Meningitis/Encephalitis Flashcards
What are the ways an infection can reach the CNS
Invade the blood stream
Retrograde neuronal path
Direct contagious spread
What is encephalomeningitis
Inflammation of brain and spinal cord
What is encaphalitis
acute inflammation of the brain parenchyma causing abn function (AMS, sz, change in behavior or speech
What is the MCC of encephalitis
Virus (70%)
also bacteria and fungi
What is primary encephalitis
Virus is seen or cultured- (+) neuronal involvement
What is post infectious encephalitis
Virus is not present, there is demyelination- (-) neuronal involvement
Increased mortality occurs in patients who
have multiple comorbidities
extremes of ages
Who is high risk for viral encephalitis
traveling to endemic areas
Out doors
Not vaccinated
immunodeficient
What organisms are associated with viral encephalitis
HSV Arthropods (west nile, St. Louis) Rabies HIV Enterovirus Measles
If bacterial, what can cause encephalitis
B. burgdorferia T. pallidum Listeria Strep Klebsiella N. meningitidis M. tuberculosis
Non-infectious causes of encephalitis are
Drugs
Autoimmune
Radiation
Paraneoplastic syndrome
How does encephalitis present
fever, *seizures, AMS, Focal neuro sx (paralysis, CN palsy, increased DTR)
What does encephalitis usually NOT present with
meningeal irritation (photophobia, nuchal rigidity)- unless it’s meningoencephalitis
What history points you in the direction of encephalitis
recent travel (vectors) recent illness season outdoor activities birth Hx HSV Parotitis (mumps) hydrophobia (rabies) zoster rash (HZV)
What will you see on Encephalitis PE
Papilledema
flaccid paralysis (WNV)
arthritis (lyme, SLE)
Diabetes insipidus, SIADH= no temp control
Retinitis (CMV, WNV, paraneoplastic syndrome)
What rashes are commonly found with encephalitis
Vesicular eruption (HSV, VZV) Maculopapular rash (EBV) Malar rash (SLE) Petechial rash (meningococcus, rickettsia) Erythema migrans (lyme) Erythema nodosum (TB, histo, sarcoidosis) Erythema multiforme (HSV, EBV, Mycoplasma) Kaposi sarcoma (AIDS)
Describe rashes by location
mucus membrane= Herpes
Gumma= tertiary syphillis
Genital lesions= HSV
How do you diagnose Encephalitis
MRI > CT
Diagnostic pro-tip
start with CT w/con if pt is really sick (if high Cr, do non-con)
It is faster and you can r/o mass lesion
also must do this before LP can be done
What is a contraindication to LP
Mass lesion! (r/o with CT first)
Sx of increased ICP (papilledema, focal neuro Sx, decreased LOC)
Severe coagulopathy or on anticoags
Skin infection
What MRI findings indicate encephalitis
Herpes: temporal lobe
Post-infectious: demyelination present
+/- hypersensitivity in edematous areas
What should you analyze with LP
opening pressure
cell count (w/ diff), glucose, protein, culture, gram stain
PCR (HSV and enterovirus)
IgM (WNV)
What is Cushing’s Triad
Respiratory depression
Bradycardia
Hypertension
How do you preform an LP
Lying or sitting, in L3-L5
Draw 15-20 ml CSF (4 tubes) and send to lab FAST
Do not refrigerate (H influenza and N meningitidis will die)
How long does cellular degradation last
ONE HOUR (must send quickly to lab
LP steps are
Measure CSF pressure, then draw 4 tubes
chem serology- microbio- hematology- special study
What does normal CSF look like
clear like water
When does it become turbid
WBC >200
RBC >400
gross body fluids RBC >6000 (GROSSLY BLOODY)
bacteria/protein >150
What can cause leukocytosis in CSF
Bacterial meningitis
vasculitis
leukemic infiltrate
traumatic tap
What does pink/red CSF indicate
Traumatic tap (blood clear by tube 3
SAH (stays uniformely bloody)
ICH
cerebral infarct
Viral Encephalitis CSF will look like this
Cloudy/straw colored Normal-increased OP Elevated white count Lymphocytes on differential 0 RBC (unless HSV) normal-increased protein normal glucose
What are other diagnostic tests you can get for Viral Encephalitis
CBC (eosinophilia, lymphocytosis) Peripheral bleed smear (malaria) Culture (bacterial? arbovirus?) IgG, IgM Ab (WNV has IgM) Electrolytes (SIADH) Sputum (TB) CXR (infx vs non-infx) Whole body PET/CT (malignancy)
What is the Gold Standard for viral encephalitis (but not really used)
Brain biopsy (it is invasive
What is your goal with viral encephalitis
ID the cause, consult infectious disease and neuro ASAP
How do you manage encephalitis
Stabilize (ET tbe, vent, circulatory support, electrolytes)
