacterial, fungal, viral or amoebic infections
b) lo [glucose] = bacterial/fungal infection (normal in viral/amoebic infections)
What does turbidity indicate about the likely cause of a CSF infection?
bacterial infection
When processing a serum sample vs CSF sample for rapid latex agglutination, why is it longer to get the results from a serum sample (30 min vs 10 min w/ CSF)?
bc serum sample needs to be processed - allow time for a clot to form ~10min
Besides biochem result and microscopy, how else can you confirm amoebic meningitis?
Culture CSF w/ lawn innoculate of E.coli -> protozoa feed on E.coli = get areas of no growth on lawn
Symptoms of viral meningitis
- milder symptoms than bacterial meningitis
- onset of symptoms >7days
