What is the appropriate management for a patient with suspected meningitis, considering different types and patient histories?

Management of Suspected Meningitis

Antibiotics must be administered within 1 hour of hospital arrival, and dexamethasone 10 mg IV should be given immediately before or simultaneously with the first antibiotic dose. 1

Immediate Actions (Within First Hour)

Initial Assessment and Stabilization

• Obtain blood cultures immediately before any antibiotics are given, but do not delay antibiotic administration beyond 1 hour to obtain them 1, 2
• Document Glasgow Coma Scale score and assess for signs of shock, sepsis, or rapidly evolving rash 2
• Examine pupils carefully, as pupillary abnormalities indicate impending cerebral herniation and contraindicate immediate lumbar puncture 2

Decision Point: Can Lumbar Puncture Be Performed Immediately?

Contraindications to immediate LP include: 2

• GCS ≤12 (or drop of >2 points)
• Focal neurological signs or abnormal pupils
• Papilledema
• Continuous or uncontrolled seizures
• Immunocompromised state
• History of CNS disease (mass lesion, stroke, focal infection)
• New onset seizure within 1 week

If NO contraindications present:

• Perform LP immediately (within 1 hour of arrival) 1, 2
• Start antibiotics and dexamethasone immediately after LP 1

If contraindications ARE present:

• Start antibiotics and dexamethasone immediately after blood cultures (do not wait for imaging) 1, 2
• Obtain non-contrast CT head to assess for mass effect, brain swelling, or midline shift 3
• Perform LP only if CT shows no contraindications 3

Empiric Antibiotic Regimens

Adults <60 Years (Immunocompetent)

Ceftriaxone 2g IV every 12 hours PLUS Vancomycin 15-20 mg/kg IV every 8-12 hours 1, 4

• This regimen covers Streptococcus pneumoniae (including penicillin-resistant strains), Neisseria meningitidis, and Haemophilus influenzae 1, 4
• Vancomycin is essential in areas where pneumococcal resistance to penicillin exceeds 1% 5

Adults ≥60 Years OR Immunocompromised

Ceftriaxone 2g IV every 12 hours PLUS Vancomycin 15-20 mg/kg IV every 8-12 hours PLUS Amoxicillin 2g IV every 4 hours 1

• The addition of amoxicillin/ampicillin is critical for Listeria monocytogenes coverage 1, 6
• Risk factors for Listeria include age >50 years, diabetes, immunosuppressive drugs (including TNF-alpha inhibitors), cancer, and other immunocompromising conditions 1, 3

Neonates (≤28 Days)

Amoxicillin/ampicillin PLUS Cefotaxime 1

• Critical warning: Ceftriaxone is contraindicated in neonates requiring calcium-containing IV solutions due to risk of fatal ceftriaxone-calcium precipitation 4
• Administer IV doses over 60 minutes in neonates to reduce risk of bilirubin encephalopathy 4

Children

Cefotaxime or Ceftriaxone PLUS Vancomycin or Rifampicin 1

• For meningitis specifically, initial dose is 100 mg/kg ceftriaxone (not to exceed 4 grams), then 100 mg/kg/day thereafter 4

Adjunctive Dexamethasone Therapy

Dexamethasone 10 mg IV every 6 hours should be given to ALL patients with suspected bacterial meningitis 7, 1, 6

Timing and Duration

• Administer immediately before or simultaneously with first antibiotic dose 7, 1
• Can still be initiated up to 12 hours after first antibiotic dose if not given initially 7
• Continue for 4 days if pneumococcal meningitis is confirmed or probable based on CSF parameters 7, 1
• Stop dexamethasone if another cause is confirmed (especially Listeria monocytogenes) 7, 5

Evidence Base

Dexamethasone reduces mortality and neurological morbidity specifically in pneumococcal meningitis 1, 6, 8

Critical Care Criteria

Transfer to ICU is mandatory for patients with: 7, 1

• Rapidly evolving rash (suggests meningococcal sepsis)
• GCS ≤12 or drop of >2 points
• Cardiovascular instability or evidence of severe sepsis
• Hypoxia or respiratory compromise
• Uncontrolled or frequent seizures
• Requiring monitoring or specific organ support

Strongly consider intubation if GCS <12 7, 1

Duration of Antibiotic Therapy

Once pathogen is identified, adjust therapy accordingly: 1

• Streptococcus pneumoniae: Continue ceftriaxone/cefotaxime for 10 days
• Neisseria meningitidis: 5 days of therapy, plus single dose ciprofloxacin 500mg PO for eradication
• Streptococcus pyogenes: Minimum 10 days of therapy 4
• Listeria monocytogenes: Typically 21 days (based on general medicine knowledge)

Common Pitfalls to Avoid

Timing Errors

• Never delay antibiotics for imaging - this increases mortality 1, 2, 6
• Never delay antibiotics beyond 1 hour waiting for LP if contraindications exist 1, 2
• Delayed antibiotic initiation is strongly associated with death and poor neurological outcomes 1

Coverage Gaps

• Failing to add ampicillin/amoxicillin in patients >50 years or immunocompromised misses Listeria coverage 1, 6
• Not recognizing that TNF-alpha inhibitors (like Humira) significantly increase Listeria risk 3
• Using suboptimal antibiotic doses that don't achieve adequate CSF penetration 1

Dexamethasone Errors

• Not giving dexamethasone early enough (must be with or before first antibiotic dose for maximum benefit) 7, 1
• Continuing dexamethasone if Listeria is confirmed (may worsen outcomes) 5

Procedural Errors

• Performing LP in patients with contraindications, risking cerebral herniation 3, 2
• Not obtaining blood cultures before antibiotics (reduces diagnostic yield) 1, 2

Special Considerations for Outpatient Therapy

After initial stabilization, consider outpatient parenteral antibiotic therapy (OPAT) if: 7

• Patient is afebrile and clinically improving
• Has reliable IV access and no other acute medical needs
• Patient and family are willing to participate

OPAT regimen: Ceftriaxone 2g IV twice daily (can switch to once daily after first 24 hours) 7

• Once daily dosing achieves adequate CSF concentrations after the first 24 hours, but twice daily is required initially for rapid CSF sterilization 7