Start Empiric Antivirals
Treat offending agent
**Isolate until cause is identified!
What can mimic a CNS infection
Tumor
Med S/E
AI
Increased ICP
What do you want to prevent and manage with viral encephalitis
secondary bacterial infections
DVT
GI ulcers
How do you manage increased ICP
elevate head of bed 30-45 degrees
Hyperventilate to PaCO2 30
+/- corticosteroids and Mannitol
What is empiric treatment for Viral encephalitis
Acyclovir (HSV, VZV) early, and refine when cultures come back
What is primary prevention for viral encephalitis
Avoid vectors (bug spray) Vaccines (MMR, polio, rabies, meningitis)
What is meningitis
inflammatory disease of leptomeninges around brain and spinal cord
What are some meningitis RF
Extremes of ages birth infection from mom immune/vaccine status exposure risk IVDU
What are meningitis symptoms
HA photophobia N/V fever neck stiffness
This means bacterial meningitis until proven otherwise
Headache + Fever
If not fatal, what are common outcomes of bacterial meningitis
Neuro sequelae
brain damage
hearing loss
learning disability
What is viral meningitis
Aseptic; meningeal inflammation WITHOUT bacterial infection
can be due to malignancy, fungal, or meds
Self-limited disease course
What are symptoms of viral meningitis
All normal +/- URI sx, rash, diarrhea
What is the MCC of viral meningitis
Enterovirus (coxsackie, herpangia, polio)
What is HSV2 preceded by
genital lesions
What does mumps meningitis present with
Headache
low grade fever
mild nuchal rigidity
Mumps parotitis
What does viral meningitis CSF look like
*Cloudy color normal-high pressure Elevated WBC Lymphocytes on differential 0 RBC *Elevated protein normal glucose (* are the only differences from viral encephalitis)
How does bacterial meningitis occur in adults
Hematogenous spread of bacteria
adjacent infected structures
penetrating injury
How does bacterial meningitis spread in neonates
Pathogens from birth canal**
also placenta or surroundings
What happens after the bacteria is acquired
Multiplies quickly (patients present w.in 24 hours) Bacteria in CSF cause inflammatory cascade--> cerebral edema and high ICP--> neuro damage and possibly death
What happens if bacterial meningitis is not treated
DEATH!!
This is an EMERGENCY
What are the causes of bacterial meningitis by age
Neonate: Group B Strep (agalactiae)
Baby/child: Strep pneumo
Teen: N. Meningitidis
Adult: Strep Pneumo
When do pregnant women get tested for group B strep
35-37 weeks gestation
If (+), they get prophylactic abx during labor to protect baby
What are general bacterial meningitis symptoms
slow or rapid onset fever, meningismus, +/- AMS, severe HA, N/V, photophobia, back pain
Neonates also: Irritable, poor feeding, floppy, high pitch cry, vomiting, lethargy
What are red flags in the history
Travel birth Hx recent infx vaccine exposure Hx drug allergies, recent abx
What do bacterial meningitis vitals show
Hypotension
tachycardia
tachypnea
+/- fever, low O2, wide pulse pressure
What are skin Sx of bacterial meningitis
Non-blanching petechiae/purpura rash
Cold/clammy (shock)
What are some HEENT findings in bacterial meningitis
bulging fontanelles and head circumference
papilledema
What are some neuro findings in bacterial meningitis
Irritability
Kernigs and Brudzinski’s
How do you manage bacterial meningitis
IV access (fluids) Cultures (2 diff sites at 2 diff times) Start Abx CBC w/ diff, CMP, coags \+/- CT or LP (dont delay abx to do these if susp. bacterial meningitis)
What does strep pneumo antigen test detect
Presence of C polysaccharide cell wall antigen
What does bacterial meningitis CSF look like
Turbid yellow color Increased OP VERY elevated WBC Neutrophils on differential 0 RBC Very elevated protein Low glucose (bacteria eat the glucose and poop the protein)
What is emperic treatment for bacterial meningitis
Ceftriaxone/Cefotaxime (3 gen ceph) + Vancomycin
Also add Ampicillin if 50+
What is emperic Tx for bacterial meningitis if allergic to penicillin
Moxifloxacin + Vancomycin
If 50+ add Bactrim
What is supportive treatment for bacterial meningitis
Fluid management
ICP control (hyperventilate, elevate bed, +/- glucocorticoid dexamethosone)
+/- induced hypothermia
What bacteria yields the worse prognosis
N. Meningitidis (teens)
What are common neuro complications with bacterial meningitis
AMS increased ICP/edema Sz focal neuro deficit hearing loss
Who should have meningitis prophylaxis
> 8 hours contact at closer than 3 feet
Direct exposure to oral secretions 7 days before Sx or 24 hours after Tx
How can you prevent bacterial meningitis
Vaccination against;
- serogroup A, C, W, Y: Menactra 9 mo- 55 y/o OR Menveo 2 mo. to 55 y/o
- Serogroup B: Trumenba 10-25 y/o OR Bexsero 10-25 y/o
When is meningococcal B (MenB) vaccine given
10+ with persistent asplenia
working with N. Meningitidis
High risk
