Meningitis Flashcards

1
Q

What is Meningitis?

A

An inflammation of the membranes that surround the brain and spinal cord

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2
Q

Where is meningitis

A

Involves arachnoid, pia mater, and CSF

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3
Q

What causes Meningitis?

A

Infection Tumors stroke trauma

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4
Q

What is bacterial meningitis

A

Acute meningeal inflammation caused by bacterial infection

Generally evokes a PMN response within the CSF

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5
Q

What is aseptic meningitis?

A

Meningeal inflammation without evidence of bacteria

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6
Q

How does bacterial meningitis happen

A

Protection to the brain
* the meninges
* skull
* The blood-brain barrier
* The blood-CSF barrier

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7
Q

What is the issue with the BBB?

A

Host defense mechanisms

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8
Q

What is the patheogenesis?

A

Hematogenous, contiguous, and direct inoculation

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9
Q

What is the general pathogenesis of

A
  1. mucosal colonization and bacterial invasion of the host and CNS
  2. Bacterial replication in subarachnoid space
  3. inflammation/ pathophysiologic changes
  4. Increased intracranial pressure, cerebral edema and neuronal damage
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10
Q

What is the inflammatory cascade?

A

Cytokines are released

Cytokines promote migrations of neutrophils into the CSF

Neutrophils release PGs, matrix metalloproteinases, etc. that cause edema and swelling

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11
Q

What are the risk factors for meningitis?

A

Traumatic defects

Previous viral infeciton

Age Elderly 60 years, young children <5 years especially infants

Low socioeconomic status, crowding

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12
Q

Exposure to pathogens?

A

Recent colonization
Contact with meningitis patient
Bacterial endocarditis
IV drug use
Surgery or trauma
Splenic dysfunction
Immunosuppression

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13
Q

What is unique about the CSF?

A

Flows unidirectionally from vnetricles to subarachnoid space then down through the spinal cord.

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14
Q

What colour is the CSF?

A

Normally clear with very few WBCs; proteins that are small, and has about 50-60% of simultaneous peripheral glucose

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15
Q

What are the most common pathogens for infants and neonates with respect to meningitis? <1 month

A
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16
Q

What are the common pathogens for infanfs and kids 1-23 months

A
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17
Q

What is the common pathogen for 2-50 years old for meningitis?

A
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18
Q

What is the common pathogens for Surgery/trauma

A
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19
Q

What is the most common pathogens for Brain abscess?

A
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20
Q

Which pathogen is most common for meningitis? In order (4)

A
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21
Q

Which pathogen use to account for about 50% of meningitis cases?

A

H. Influenzae

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22
Q

What is the classic triad of Meningitis symptoms?

A

Headache, Fever, and neck stiffness

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23
Q

What are the other signs and symptoms of meningitis

A

Altered mental status
Malaise
Seizures
Vomiting

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24
Q

What can be evaluated in patients with suspected meningitis?

A

Classic triad only in 25-50%
Stick neck only present ~30% of the time
Seizures occur in 5 to 28% adults and 1/3 of kids

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25
Q

Laboratory tests

A

Lumbar puncture
CSF gram stain and culture
CSF chemistry
CSF WBC counts and differential

26
Q

What is checked for in the CSF lumbar puncture?

A
  • To obtain fluid for cell counts
  • For gram stain and C & S
  • The opening pressure and appearance is noted
  • Must be careful or even not do puncture with elevated intracranial pressure
27
Q

What is the CSF gram stain?

A

 May be negative (ex. if patient was recently on antibiotics for AOM)

 Will need to start empirical antibiotics until the infecting pathogen is identified –
considered a medical emergency; begin antibiotics within 1 hour of diagnosis

28
Q

What is being looked at the CSF WBC count and differential

A
  • Normally < 5 WBC x 106/L; mostly monocytes
  • In bacterial meningitis – often >500 WBC x106/L; mostly PMNs
  • May not see anything out of the ordinary if patient is immunocompromised
29
Q

What are some other things that should be monitored?

A
  • Check for antibodies towards certain bacteria
  • CSF lactate levels – increased in infection
  • Check for endotoxins of bacteria
  • Electrolytes
30
Q

What is the treatment considerations for meningitis?

