Infection Flashcards
encephalitis
inflammation/infection of brain
meningitis
inflammation/infection of meninges
hydrocephaly
accumulation of CSF due to..
(communicating) deficient resorption
(internal) obstruction of the flow pathway through the brain
hydrocephaly ex-vaccuo
brain shrinks and CSF replaces it
meningismus
resistance to neck flexion due to pain when inflamed meninges are stretched
Kernig’s sign
involuntary flexion of the knee when lower limb is flexed at the hip–occurs because the inflamed meninges are stretched by stretch of the sacral nerve roots
pleocytosis
presence of excessive number of white blood cells in spinal fluid
Brudzinski’s sign
involuntary flexion of the knee when the neck is flexed; this occurs because the inflamed meninges are stretched by the flexing of the neck and tesnion can be relieved osmewhat by taking tension off of the sacral nerve roots by flexing knees
parameningeal
processes (particularly infections) that occur outside of the dura but which are adjacent to it (producing some signs-particularly in the CSF) of inflammation
most common cause of acute meningitis
bacteria
empyema
pus or abscess in subdural or epidural space
signs of bacterial meningitis
fever
meningismus
>7 WBC/cubic mm of CSF
newborn organisms for BM
group b strep
e.coli
listeria onocytogenes
childhood organisms for BM
neisseria meningitis
strep pneumonia
elderly organisms for BM
strep pneumoniae
listeria monocytogenes
organisms for neurosurgerical patients
stap aureus
ways to get into brain
nasopharyngeal colonization blood stream-->BBB entry into CSF by leak/cribiform plate exudate in subarachnoid can inflame blood vessels and result in stroke
where does exudate/pus develop?
subarachnoid space
exudate is
yellow
exudate is comprised mostly of
neutrophilic white blood cells–>swelling of brain and obstruction of free movement of CSF–> increase in ICP–>herniation
can also result in small strokes due to inflammed arteries
symptoms of meningitis
fever, headache, meningismus
kernig, brudzinski, photophobia, vomiting
toxic appearing–>increased ICP
first thing you do when you think meningitis
antibiotics prophylacticly! before any other lengthy test
what should be your first test
CT before spinal taP!
why CT before spinal tab
patients with abscesses should not be spinal tapped, but should not delay LP for any prolonged period just to get a scan
CSF of bacterial meningitis
cloudy high pressure WBC: high RBC: variable protein high glucose low
go to antibiotic
ceftriaxone
antibiotic for listeria
ampicilin
resistant organisms
vancomycin
neurosurgical patients
vancomysin
what other treatment can you give
steroids to reduce vasogenic swelling due to inflammation
prognosis
3-20%
CSF of viral meningitis
clear normal pressure (<5 protein low glucose normal
viral meningitis symptoms
same, but less severe
no impairment of consciousness
therapy of viral meningitis
bedrest, fluids, analgesia
fungal meningitis is ___ but ___
rare, but severe
setting of fungal meningitis
may occur in the setting of immunosuppression of invasive procedure
onset of fungal meningitis
less acute with more insidious onset
CSF fungal meningitis
hazy variable pressure high WBC (<200)-lymphocytes RBC normal protein high glucose low eosinophilia! india ink
most common fungus
cryptococcus neoformans
symptoms of fungal meningitis
early on malaise and fatigue–>progresses to dementia/cranial nerve dysfunction
mycobacterial meningitis is
tuberculosis meningitis
seen in HIV, children, immunosuppression
myco men is actually a
reactivation of a previous infection
symptoms of mycobacterial meningitis
headaches
low grade fevers
night sweats
what else do you see with myco men?
