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PHAR 255 > Meningitis > Flashcards

Meningitis Flashcards

1
Q

What is meningitis?

A

An inflammation of the membranes that surround the brain and spinal cord
- Involves arachnoid, pia mater, and CSF
- Inflammatory process in the subarachnoid space can extend around the brain, spinal cord and ventricles
- Inflammation due to infection, tumors, stroke, trauma, etc.

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2
Q

What is bacterial meningitis? (2)

A
  • Acute meningeal inflammation caused by bacterial infection
  • Generally evokes a PMN response within the CSF
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3
Q

What is aseptic meningitis?
What can it be caused by? (4)

A
  1. There is no readily identifiable organism on routine culture
  2. Could be anything that is not bacterial - BUT also includes some bacteria causes not easily grown
  3. Could be viral, fungal, syphilis, TB, Lyme disease, atypical bacteria
  4. Could also be from chemical irritation, malignancy or drug induced
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4
Q

What are 4 protective structures of the brain?

A
  1. The meninges
  2. Skull
  3. The BBB
  4. The blood-CSF barrier
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5
Q

What are 3 sources of meningitis (not bacteria, but how does the person actually get the bacteria?)?

A
  1. Hematogenous
    - Spread from the blood
  2. Contiguous
    - From a URTI - e.g., sinusitis, acute otitis media
  3. Direct inoculation
    - Surgery or trauma
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6
Q

Describe the pathogenesis of meningitis (4)

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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7
Q

Bacteria that commonly cause meningitis have properties that enhance their virulence. Give 3 examples

A
  1. H. influenza, N. meningitidis, S. pneumoniae all make immunoglobulin A proteases
  2. Allows these bacteria to colonize the nasopharyngeal mucosa by cleaving certain antibodies
  3. N. meningitidis can adhere to cells by means of pili (especially if cell damaged by URTI or smoking)
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8
Q

What are the 3 most common bacteria that cause meningitis?

A
  1. H. influenza
  2. N. meningitidis
  3. S. pneumoniae
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9
Q

All 3 bacteria that cause meningitis are encapsulated by a ______________ _______
Why?

A

polysaccharide capsule
- Helps to inhibit phagocytosis and complement activity within the bloodstream

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10
Q

Go through the pathogenesis of meningitis using these 2 points:
1. There are poor host defenses in the CSF (2)
2. Inflammatory cascade is triggered (3)

A

Poor host defenses in the CSF:
1. Low complement levels, low antibody levels
2. Bacteria are able to quickly multiply
Inflammatory cascade is triggered:
1. Cytokines (IL1, TNF, etc) are released
2. Cytokines promote migration of neutrophils into the CSF
3. Neutrophils release PGs, matrix metalloproteinases, etc., that cause edema and swelling

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11
Q

What are the risk factors for meningitis? (5)

A
  1. Congenital or traumatic defects
  2. Previous viral infection
  3. Age
    - Elderly (>60 years)
    - Young children (<5 years)
    - Especially infants
  4. Low SES
  5. Crowding (orphanage, dorm rooms, etc.)
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12
Q

Exposure to pathogens is a risk factor for meningitis. What are some examples as to what kinds of exposure (7)

A
  1. Recent colonization
  2. Contact with meningitis patient
  3. Bacterial endocarditis
  4. IV drug use
  5. Surgery or trauma
  6. Splenic dysfunction
  7. Immunosuppression
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13
Q

Should know how CSF flows through the body. Why is this important when it comes to drug administration?

A

Uni-directionally from ventricles to subarachnoid space then down through spinal cord
- So drug administration in lumbar area will not result in sig concentrations above that point

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14
Q

Should know the normal composition of CSF (3)

A
  1. Normally clear with very few WBCs
  2. Protein <500mg/mL
  3. Glucose conc approx. 50-60% of simultaneous peripheral glucose
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15
Q

What are the most common pathogens that cause meningitis in premature infants and neonates (<1 months) (ELKS)

A
  1. E. coli
  2. L. monocytogenes
  3. Klebsiella species
  4. Strep agalactiae
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16
Q

What are the most common pathogens that cause meningitis in infants and kids (1-23 months) (NSH)?

A
  1. N. meningitidis
  2. S. pneumoniae
  3. H. influenza
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17
Q

What are the most common pathogens that cause meningitis in 2-50 years old? (SN)

A
  1. S. pneumoniae
  2. N. meningitidis
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18
Q

What are the most common pathogens that cause meningitis in >50 years old? (SNLG)

A
  1. S. pneumoniae
  2. N. meningitidis
  3. L. monocytogenes
  4. Gram negative enterics
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19
Q

What are the most common pathogens that cause meningitis from surgery/trauma? (SG)

A
  1. Staph infection
  2. Gram (-) bacilli
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20
Q

With a brain abscess what kinds of pathogens can cause meningitis?