A

Adequate concentration of antibiotics in the CSF
Not all drugs cross the BBB
Efflux pumps are inhibited

31
Q

With respect to Adequate concentration of antibiotics in the CSF what should be considered?

A

Lipid solubility, plasma protein binding, molecular weight and ionizaton

Antibiotic penetration will increase with inflammation
(Do not decrease dose as patient gets better as penetration is going to decrease)

32
Q

Which antibiotics penetrate the CSF regardless of inflammation?

A
33
Q

Which antibiotics penetrate the CSF with inflammation

A
34
Q

Which antibiotics in the CSF with or without inflammation?

A
35
Q

What is important to know about the activity of anbiotics in CSF

A

pH, pharmacokinetics, etc in CSF are different
* Drugs rapidly cleared from CSF by efflux
* AMG and FQs work less well in the pH of the CSF
* CSF has impaired host defence activity
***
* Requires bactericidal agents

36
Q

What are the Antibiotic administrations?

A

INtralumbar
Intracisternal
Intraventricular (Mostly)

37
Q

What is the treatment duration for S. Pneumoniae?

A

10-14 days

38
Q

What is the treatment duration for N. Meningitidis?

A

5 to 7 days

39
Q

What is the treatment duration for H. Influenzae?

A

7-14 days

40
Q

What is the treatment duration for Group B strep?

A

14-21 days

41
Q

What is the treatment duration for Gram negative bacilli?

A

21 days

42
Q

What is the treatment duration for Abscess?

A

4-6 weeks

43
Q

What is the empiric antibiotic regiment for <1 month

A

Ampicillin + cefotaxime or ampicillin + AMG

44
Q

What is the empiric antibiotic regiment for 1 month to 50yrs

A

Vancomycin + 3rd generation cephalosporin (cefotaxime or ceftriaxone)

45
Q

What is the empiric antibiotic regimen for > 50yrs

A

 Vancomycin + ampicillin + 3rd gen. cephalosporin

46
Q

What is the emperic antibiotic regimen for Penetrating trauma or neurosurgery

A

Vancomycin + cefepime, vancomycin + ceftazidime, or vancomycin + meropenem

47
Q

What are the antibiotics of choice for S.Pneumoniae?

A
  • vancomycin + 3rd gen cephalosporin
  • Pen G or ampicillin if pen susceptible
  • Alt: meropenem, FQ
48
Q

What is the antibiotics of choice for Neisseria meningitidis

A
  • 3rd gen cephalosporin, penicillin G, ampicillin
  • Alt: ampicillin, (chloramphenicol), FQ
49
Q

What is the antibiotics of choice for Listeria monocytogenes

A
  • Ampicillin or penicillin G + AMG
  • TMP/SMX, meropenem
50
Q

What is the antibiotics of choice for S. Agalactiae?

A

Ampicillin or penicillin G
Alt:3rd generation cephalosporin

51
Q

What is the antibiotic of choice for Haemophilus influenzae?

A

3rd generation cephalosporin

Cefepime, meropenem, FQ

52
Q

What is the antibiotic of choice for E. Coli

A

3rd generation Cehpalosoprin
Cefepime, meropenem, FQ, TMP/SMX

53
Q

What is special about the AMGs?

A

penetrate CSF poorly, even
in the presence of inflammation
and have decreased activation
within the CSF

54
Q

If you are using AMGs whenre must be be given?

A
  • Must be given directly into CSF in
    everyone except neonates
  • When used in combination with
    penicillin (for synergy) have been
    proven effective in IV form
55
Q

Which generation of of cephalosporins can penetrate?

A
56
Q

What is the supportive therapy for Meningitis?

A

Dexamethasone 0.15mg/kg q6h for 2-4 days

57
Q

When should corticosteroids be administered?

A

before or within 2 hours of antimicrobials

58
Q

What are the monitoring parameters for prophylaxis?

A
59
Q

What is the Prophylaxis treatment for Meningococcal?

A
60
Q

What is the H.Influenzae prophylaxis?

A
61
Q
A