Key Points
- Use the highest‑yield diagnostic test early; do not let testing delay time‑critical therapy.
- Set objective targets and reassess frequently.
- Plan definitive source control or disease‑specific therapy when indicated; document follow‑up and patient education.
Algorithm
- Draw blood cultures; start dexamethasone and empiric antibiotics immediately.
- Assess need for head CT; perform LP if safe; tailor therapy to CSF and cultures.
- Monitor for complications (seizures, SIADH); manage ICP; complete vaccination counseling.
Clinical Synopsis & Reasoning
Give empiric antibiotics immediately after blood cultures; dexamethasone should precede or accompany first antibiotic dose in suspected pneumococcal meningitis. CT before LP if focal deficit, seizure, immunocompromise, or papilledema; otherwise proceed directly to LP.
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 |
|---|
| Blood cultures and immediate empiric therapy | Timing | Do not delay antibiotics | Outcome critical |
| LP with CSF studies (cell count, glucose, protein, Gram stain/culture) | Diagnosis | Neutrophilic pleocytosis, low glucose | Targeted therapy |
| Head CT prior to LP (selected) | Safety | Raised ICP risk | Avoid delay if not indicated |
High-Risk & Disposition Triggers
| Trigger | Why it matters | Action |
|---|
| Sepsis, shock, or respiratory compromise | High mortality | ICU; early vasopressors/airway |
| Immunocompromise, age >50, or pregnancy | Listeria risk | Add ampicillin; ID consult |
| New focal deficit, seizures, or papilledema | Raised ICP risk | CT before LP; do not delay antibiotics |
| Petechial rash/purpura | Meningococcemia | Public health notification; prophylaxis for contacts |
| Delayed presentation >24 h | Worse outcomes | Aggressive management and monitoring |
Pharmacology
| Medication/Intervention | Mechanism | Onset | Role in Therapy | Limitations |
|---|
| Ceftriaxone 2 g IV q12h + Vancomycin (trough 15–20) ± Ampicillin 2 g IV q4h (>50 yrs/immunocompromise) | Empiric antibiotics | Hours | Cover S. pneumoniae, N. meningitidis, Listeria | Adjust to susceptibilities |
| Dexamethasone 10 mg IV q6h ×4 days | Adjunct | Immediate | Reduce neurologic sequelae (pneumococcus) | Start before/with first dose |
| Droplet precautions and prophylaxis for contacts (meningococcus) | Public health | Hours | Prevent spread | Rifampin/ciprofloxacin |
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 meningitis guidelines — Link