CNS Infections - Young Flashcards
what is the definition of meningitis?
Inflammation of the meninges of the brain and/or spinal cord
what are the 3 layers of the meninges?
dura mater (out layer lining skull)
arachnoid mater (contains blood vessels)
pia mater (covers brain)
2 most common types of meningitis?
Bacterial (acute bacterial meningitis)
Viral (aseptic meningitis)
what is a type of bacterial aseptic meningitis?
Lyme
what is the onset of acute bacteria meningitis?
rapid, >50% pts hav sx’s develop over 24hrs
what are the cardinal sx’s of acute bacterial meningitis?
HA, fever, neck stiffness
also AMS, but w/this need to think encephalitis is involved
what features of meningitis are also fond in non-meningeal conditions? it is NOT considered bacterial meningitis, if what sx is not the MAIN sx?
fever and HA
-not bacterial meningitis if HA is not MAIN sx
how does the pt describe the HA in meningitis?
generalized and severe “unlike” other HA’s
what is the most sensitive classic sign of meningitis? what does hypothermia represent?
fever
hypothermia may be seen and is sign of potential sepsis
what may AMS indicate in meningitis?
elevated ICP secondary to meningoencephalitic inflammation and cerebral edema or possibly delirium secondary to fever
what sx of bacterial meningitis will viral meningitis not have?
focal neurologic deficits
what are the focal neurologic deficits in bacterial meningitis?
palsy/dysfunction of CN III, VI, VII, VIII
-d/t focal thrombosis in the brain
CN 6 palsy -> get unopposed LR muscle (eye drifts medially)
what are the dermatologic findings of meningitis?
Petechiae and Purpuric rash
where are petechiae FIRST found in meningitis?
the palate
where are purpura found in meningitis?
posterior part of LE’s (dependent parts of the body)
what are petechiae due to? what do they look like when you press on them?
broken capillaries
they don’t blanch
what are purpura?
petechiae that cluster together
what are risk factors for meningitis?
- > 50yo
- ***Upper respiratory infection (pts usually have a hx of URI)
- Otitis media
- Sinusitis
- Mastoiditis
what do pts with meningitis usually present with a hx of?
hx of URI
how do elderly people with meningitis present?
atypically
HA, but maybe no fever or neck stiffness
what is one thing to always ask pt with acute bacterial meningitis about?
ASPLENIA - b/c spleen gets rid of encapsulated organisms, so if don’t have spleen can’t get rid of bacterial meningitis
what type of bacteria causes acute bacterial meningitis?
encapsulated bacteria colonized the naso-oropharynx that penetrate the intravascular space
acute bacterial meningitis may also occur secondary to what?
bacteremia in remote focus (endocarditis, pneumonia)
what are the most common pathogens for acute bacterial meningitis?
Streptococcus pneumoniae (adults and kids)
Neisseria meningitides (adults and kids)
Haemophilus influenza type B (adults)
Group B streptococcus (adults)
Listeria monocytogenes (adults)
what 2 bacteria cause acute bacterial meningitis in kids?
Streptococcus pneumoniae
Neisseria meningitides
how does aseptic meningitis (viral meningitis) resolve?
without specific therapy/spontaenously
what is the most common virus that causes aseptic meningitis?
enterovirus
how is enterovirus transmitted?
from direct contact respiratory secretions, fecal-oral contact
ie. changing diaper infected infant
common viral causes of aseptic meningitis?
Enterovirus (most common)
HSV 1/2 (ask pt if have hx of herpes, ask when their last flare was)
most common presentation of aseptic meningitis?
abrupt onset headache, fever, nausea, vomiting, ***photophobia, nuchal rigidity
what is the most common fungal cause of aseptic meningitis?
cryptococcus (esp if immunocompromised)
dx studies for meningitis?
(1) CBC
(2) Chem-7
(3) Lactate
(4) CRP, ESR
(5) Blood cx’s
(6) ***LP
(7) Head CT
what will the CBC be like in elderly with meningitis?
normal CBC
what is a poor prognostic indicator of meningitis?
thrombocytopenia
what will CHEM-7 look like for meningitis?
Vomiting may cause evidence of volume contraction and dehydration (ie high Cr, BUN, low HC03 if poor perfusion)
Hyponatremia (SIADH)
what lab value is a poor predictor of mortality in pts with meningitis?
Lactate >4 (22% die at 3 days)
when do you obtain blood cultures for meningitis, after or before abx therapy?
