Bacterial Meningitis Treatment Protocol
For suspected bacterial meningitis, immediately initiate empirical antibiotic therapy with vancomycin PLUS a third-generation cephalosporin (ceftriaxone or cefotaxime), combined with dexamethasone given before or with the first antibiotic dose. 1, 2
Immediate Management Algorithm
Step 1: Clinical Assessment and Blood Cultures
- Obtain blood cultures immediately upon suspicion
- Do NOT delay antibiotics for imaging or lumbar puncture if any of these are present:
Step 2: Empirical Antibiotic Therapy (Start Immediately)
Age-Based Regimens:
Specific Dosing:
- Ceftriaxone: 2g IV every 12 hours (adults)
- Vancomycin: 15-20 mg/kg IV every 8-12 hours
- Ampicillin: 2g IV every 4 hours (when indicated) 3
Step 3: Adjunctive Dexamethasone (Critical)
Dexamethasone must be given before or with the first antibiotic dose to reduce mortality in pneumococcal meningitis and prevent hearing loss 2:
- Adults: 10 mg IV every 6 hours for 4 days
- Children: 0.15 mg/kg IV every 6 hours for 4 days
- Do NOT use in neonates (insufficient evidence) 2
Important caveat: Dexamethasone is most beneficial in high-income countries with high standards of care and specifically reduces mortality in pneumococcal meningitis 2. If not started with first antibiotics and CSF bacterial load is already low, benefit is uncertain.
Step 4: Lumbar Puncture Timing
- If no contraindications present: Perform LP immediately after clinical exam, then start antibiotics 3
- If contraindications present: Start dexamethasone + antibiotics immediately, obtain CT head, then LP if safe 1, 3
CT head is indicated before LP only if:
- Age ≥60 years
- Immunocompromised state
- History of CNS disease
- New-onset seizures within past week
- Altered consciousness
- Focal neurological deficits 1
Step 5: Targeted Therapy (Once Pathogen Identified)
Adjust antibiotics based on culture and susceptibility:
- Streptococcus pneumoniae (penicillin-susceptible): Switch to penicillin G or ceftriaxone alone
- S. pneumoniae (penicillin-resistant): Continue vancomycin + ceftriaxone 2
- Neisseria meningitidis: Switch to penicillin G or ceftriaxone alone
- Listeria monocytogenes: Ampicillin + gentamicin 1, 2
Critical Management Points
Intensive Care Monitoring
All bacterial meningitis patients should be managed in ICU initially due to high risk of:
- Neurological complications (50% develop focal deficits)
- Hemodynamic instability (33% develop shock)
- Respiratory insufficiency
- Seizures 2, 3
What NOT to Do (Grade D Recommendations)
Avoid routine use of:
- Mannitol
- Acetaminophen for fever
- Prophylactic antiepileptic drugs
- Hypertonic saline
- Hypothermia (associated with HIGHER mortality)
- Glycerol (contraindicated in adults)
- Immunoglobulins, heparin, or activated protein C 2
Contact Prophylaxis (Meningococcal Cases Only)
Treat all close contacts within 24 hours with ONE of:
- Ceftriaxone: 250 mg IM single dose (preferred in pregnancy)
- Ciprofloxacin: 500 mg PO single dose (adults >16 years; avoid in pregnancy)
- Rifampicin: 600 mg PO twice daily for 2 days 2
Close contacts defined as: Household members, childcare contacts, anyone directly exposed to oral secretions 2
Common Pitfalls to Avoid
Delaying antibiotics for imaging or LP: This increases mortality. Start treatment immediately if contraindications to LP exist 3, 4
Starting dexamethasone late: Benefit is lost if not given before/with first antibiotic dose 2
Forgetting ampicillin in older adults: Listeria coverage is essential in patients >50 years 1, 3
Using glycerol or hypothermia: These are contraindicated and worsen outcomes 2
Not treating meningococcal contacts: Risk is 400-800 fold higher; prophylaxis prevents secondary cases 2