Treatment of Bacterial Meningitis
The recommended treatment for bacterial meningitis is immediate administration of a third-generation cephalosporin (ceftriaxone or cefotaxime), with the addition of vancomycin or rifampin if Streptococcus pneumoniae with reduced susceptibility is suspected, and ampicillin for patients over 50 years or those with risk factors for Listeria monocytogenes. 1
Initial Management
- Treatment should begin as soon as possible after clinical suspicion of bacterial meningitis, ideally within 1 hour of presentation, even if lumbar puncture is delayed 1
- Administer 10 mg IV dexamethasone every 6 hours, with the first dose given shortly before or simultaneously with the first antibiotic dose 1
- Continue dexamethasone for 4 days if pneumococcal meningitis is confirmed or suspected; discontinue if another cause is identified 1
Empiric Antibiotic Selection by Age Group
- Neonates: Ampicillin plus cefotaxime or ampicillin plus an aminoglycoside (cefotaxime 50 mg/kg q8h; ampicillin 50 mg/kg q8h for age <1 week) 1, 2
- Children (1 month to 18 years): Ceftriaxone (50 mg/kg q12h, max 2g q12h) or cefotaxime (75 mg/kg q6-8h) plus vancomycin or rifampin 1, 3
- Adults (18-50 years): Ceftriaxone (2g q12h or 4g q24h) or cefotaxime (2g q4-6h) plus vancomycin or rifampin 1
- Adults (>50 years or with risk factors for Listeria): Ceftriaxone or cefotaxime plus vancomycin or rifampin plus ampicillin (2g q4h) 1, 2
Pediatric Dosing Considerations
- For pediatric patients 3 months and older with bacterial meningitis, meropenem can be administered at 40 mg/kg every 8 hours (maximum dose 2 grams every 8 hours) 4
- Ceftriaxone at 100 mg/kg on day one, followed by 80 mg/kg daily as a single dose has been shown to be effective in pediatric meningitis 5
- For children with suspected pneumococcal meningitis, combination treatment including cefotaxime (300 mg/kg per day) or ceftriaxone (100mg/kg per day) and vancomycin (60 mg/kg per day) is recommended 3
Pathogen-Specific Treatment (After Identification)
- Streptococcus pneumoniae:
- If penicillin MIC <0.1 μg/mL: penicillin G or ampicillin
- If penicillin MIC 0.1-1.0 μg/mL: third-generation cephalosporin
- If penicillin MIC ≥2.0 μg/mL or cefotaxime/ceftriaxone MIC ≥1.0 μg/mL: vancomycin plus third-generation cephalosporin 1
- Neisseria meningitidis:
- Haemophilus influenzae:
- Listeria monocytogenes: Ampicillin for 3 weeks, associated with gentamycin or cotrimoxazole 3
Duration of Therapy
- S. pneumoniae: 10-14 days 1, 3
- N. meningitidis: 7 days 1
- H. influenzae: 7-10 days 1, 3
- Culture-negative meningitis: At least 14 days 1
- Listeriosis: 21 days 3
Critical Care Considerations
- Intensive care referral is recommended for patients with:
- Rapidly evolving rash
- Limb ischemia
- Cardiovascular instability
- Acid/base disturbance
- Hypoxia or respiratory compromise
- Frequent seizures
- Altered mental state (GCS ≤12 or drop >2 points) 1
- Consider intubation for patients with GCS <12 1
Common Pitfalls and Caveats
- Do not delay antibiotic administration waiting for imaging or lumbar puncture results if bacterial meningitis is suspected 1
- Vancomycin should never be used as monotherapy for bacterial meningitis, even for highly resistant pneumococcal strains 1
- Dexamethasone may reduce CSF penetration of vancomycin - when using dexamethasone with suspected resistant pneumococci, consider adding rifampin to the regimen 1, 6
- Rifampin should never be used as monotherapy due to rapid development of resistance 1
- The blood-brain barrier presents a challenge for antibiotic penetration, requiring higher doses of antibiotics to achieve bactericidal concentrations in the CSF 6
- Second-line antibiotic therapy should be adapted according to clinical and bacteriological response on Day 2 3
- For pneumococcal strains with MIC less than 0.5mg/L, third-generation cephalosporin can be continued alone; otherwise, a second lumbar puncture is necessary and the initial regimen should be continued, with or without rifampicin 3