BEFORE abx therapy
what is the ONLY way to dx meningitis?
Lumbar Puncture
why MUST you consider doing CT prior to LP for meningitis?
if think pt has elevated ICP, want to do head CT BEFORE LP so as not to put at risk for herniation
criteria for doing head CT BEFORE LP for meningitis?
- Abnormal mental status
- Seizure within 1-week presentation
- Known CNS lesion/disease
- Focal neuro findings on exam
- Papilledema
- > 60yo
- Immunocompromised
what are 2 signs of elevated ICP?
posturing (rigidity) and aniscoria from CN3 palsy (sign pt is herniating)
do you delay abx therapy if high suspicion for acute bacterial meningitis even w/o LP or Ct?
NO!!!!
how long do you have to do LP after give abx for acute bacterial meningitis?
2-4 hours
what must you obtain when do LP for meningitis? how much CSF to obtain for PCR analysis?
opening pressure (elevate at 20-50mmhg)
obtain 4-8ml of CSF for PCr analysis
in what position can opening pressure ONLY be obtained?
Lateral-recumbinant position
at what WBC level does CSF have that increases likelihood of bacterial source?
CSF WBC >500
bacterial meningitis LP CSF findings (WBCs, glucose, protein)
WBC 100-500 PMN’s
Glucose decreased
Protein elevated
viral (aseptic) meningitis LP CSF findings (WBCs, glucose, protein)
WBC elevated 10-500 lymphocytic
Glucose normal
Protein elevated
fungal meningitis LP CSF findings (WBCs, glucose, protein)
WBC 0-500 lymphocytic
Glucose normal to decrease
Protein elevated
Tb meningitis LP CSF findings (WBCs, glucose, protein)
WBC 0-500 lymphocytic
Glucose decreased
Protein elevated
tx for meningitis
abx (initial therapy)
steroids (dexamethasone)
antivirals (if think aseptic meningitis)
mannitol (if ICP elevated and increased OP)
when are steroids given for meningitis?
PRIOR TO OR WITH first dose of antibiotics
steroids are especially effective in tx of what bacteria causing meningitis?
S. pneumoniae
what steroid is used for meningitis and at what dose?
Dexamethasone HIGH DOSE (10mg IV)
what antibiotics are used in 16-50 y/o’s with meningitis and for what bacteria?
Vanco AND 3rd gen cephalosporin
Bacteria:
-N. meningitides, S. pneumo, H. influenzae
what antibiotics are used in >50 y/o’s with meningitis and for what bacteria?
Vanco AND 3rd gen cephalosporin AND ampicillin
Bacteria:
-S. pneumo, N. meningitidis, ***Listeria, aerobic GN bacilli
why give ampicillin for meningitis in >50 y/o’s?
b/c want to cover for Listeria
what antibiotics are used in immunocompromised (drunk, DM, HIV, etc.) with meningitis and for what bacteria?
Vanco AND 3rd gen ceph AND ampicillin
Bacteria:
-Listeria, aerobic GN bacilli, S. pneumo, N. meningitidis
what antibiotics are used in neurosurgery, head trauma, cerebrospinal trauma with meningitis and for what bacteria?
Vanco AND either 3rd gen cephalosporin with anti-pseudomonas or meropenem
Bacteria:
-Staph, aerobic GN bacilli, S. pneumo
aseptic bacterial meningitis usually managed as what?
outpatient
management options for likely viral meningitis includes…
Admit and treat IV ABX with CSF culture results in 24hrs
if confident and patient comfortable and reliable then d/c 24-48hr f/u +/- single dose of antibiotics
(ie. could use IM ceftriaxone which is q24hr)
what is encephalitis?
inflammation of brain parenchyma (inflammation of your brain tissue)
how does encephalitis occur?
Direct viral invasion (many different viruses cause this)
Hypersensitivity reaction to a virus or another foreign protein several weeks after exposure (Ex. Vaccine)
what brain mater does encephalitis affect more?
gray matter > white matter
what is the HALLMARK sign of encephalitis?
AMS
encephalitis often accompanied by?
seizures (esp HSV)
what is encephalomyelitis?
encephalitis that involves the spinal cord
what is encephalomyeloradiculitis?
encephalitis that involves the nerve roots
what are the manifestations of encephalitis? what’s the M/C?
primary (M/C) and secondary
what is primary manifestations of encephalitis?
Get virus and IT causes encephalitis -> ***M/C
causes of epidemic primary encephalitis?