A

Polymicrobial (aerobic and anaerobic)

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21
Q

What is the classic triad of meningitis physical examination signs and symptoms?

A
  1. Headaches
  2. Fever
  3. Neck stiffness
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22
Q

What are the other potential signs and symptoms of meningitis on a physical examination aside from the classic triad? (4)

A
  1. Altered mental status
  2. Malaise
  3. Seizures
  4. Vomiting
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23
Q

What are 2 signs that can be assessed during a physical exam to check for meningitis?

A

The Kernig and Brudzinski signs

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24
Q

Certain meningitis patients don’t always have classic features. What non-specific signs might you see in infants? (8)

A
  1. Irritability
  2. Lethargy
  3. Poor feeding
  4. Fever
  5. Seizures
  6. Rash
  7. Breathing changes
  8. Bulging fontanelle
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25
Q

Certain meningitis patients don’t always have classic features. What might be seen in elderly patients?

A

Frequently the only sign is altered mental status or confusion

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26
Q

What are the 3 main laboratory tests done to diagnose meningitis? How are they obtained?

A
  1. CSF gram stain and culture
  2. CSF chemistry
  3. CSF WBC count and differential
    Obtained via a lumbar puncture
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27
Q

When should a lumbar puncture not be done/be careful?

A

Elevated intracranial pressure

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28
Q

Until the infecting pathogen is identified, what must be done in the meantime (meningitis)?

A

Start empirical antibiotics - considered a medical emergency; begin antibiotics within 1 hour of diagnosis

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29
Q

How is CSF glucose and protein altered in meningitis?

A

Glucose - CSF/serum ratio usually 50 to 60% of simultaneous peripheral glucose; is lower in bacterial meningitis
Protein - normally <0.5g/L; elevated in bacterial meningitis

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30
Q

How does CSF WBC count and differential change during meningitis? (3)

A
  1. Normally <5 WBC x 10^6/L; mostly monocytes
  2. In bacterial meningitis - often >500 WBC x 10^6; mostly PMNs
  3. May not see anything out of the ordinary if patient is immunocompromised
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31
Q

What are some ‘other’ lab tests that may be performed to help diagnose meningitis? (4)

A
  1. Check for antibodies towards certain bacteria
  2. CSF lactate levels - increased in infection
  3. Check for endotoxins of bacteria
  4. Electrolytes
32
Q

Besides a physical exam and lab tests, what are 3 other pieces of information to help with diagnosis of meningitis?

A
  1. Age of patient - clue to organisms
  2. History of present illness - do the pieces “add up”?
  3. Past medical history - IV drug use, asplenic, immunocompromised
33
Q

What are some acute complications of bacterial meningitis? (11 - maybe know 5 or so)

A
  1. Shock
  2. Respiratory failure/distress/arrest
  3. Apnea
  4. Altered mental status/coma
  5. Increased intracranial pressure
  6. Seizures
  7. Disseminated intravascular coagulation (DIC)
  8. Subdural effusions
  9. Subdural abscess
  10. Intracerebral abscess
  11. Death
34
Q

What are some sequelae of bacterial meningitis? (Meaning, what are some post-infection consequences that develop) (7 - know 4ish)

A
  1. Seizure disorder
  2. Impaired intellectual functioning
  3. Impaired cognition
  4. Personality changes
  5. Dizziness
  6. Gait disturbances
  7. Focal neurologic deficits
    - Deafness/sensorineural hearing loss
    - Blindness
    - Paralysis
    - Paresis
35
Q

What are some of the CNS specific structural sequelae that might be seen with meningitis? (8)

A
  1. Hydrocephalus
  2. Brain abscess
  3. Subdural abscess
  4. Subdural effusion
  5. Subdural empyema
  6. Epidural abscess
  7. Cerebral thrombosis
  8. Cerebral vasculitis
36
Q

What are 3 treatment considerations to be aware of when treating meningitis?

