Bacterial Meningites Flashcards

1
Q

What are the risk factors associated with bacterial meningites?

A
  1. Head trauma
  2. CNS shunts
  3. Neurosurgical patients
  4. CSF fistula/leaks
  5. Local infections: sinusitis, otitis media, pharyngitis
  6. Immunosuppressed
  7. Splenectomized patients
  8. Congenital defects
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2
Q

Describe the pathophysiology of bacterial meningites

A

Risk factors predispose patients of infection and colonization by bacteria causing meningites

Bacteria then gains entry by various mechanisms:
1. Invasion of mucosal surface then hematogenous spread to brain
2. Spread from para-meningeal focus
3. Penetrating head trauma
4. Anatomic defect in meninges
5. Previous neurosurgical procedures

Bacteria enter CNS and colonize the meninges

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3
Q

Describe the clinical presentations of bacterial meninges

A

Fever and chills
Traid of headache, backache and neck rigidity
Mental status change
Photophobia
Nausea and vomiting
Petechiae and purpura

Infants having poor feeding habits

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4
Q

What are some physical signs of patients with bacterial meningitis?

A

Kernig sign
Brudzinski sign
Bulging fontane

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5
Q

How is bacterial meningitis diagnosed?

A

Lumbar puncture to check for CSF composition, CSF gram stain and culture and CSF PCR

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6
Q

What are the components of CSF to look out for in diagnosing bacterial meningitis?

A

Glucose
Protein
WBC
Physical observation of CSF

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7
Q

What is the CSF composition in one with bacterial meningitis?

A

Glucose low
Protein raised
WBC raised with predominant neutrophils
Turbid fluid

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8
Q

What is the CSF composition in one with viral meningitis?

A

Glucose: normal to slightly low
Protein: Normal to mildly raised
WBC: Raised with predominant leukocytes
Clear fluid

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9
Q

Is radiology often done for bacterial meningitis?

A

No. Usually done to evaluate differential diagnosis and complications

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10
Q

Why is a radiology test done before the lumbar puncture?

A

Concerns of brain shift due to mass lesions and also potential risk of brain hernia during lumbar puncture

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11
Q

What are the different age groups in bacterial meningitis?

A

Neonates
Infants and children
Children and adults
Adults > 50y

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12
Q

What are the type of pathogens identified for bacterial meninigitis in neonates?

A

Group B Streptococcus
E.Coli
Listeria monocytogenes

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13
Q

What are the type of pathogens identified for bacterial meninigitis in infants and children (1-23 months old)?

A

Group B Streptococcus
E.coli
Neisseria meningitidis
S.Pneumoniae

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14
Q

What are the type of pathogens identified for bacterial meninigitis in children and adults (2-50 years)?

A

Neisseria meningitidis
S.Pneumoniae

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15
Q

What are the type of pathogens identified for bacterial meninigitis in adults > 50 y?

A

Neisseria meningitidis
S.Pneumoniae
Listeria monocytogenes
Other gram negatives including E.coli, Klebsiella

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16
Q

How is empiric therapy initiated for neonates?

A

Ceftriaxone + Ampicillin

17
Q

How is empiric therapy initiated for infants and children (2-23 months)?

A

Ceftriaxone + Vancomycin

18
Q

How is empiric therapy initiated for children and adults?

A

Ceftriaxone + Vancomycin

19
Q

How is empiric therapy initiated for adults > 50y?

A

Ceftriaxone + Vancomycin + Ampicillin

20
Q

What should be done upon receiving AST results? What antibiotic therapy to initiate if AST results negative?

A

Begin culture-directed therapy

If AST negative, to treat empiric antibiotic for more than or equal to 14 days

21
Q

What antibiotics should be considered for S.Pneumoniae?
Format your answer to consider penicillin susceptible, penicillin resistant and cephalosporin resistant strains. State the duration of therapy.

A

Penicillin G/ Ampicillin

Penicillin resistant: Ceftriaxone

Penicillin and cephalosporin resistant: Vancomycin + Rifampicin

Duration: 10-14 days

22
Q

What antibiotics should be considered for Neisseria meningitidis?
Format your answer to consider penicillin susceptible, penicillin resistant strains. State the duration of therapy.

A

General: Penicillin G / Ampicillin

Penicillin resistant OR beta lactam allergy: ceftriaxone

Duration: 5-7 days

23
Q

What antibiotics should be considered for Listeria monocytogenes?
Format your answer to consider penicillin susceptible, penicillin resistant and cephalosporin resistant strains. State the duration of therapy.

A

General: Penicillin G / Ampicillin

Penicillin resistant / allergy: Co-trimoxazole; Meropenem

Duration > 21 days

24
Q

What antibiotics should be considered for Group B Streptococcus?
Format your answer to consider penicillin susceptible, penicillin resistant and cephalosporin resistant strains. State the duration of therapy.

A

General: Penicillin G/ Ampicillin

Penicillin resistant / mild allergy: Ceftriaxone

25
Q

What other adjunctive treatment can I consider for bacterial meningitis? Which group of patients can benefit from this?

A

Adjunctive dexamethasone therapy

Good for patients more than 6 weeks old with H.Influenzae or S.Pnuemoniae bacterial meningitis

26
Q

What dose and how should dexamethasone be administered?

A

10mg every 6 hours for 4 days

Administer 10-20 minutes before / at same time as first dose of antibiotics

27
Q

What are the benefits and risks of initiating dexamethasone?

A

Benefits: Decreasing hearing loss and other neurologic sequelae from H.Influenzae infection; decreased mortality in S.Pneumoniae meningitis

Risks: Decreases antibiotic penetration and increased ADR

28
Q

How should pharmacist monitor patient’s response?

A

Duration of improvement should be seen within 48h

If not, use brain imaging to check for cerebrovascular complications

Check for adverse drug reactions and advice patient on long term issue of morbidity

29
Q

Discuss the criterias for antibiotics used in meningitis

A

Should distribute to CSF and achieve adequate CSF concentration

Need high dose and IV administration

Should be active against likely pathogens

Does not aggravate CNS morbidity

30
Q

Who are eligible for chemoprophylaxis of meningitis?

A

Close contact with meningococcal disease due to household / day care contact

Exposed to oral secretions of index case

31
Q

What are the possible chemoprophylaxis in infants and children for bacterial meningitis? List dose, duration and frequency

A

Infant
- 5mg /kg every 12 hours (4 doses)

Children
- 10 mg/kg every 12 hours (4 doses)

32
Q

What are the possible chemoprophylaxis in adults for bacterial meningitis? List dose, duration and frequency

A

Rifampicin 600mg every 12 hours (4 doses)

Ciprofloxacin 500mg orally (1 dose)

Ceftriaxone 125-250mg IM (1 dose)