Bacterial Meningites Flashcards
What are the risk factors associated with bacterial meningites?
- Head trauma
- CNS shunts
- Neurosurgical patients
- CSF fistula/leaks
- Local infections: sinusitis, otitis media, pharyngitis
- Immunosuppressed
- Splenectomized patients
- Congenital defects
Describe the pathophysiology of bacterial meningites
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
Describe the clinical presentations of bacterial meninges
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
What are some physical signs of patients with bacterial meningitis?
Kernig sign
Brudzinski sign
Bulging fontane
How is bacterial meningitis diagnosed?
Lumbar puncture to check for CSF composition, CSF gram stain and culture and CSF PCR
What are the components of CSF to look out for in diagnosing bacterial meningitis?
Glucose
Protein
WBC
Physical observation of CSF
What is the CSF composition in one with bacterial meningitis?
Glucose low
Protein raised
WBC raised with predominant neutrophils
Turbid fluid
What is the CSF composition in one with viral meningitis?
Glucose: normal to slightly low
Protein: Normal to mildly raised
WBC: Raised with predominant leukocytes
Clear fluid
Is radiology often done for bacterial meningitis?
No. Usually done to evaluate differential diagnosis and complications
Why is a radiology test done before the lumbar puncture?
Concerns of brain shift due to mass lesions and also potential risk of brain hernia during lumbar puncture
What are the different age groups in bacterial meningitis?
Neonates
Infants and children
Children and adults
Adults > 50y
What are the type of pathogens identified for bacterial meninigitis in neonates?
Group B Streptococcus
E.Coli
Listeria monocytogenes
What are the type of pathogens identified for bacterial meninigitis in infants and children (1-23 months old)?
Group B Streptococcus
E.coli
Neisseria meningitidis
S.Pneumoniae
What are the type of pathogens identified for bacterial meninigitis in children and adults (2-50 years)?
Neisseria meningitidis
S.Pneumoniae
What are the type of pathogens identified for bacterial meninigitis in adults > 50 y?
Neisseria meningitidis
S.Pneumoniae
Listeria monocytogenes
Other gram negatives including E.coli, Klebsiella
How is empiric therapy initiated for neonates?
Ceftriaxone + Ampicillin
How is empiric therapy initiated for infants and children (2-23 months)?
Ceftriaxone + Vancomycin
How is empiric therapy initiated for children and adults?
Ceftriaxone + Vancomycin
How is empiric therapy initiated for adults > 50y?
Ceftriaxone + Vancomycin + Ampicillin
What should be done upon receiving AST results? What antibiotic therapy to initiate if AST results negative?
Begin culture-directed therapy
If AST negative, to treat empiric antibiotic for more than or equal to 14 days
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.
Penicillin G/ Ampicillin
Penicillin resistant: Ceftriaxone
Penicillin and cephalosporin resistant: Vancomycin + Rifampicin
Duration: 10-14 days
What antibiotics should be considered for Neisseria meningitidis?
Format your answer to consider penicillin susceptible, penicillin resistant strains. State the duration of therapy.
General: Penicillin G / Ampicillin
Penicillin resistant OR beta lactam allergy: ceftriaxone
Duration: 5-7 days
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.
General: Penicillin G / Ampicillin
Penicillin resistant / allergy: Co-trimoxazole; Meropenem
Duration > 21 days
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.
General: Penicillin G/ Ampicillin
Penicillin resistant / mild allergy: Ceftriaxone
What other adjunctive treatment can I consider for bacterial meningitis? Which group of patients can benefit from this?
Adjunctive dexamethasone therapy
Good for patients more than 6 weeks old with H.Influenzae or S.Pnuemoniae bacterial meningitis
What dose and how should dexamethasone be administered?
10mg every 6 hours for 4 days
Administer 10-20 minutes before / at same time as first dose of antibiotics
What are the benefits and risks of initiating dexamethasone?
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
How should pharmacist monitor patient’s response?
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
Discuss the criterias for antibiotics used in meningitis
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
Who are eligible for chemoprophylaxis of meningitis?
Close contact with meningococcal disease due to household / day care contact
Exposed to oral secretions of index case
What are the possible chemoprophylaxis in infants and children for bacterial meningitis? List dose, duration and frequency
Infant
- 5mg /kg every 12 hours (4 doses)
Children
- 10 mg/kg every 12 hours (4 doses)
What are the possible chemoprophylaxis in adults for bacterial meningitis? List dose, duration and frequency
Rifampicin 600mg every 12 hours (4 doses)
Ciprofloxacin 500mg orally (1 dose)
Ceftriaxone 125-250mg IM (1 dose)
