What is the treatment for pyogenic meningitis?

Treatment of Pyogenic Meningitis

The treatment of pyogenic meningitis requires immediate administration of empiric antibiotics based on age and risk factors, with ceftriaxone or cefotaxime plus vancomycin as the cornerstone therapy for most adult patients, along with adjunctive dexamethasone. 1

Initial Management

Timing of Antibiotic Administration

• Antibiotics must be started as soon as possible after clinical suspicion of bacterial meningitis
• Time from hospital entry to antibiotic administration should not exceed 1 hour 1
• If lumbar puncture is delayed (e.g., due to CT scan), start antibiotics immediately after drawing blood cultures 1

Empiric Antibiotic Therapy by Age Group

1. Neonates (<1 month)

   • Amoxicillin/ampicillin/penicillin plus cefotaxime, OR
   • Amoxicillin/ampicillin plus an aminoglycoside
   • Dosing:
     • Age <1 week: cefotaxime 50 mg/kg q8h; ampicillin 50 mg/kg q8h
     • Age 1-4 weeks: ampicillin 50 mg/kg q6h; cefotaxime 50 mg/kg q6-8h 1

2. Infants and Children (1 month to 18 years)

   • Cefotaxime or ceftriaxone plus vancomycin or rifampin
   • Dosing:
     • Cefotaxime 75 mg/kg q6-8h (maximum 2g q4-6h)
     • Ceftriaxone 50 mg/kg q12h (maximum 2g q12h)
     • Vancomycin 10-15 mg/kg q6h (target trough 15-20 μg/mL) 1

3. Adults (18-50 years)

   • Cefotaxime or ceftriaxone plus vancomycin or rifampin
   • Dosing:
     • Ceftriaxone 2g q12h or 4g q24h
     • Cefotaxime 2g q4-6h
     • Vancomycin 10-20 mg/kg q8-12h (target trough 15-20 μg/mL)
     • Rifampin 300 mg q12h 1

4. Adults (>50 years or with risk factors for Listeria)

   • Cefotaxime or ceftriaxone plus vancomycin or rifampin plus amoxicillin/ampicillin
   • Risk factors for Listeria: diabetes mellitus, immunosuppressive drugs, cancer, other immunocompromising conditions
   • Dosing: Same as adults 18-50 plus amoxicillin/ampicillin 2g q4h 1

Adjunctive Therapy

Dexamethasone

• Recommended dose: 0.15 mg/kg q6h for 2-4 days 1 or 10 mg IV q6h for 4 days 2
• Should be administered with or before the first dose of antibiotics 1, 2
• Can still be started up to 4 hours after first antibiotic dose 1
• Most beneficial in pneumococcal meningitis 1
• Consider discontinuation if pathogens other than S. pneumoniae or H. influenzae are identified 1
• Specifically discontinue if Listeria is identified (associated with increased mortality) 1

Pathogen-Specific Treatment After Culture Results

Duration of Therapy

• Meningococcal meningitis: 5 days with clinical improvement
• Pneumococcal meningitis: 10-14 days (14 days for resistant strains) 2
• Generally, continue therapy for at least 2 days after signs and symptoms have disappeared 3
• Total duration typically 7-14 days depending on pathogen 1, 2

Antibiotic Adjustments Based on Identified Pathogen

• Once pathogen is identified and susceptibility results are available, narrow therapy accordingly
• For penicillin-resistant pneumococci: continue combination of high-dose cephalosporins plus vancomycin and consider adding rifampin 2, 4
• When using vancomycin, maintain serum trough concentrations of 15-20 μg/mL 1

Special Considerations

Antibiotic Resistance

• In areas with high rates of penicillin and cephalosporin-resistant pneumococci, initial empiric therapy should include two antibiotics 4
• When dexamethasone is used with resistant pneumococci, the combination of ceftriaxone and rifampin is preferred over vancomycin, as dexamethasone reduces vancomycin penetration into CSF 4, 5

Intensive Care Management

• Refer to intensive care for patients with GCS ≤12, rapidly evolving rash, cardiovascular instability, respiratory compromise, uncontrolled seizures, or severe sepsis 2
• Intracranial pressure (ICP)-based treatment strategies are not recommended for routine care until further evidence from RCTs 1

Pitfalls to Avoid

1. Delayed antibiotic administration - mortality increases with delays; start antibiotics within 1 hour of presentation 1
2. Inadequate coverage for resistant organisms - always include vancomycin or rifampin with cephalosporins until susceptibility is known 6
3. Forgetting Listeria coverage in at-risk populations - adults >50 years or immunocompromised patients need amoxicillin/ampicillin 1
4. Administering dexamethasone after antibiotics - dexamethasone should be given before or with the first antibiotic dose for maximum benefit 1, 2
5. Continuing dexamethasone with Listeria meningitis - associated with increased mortality 1
6. Drug interactions - ceftriaxone must not be administered simultaneously with calcium-containing IV solutions 3

By following these evidence-based guidelines, the mortality and morbidity associated with pyogenic meningitis can be significantly reduced.