Echo virus, Coxsackie virus, Arbovirus, Polio
causes of sporadic primary encephalitis?
HSV, VZV, Mumps, Rabies
what is secondary manifestation of encephalitis?
Post-infectious -> d/t own bodies immune response from viral infection or vaccine
how do you dx primary vs secondary encephalitis?
LP and CSF PCR data excluding acute primary illness
***NO IRAL PROTEINS IN SECONDARY ENCEPHALITIS (b/c not actively infected)
what is the most common etiology WORLDWIDE of secondary encephalitis?
antecedent URI with measles
what are the M/C viruses causing encephalitis in immunocompetent pts?
HSV 1/2 and Enterovirus
what is the M/C cause of viral encephalitis?
HSV 1/2
-can be from reactivation from dormant HSV in trigeminal ganglia
other causes of encephalitis?
Arbovirus (West Nile Virus from mosquito)
Rabies
Powassan Virus (tick-borne)
what is the ONLY tick-borne cause of encephalitis?
Powassan Virus
what’s the mortality rate of rabies?
100%
sx’s of Arbovirus (West Nile)
“summer” flu
what is the greatest RF for Arbovirus (West Nile)?
being elderly
how do you dx Arbovirus (West Nile)?
LP or serum IgM test
tx of Arbovirus (West Nile)?
SUPPORTIVE TX
who does LaCrosse Encephalitis occur in?
<16 y/o
if survive Eastern Equine Encephalitis, what complications are they left with?
neurologic
what is the greatest RF for St. Louis Encephalitis?
being elderly
how to prevent Japanese Encephalitis?
vaccine for travelers
what is given to pt if bitten by rabid animal?
PEP - active and passive immunization
what mammals are vectors for rabies?
Raccoon, Fox, Coyote, Skunk, Bat
is there a tx for rabies?
NO!!!
what do you do for possible rabid domestic animals (dogs)?
10-day observation in quarantine to see if rabid behavior comes out
at what age do most contracts rabies from dogs?
<15 y/o
what is paraneoplastic encephalitis? d/t?
cancer related encephalitis
d/t: SCLC, Testicular cancer, thymoma, Breast, HL
what is autoimmune encephalitis?
Abs to neuronal cell surface/synaptic proteins
-presence or absence of malignancy
Anti-NMDA
what are the sx’s of autoimmune encephalitis? females with this most often associated with?
psychiatric manifestation, cognitive/speech dysfunction, seizures, autonomic instability, dyskinesia’s
Females often associated with teratomas
dx for paraneoplastic and autoimmune encephalitis?
LP/CSF w/ antibody testing on serum and CSF
tx of paraneoplastic and autoimmune encephalitis?
Early immunotherapy with IVIG and IV methylprednisolone
Early tumor resection (if have teratoma)
what are the classic sx’s of encephalitis?
Fever, Headache, Change in MS
what is the typical HPI of someone with encephalitis?
mild ‘flu’ or febrile viral illness with likely some evidence for meningeal involvement
important risk factor for encephalitis, esp Arbovirus?
travel
dx of encephalitis?
LP for CSF exam
CSF PCR -> HSV 1/2, VZV, Enterovirus
Head CT/MRI/EEG b/c pts have AMS
what does Head CT/MRI show for encephalitis that is classic for HSV?
BITEMPORAL APPEARANCE AND ORBITOFRONTAL APPERANCE (CLASSIC OF HSV)
what does EEG show if pt is having seizure?
focal spiking
what’s the tx for encephalitis?
Acyclovir for HSV - otherwise supportive tx
Benzo’s/Anticonvulsants for seizures and for ppx
what’s the M/C location for epidural abscess?
spinal (thoracolumbar region)
M/C causes of epidural abscess?
hematogenous seeding from IVDA
direct extension from osteomyelitis
median age for spinal epidural abscess?
50 y/o (35 y/o in IVDU)
what are the 4 clinical stages of spinal abscess?
- ***Fever and focal back pain (M/C)
- Nerve root compression: radiculopathy; “shooting pain”
- Spinal cord compression: Cauda Equina sx’s
- Paralysis: abscess infarcts cord
what’s the M/C sx of spinal abscess?
fever and FOCAL BACK PAIN
what’s the FIRST SIGN of cauda equina?
Difficulty start/stop stream
thinking of spinal epidural abscess is KEY in pts with what sx’s?
fever and SEVERE focal back pain
how do dx spinal epidural abscess?
MRI
what’s C/I in spinal epidural abscess?
LP
