Meningitis Treatment
Immediate Action: Start Antibiotics Within 1 Hour
Administer empiric antibiotics within 60 minutes of hospital presentation—delays beyond this window directly increase mortality and neurological sequelae. 1 Obtain blood cultures before the first dose, but never postpone antibiotics to acquire them. 1, 2 If lumbar puncture is delayed for imaging (focal deficits, new seizures, altered mental status, immunocompromise), give antibiotics immediately before the scan. 1, 3
Empiric Antibiotic Regimens by Age and Risk
Neonates (≤ 4 weeks)
- < 1 week old: Ampicillin 50 mg/kg IV q8h + Cefotaxime 50 mg/kg IV q8h ± Gentamicin 2.5 mg/kg IV q12h 1
- 1–4 weeks old: Ampicillin 50 mg/kg IV q6h + Cefotaxime 50 mg/kg IV q6–8h ± Gentamicin 2.5 mg/kg IV q8h 1
- Rationale: Covers Group B Streptococcus, E. coli, and Listeria monocytogenes—the dominant neonatal pathogens. 1
Children (1 month – 18 years)
- Ceftriaxone 50 mg/kg IV q12h (max 2 g/dose) OR Cefotaxime 75 mg/kg IV q6–8h PLUS Vancomycin 10–15 mg/kg IV q6h (target trough 15–20 µg/mL) 1, 2
- Rationale: Ensures coverage of S. pneumoniae (including resistant strains), N. meningitidis, and H. influenzae. 1
- Alternative in low-resistance areas: Replace vancomycin with Rifampicin 10 mg/kg IV q12h (max 600 mg/day). 1
Adults 18–50 Years (Immunocompetent)
- Ceftriaxone 2 g IV q12h (or 4 g IV q24h) OR Cefotaxime 2 g IV q4–6h PLUS Vancomycin 10–20 mg/kg IV q8–12h (target trough 15–20 µg/mL) 1, 2, 3
- Rationale: Covers S. pneumoniae (including resistant strains) and N. meningitidis—the most common adult pathogens. 1
- Alternative in low-resistance settings: Rifampicin 300 mg IV q12h may substitute for vancomycin. 1
Adults > 50 Years OR Immunocompromised (Any Age)
- Ceftriaxone 2 g IV q12h (or 4 g IV q24h) OR Cefotaxime 2 g IV q4–6h PLUS Vancomycin 10–20 mg/kg IV q8–12h PLUS Ampicillin 2 g IV q4h (or Amoxicillin 2 g IV q4h) 1, 2, 3
- Rationale: Adds ampicillin for Listeria monocytogenes coverage, which cephalosporins cannot treat. 1, 3
- Listeria risk factors: Age > 50, diabetes, immunosuppressive drugs, malignancy, other immunocompromising conditions. 1, 2
Adjunctive Dexamethasone: Give With or Before First Antibiotic Dose
Dexamethasone reduces mortality and neurological sequelae—administer it with or 10–20 minutes before the first antibiotic dose. 1, 4
- Adults: Dexamethasone 10 mg IV q6h for 4 days 1, 3, 4
- Children: Dexamethasone 0.15 mg/kg IV q6h for 2–4 days 1, 4
- Timing: If omitted initially, can still start up to 4 hours after antibiotics without losing benefit. 1
- Greatest benefit: Pneumococcal and H. influenzae meningitis—reduces hearing loss, neurological deficits, and death (mortality 14% vs 34% in pneumococcal cases). 1
- Discontinue if: Listeria is identified (steroids linked to increased mortality in neurolisteriosis). 1
- Do NOT use in neonates: Insufficient evidence of benefit and potential harm. 1
Pathogen-Specific Therapy After Identification
| Pathogen | Susceptibility | Definitive Therapy | Duration |
|---|---|---|---|
| S. pneumoniae | Penicillin-sensitive (MIC < 0.1 mg/L) | Penicillin G or Ampicillin [2] | 10–14 days [2,5] |
| S. pneumoniae | Penicillin-intermediate (MIC 0.1–1.0 mg/L) | Ceftriaxone or Cefotaxime [2] | 10–14 days [2] |
