What is the recommended empiric treatment and overall management for a patient with suspected Neisseria meningitidis meningitis, including antibiotics, adjunctive dexamethasone, infection control precautions, and chemoprophylaxis for close contacts?

Management of Suspected Neisseria meningitidis Meningitis

For suspected Neisseria meningitidis meningitis, initiate ceftriaxone 2g IV every 12 hours (or cefotaxime 2g IV every 4-6 hours) within 60 minutes of hospital arrival, start adjunctive dexamethasone 10mg IV every 6 hours for 4 days with or before the first antibiotic dose, implement droplet precautions for 24 hours after antibiotics begin, and provide chemoprophylaxis (ciprofloxacin 500mg PO once or rifampin 600mg PO twice daily for 2 days) to all close contacts within 24 hours of case identification. 1, 2, 3

Immediate Antibiotic Therapy

Critical Timing

• Administer antibiotics within 60 minutes of hospital presentation—delays beyond this window directly increase mortality and neurological sequelae. 1, 2, 3
• Start antibiotics immediately on clinical suspicion without waiting for lumbar puncture, CSF results, or imaging. 4, 1
• Obtain blood cultures before antibiotics but never delay treatment beyond 1 hour to obtain them. 1, 2
• If CT imaging is required (focal deficits, new seizures, GCS <10, severe immunocompromise), give antibiotics first, then image. 1, 2, 3

Empiric Antibiotic Regimens by Age

Adults 18-50 years (immunocompetent):

• Ceftriaxone 2g IV every 12 hours OR cefotaxime 2g IV every 4-6 hours 4, 1, 2
• Add vancomycin 15-20 mg/kg IV every 8-12 hours (target trough 15-20 µg/mL) only if recent travel to areas with high pneumococcal resistance 4, 1, 2

Adults >50 years or immunocompromised:

• Ceftriaxone 2g IV every 12 hours OR cefotaxime 2g IV every 4-6 hours 4, 1, 2
• PLUS ampicillin 2g IV every 4 hours (for Listeria coverage) 4, 1, 2, 3
• PLUS vancomycin 15-20 mg/kg IV every 8-12 hours if pneumococcal resistance suspected 4, 1, 2

Children 1 month to 18 years:

• Ceftriaxone 50 mg/kg IV every 12 hours (max 2g/dose) OR cefotaxime 75 mg/kg IV every 6-8 hours 4, 3
• PLUS vancomycin 10-15 mg/kg IV every 6 hours (target trough 15-20 µg/mL) 4, 3

Neonates <1 month:

• <1 week: Ampicillin 50 mg/kg IV every 8 hours + cefotaxime 50 mg/kg IV every 8 hours + gentamicin 2.5 mg/kg IV every 12 hours 4, 3
• 1-4 weeks: Ampicillin 50 mg/kg IV every 6 hours + cefotaxime 50 mg/kg IV every 6-8 hours + gentamicin 2.5 mg/kg IV every 8 hours 4, 3

Adjunctive Dexamethasone

Dosing and timing:

• Adults: Dexamethasone 10mg IV every 6 hours for 4 days 4, 1, 5
• Children: Dexamethasone 0.15 mg/kg IV every 6 hours for 2-4 days 4, 6
• Give dexamethasone with or 10-20 minutes before the first antibiotic dose 4, 5
• Can still be started up to 4 hours after antibiotics if initially omitted 4

Evidence for meningococcal meningitis:

• For N. meningitidis, dexamethasone shows no clear benefit or harm—the decision to continue can be made on an individual basis, though most guidelines support its use given the lack of harm. 4
• The primary benefit of dexamethasone is for S. pneumoniae and H. influenzae meningitis (reduces mortality and hearing loss), but it is recommended to start empirically before pathogen identification. 4, 5
• Discontinue dexamethasone if Listeria is identified, as it increases mortality in neurolisteriosis. 4

Mechanism and safety:

• Dexamethasone reduces subarachnoid inflammation, cerebral edema, and intracranial pressure without impairing vancomycin CSF penetration when adequate dosing is used. 7, 5, 8

Pathogen-Specific De-escalation

Once N. meningitidis is confirmed:

• Continue ceftriaxone 2g IV every 12 hours OR cefotaxime 2g IV every 6 hours for 5-7 days total 1, 2, 3
• If penicillin-sensitive (MIC <0.1 mg/L), may switch to benzylpenicillin 2.4g IV every 4 hours 3
• Discontinue vancomycin and ampicillin if they were added empirically 2, 3
• Give a single dose of ciprofloxacin 500mg PO to the patient to eliminate nasopharyngeal carriage 2

Infection Control Precautions

Droplet precautions:

• Implement droplet precautions immediately upon suspicion of meningococcal meningitis 1
• Continue for 24 hours after effective antibiotics are started 1
• Healthcare workers require surgical masks when within 3 feet of the patient 1

Chemoprophylaxis for Close Contacts

Who requires prophylaxis:

• Household members, daycare contacts, anyone with direct exposure to oral secretions (kissing, sharing utensils, intubation, suctioning) within 7 days before symptom onset 1, 2
• Healthcare workers who had unprotected direct exposure to respiratory secretions 1

Prophylaxis regimens (choose one):

• Ciprofloxacin 500mg PO single dose (preferred for adults) 2
• Rifampin 600mg PO twice daily for 2 days (adults); 10 mg/kg PO twice daily for 2 days (children) 2
• Ceftriaxone 250mg IM single dose (alternative, especially in pregnancy) 2

Timing:

• Administer prophylaxis within 24 hours of case identification—efficacy decreases significantly after this window 1, 2

Common Pitfalls to Avoid

• Never delay antibiotics for lumbar puncture or imaging—the 1-hour window is absolute and non-negotiable. 4, 1, 2
• Never omit ampicillin in patients ≥50 years or immunocompromised when meningococcal meningitis is not yet confirmed, as Listeria coverage is essential until pathogen identification. 1, 2, 3
• Never underdose antibiotics—meningitis requires high-dose therapy (ceftriaxone 2g every 12 hours, not lower doses) to achieve adequate CSF penetration. 2, 3
• Never fail to provide chemoprophylaxis to close contacts—this is a public health emergency requiring immediate contact tracing and prophylaxis within 24 hours. 1, 2
• Never continue dexamethasone if Listeria is identified—this increases mortality and must be stopped immediately. 4
• Never assume adequate coverage without considering local resistance patterns—add vancomycin if recent travel to high-resistance areas or local resistance rates are elevated. 4, 1, 2