Meningitis treatment
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"bacterial meningitis" AND treatment
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PMID: 40393410
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Meningitis: Treatment
Meningitis is a medical emergency with untreated bacterial meningitis carrying near-100% mortality. Treatment must be initiated as rapidly as possible - delay is the single most critical factor in determining morbidity and mortality.
1. Initial Emergency Actions
Before or immediately after LP (do not delay antibiotics for CT/LP if clinical suspicion is high):
- Blood cultures x2 - draw before antibiotics if possible (takes <5 min)
- Lumbar puncture - only if no contraindications (papilledema, focal neuro signs, GCS <10, coagulopathy)
- Start empiric antibiotics immediately
- Start dexamethasone - before or with the first antibiotic dose
- IV access, fluids, ICU admission for bacterial meningitis
2. Empiric Antibiotic Therapy
Based on age/immune status (tailor once culture and sensitivity results available):
| Patient Group | Empiric Regimen | Target Organisms |
|---|---|---|
| Immunocompetent adult (18-49 y) | Ceftriaxone 2 g IV q12h (or cefotaxime 2 g IV q4-6h) + Vancomycin 15-20 mg/kg IV q8-12h | S. pneumoniae, N. meningitidis |
| Age >50 y or immunocompromised | Above regimen + Ampicillin 2 g IV q4h | Add L. monocytogenes coverage |
| Immunocompromised | Vancomycin + Ampicillin + Cefepime 2 g IV q8h (or meropenem 2 g q8h) | Broader gram-negative coverage |
| Post-neurosurgery / CSF shunt | Vancomycin + Ceftazidime 2 g IV q8h (or cefepime 2 g q8h) | Staphylococci, gram-negatives, P. aeruginosa |
| Neonate (0-28 days) | Ampicillin 100 mg/kg q8h + Gentamicin 4 mg/kg q24h | Group B Strep, E. coli, Listeria |
| Infant 28-90 days | Ampicillin 100 mg/kg q6h + Gentamicin 2.5 mg/kg q8h (or Cefotaxime 100 mg/kg q8h) | Group B Strep, gram-negative bacilli |
| Child >3 months | Vancomycin 15 mg/kg q6h + Ceftriaxone 50 mg/kg q12h (or Cefotaxime 100 mg/kg q8h) | S. pneumoniae, N. meningitidis, H. influenzae |
Penicillin allergy: Replace ceftriaxone with meropenem 2 g IV or moxifloxacin 400 mg IV; replace ampicillin with TMP-SMX 15-20 mg/kg/d.
Suspected HSV encephalitis: Add acyclovir 10 mg/kg IV q8h empirically.
- Tintinalli's Emergency Medicine, Table 120-1 and 174-4
- Washington Manual of Medical Therapeutics, p. 521
3. Targeted Therapy (Once Organism Known)
| Organism | Preferred Treatment | Duration |
|---|---|---|
| S. pneumoniae (penicillin-sensitive, MIC <0.06) | Penicillin G 4 MU IV q4h | 14 days |
| S. pneumoniae (cephalosporin-sensitive, MIC ≤0.5) | Ceftriaxone or cefotaxime | 14 days |
| S. pneumoniae (resistant, MIC >1) | Vancomycin 45-60 mg/kg/day ± Rifampin | 14 days |
| N. meningitidis | High-dose ceftriaxone or cefotaxime; or penicillin if MIC <0.1 | 7 days |
| L. monocytogenes | Ampicillin ≥3 weeks ± Gentamicin (critically ill) | 21+ days |
| S. aureus (MSSA) | Nafcillin | Variable |
| S. aureus (MRSA) | Vancomycin 20 mg intraventricular if IV fails | Variable |
| Gram-negative bacilli | Ceftazidime or cefepime; meropenem or ciprofloxacin as alternatives | 21 days |
| Repeat LP at 24-36h for pneumococcal meningitis to confirm CSF sterilization |
- Harrison's Principles of Internal Medicine 22E, p. 1166
- Washington Manual, p. 521
4. Adjunctive Dexamethasone
Why: Bactericidal antibiotics lyse bacteria, releasing cell-wall components that trigger IL-1β and TNF-α production, amplifying CNS inflammation. Dexamethasone blocks this cytokine cascade at the mRNA level and stabilizes the blood-brain barrier.
Dosing: Dexamethasone 10 mg IV q6h x 4 days (adults); 0.15 mg/kg IV q6h x 4 days (children)
Timing is critical: Must be given 15-20 minutes before (or at least concurrent with) the first antibiotic dose. Unlikely to help if started >6 hours after antibiotics.
Evidence:
- A European RCT showed dexamethasone reduced unfavorable outcomes (15% vs 25%, p=0.03) and death (7% vs 15%, p=0.04), with greatest benefit in pneumococcal meningitis.
- Reduces sensorineural hearing loss in H. influenzae meningitis.
- Reduces hearing loss and neurologic sequelae in high-income country settings.
Important caveat: Dexamethasone reduces vancomycin CSF penetration - compensate by using vancomycin at 45-60 mg/kg/day. Consider intraventricular vancomycin if IV fails.
When NOT to use: Sub-Saharan Africa and low-income settings - three large RCTs failed to show benefit (attributed to late presentation, HIV, malnutrition, antibiotic pretreatment). Patients with negative Gram stain/culture in these settings should not receive dexamethasone. Also not beneficial (and potentially harmful) in cryptococcal meningitis.
- Harrison's Principles of Internal Medicine 22E, p. 1166-1167
5. Increased Intracranial Pressure (ICP) Management
For patients with signs of raised ICP:
- Head elevation to 30-45°
- Endotracheal intubation and hyperventilation (target PaCO₂ 25-30 mmHg)
- Mannitol IV
- Transfer to ICU with ICP monitoring device
6. Viral Meningitis
The mainstay is supportive care (analgesics, hydration, antiemetics). Specific treatments:
- HSV meningoencephalitis: Acyclovir 10 mg/kg IV q8h
- Lyme meningitis (B. burgdorferi): Ceftriaxone IV or doxycycline PO
- Enteroviruses, most other viral causes: supportive only
7. Fungal Meningitis (Cryptococcal)
- Induction: Amphotericin B deoxycholate + flucytosine (flucytosine is superior to fluconazole when combined with amphotericin B)
- Consolidation: Fluconazole
- Note: Corticosteroids are NOT beneficial and may be harmful in cryptococcal meningitis (exception: immune reconstitution inflammatory syndrome)
8. Tuberculous Meningitis
- Standard 4-drug anti-TB therapy (RHEZ: rifampin, isoniazid, ethambutol, pyrazinamide)
- Adjunctive dexamethasone is beneficial in TBM (unlike cryptococcal meningitis)
9. Meningococcal Prophylaxis for Close Contacts
Contacts of N. meningitidis cases (household, healthcare workers with unprotected airway exposure) require chemoprophylaxis. Options:
- Ciprofloxacin 500 mg PO once
- Rifampin 600 mg PO q12h x 2 days
- Ceftriaxone 250 mg IM once
Patients should be placed in droplet isolation for 24 hours after starting treatment.
- Washington Manual, p. 521
Recent Evidence (2024-2026)
A 2024 systematic review in JAMA Network Open analyzing global case fatality over 80 years confirms that despite antibiotics and adjunctive steroids, bacterial meningitis mortality remains substantial, underscoring the importance of rapid treatment initiation (PMID: 39093565). A 2024 meta-analysis in European Journal of Pediatrics found that shorter antibiotic courses in children with bacterial meningitis may not be inferior for certain organisms, though standard durations remain recommended pending further data (PMID: 37870611).
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