What is the treatment for meningitis?

Treatment of Meningitis

Start empiric antibiotics within 1 hour of hospital arrival for suspected bacterial meningitis—this is a neurological emergency where every hour of delay increases mortality and poor neurologic outcomes. 1, 2

Immediate Management (First 60 Minutes)

• Draw blood cultures immediately upon suspicion, but never delay antibiotics while awaiting results 1, 2
• Administer antibiotics within 60 minutes of hospital presentation, even before lumbar puncture or imaging 1, 2
• Perform lumbar puncture immediately if clinically safe—do not delay for imaging unless specific contraindications are present 2, 3
• CT imaging before lumbar puncture is only indicated if the patient has: focal neurologic deficits, new-onset seizures, severely altered mental status, or severely immunocompromised state 1, 2, 3

Critical pitfall: If imaging or lumbar puncture is delayed for any reason, start antibiotics first—bacterial meningitis cannot wait 2, 3

Empiric Antibiotic Regimens (Start Immediately)

Adults <60 Years

• Ceftriaxone 2g IV every 12 hours PLUS vancomycin 15-20 mg/kg IV every 8-12 hours 1, 2
• This combination covers Streptococcus pneumoniae (including resistant strains), Neisseria meningitidis, and Haemophilus influenzae 1, 4

Adults ≥60 Years

• Ceftriaxone 2g IV every 12 hours PLUS vancomycin 15-20 mg/kg IV every 8-12 hours PLUS ampicillin 2g IV every 4 hours 1, 2
• The addition of ampicillin is essential to cover Listeria monocytogenes, which has increased incidence in older adults 1, 2, 5

Children (1 Month to 18 Years)

• Ceftriaxone 50 mg/kg IV every 12 hours (max 2g per dose) PLUS vancomycin 10-15 mg/kg IV every 6 hours 1, 2, 6

Neonates (<1 Month)

• Ampicillin 50 mg/kg IV every 6-8 hours PLUS cefotaxime 50 mg/kg IV every 6-8 hours 1
• Ceftriaxone is contraindicated in neonates due to risk of bilirubin encephalopathy and precipitation with calcium-containing solutions 7
• If ceftriaxone must be used in neonates, administer over 60 minutes (not 30 minutes) to reduce bilirubin encephalopathy risk 1, 7

Adjunctive Dexamethasone Therapy

• Dexamethasone 10mg IV every 6 hours should be started with or just before the first antibiotic dose in adults with suspected pneumococcal meningitis 1, 2, 5
• Continue dexamethasone for 4 days if pneumococcal meningitis is confirmed 1, 2
• Dexamethasone reduces mortality and adverse neurologic outcomes by attenuating the subarachnoid inflammatory response 2, 5

Pathogen-Specific Definitive Therapy (After Culture Results)

Streptococcus pneumoniae (Pneumococcal Meningitis)

• Ceftriaxone 2g IV every 12 hours for 10-14 days 1, 2, 8
• Use the longer duration (14 days) if clinical response is delayed 8
• Alternative: Benzylpenicillin 2.4g IV every 4 hours if MIC <0.5 mg/L 1, 6

Neisseria meningitidis (Meningococcal Meningitis)

• Ceftriaxone 2g IV every 12 hours for 5-7 days 1, 2, 8
• This is the shortest duration among bacterial causes 8
• Alternative: Benzylpenicillin 2.4g IV every 4 hours 1, 5

Listeria monocytogenes

• Ampicillin 2g IV every 4 hours for 21 days 1, 2, 8
• The 21-day duration is essential due to the intracellular nature of this pathogen 8, 4
• Alternative: Co-trimoxazole 10-20 mg/kg IV in 4 divided doses 1
• Common pitfall: Listeria is frequently undertreated—ensure the full 21-day course 8

Haemophilus influenzae

• Ceftriaxone 2g IV every 12 hours for 10 days 8, 6

Staphylococcus aureus

• At least 14 days of therapy is recommended 8

Gram-Negative Bacilli (Enterobacteriaceae)

• 21 days of treatment is required 8

Special Considerations

Penicillin Allergy

• Chloramphenicol 25 mg/kg IV every 6 hours is the recommended alternative 1, 4

Culture-Negative Meningitis

• Continue empiric treatment for at least 14 days when CSF is suggestive of bacterial meningitis but cultures and PCR remain negative 8

High Penicillin-Resistant Pneumococci Regions

• Add vancomycin 15-20 mg/kg IV every 12 hours OR rifampicin 600mg every 12 hours if recent travel to high-resistance areas 2, 3

Viral Meningitis (Herpes Simplex Encephalitis)

• Aciclovir 10-15 mg/kg IV every 8 hours for 10-14 days 1

Critical Pitfalls to Avoid

• Never delay antibiotics for lumbar puncture or imaging—bacterial meningitis is a time-sensitive emergency where every hour counts 2, 9, 3
• Do not shorten treatment duration based on early clinical improvement alone—complete the full pathogen-specific course 2, 8
• Do not use short-course therapy (5-7 days) for pneumococcal meningitis—this requires 10-14 days minimum 8
• Ensure adequate treatment duration for Listeria (21 days)—this is frequently undertreated due to confusion with other bacterial causes 8
• Do not use diluents containing calcium with ceftriaxone due to precipitation risk 7
• Extend therapy if clinical response is delayed—standard durations assume appropriate clinical improvement 8