A
  1. Adequate concentration of antibiotic in the CSF
  2. Activity of antibiotic in CSF
  3. Direct (focal) antibiotic administration
37
Q

What does antibiotic concentration in the CSF/BBB depend on? (2)

A
  1. Depends on lipid solubility, plasma protein binding, molecular weight and ionization
  2. Antibiotic penetration will increase with inflammation
    - Careful not to decrease dose as patient gets better as penetration is going to decrease
38
Q

What are the antibiotics that can achieve therapeutic levels in the CSF WITHOUT inflammation? (9)

A
  1. Acyclovir
  2. Chloramphenicol
  3. Ciprofloxacin, levofloxacin, moxifloxacin
  4. Fluconazole
  5. Linezolid
  6. Metronidazole
  7. Sulfonamides, trimethoprim
  8. Pyrazinamide, rifampin, isoniazid
  9. Flucytosine, foscarnet, fosfomycin, ganciclovir, voriconazole
39
Q

What are the antibiotics that can achieve therapeutic levels in the CSF with meningeal inflammation? (6)

A
  1. Ampicillin, penicillin G, piperacillin, nafcillin, ticarcillin
  2. Aztreonam
  3. Cefotaxime, ceftriaxone, cefepime, ceftazidime, cefuroxime
  4. Imipenem, meropenem
  5. Vancomycin
  6. Colistin, daptomycin, ethambutol, ofloxacin, pyrimethamine
40
Q

Should know which antibiotics have nontherapeutic levels in CSF with or without inflammation (7)

A
  1. Aminoglycosides
  2. First generation cephalosporins
  3. Second generation cephalosporins
  4. Doxycycline
  5. Intraconazole
  6. Amphotericin B
  7. Beta-lactamase inhibitors
41
Q

Bactericidal vs. bacteriostatic antibiotics. Can either be used in bacterial meningitis?

A

No - requires bactericidal agents to be used.
Bacteriostatic drugs are not good here b/c there are not enough immune cells in the CSF to eliminate the bacteria.

42
Q

What are the 3 routes of antibiotic administration in meningitis?

A
  1. Intralumbar (intathecal)
    - Into the subarachnoid space
  2. Intracisternal
    - Large cavities within the subarachnoid space
  3. Intraventricular
43
Q

What are some considerations/consequences that may be associated with direct (focal) antibiotic administration? (3)

A
  1. Drug may cause chemical meningitis
    - Use preservative free whenever possible
  2. May introduce nosocomial infection
  3. Consider conc. of the drug, vehicle, additives
    - Also think of volume to be used
44
Q

What are some general treatment considerations to be aware of when treating meningitis? (5)

A
  1. Start antibiotic immediately! - is a medical emergency
  2. Empiric therapy is based on age, history, underlying disease and gram stain
  3. Give full doses for the entire course of therapy
  4. Generally will be IV administration
  5. Repeat lumbar puncture in 1-2 days to ensure sterilization of CSF (may not be done if common pathogen and pt responding well)
45
Q

What are some situations in which duration of therapy would be extended? (4)

A
  1. Subdural abscess
  2. Delayed sterilization of CSF
  3. Prolonged fever
  4. Persistence of signs and symptoms
46
Q

What is the duration of treatment (if the patient is responding well) if bacterial meningitis is caused by S. pneumoniae?

A

10-14 days

47
Q

What is the duration of treatment (if the patient is responding well) if bacterial meningitis is caused by N. meningitidis?

A

5-7 days

48
Q

What is the duration of treatment (if the patient is responding well) if bacterial meningitis is caused by H. influenzae?

A

7-14 days

49
Q

What is the duration of treatment (if the patient is responding well) if bacterial meningitis is caused by Group B Strep?

A

14-21 days

50
Q

What is the duration of treatment (if the patient is responding well) if bacterial meningitis is caused by Gram negative bacilli?

A

21 days

51
Q

What is the duration of treatment (if the patient is responding well) of meningitis if there is an abscess?

A

4-6 weeks

52
Q

What are the empiric antibiotics used in meningitis if patient is age < 1month? (2 combos)

A
  1. Ampicillin + cefotaxime
  2. Ampicillin + AMG
53
Q

What are the empiric antibiotics used in meningitis if patient is age 1 month to 50 years? (1 combo)

A

Vancomycin + 3rd generation cephalosporin (cefotaxime or ceftriaxone)

54
Q

What are the empiric antibiotics used in meningitis if patient is age >50 years? (1 combo)

A

Vancomycin + ampicillin + 3rd generation cephalosporin

55
Q

What are the empiric antibiotics used in meningitis if patient has penetrating trauma or neurosurgery? (3 combos)

A
  1. Vancomycin + cefepime
  2. Vancomycin + ceftazidime
  3. Vancomycin + meropenem
56
Q

What are the first line antibiotics for Streptococcus pneumoniae caused meningitis? (2)
What are the alternatives? (2)

A
  1. Vancomycin + 3rd gen cephalosporin
  2. Pen G or ampicillin if pen susceptible
    Alternatives:
  3. Meropenem
  4. Fluoroquinolone
57
Q

What are the first line antibiotics for Neisseria meningitidis caused meningitis? (3)
What are the alternatives? (2)

A
  1. 3rd gen cephalosporin
  2. Penicillin G
  3. Ampicillin
    Alternatives:
  4. Fluoroquinolone
  5. Chloramphenicol
58
Q

What are the first line antibiotics for Listeria monocytogenes caused meningitis? (4)

A
  1. Ampicillin
  2. Penicillin G +/- aminoglycoside
  3. TMP/SMX
  4. Meropenem
59
Q

What are the first line antibiotics for Streptococcus agalactiae caused meningitis? (2)
What is the alternative?

