A 62-year-old man is admitted with community-acquired pneumonia: temperature 39.2°C, HR 112, BP 98/60 mmHg, RR 28, new consolidation in left lower lobe, creatinine 2.1 mg/dL, BUN 38 mg/dL. PSI (PORT) score places him in Class V. Which statement regarding site of care is MOST accurate?

• A PSI Class V patients can be treated as outpatients with oral amoxicillin
• B CURB-65 score is superior to PSI for determining ICU admission
• C Procalcitonin level should guide antibiotic initiation, not severity scores
• D PSI Class V patients have the highest mortality risk and require ICU-level care or hospital admission ✓

Explanation

The PSI (Pneumonia Severity Index) classifies CAP into Risk Classes I–V: Class V (score >130) carries the highest 30-day mortality (>27%) and mandates hospital admission; ICU admission should be considered using ATS/IDSA criteria (major: septic shock or mechanical ventilation; minor: ≥3 of respiratory rate ≥30, PaO2/FiO2 <250, multilobar infiltrates, confusion, BUN ≥20, leukopenia, thrombocytopenia, hypothermia, hypotension requiring fluids). Both PSI and CURB-65 are validated tools; neither alone determines ICU need. Procalcitonin guides antibiotic duration, not initiation.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.