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
- Confirm infiltrate; assess severity with PSI/CURB‑65; decide site of care.
- Start empiric antibiotics tailored to risk; obtain cultures in severe disease.
- Reassess at 48–72 h; switch to PO when stable; total duration typically 5–7 days if improving.
Clinical Synopsis & Reasoning
Fever, cough, pleuritic chest pain with infiltrate on imaging. Use PSI or CURB‑65 for disposition. Start guideline‑concordant empiric antibiotics and consider MRSA/Pseudomonas coverage based on risk factors; treat for atypicals as indicated and switch to oral therapy when stable.
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 |
|---|
| CXR (or CT if equivocal) | Diagnosis | New infiltrate | Required for diagnosis |
| Pulse ox/ABG and labs (CBC, BMP, procalcitonin optional) | Severity | Hypoxemia/severity | Guide site of care |
| Cultures (in severe CAP) and viral testing | Etiology | Pathogen ID | Tailor therapy |
High-Risk & Disposition Triggers
| Trigger | Why it matters | Action |
|---|
| Septic shock or respiratory failure | High mortality | ICU; broad therapy; NIV/intubation |
| CURB-65 ≥3 or PSI Class IV–V | High risk | Admit; telemetry |
| MRSA/Pseudomonas risk factors | Inadequate coverage risk | Add specific agents |
| Severe CAP criteria (1 major or ≥3 minor) | ICU indication | Escalate care |
| Pregnancy or significant immunosuppression | Complex course | ID/OB consults |
Pharmacology
| Medication/Intervention | Mechanism | Onset | Role in Therapy | Limitations |
|---|
| Outpatient: Amoxicillin/clavulanate + Azithromycin (or Doxycycline) | Empiric | Hours | Typical + atypical coverage | Allergy/resistance considerations |
| Inpatient non‑ICU: Ceftriaxone + Azithromycin (or Respiratory fluoroquinolone) | Empiric | Hours | Severe risk coverage | — |
| Add MRSA (vancomycin/linezolid) or Pseudomonas (piperacillin‑tazobactam/cefepime) if risk factors | Expanded coverage | Hours | Risk‑based | De‑escalate with cultures |
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/ATS guideline on community-acquired pneumonia — Link