cranial nerve palsies–caseating granulomas accumulate at bse of brain where cranial nerves exit the brain–>obstructive hydrocephalus
treatment myco men
tuberculostatic treatment
3-4 antibiotic regimens
types of lymphocytes in NS
bacterial meningitis-polys
viral meningitis- first polys, then lymphs
chronic, fungal, ruber- mostly lymphs
how is encephalitis distinguished from meningitis
altered consciousness–progresses to seizures or focal neuro symptoms such as hemiparesis or aphasia
Herpes simplex encephalitis
usually herpes type 1; gets to brain via trigem- sits next to medial part of temporal
impairment of consciousness, confusion, seizures, headache, fever, meningismus
diagnosis and treatment
EEG-PLEDS over area of inflamed brain
MRI-inflamed temporal lobe
treatment of viral encephalitis
acyclovir–start AS SOON as suspected
other viruses that cause viral encephalitis
arboviruses- mosquito borne
viral myelitis- poliomyelitis
rabies; 2-12 week latent period, 2-10 day death course frm tme of symptoms
CSF viral encephalits
clear normal pressure WBC <500 lymphs RBC variable protein high glucose normal
bacterial encephalitis
neurosyphilis and lime disease
also produces NEURITIS
neurosyphilis
treponema pallidum
early signs neurosyph
meningitis, cranial neuritis
tertiary neurosyphilis
tabes dorsalis: sensory ataxia- shooting pains
general paresis: dementia with psychosis
charcot joints: joint damage by affecting innervation of jonts
difference between CSF in tertiary syph and CSF in fungal
you get VDRL positive
LYME DISEASE
borrelia burgdorferi
erythema migrans (bulls eye) and arthralgia
polyradiculitis : radiating back pain bilateral VII nerve palsy
CSF: lyme titers
treatment lyme disease
ceftriaxone
herpes zoster
infection of dorsal root ganglia neurons–reactivation of varcella zoster virus in forsal root ganglion–>shingles
diagnosis of herpes zoster
clinical, skin biopsy, pcr csf
treatment herpes zoster
acyclovir
complication herpes zoster
postherpetic neuralgia (persistent pain)
if herpes infects opthalmic divsiion of trigem zoster–>
bad because can lead to corneal scars and potential blindness
brain abscess
anaerobic or mix of bacteria
secondary to other infections
brain absecses on scans
no blood vessels therefore no enhancement
darekr around it due to edema
light colored ring because blood vessels disturbed BBB; contrasts escapes from vessels to tissues
other signs of brain abscesses (bacterial, fungal)
cerebritis: headache, normal CSG
encapsulation: no fever, increased ICP, focal signs, seizures
rupture: meningitis, death
therapy of brain abscesses
antibiotics, anti convuslants, aspiration or surgery
LP can ONLY be done
after scans show no significant distrotion of brain (even if CSVF normal!0–>can trigger brain herniation and death
parasitic brain abcess
toxoplasma
cysticercosis
toxo
ring enhancing lesions deep in brain
common in AIDS
correlates with CD4 count or viral load
treatment toxo
pyrimethamin
sulfadiazin [[antibiotics]]
if lesion disappears you are good
cysticercosis
invasion of tissue with larval stage of taenia solium
invades liver, muscles, brain, eye
enhancing cystic, calcified lesions
treat only for focal signs
epidural abscess
usually staph
fever and back pain
MRI scan you can see pus extending into epidural space
opportunistic infections in HIV
toxo tuberculous meningitis cryptococcal men syphillis PML CML direct hiv
PML
JC virus
white matter lesions
before treating JC with ____, check for____
natalizumab
antibodies to JC virus- would show already harbots virus
treatment PML
supportive
how to treat direct infection of brain by HIV
decrease viral load
Creutzfield Jacob Disease
spongiform encephalopathy via prions
how is CJD transmitted
prions; brain contact
what happens in CJD
rapid dementia, death over several months
myoclonic jerks, muscle twitches
how to test CJD
normal CSF, normal imaging besides diffusion image
toxins
teatnus and botulism
how do tetnus and botulism work?
heavy nad light chain-
heavy chain bind to neuronal membrane and get light chain into nerve terminal
light chain cleaves synaptobrevin
both are involved in vesicle binding and release
botulin toxin blocks
neuromuscular transmission; toxin binds to presyn nerve terminal at NMJ–>prevents release of ach
starts with face, eyes and neck
tetanus
heavy chain binds to membrane gangliosides and the toxin is internalized
binds to GABA via retrograde transmission
–>results in uncontrolled firing and muscle stiffness
chronic encephalitis
usually viral!- HIV, PML,CJD
usually produce subacute dementia with minimal signs of infection and no meningeal signs
