Community-Acquired Pneumonia — ABIM Board MCQ

Correct answer: D — Septic shock requiring vasopressors

The correct answer is D. Severe community-acquired pneumonia is defined by either one major criterion or at least three minor criteria. The two major criteria are septic shock requiring vasopressors and respiratory failure requiring mechanical ventilation; either indicates critical illness and supports ICU-level management. A BUN of 22 mg/dL, respiratory rate of 32/min, multilobar infiltrates, and confusion/disorientation are each minor severity criteria. Although these findings increase risk, no one of them alone meets the ATS/IDSA definition of severe CAP. Thus, septic shock requiring vasopressors is the only major criterion listed.

Reference: Infectious Diseases Society of America. Community Acquired Pneumonia (CAP) Clinical Pathway Overview, Table 2: Criteria for Defining Severe Community-acquired Pneumonia. 2026. https://www.idsociety.org/globalassets/idsa/practice-guidelines/community-acquired-pneumonia-in-adults/cap-clinical-pathway-overview.pdf