Key Points
- Use the highest‑yield diagnostic test early; do not let testing delay time‑critical therapy.
- Set objective targets (hemodynamic, neurologic, respiratory) and reassess frequently.
- Plan definitive source control or reperfusion when indicated; document follow‑up and patient education.
Algorithm
- Suspect meningitis → obtain blood cultures immediately.
- Give dexamethasone, then start empiric antibiotics without delay.
- CT head only if focal neuro signs, new seizure, immunocompromise, or papilledema; otherwise proceed directly to LP.
- Perform LP; send CSF for Gram stain, culture, cell count, glucose, protein, PCR.
- Tailor antibiotics to organism/MIC; continue dexamethasone if pneumococcal confirmed.
- Implement droplet precautions when N. meningitidis suspected; give prophylaxis to close contacts.
Clinical Synopsis & Reasoning
Treat immediately: draw blood cultures, give dexamethasone and empiric antibiotics before/with first dose, and obtain CT only when indicated (focal deficit, immunocompromise, papilledema). Tailor regimen by age/risk (Listeria coverage if >50 or immunocompromised).
Treatment Strategy & Disposition
Stabilize ABCs. Initiate guideline‑concordant first‑line therapy with precise dosing and continuous monitoring. Escalate to advanced/procedural interventions based on explicit failure criteria. Define ICU, step‑down, and ward disposition triggers; involve specialty teams early.
Epidemiology / Risk Factors
- Risk varies by comorbidity and precipitants; see citations for condition‑specific data.
Investigations
| Test | Role / Rationale | Typical Findings | Notes |
|---|---|---|---|
| CT head (only with risk features) | Safety screen for LP | Mass effect risk | Do not delay antibiotics/dexamethasone |
| Lumbar puncture | Definitive CSF | Neutrophilic pleocytosis, low glucose, high protein | Send Gram stain/culture/PCR |
| Blood cultures | Pathogen ID | Often positive | Draw before antibiotics if possible |
Pharmacology
| Medication/Intervention | Mechanism | Onset | Role in Therapy | Limitations |
|---|---|---|---|---|
| Dexamethasone 10 mg IV q6h x4 days | Glucocorticoid | Hours | Reduce neurologic sequelae (pneumococcal) | Give before/with first antibiotic dose |
| Ceftriaxone 2 g IV q12h + Vancomycin | Antibiotics | Hours | Empiric 18–50 years | Adjust to MICs |
| Add Ampicillin 2 g IV q4h | Antibiotic | Hours | Add if >50 or immunocompromised (Listeria) | Dose by renal function |
Prognosis / Complications
- Outcome depends on timeliness of diagnosis and definitive therapy; monitor for complications.
Patient Education / Counseling
- Provide red‑flag education, adherence guidance, and explicit return precautions; arrange timely specialty follow‑up.
References
- IDSA Practice Guideline: Bacterial Meningitis (Adults) — Link