CNS Infections Flashcards
What do all CNS infections have in common?
Can cause headache/fever/nausea/vomiting/seizures
Most likely dx for:
1- stiff neck, photophobia, meningismus
2- confusion
3- focal neuro deficits
1- meningitis
2 - encephalitis
3 - abscess
Meningitis causing species
S. Pneumo (60%) GBS (14%) H. Flu (7%) N. Meningitids (adolescents with rash, 15%) Listeria (2%)
S. Pneumo is most common for all comers
Meningitis presentations: name the likely species
1- AIDS pt with
1-cryptococcus 2-lyme 3-rickettsia 4-viral 5-nesseria
Best initial/most accurate test for meningitis?
Lumbar Puncture
When os staph a meningitis concern?
Recent neurosurgery
Bacterial vs viral meningitis
Bacterial: thousands of neutrophils, low glucose (bugs eating it), elevated protein, +stain/culture
Viral: negative stain/culture, 10’s-100’s of neutrophils, normal protein and glucose
TB: like viral but with markedly elevated protein
When is a head CT the best initial test?
Only when a space occupying lesion is suspected:
Papillidema
Seizures/ confusion
Focal deficits
Otherwise get an LP
What is a latex agglutination test and when do you use it?
Bacterial antigen test. Used when patient has been treated for bacterial meningitis prior to LP, and you suspect a false negative
What tests are done for the meningeal bugs?
Cryptococcus: india ink
Lyme/rickettsia: elisa/western blot/pcr
TB: acid fast stain with 3 high volume punctures
What to treat bacterial meningitis with?
Ceftriaxone/Vanc/steroids.
Add ampicillin for listeria
When to suspect listeria meningitis?
Pregnant Elderly Neonates Immunocompromised Steroid use
What are the hallmarks of encephalitis?
Acute onset of fever and confusion (confusion=head CT) Usually herpes (PCR is most accurate test)
Best treatment for Herpes Encephallitis?
Acyclovir (has some renal toxicity)
Foscarnet for acyclovir resistance (has more renal toxicity)