| S. pneumoniae | Penicillin-resistant (MIC ≥ 2 mg/L) OR Cephalosporin-resistant (MIC ≥ 1 mg/L) | Vancomycin + Third-generation cephalosporin [2] | 10–14 days [2] |
| N. meningitidis | Any | Ceftriaxone 2 g IV q12h OR Penicillin G [2] | 5–7 days [2] |
| L. monocytogenes | Any | Ampicillin 2 g IV q4h [2,6] | 21 days [2] |
| H. influenzae | Any | Ceftriaxone 2 g IV q12h OR Cefotaxime 2 g IV q6h [2] | 10 days [2] |
Regional Resistance Considerations
- In areas with high pneumococcal penicillin or cephalosporin resistance: Add vancomycin or rifampicin to the third-generation cephalosporin. 1, 3
- When true cephalosporin resistance (MIC > 2 mg/L) is unlikely: Ceftriaxone/cefotaxime alone may be considered, but adding vancomycin is recommended as a safety measure. 1
- Animal model data: Ceftriaxone combined with vancomycin or rifampicin achieves superior CSF sterilization compared to ceftriaxone alone in resistant pneumococcal meningitis. 1
Critical Pitfalls to Avoid
- Never delay antibiotics for imaging: Give antibiotics first, then obtain CT if indicated. 1, 3, 4
- Never omit ampicillin in patients > 50 years or immunocompromised: Cephalosporins lack activity against Listeria—omission can be fatal. 1, 3
- Never underdose: Meningitis requires high-dose regimens to achieve adequate CSF penetration; standard dosing leads to treatment failure. 1
- Never fail to obtain blood cultures before antibiotics: But do not let culture acquisition postpone treatment beyond the 1-hour window. 1, 2
- Never administer dexamethasone more than 4 hours after the first antibiotic dose: Timing is critical for benefit. 1
- Never use ceftazidime as empiric therapy for community-acquired meningitis: Reserve it for Pseudomonas coverage in nosocomial or post-neurosurgical cases. 1
- Never use vancomycin alone: It must be combined with a third-generation cephalosporin due to inadequate CSF penetration. 1
When to Perform CT Before Lumbar Puncture
Perform urgent head CT before lumbar puncture if the patient has: 1
- Age ≥ 60 years
- Immunocompromise
- History of CNS disease (mass lesion, stroke, focal infection)
- New-onset seizure (within past week)
- Altered consciousness or inability to follow commands
- Focal neurological deficits (gaze palsy, facial weakness, limb drift)
- Papilledema
If none of these criteria are present: Perform lumbar puncture immediately after obtaining blood cultures. 1
ICU Transfer Criteria
Transfer to ICU if: 1
- Rapidly evolving rash (suggests meningococcemia)
- Glasgow Coma Scale ≤ 12
- Cardiovascular instability or hypoxia
- Requiring specific organ support or intensive monitoring
Outpatient Parenteral Antibiotic Therapy (OPAT)
Consider OPAT after 5 days of inpatient therapy if: 2, 5
- Patient is afebrile and clinically improving
- Reliable IV access
- Can access medical care 24 hours/day
- No other acute medical needs
- Willing to participate
OPAT regimen: Ceftriaxone 2 g IV twice daily (or 4 g IV once daily after first 24 hours). 2
Treatment Duration Summary
- Pneumococcal meningitis: 10–14 days 2, 5
- Meningococcal meningitis: 5–7 days 2
- Listeria meningitis: 21 days 2
- H. influenzae meningitis: 10 days 2
- Unknown pathogen (clinically recovered): 10 days 2
Never stop antibiotics prematurely based solely on clinical improvement—complete the pathogen-specific duration to prevent relapse and complications. 2, 5