Meningitis/Encephalitis Flashcards
listeria mortality rate
25%
gram + rod (positive purple listeria)
listeria empiric Tx
definitive Tx
ceftrixone and ampicillin
definitive: ampicillin and gentamicin
Gentlemen get amped up on Listerine.
most common cause VIRAL M&E in summer/fall
enterovirus
cell wall inhibitors mech (general)
inhibit transpeptidation of peptidoglycan (inhibit cell wall* synthesis)
Listeria monocytogenes
gram ___
big 3 and ___
virulence
gram + rod (purple positive listerine)
big 3 and nuchal rigidity and diarrhea from soft cheese, deli, etc.
internalin induces phagocytosis
phospholipase and listeriolysin O allow escape
actin tail
if focal mass lesion, labs
no LP – increased risk of brain herniation = BAD
risks with 3rd generation cephalosporin: ceftriaxone
increased risk of neurotoxic side effects
Why treat empirically with ceftriaxone?
bactericidal small lipophilic can cross BBB not a ligand for efflux pumps streptococci + serious gram -
most aggressive empiric treatment combo
ceftriaxone
vancomycin
acyclovir
dexamethasone
encephalitis vs encephalopathy
encephalitis: infection (fever, headache, focal neuro signals, seizures)
encephalopathy: diffuse cerebral dysfunction WITHOUT inflammation, usually due to toxin or metabolic dysfunction
where's waldo: meningitis encephalitis abscess myelitis
m: subarachnoid space
e: diffuse parenchyma
a: focal parenchyma
my: spinal cord
etiology of encephalitis
33-66% unknown then viral (entero, adeno, herpes, rabies) also nonviral (ricketssia, mycoplamsa, ADEM)
STAT TO DO with CNS infection
- H and P*
- blood culture*
- start abx*
- neuroimaging*
- LP/biopsy
- ID organism (gram stain/PCR/RT-PCR)
- switch to definitive Tx
BM labs
increased pressure increased WBC >80% PMNs elevated protein decreased glucose
VM labs
mod WBC count >50% Ls <20% PMNs mod protein normal glucose
FM labs
increased pressure m100 WBC >50% Lymphocytes mod elevated prto normal glucose
Aseptic meningitis
> 85% VIRAL: enterovirus/picornavirus, HSV2, arthropod, HIV
highest incidence within 12mo old
Sx: fever, HA, photophobia, dec nuchal rigidity, change mental status
CSF: increased Lymphocytes and PMNs, mod inc protein, normal glucose
Tx: supportive therapy
can be fatal in neonatal period
Septic meningitis
BACTERIAL: streptococcus pneumonia+ lancet (adults), neisseria meningitides - diplococci (teen/college), homophiles influenza type B - pleomorphic (babies, w/ no vaccine)
Sx: fever, nuchal rigidity, iritability, neuro dysfxn
CSF: inc PMNs, inc protein, dec glucose
LIFE THREATENING, PROMPT EMPIRIC TX
ceftriaxone, vanco (MRSA), acyclovir (HSV2), cefeprime (psuedomonas), ampicillin (listeria)
Chronic meningitis
SPIROCHETES - treponema pallidum/syphilis, borrelia burgdorfori
MYOCBACTERIUM TUBERCULOIS (india ink*)
FUNGI - cryptococcus neoformances, coccoides, candida albicans
IMMUNOCOMPROMISED
Tx: 4 drugs RIPE Ri Isoniazid P E
TORCH infections (perinatal)
Toxoplasma Other: syphilis, VZV, parvovirus B19, group B strep, e. coli Rubella (german measles) CMV cytomegalovirus HSV-2/HIV
HSV associated with
temporal lobe (would see on MRI)
BM gross
PURULENT/PUS
particularly dense over engorged blood vessels
VM gross
swollen, or look normal (no pus/exudate)
BM micro
NEUTROPHILS inside vessels = phlebitis, into brain tissue = cerebrates
FIBRIN in exudate: healing stage in exudate > BAD = disrupts absorption of CSF > hydrocephalus
VM micro
lymphocytic infilatrion, mild
mononuclear: round, dark cell
mycobacterium tuberculosis
more chronic fashion acid fast basal exudate that obliterates cisterns (interferes with cistern magnum and CNs) exudate more GELATINOUS/CREAMY ADHESIONS/STRINGY MONONUCLEAR CELLS GRANULOMAS: obliterative endarteritis caseating hisitocytes
pathology of acute inflammation
neutrophils
vessels larger and leakeir
“busy”
mickey mouse nuclei
abscess: neutrophils stick around
circumscribed collection of pus, GREEN NEUTROPHIL EXUDATE
chronic: mononuclear cells, more uniform than “busy”
gliosis
astryocyte rxn to injury
migroglial cells
proliferate around single neuron dying off, around areas of necrosis
hydrocephalus from meninigitis…how
if healing blocked ventricles = communicating = all vent sys involved
CNS infections
Meningitis: Neiserria, strep pneu, h influ, fungal
Encephalitis: viral (herpes)
Abscess: strep, staph
abscess
mix of bacteria: strep pseudomonas haemophilus staph bacteroides
enterovirus
single stranded + sense RNA
capsid
no envelope
transmission/development
muscosal colonization > invasion and multiplication in bloodstream > cross BBB > in CSF > release inflammatory cytokines in CSF by astrocytes and microglia > increased perm BBB > diapedesis of leukocytes > edema > inc ICP > HA > neuronal injury
virulence factors
capsule IMPT IgA protease Pili help attach to mucosa endotoxin (by gram -) outer membrane proteins
Neisseria meningitides virulence special
LOS: looks like brain sphinoglipids, so is recognized as self
skin rash
transmitted through respiratory droplets
H flu type B special because
B capsular polysaccharide help facilitate its invasion into the brain
CHOCOLATE AGAR
Mycobacterium tuberculosis special because
ACID FAST bacilli stain
RIPE Tx
RIPE Tx
Rifampin - inhibits dDNA RNA pol, inhibits cypP450
Isoniazid - inhibits mycolic acids
Ethambutol - inhibits cell wall synthesis by binding arabinysyl transferase
Pyrazinamide
cryptococcus neoformans special because
INDIA INK STAIN
inhaled as spores, like yeast
in IC
fluconazole 4 lyfe
site of herpes latency
NEURON
herpes viruses are Baltimore class
Class I
ds DNA
VZV most comomon cause of encephalitis among
IC patients
particularly if have HIV/AIDS or stem cell transplantation
only alpha herpes virus produce
thymidine kinase
so can use acyclovir
acyclovir
DNA polymerase chain inhibitor, stops new DNA made, dGTP switched out
Tx betaherpesviruses
gancyclovir
post-infectious encephalitis
ADEM acute disseminated encephalomyelitis MOST COMMON
inflammatory demyelinating condition, monophasic, pediatric usually, days to weeks post-inf
also
APME acute disseminated encephalomyelitis (demyelination, M and S defects)
SSPE subacute sclerosing panencepthalitis MOST SCARY
measles virus
Class V, ssRNA -
enveloped
