neuro- CNS infections Flashcards
types of CNS infections- 4
meningitis
encephalitis
space-occupying infection lesion
prion disease
3 large groups of meningitis
acute bacterial (BAD!, go to ER!)
aseptic/viral/encephalitis
chronic
3 major risk factors for CNS infections
immunosuppressed, cranial trauma, pediatric pt
main types of meningitis
bacterial (emergency) , viral, fungal or mycobacterium TB (chronic)
what is the percentage mortality for S pneumoniae and gram neg. organism meningitis?
36%
bacterial meningitis epidemiology: the ___ of the pt often suggests the likely etiologic organism
age 1month - 4y : HIB 4-30 : meningococcal men. 30+: S. pneumoniae * infants-30yo get bacterial meningitis more than older people
____ is an antibiotic for prophylaxis for those who have been exposed to meningitis
rifampin
bacterial meningitis transmission
exposure: birth canal, other routes
colonization: nasopharynx (respiratory)
BBBBBB: Bad Bug Breaches Blood Brain Barrier : organism that invades meninges, subarachnoid, CSF
clinical diagnosis of bacterial meningitis includes: S&S and “signs” , progression?
fever, HA, stiff neck, petechial rash w/ meningococcus (non-blanchable)
- nuchal rigidity (stiff neck)
- budzinski (move neck and legs bend) and kernig’s signs (lift leg, cant straighten, pain)
- progression - quickly worsen
what procedure would you do to clinically diagnose bact. meningitis?
LP for CSF abnormalities
-CT scan head before ONLY if they have one of the following risk factors (immunocompromised, CNS disease, new seizure, papilledema, LOC off, focal neuro deficit)
…otherwise do it right away
if clinical exam does not suggest ____, do LP w/out CT, why?
elevated ICP
one hour with bact. meningitis is BAD
if exam reveals uncertainty about presence of elevated ICP… follow these 5 steps
- draw blood for C&S
- start IC steroid/abx
- CT
- no elevated ICP ? LP!
- cell count, gram stain, C&S of CSF
meningitis CSF will look…with what predominating in it? opening pressure will be…
cloudy or grossly purulent
- PMN predominating (neutrophils)
- opening pressure is elevated! (normal is about 18cm, meningitis is 30-40 )
what abx and why steroids with them for meningitis?
bacteriocidal to kill
steroids to deal with immune/inflamm response from taking the bacteriocidal
viral meningitis lab- what is the go-to?
PCR of virus from CSF - very sensitive
how to distinguish encephalitis/viral men. from bacterial menin. ?
encephalitis- level of consciousness changes and neurological signs
-virus can penetrate tissues where bacteria cant
bacterial vs viral meningitis, WBC and lymph cell counts?
bacterial- WBC high
viral- WBC low, lymphs high
rabies encephalitis: how can you get it? incubation period?
serious viral encephalitis from salivary transmission of infected animal but recent cases show “casual contact” routes of infection
incubation: 10 days to 1 year
- death certain if untreated and symptomatic
txt for rabies encephalitis
rabies immunoglobis and rabies vaccine of exposed individuals
-amount of immunoglobin depends on pt’s body weight
west nile virus: what is it? what can it cause? symptoms? txt?
mosquito-born significant viral encephalitis
- possible permanent neuro damage
- most are asymmptomatic , flu symptoms in summer = west nile
- txt is supportive
chronic meningitis from fungal or mycobacterium/TB - CSF findings…?
vague, look like viral
chronic meningitis S &S
evolves over a long time
- meningeal signs (more subtle)
- cranial nerve palsys (brain expanding)
- CSF rhinorrhea
- chronic infection –> arachnoid fibrosis (can’t reabs. CSF), hydrocephalus, brain infarction
- often fatal
txt for chronic meningitis?
culture to diagnose
- multiple drugs for TB
- syst. antifungals
- debridement of sinuses (if it came from there)
3 space occupying lesions in the CNS
- cycticerosis
- toxoplasmosis
- abscesses
- symptoms common w/ tumors –> HA, seizure, LOC
cysticerosis: how do you get it?
caused by larva of pork tapeworm, get by eating eggs not the larvae (if you ate the larvae you would just get a tapeworm).
- assoc. with dirt eating “pica”
- poor hand washing
- contaminated water
txt of cysticerosis
treat only acute CNS- w/ symptoms- self-limiting, will not spread or worsen as the eggs die
- antihelminthic may inc symptoms b/c of inc inflamm when the larvae die –> need to treat with steroids as well
- seizure meds if anatomic defect remains
- drugs- albendazole or praziquantel
toxoplasmosis: how can you get it?
caused by parasite- ingesting raw beef , oral-fecal or to fetus in third trimester
4 types of toxoplasmosis infection - where can you get it?
asymptomatic infection
CNS (space-occupying lesion)
respiratory
ocular
Dx of toxoplasmosis
serology IgM and IgG may be detected in CSF and serum
MRI- shows ring-enhancing lesions in brain
txt of toxoplasmosis
- trimethoprim/sulfamethoxazole (septra/bactrim)
- longterm prophylaxis for immunosuppressed pts
brain abscess - why is this worse than other parts of the body?
not much immune function in the brain
brain abscess epidemiology
rare disease
in 2-30% of toxoplasmosis infection in AIDs patients
patho of brain abscess
starts in outside CNS and spreads into CNS
or direct inoculation
-look for a source: ear, lung, sinus
S&S of brain abscess
fever, drowsy, HA, focal neuro deficits, seizures
-most have symptoms for 2 weeks or less
BA workup
CBC
CT/MRI (localize and determine capsule size- shows ring-enhancing lesion)
aspiration of biopsy abscess
*LP is contraindicated
txt BA
surgical drainage,
abx
intrathecal (into spinal canal) admin of drugs
txt underlying infection cause
what is the mortality rate for a BA?
40-60%
prions
“protein-infectious cause”
- i.e. mad cow- get by eating infected tissue
- kuru- cannibalism
- progressive encephalitis
txt and prognosis for prions?
no txt, bad prognosis
