Suspected Bacterial Meningitis
Fever + headache + neck stiffness, or altered mental status with infectious symptoms
All Pathways
Infectious DiseaseEmergency
Bacterial Meningitis Management (IDSA 2004)
Bacterial Meningitis Management (IDSA 2004): Suspected Bacterial Meningitis → Rapid Clinical Assessment → CT Before LP Indicated? → START Empiric Antibi...
Pathway Overview
15 steps
Algorithm Steps
15 total
01Start 02Action Rapid Clinical Assessment
Assess severity and identify contraindications to LP
- Meningeal signs: Nuchal rigidity, Kernig sign, Brudzinski sign
- Neurologic exam: GCS, focal deficits, papilledema
- Signs of sepsis/shock
- Petechial/purpuric rash (suggests N. meningitidis)
03Decision CT Before LP Indicated?
Assess for contraindications to immediate LP
- CT BEFORE LP if: Immunocompromised, CNS disease history, new-onset seizure, papilledema, altered consciousness, focal neurologic deficit
- If none present, proceed directly to LP
04Action START Empiric Antibiotics IMMEDIATELY
Do NOT delay antibiotics for CT or LP
- Blood cultures x2 first (if <30 min delay)
- Dexamethasone 0.15 mg/kg IV q6h BEFORE or WITH first antibiotic dose
- Empiric antibiotics within 1 hour of presentation
- Continue dexamethasone x4 days if pneumococcal meningitis
05Action CT Head (without contrast)
Evaluate for mass effect, abscess, hemorrhage
- Give antibiotics BEFORE CT
- LP after CT if no mass effect/herniation risk
06Action Empiric Antibiotic Selection by Age
Based on most likely pathogens
- Age 2-50: Ceftriaxone 2g IV q12h + Vancomycin 15-20 mg/kg IV q8-12h
- Age >50 or immunocompromised: ADD Ampicillin 2g IV q4h (for Listeria)
- Penicillin allergy: Meropenem + Vancomycin (or Chloramphenicol + TMP-SMX)
- Target vancomycin trough 15-20 mcg/mL
07Decision CSF Results
Interpret CSF findings
- Bacterial: WBC >1000 (PMN predominant), protein >100, glucose <40 (ratio <0.4)
- Gram stain: 60-90% sensitive if untreated
- Opening pressure typically >25 cm H2O
08Action Gram-Positive Cocci
Likely S. pneumoniae
- Continue Ceftriaxone + Vancomycin
- Narrow when susceptibilities available
- If PCN-susceptible: Penicillin G or Ampicillin
- Continue dexamethasone x4 days
09Action Treatment Duration & Monitoring
Pathogen-specific duration
- N. meningitidis: 7 days
- H. influenzae: 7 days
- S. pneumoniae: 10-14 days
- S. agalactiae: 14-21 days
- L. monocytogenes: 21 days or longer
- Gram-negative bacilli: 21 days
10Warning Watch for Complications
Monitor for neurologic and systemic complications
- Seizures: ~30% of patients
- Cerebral edema/herniation
- Hearing loss (especially pneumococcal)
- Subdural effusion/empyema
- Hydrocephalus
- SIADH/cerebral salt wasting
11Outcome Clinical Improvement
Defervescence typically within 3-5 days
- Repeat LP if no improvement by 48-72 hours
- Consider imaging for persistent symptoms
- Hearing evaluation before discharge
12Warning Poor Response
No improvement or worsening
- Repeat LP and imaging
- Consider resistant organism
- Evaluate for complications (abscess, empyema)
- Neurosurgery consultation if needed
13Action Gram-Negative Diplococci
Likely N. meningitidis
- Continue Ceftriaxone (can discontinue vancomycin)
- Duration: 7 days
- Close contacts: Chemoprophylaxis (rifampin, ciprofloxacin, or ceftriaxone)
- Report to public health
- Path rejoins step 09Shared downstream outcome
14Action Gram-Negative Rods
Listeria, H. influenzae, or Enterobacteriaceae
- GNR: Consider Ceftriaxone + Ampicillin
- If Listeria suspected: Ampicillin + Gentamicin
- If resistant GNR: Meropenem
- Duration: 21 days for Listeria, 7-14 days for others
- Path rejoins step 09Shared downstream outcome
15Action Proceed to LP
No CT contraindications - perform LP immediately
- Opening pressure measurement
- CSF: Cell count, protein, glucose, Gram stain, culture
- Consider: Latex agglutination, PCR panel
- Blood glucose for CSF:serum ratio
- Path rejoins step 06Shared downstream outcome
Guideline Source
Practice Guidelines for the Management of Bacterial Meningitis - IDSA 2004
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Does not replace clinical judgment - individual patient factors may require deviation
- Antibiotic choices should be guided by local resistance patterns
- Does not address pediatric-specific dosing in detail
- CSF interpretation requires clinical correlation
- Immunocompromised patients may require broader coverage
Contraindicated Populations
neonatal
Applicable Regions
USEUInternational
EU: Similar approach; consider local pneumococcal resistance patterns
US: Ceftriaxone + vancomycin empiric therapy standard; add ampicillin for Listeria coverage if >50 years
International: Resource-limited settings may require modified approaches based on available antibiotics
Version 1Next review: 2027-01-01
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Frequently Asked Questions
What is the Bacterial Meningitis Management (IDSA 2004)?
The Bacterial Meningitis Management (IDSA 2004) is a emergency clinical algorithm for Infectious Disease. It provides a structured decision tree to guide clinical decision-making, based on Practice Guidelines for the Management of Bacterial Meningitis - IDSA 2004.
What guideline is the Bacterial Meningitis Management (IDSA 2004) based on?
This algorithm is based on Practice Guidelines for the Management of Bacterial Meningitis - IDSA 2004 (DOI: 10.1086/425368).
What are the limitations of the Bacterial Meningitis Management (IDSA 2004)?
Known limitations include: Does not replace clinical judgment - individual patient factors may require deviation; Antibiotic choices should be guided by local resistance patterns; Does not address pediatric-specific dosing in detail; CSF interpretation requires clinical correlation; Immunocompromised patients may require broader coverage. Individual patient factors may require deviation from these recommendations.
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