What is the treatment for bacterial meningitis in infants?

Treatment of Bacterial Meningitis in Infants

For infants with suspected bacterial meningitis, immediately initiate empiric antibiotic therapy with ampicillin plus cefotaxime (or ceftriaxone) without delay, as any postponement significantly increases mortality and neurologic morbidity. 1, 2

Immediate Management Priorities

Timing is Critical

• Antibiotics must be administered within 1 hour of hospital arrival or clinical suspicion 2
• Never delay antibiotics for lumbar puncture or imaging - if LP cannot be performed immediately, obtain blood cultures and start empiric treatment first 1, 2
• Delay in antibiotic administration is strongly associated with death and poor neurological outcomes 2

Diagnostic Approach

• Obtain blood cultures before antibiotics whenever possible 2
• Perform lumbar puncture emergently unless contraindicated 1
• In neonates, clinical examination alone cannot rule out meningitis - maintain a low threshold for LP 1

Empiric Antibiotic Regimens by Age

Neonates (≤28 days postnatal age)

Ampicillin PLUS Cefotaxime 3, 2, 4

Ampicillin dosing for bacterial meningitis in neonates: 4

• Gestational age ≤34 weeks:
  • Postnatal age ≤7 days: 100 mg/kg/day divided every 12 hours
  • Postnatal age 8-28 days: 150 mg/kg/day divided every 12 hours
• Gestational age >34 weeks:
  • Postnatal age ≤28 days: 150 mg/kg/day divided every 8 hours

Cefotaxime: 200-300 mg/kg/day in divided doses 5

Rationale: This combination covers Group B Streptococcus, E. coli, other gram-negative organisms, and critically, Listeria monocytogenes (which cephalosporins do not cover) 3, 4

Infants 1-3 months

Ampicillin PLUS Cefotaxime (or Ceftriaxone) 3, 2

• Cefotaxime: 300 mg/kg/day OR Ceftriaxone: 100 mg/kg/day 5
• Ampicillin: 150-200 mg/kg/day divided every 6-8 hours 4

Key consideration: Continue ampicillin coverage for Listeria in this age group 3, 2

Infants and Children >3 months

Cefotaxime (or Ceftriaxone) PLUS Vancomycin 2, 5

• Cefotaxime: 300 mg/kg/day OR Ceftriaxone: 100 mg/kg/day 5
• Vancomycin: 60 mg/kg/day 5

Rationale: This covers S. pneumoniae (including penicillin-resistant strains), N. meningitidis, and H. influenzae 2, 5

Adjunctive Dexamethasone Therapy

Administer dexamethasone 0.15 mg/kg IV every 6 hours for 4 days, given before or with the first antibiotic dose 3, 2

• Dexamethasone reduces sensorineural hearing loss and neurologic sequelae when given early 6
• Critical timing: Must be administered before or simultaneously with antibiotics - not effective if delayed 6

Pathogen-Specific Adjustments (After Culture Results)

If Streptococcus pneumoniae identified:

• MIC to cephalosporin <0.5 mg/L: Continue cefotaxime/ceftriaxone alone for 10 days 5
• MIC ≥0.5 mg/L: Continue cefotaxime/ceftriaxone PLUS vancomycin for 14 days; consider adding rifampin; perform repeat LP to assess response 5

If Neisseria meningitidis or H. influenzae:

• Cefotaxime or ceftriaxone alone is sufficient 5
• Duration: 7-10 days for uncomplicated cases 6

If Listeria monocytogenes:

• Ampicillin (or amoxicillin) for 21 days PLUS gentamicin or trimethoprim-sulfamethoxazole 5

If Gram-negative Enterobacteriaceae (especially in neonates):

• Continue cefotaxime PLUS add aminoglycoside (amikacin or gentamicin) 5, 6
• Duration: Minimum 15-21 days for gram-negative meningitis 3, 6

Treatment Duration

• Uncomplicated bacterial meningitis: 7-10 days 6
• Gram-negative meningitis: Minimum 14-21 days 3, 6
• Neonatal meningitis: At least 15 days; 21 days for gram-negative organisms 6
• Group A Streptococcus: Minimum 10 days to prevent rheumatic fever 4
• Continue treatment for 48-72 hours beyond clinical improvement or bacterial eradication 4

Supportive Care and Monitoring

Fluid Management

• Avoid aggressive fluid resuscitation unless septic shock is present 3
• If shock develops: administer 20 mL/kg boluses of isotonic crystalloid up to 60 mL/kg total, reassessing after each bolus 3

Monitoring for Complications

• Neurologic deterioration warrants cranial imaging (MRI preferred over CT for superior resolution) 1
• Common complications include seizures (9-34% in neonates), hydrocephalus, cerebral infarctions, and shock 1
• Transfer to pediatric intensive care if patient deteriorates despite appropriate treatment 3

Repeat Lumbar Puncture

• Indicated if clinical progress is unsatisfactory or for resistant organisms 3, 5
• Not routinely necessary for uncomplicated cases 1

Follow-Up Care

Hearing Assessment (MANDATORY)

• Perform otoacoustic emission screening during admission 3
• Formal audiometry at 6-12 months post-treatment 3
• Rationale: 5-35% of bacterial meningitis survivors develop sensorineural hearing loss; 4% have severe bilateral hearing loss 1, 3

Neuropsychological Evaluation

• Assess for cognitive deficits, motor deficits, seizures, and behavioral problems 3
• Approximately one-third of survivors have persistent neurologic sequelae 1, 3

Critical Pitfalls to Avoid

1. Delaying antibiotics for any reason - imaging, LP difficulties, or awaiting cultures 2
2. Omitting ampicillin in infants <3 months - this is the only drug that covers Listeria 3, 2
3. Inadequate CSF penetration - ensure proper dosing; suboptimal doses fail to achieve therapeutic CSF levels 2
4. Forgetting dexamethasone - must be given before or with first antibiotic dose to be effective 3, 6
5. Premature discontinuation - gram-negative meningitis requires prolonged therapy (14-21 days minimum) 3, 6
6. Neglecting hearing evaluation - this is the most common preventable sequela if detected early 3