What is the treatment for meningitis?

Treatment for Meningitis

Start empiric antibiotics immediately within 1 hour of hospital arrival upon clinical suspicion of bacterial meningitis, even before lumbar puncture or imaging, as every hour of delay significantly increases mortality and poor neurologic outcomes. 1, 2

Immediate Actions (First 60 Minutes)

• Draw blood cultures immediately upon suspicion, but do not delay antibiotics while awaiting any test results 1, 2
• Administer empiric antibiotics within 60 minutes of hospital presentation—this is the single most critical intervention affecting survival 1, 2, 3
• Perform lumbar puncture immediately if clinically safe; if imaging or contraindications delay LP, give antibiotics first 2, 4
• CT imaging before LP is only indicated for: focal neurologic deficits, new-onset seizures, severely altered mental status, or severely immunocompromised state 1, 2

Empiric Antibiotic Regimens by Age

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 penicillin-resistant Streptococcus pneumoniae (37% resistance rate) and other common pathogens 1, 5

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 ampicillin addition is essential to cover Listeria monocytogenes, which has increased incidence in this age group 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
• Alternative: cefotaxime 300 mg/kg per day can replace ceftriaxone 6

Neonates (<1 Month)

• Ampicillin 50 mg/kg IV every 6-8 hours PLUS cefotaxime 50 mg/kg IV every 6-8 hours 1
• Critical warning: Ceftriaxone is contraindicated in neonates receiving calcium-containing IV solutions due to fatal precipitation risk 7
• Administer IV doses over 60 minutes in neonates to reduce bilirubin encephalopathy risk 7

Adjunctive Dexamethasone Therapy

• Give dexamethasone 10mg IV every 6 hours with or just before the first antibiotic dose in adults with suspected pneumococcal meningitis 1, 2, 4
• Continue for 4 days if pneumococcal meningitis is confirmed 1, 2
• Dexamethasone reduces mortality and adverse neurologic outcomes by attenuating subarachnoid inflammation 2, 4
• Also recommended in children with suspected S. pneumoniae or H. influenzae meningitis 4

Pathogen-Specific Definitive Therapy (After Culture Results)

Streptococcus pneumoniae (Pneumococcal Meningitis)

• Ceftriaxone 2g IV every 12 hours for 10-14 days 1, 2, 8
• If MIC <0.5 mg/L, continue ceftriaxone alone 6
• If MIC ≥0.5 mg/L, continue ceftriaxone plus vancomycin, consider adding rifampicin, and perform repeat LP to document CSF sterilization 6
• Use the longer 14-day duration if clinical response is delayed 8

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 if no penicillin resistance 1, 4

Listeria monocytogenes

• Ampicillin 2g IV every 4 hours for 21 days 1, 2, 8
• Alternative: co-trimoxazole 10-20 mg/kg IV in 4 divided doses 1
• Add gentamicin for synergy in severe cases 6
• Common pitfall: This pathogen is frequently undertreated—the full 21-day course is essential due to its intracellular nature 8

Haemophilus influenzae

• Ceftriaxone 2g IV every 12 hours for 10 days 8, 6
• Third-generation cephalosporin alone is sufficient (12% resistance rate to penicillin) 5

Gram-Negative Bacilli (Enterobacteriaceae)

• Ceftriaxone 2g IV every 12 hours for 21 days 8
• Add aminoglycosides, especially in neonates <3 months 6

Staphylococcus aureus

• Continue vancomycin-containing regimen for at least 14 days 8

Culture-Negative Bacterial Meningitis

• If CSF suggests bacterial meningitis but cultures/PCR are negative, continue empiric treatment for at least 14 days 8

Special Situations

Penicillin Allergy

• Chloramphenicol 25 mg/kg IV every 6 hours 1
• Alternative combinations may include vancomycin, fluoroquinolones, or linezolid depending on severity 5

High Penicillin-Resistant Pneumococcal Risk (Recent Travel)

• Add vancomycin 15-20 mg/kg IV every 12 hours OR rifampicin 600mg every 12 hours to standard regimen 2

Viral Meningitis (Herpes Simplex)

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

Critical Administration Details

• Ceftriaxone should be infused over 30 minutes in adults, 60 minutes in neonates 7
• Never use calcium-containing diluents (Ringer's, Hartmann's) with ceftriaxone—fatal precipitation can occur 7
• In non-neonates, ceftriaxone and calcium solutions may be given sequentially if lines are thoroughly flushed 7
• Maximum daily ceftriaxone dose: 4g in adults, 4g in children with meningitis 7

Critical Pitfalls to Avoid

• Never delay antibiotics for LP or imaging—bacterial meningitis is a neurological emergency where every hour counts 2, 9, 3, 4
• Do not shorten treatment based on early clinical improvement—complete the full pathogen-specific course 2, 8
• Do not use short-course therapy (5-7 days) for pneumococcal meningitis—requires minimum 10-14 days 8
• Ensure full 21-day course for Listeria—this is the most commonly undertreated pathogen due to confusion with other causes 8
• Do not forget ampicillin in patients ≥60 years—Listeria coverage is essential in this population 1, 2