Treatment of Suspected Bacterial Meningitis
Antibiotics must be administered within 1 hour of hospital arrival, and this should never be delayed for lumbar puncture or neuroimaging. 1
Immediate Actions (Within First Hour)
Stabilization and Initial Assessment
- Stabilize airway, breathing, and circulation immediately upon patient arrival 1, 2
- Document Glasgow Coma Scale score to assess severity and identify patients requiring intubation (strongly consider if GCS <12) 1, 2
- Obtain blood cultures within the first hour, before antibiotic administration 1, 2
- Assess for signs of shock, sepsis, or rapidly evolving rash, which alter management urgency 1, 2
Determine Need for CT Before Lumbar Puncture
Do not delay antibiotics while waiting for imaging. 1, 2 CT is indicated only if the patient has: 1, 2
- Age ≥60 years
- Immunocompromised state
- History of CNS disease (mass lesion, stroke, focal infection)
- New-onset seizure within 1 week
- Altered mental status or GCS ≤12
- Focal neurological deficits (including abnormal pupils)
- Papilledema
- Signs of increased intracranial pressure
Empiric Antibiotic Therapy
Standard Adult Regimen (<60 years, immunocompetent)
Ceftriaxone 2g IV every 12 hours PLUS Vancomycin 15-20 mg/kg IV every 8-12 hours 1, 3
- Ceftriaxone should be administered intravenously over 30 minutes 3
- This regimen provides coverage for Streptococcus pneumoniae (including resistant strains), Neisseria meningitidis, and Haemophilus influenzae 1, 3
Adults ≥60 Years or Immunocompromised
Add Amoxicillin 2g IV every 4 hours to the standard regimen for Listeria monocytogenes coverage 1
- Risk factors for Listeria include age >50 years, diabetes mellitus, immunosuppressive drugs, cancer, and other immunocompromising conditions 1
Pediatric Regimens
- Neonates: Amoxicillin/ampicillin PLUS cefotaxime 1
- Children: Cefotaxime or ceftriaxone PLUS vancomycin 1
- Important: In neonates, ceftriaxone should be infused over 60 minutes (not 30) to reduce risk of bilirubin encephalopathy 1, 3
Adjunctive Dexamethasone Therapy
Dexamethasone 10mg IV every 6 hours should be administered immediately before or simultaneously with the first antibiotic dose 1
- Continue for 4 days if pneumococcal meningitis is confirmed or probable 1
- This reduces mortality and neurological morbidity in pneumococcal meningitis 1
- Do NOT use steroids for cerebral malaria, as they worsen outcomes 4
Timing of Lumbar Puncture
If No Contraindications Present
- Perform LP within 1 hour of hospital arrival 2
- Antibiotics can be given immediately after LP is completed 1, 2
If CT Required or LP Delayed
- Give antibiotics immediately after blood cultures, do not wait for LP 1, 2
- If antibiotics are given before LP, still perform LP within 4 hours when possible 2
- CSF findings (elevated WBC, decreased glucose, elevated protein) remain diagnostically useful even after antibiotics are started 1
Critical Care Considerations
Transfer to ICU if: 1
- Rapidly evolving rash
- GCS ≤12
- Cardiovascular instability or hypoxia
- Requiring monitoring or specific organ support
- Uncontrolled seizures
Fluid Management
- Maintain euvolemia to preserve normal hemodynamic parameters 4
- Initial fluid bolus of 500 mL crystalloid for signs of shock 4
- Caution: Fluid overload can precipitate pulmonary edema, ARDS, or worsen cerebral edema 4
Common Pitfalls to Avoid
- Delaying antibiotics for imaging: This is the most critical error and increases mortality 1, 2, 5
- Inadequate Listeria coverage: Failing to add ampicillin/amoxicillin in patients >50 years or immunocompromised 1
- Not obtaining blood cultures: These must be drawn before antibiotics, but should not delay treatment beyond 1 hour 1, 2
- Insufficient antibiotic dosing: Use full meningitis doses to achieve adequate CSF penetration 1
- Failing to recognize LP contraindications: Abnormal pupils, focal deficits, or papilledema indicate increased intracranial pressure and mandate CT before LP 1, 2