8 - Meningitis Flashcards
What are the risk factors for meningitis?
- Nasopharyngeal colonization w/ N. meningitides, S. pneumoniae, H. influenzae
- Prior URTI, cochlear implants
- Cranial anatomical defects, trauma, fracture, neurosurgery, prosthesis drains
- Neonates, advanced age, pregnancy
- Immunocompromised (HIV, malignancy, chemotherapy, corticosteroids, splenectomy)
What are the most likely pathogens of meningitis according to pt age?
- Neonates = S. agalactiae, E. coli
- Children = N. meningitidis, S. pneumoniae; H. influenzae if unvaccinated
- Adolescents/ young adults = S. pneumoniae, N. meningitidis
- Neonates, advanced age > 60 y/o, immunocompromised, pregnancy = L. monocytogenes
- Immunocompromised, health-care associated = S. aureus, gram neg bacilli
Gram stain of S. agalactiae
- Gram pos diplococci
- Part of group B strep family
Gram stain of N. meningitidis
Gram neg diplococci
Gram stain of H. influenzae
Gram neg rod
Gram stain of Listeria monocytogenes
Gram pos bacilli
What are the most common clinical signs of meningitis?
- Fever > 40 C
- Nuchal rigidity or neck stiffness
- CNS (headache, photophobia, confusion, reduced consciousness, seizures)
- Neonates = non-specific sx +/- fever, seizures, respiratory distress, septic shock
- CSF = protein elevated and low glucose
- Skin lesions may indicate N. meningitidis or H. influenzae involvement (rarely occur w/ pneumococcal)
What are some possible complications of meningitis?
- Herniation – diffuse swelling, hydrocephalus
- Infarction – inflammatory occlusion of basal arteries
- Seizures (cortical inflammation)
- Significantly influenced by pathogen, pt age, health status, and tx
What are the antimicrobial fundamentals for meningitis?
- Early, prompt initiation
- CSF penetration (molecular size, lipophilicity, ionization, protein binding; barrier inflammation)
- Rapid sterilization
What role does inflammation play in penetration of antibiotics in CSF?
Helps antibiotics enter CSF b/c it weakens tight junctions
Empirical antimicrobial therapy for meningitis in infants under 1 month?
- Cefotaxime + ampicillin +/- gentamicin
- Gent added to make cefotaxime cidal against group B strep
- Aminoglycosides don’t cross CSF, but in this case are being used for synergy so much lower levels are needed
- Can’t use ceftriaxone b/c of calcium binding and depositing in soft tissue
Empirical antimicrobial therapy for meningitis in children 1 month to 17 years?
- Cefotaxime/ ceftriaxone + vanco
- Cefotaxime/ ceftriaxone for neisseria
- Vanco used for PRSP w/ reduced susceptibility to 3rd gen cephalosporins
Empirical antimicrobial therapy for meningitis in 18-50 y/o?
Cefotaxime/ ceftriaxone + vanco
Empirical antimicrobial therapy for meningitis in over 50 y/o?
- Cefotaxime/ ceftriaxone + vanco + ampicillin
- Ampicillin covers listeria
What therapy would be used for listeria meningitis?
Ampicillin, but since not cidal would be +/- gent
Empirical antimicrobial therapy for healthcare-associated meningitis?
(Meropenem or ceftazidime) + vanco
Empirical antimicrobial for meningitis in immunocompromised?
Meropenem + vanco + ampicillin
Dosing of cefotaxime for meningitis?
2 g q4h
Dosing of ceftriaxone for meningitis?
2 g q12h
Dosing of ampicillin for meningitis?
2 g q4h
Dosing of vancomycin for meningitis?
15-20 mg/kg q8h (troughs 15-20 mg/L)
Dosing of meropenem for meningitis?
2 g q8h
Dosing of ceftazadime for meningitis?
2 g q8h
Dosing of penicillin G for meningitis?
4 million units q4h
Dosing of rifampin for meningitis?
600 mg q24h
What is the antimicrobial therapy for S. pneumoniae meningitis (Pen-S, MIC < 0.06)?
Pen G or ampicillin
What is the antimicrobial therapy for S. pneumoniae meningitis (Pen-R, MIC > 0.12)?
Cefotaxime/ ceftriaxone
What is the antimicrobial therapy for S. pneumoniae meningitis (3rd gen cephalosporin, MIC > 1)?
Cefotaxime/ ceftriaxone + vanco
What is the antimicrobial therapy for S. pneumoniae meningitis (3rd gen cephalosporin, MIC > 2)?
Cefotaxime/ ceftriaxone + vanco + rifampin
What are the alternatives for S. pneumoniae meningitis? What is the duration of therapy?
- Duration = 10-14 days
- Alternatives = levo/ moxi + vanco; [chloramphenicol, linezolid]
What is the antimicrobial therapy for N. meningitidis meningitis (Pen-S, MIC < 0.06)?
Pen G or ampicillin
What is the antimicrobial therapy for N. meningitidis meningitis (Pen-RS, MIC 0.12-1)?
Cefotaxime/ ceftriaxone
What are the alternatives for N. meningitidis meningitis? What is the duration of therapy?
- Duration = 5-7 days
- Alternatives = cipro; [chloramphenicol]
What is the antimicrobial therapy for L. monocytogenes meningitis? What is the duration?
- (Pen G or amp) + gent
- [TMP-SMX, linezolid]
- Duration = at least 21 days
What is the antimicrobial therapy for H. influenzae meningitis (Amp-S)?
Ampicillin
What is the antimicrobial therapy for H. influenzae meningitis (Amp-R, non-beta-lactamase)?
Cefotaxime/ ceftriaxone
What is the antimicrobial therapy for H. influenzae meningitis (Amp-R, beta-lactamase)?
Meropenem
What are the alternatives for H. influenzae meningitis?
Cipro; [chloramphenicol]
What is the antimicrobial therapy for S. agalactiae meningitis? What is the duration?
- (Pen G or amp) + gent x 5 d
- [Vanco, chloramphenicol]
- Duration = 14-21 days (pen G or amp)
What is the timeline for response for meningitis?
- Fever = resolution w/in 24-48 h
- Neck stiffness = resolution over 48-72 h
- CSF = culture negative w/in 24 h, normal glucose by day 3 and normal protein by day 7-10
- Rash = resolution over 7 days
When is dexamethasone adjunctive therapy recommended for meningitis?
- Immunocompetent adults w/ suspected or proven pneumococcal meningitis
- Infants or children w/ H. influenzae or pneumococcal meningitis
What is the dosage and duration of dexamethasone for meningitis?
- 0.15 mg/kg q6h x 2-4 days initiated 10-20 min before or w/ 1st antibiotic dose
- Only continue if gram pos diplococci (S. agalactiae) or S. pneumoniae culture
What are some ways to prevent meningitis?
Vaccinations (H. influenzae, pneumococcal conjugate 13 valent, meningococcal C conjugate, and pneumococcal polysaccharide)
When is meningococcal prophylaxis recommended and which antimicrobials are used?
- For pt w/ close contacts w/in 60 days
- Cipro 500 mg po x 1 dose
- Rifampin 600 mg po q12h x 4 doses
- Ceftriaxone 250 mg IM x 1 dose