In 2019, the American Thoracic Society/Infectious Disease Society of America (ATS/IDSA) revised their guidelines towards the evaluation and management of Community Acquired Pneumonia (CAP). Regardless of the criticisms regarding the quality of evidence, there are quite a few recommendations I think are worth noting for my co-residents.

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Evaluation

First, recall 2007 recommendations on classifying CAP as non-severe or severe

• Severe is 1 Major Criteria or ≥ 3 Minor Criteria

• Sputum and Blood Cultures? Obtain Sputum/Blood cultures ONLY in severe disease or history of MRSA/Pseudomonas
• Legionella Ag? Legionella testing only in Severe CAP or if known outbreak.
• Procalcitonin? Procalcitonin does not substitute clinical judgement in decision to treat even if  Procalcitonin levels are low.
• Risk Stratification? Pneumonia Severity Index (PSI) is recommended over CURB-65 for prognostication.

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The guidelines also revised their recommendations regarding treatment options. Given that most are tagged with a low or moderate quality of evidence, we as clinicians are obviously encouraged to use our clinical judgement by monitoring for clinical improvement and to use our hospital biograms.

Treatment | Inpatient

• Empirically treating patients with broad spectrum antibiotics (Vancomycin and Zosyn/Cefepime) just because of hospitalization within the past 90 days is no longer recommended.
• Non-Severe CAP with no MRSA/Pseudomonas risk factors
  • Combo therapy: Beta-lactam + Macrolide
  • Monotherapy: Respiratory Floroquinolone
  • May use Beta-lactam + Doxycycline if contraindication to Macrolide or Quinolone
• Severe CAP with no/low suspicion for MRSA/Pseudomonas
  • Combo therapy: Beta-lactam + Macrolide OR Beta-lactam + Floroquinolone
• Do not need to cover for Anaerobes unless concerns for lung abscess or empyema.
• Use Vancomycin for MRSA history or Zosyn or Cefepime for Pseudomonas history
• De-escalate MRSA/Pseudomonas coverage based on cultures.
• Steroids: not recommended.
• Treatment length of at least 5 days and patient achieving clinical stability.

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Treatment | Outpatient

• No comorbidities: Amoxicillin 1g TID, Doxycycline 100 BID, or Azithromycin 250 daily (if local resistance to macrolides <25%)
• Comorbidities (CHF, Liver disease, Renal disease, Diabetes, EtOH, Cancer, Asplenia)
  • Combo therapy with Augmentin 500/125 TID or 875/125 BID or Cephalosporin (Cefpodoxime 200mg BID or Cefuroxime 500mg BID) + Macrolide (or Doxycycline if contraindication to macrolide).
  • Monotherapy with respiratory Floroquinolone

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As a summary….

I’m a big fan of the history of medicine and it is interesting to see how these guidelines have changed.

References

1. American Journal of Respiratory and Critical Care Medicine, Volume 200, Issue 7, 1 October 2019, Pages e45-e67,  https://www.atsjournals.org/doi/full/10.1164/rccm.201908-1581ST
2. PulmCCM, October 21, 2019. Jon-Emile S. Kenny. “2019 IDSA Guidelines for Community Acquired Pneumonia in Adults: To HCAP, we just say fare thee well.”

Post reviewed and edited by @udaygulati

• Infectious Disease
• Pulmonology