A
  1. Ampicillin
  2. Penicillin G
    Alternative:
  3. 3rd generation cephalosporin
60
Q

What is the first line antibiotic for Haemophilus influenzae caused meningitis? (1)
What are the alternatives? (4)

A
  1. 3rd generation cephalosporin
    Alternatives:
  2. Chloramphenicol
  3. Cefepime
  4. Meropenem
  5. Fluoroquinolone
61
Q

What is the first line antibiotic for E. coli caused meningitis? (1)
What are the alternatives? (4)

A
  1. 3rd generation cephalosporin
    Alternatives:
  2. Cefepime
  3. Meropenem
  4. Fluoroquinolone
  5. TMP/SMX
62
Q

Aminoglycosides penetrate the CSF poorly even in the presence of inflammation and have decreased activation within the CSF. How then, should it be given? (2)

A
  1. Must be given directly into CSF in everyone except neonates
  2. When used in combination with penicillin (for synergy) have been proven effective in IV form
63
Q

What are some supportive therapies to prevent/treat edema, hydrocephalus, and inflammation in meningitis? (3)

A
  1. Mannitol - an osmotic diuretic that can decrease intracranial pressure
  2. Shunts - used to drain excess fluid from the brain
  3. Steroids
64
Q

Why are shunts used in meningitis (hydrocephalus)?

A

In hydrocephalus - ventricles become enlarged with CSF. This causes brain tissue to become compressed, causing serious neurological problems. Shunting is necessary to drain the excess fluid and relieve pressure

65
Q

What is the dosing of dexamethasone in meningitis supportive therapy?
How should it be administered?

A

0.15mg/kg Q6H for 2-4 days
Administer BEFORE or within 2 hours of antimicrobials

66
Q

Why might steroid use in meningitis be controversial? (2)

A
  1. B/c decreasing inflamamtion will decrease antibiotic penetration
  2. But death of organisms results in inflammatory mediators from release of toxins
67
Q

When should steroid supportive therapy in meningitis be discontinued?

A

Ds/c within 48 hours if H. influenzae or Strep pneumoniae not cultured

68
Q

What are 6 things to monitor for during meningitis treatment?

A
  1. Check C&S results
  2. Lab - CBC
  3. Repeat of lumbar puncture
    - In ~2 days after the 1st one (if lack of response or unusual organism)
  4. Resolution of signs and symptoms - every 4 hours
  5. And for complications
  6. Antibiotic adverse effects
69
Q

When is prophylaxis for meningitis recommended?

A

For high risk contacts
- Risk after exposure to patient is 500 times greater than general population

70
Q

Meningitis prophylaxis: High risk individuals include: (4)

A
  1. Household or close contacts (i.e., those who slept or ate in the same house)
  2. Intimate non-household contacts
  3. Those with direct exposure to secretions (i.e., used same fork/spoon or toothbrush, kissing)
  4. School/daycare contacts
    This means contact within the prior seven days before patient got sick
71
Q

What is the first-line antibiotic therapy for prophylaxis of meningococcal meningitis in:
- Adults, kids, infants? (don’t need to memorize dosing)

A

Rifampin:
- Adults - 600mg BID for 2 days
- Kids (1-12 years) - 10mg/kg Q12H for 2 days
- Infants - 5mg/kg Q12H for 2 days

72
Q

What are the alternative antibiotics used for prophylaxis of meningococcal meningitis? (2)

A
  1. Ciprofloxacin 500mg one dose - adults only
  2. Ceftriaxone 250mg IM one dose (over age of 12) or 125mg IM one dose (for kids <12)
73
Q

What is the first-line antibiotic therapy for prophylaxis of H. influenzae meningitis in adults and kids?

A

Rifampin:
- Adults - 600mg OD for 4 days
- Kids: 20mg/kg/day OD for 4 days

74
Q

What is the first-line antibiotic therapy for prophylaxis of pneumococcal meningitis in adults and kids

A

Prophylaxis is not given for pneumococcal meningitis

75
Q

Vaccines for meningitis? Yay or nay?

A

Yay

PHAR 255 (14 decks)

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