Community-acquired pneumonia

From IDWiki

Background

Microbiology

Clinical Manifestations

  • Acute onset cough, dyspnea, and fever
  • If effusion, consider Legionella

Severity

  • Per IDSA guidelines1, severe CAP includes either one major criterion or three or more minor criteria
  • Minor criteria
    • Respiratory rate ≥ 30 breaths/min
    • PaO2/FiO2 ratio ≤ 250
    • Multilobar infiltrates
    • Confusion/disorientation
    • Uremia (blood urea nitrogen level ≥ 20 mg/dl)
    • Leukopenia not due to chemotherapy (white blood cell count < 4,000 cells/μl)
    • Thrombocytopenia (platelet count < 100,000/μl)
    • Hypothermia (core temperature < 36°C)
    • Hypotension requiring aggressive fluid resuscitation
  • Major criteria
    • Septic shock with need for vasopressors
    • Respiratory failure requiring mechanical ventilation

Investigations

  • Always add Legionella testing in immunocompromised, critical illness, recent travel, significant alcohol, and consider when pleural effusion is present

Further Reading

  1. Gadsby NJ, Musher DM. The Microbial Etiology of Community-Acquired Pneumonia in Adults: from Classical Bacteriology to Host Transcriptional Signatures. Clin Microbiol Rev. 2022 Sep 27:e0001522. doi: 10.1128/cmr.00015-22. Epub ahead of print. PMID: 36165783.

References

  1. ^  Joshua P. Metlay, Grant W. Waterer, Ann C. Long, Antonio Anzueto, Jan Brozek, Kristina Crothers, Laura A. Cooley, Nathan C. Dean, Michael J. Fine, Scott A. Flanders, Marie R. Griffin, Mark L. Metersky, Daniel M. Musher, Marcos I. Restrepo, Cynthia G. Whitney. Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America. American Journal of Respiratory and Critical Care Medicine. 2019;200(7):e45-e67. doi:10.1164/rccm.201908-1581st.