Treatment of Bacterial Meningitis
Bacterial meningitis requires immediate antibiotic therapy within 1 hour of clinical suspicion, with empiric treatment based on patient age and risk factors, even before diagnostic confirmation. 1
Initial Management
- Antibiotic therapy should be started as soon as possible after bacterial meningitis is suspected, with the time period from hospital entry to antibiotic administration not exceeding 1 hour 1
- Blood cultures must be obtained before initiating antibiotics 1
- If lumbar puncture is delayed (e.g., due to need for cranial CT), empiric treatment must be started immediately on clinical suspicion 1
- Delay in treatment is strongly associated with death and poor neurological outcomes 1
Empiric Antibiotic Therapy by Age Group
Neonates (<1 month)
- Recommended regimen: Amoxicillin/ampicillin/penicillin plus cefotaxime, OR amoxicillin/ampicillin plus an aminoglycoside 1
- Dosing:
- Age <1 week: cefotaxime 50 mg/kg q8h; ampicillin/amoxicillin 50 mg/kg q8h; gentamicin 2.5 mg/kg q12h
- Age 1-4 weeks: ampicillin 50 mg/kg q6h; cefotaxime 50mg/kg q6-8h; gentamicin 2.5 mg/kg q8h 1
Children (1 month to 18 years)
- Recommended regimen: Cefotaxime or ceftriaxone plus vancomycin or rifampicin 1, 2
- Dosing:
- Cefotaxime 75 mg/kg q6-8h or ceftriaxone 50 mg/kg q12h (maximum 2g q12h)
- Vancomycin 10-15 mg/kg q6h to achieve serum trough concentrations of 15-20 μg/mL
- Rifampicin 10 mg/kg q12h up to 600 mg/day 1
Adults (18-50 years)
- Recommended regimen: Cefotaxime or ceftriaxone plus vancomycin or rifampicin 1
- Dosing:
- Ceftriaxone 2g q12h or 4g q24h; cefotaxime 2g q4-6h
- Vancomycin 10-20 mg/kg q8-12h to achieve serum trough concentrations of 15-20 μg/mL
- Rifampicin 300 mg q12h 1
Older Adults (>50 years) or Immunocompromised
- Recommended regimen: Cefotaxime or ceftriaxone plus vancomycin or rifampicin plus amoxicillin/ampicillin/penicillin G (to cover Listeria) 1
- Dosing: Same as adults plus amoxicillin or ampicillin 2g q4h 1
Special Considerations
- For pediatric patients with bacterial meningitis, meropenem can be used at a dose of 40 mg/kg every 8 hours (maximum 2 grams every 8 hours) 3
- In areas with high pneumococcal resistance to penicillin, vancomycin should be added to the empiric regimen 1, 4
- Risk factors for Listeria monocytogenes (requiring ampicillin/amoxicillin coverage) include: age >50 years, diabetes mellitus, immunosuppressive drugs, cancer, and other immunocompromising conditions 1
Adjunctive Therapy
- Dexamethasone should be administered to both children and adults with suspected bacterial meningitis before or at the time of first antibiotic dose 1, 4, 5
- Dexamethasone is particularly beneficial in pneumococcal and H. influenzae meningitis 4
Duration of Therapy
- Treatment duration should be guided by the microbiological diagnosis 4
- Generally, 10-14 days for most common pathogens, with longer courses (21 days) for Listeria monocytogenes 2
Common Pitfalls to Avoid
- Delaying antibiotics for imaging: Never delay antibiotic administration beyond 1 hour after first contact with health services, even if imaging is needed 1, 6
- Inadequate coverage: Failing to cover for Listeria in patients >50 years or immunocompromised 1
- Insufficient dosing: Using suboptimal antibiotic doses that don't achieve adequate CSF penetration 1
- Neglecting blood cultures: Always obtain blood cultures before starting antibiotics 1
- Overlooking adjunctive therapy: Failing to administer dexamethasone with or before the first antibiotic dose 5
Bacterial meningitis is a neurological emergency where rapid diagnosis and treatment are critical for reducing mortality and neurological sequelae. The empiric antibiotic regimen should be tailored to the patient's age and risk factors, with prompt adjustment once culture and susceptibility results become available 6, 5.