Practice Guidelines

Community-Acquired Pneumonia: Updated Recommendations from the ATS and IDSA

 

Am Fam Physician. 2020 Jul 15;102(2):121-124.

Author disclosure: No relevant financial affiliations.

Key Points for Practice

• Routine blood cultures, sputum cultures, and urinary antigen testing are not beneficial in patients with nonsevere CAP.

• The Pneumonia Severity Index is recommended to determine the need for hospitalization, whereas the ATS/IDSA criteria for severe CAP are recommended to predict the need for intensive care.

• Routine treatment of CAP with macrolide monotherapy is no longer recommended unless local resistance is low. Amoxicillin and doxycycline are preferred in low-risk patients.

• Five-day treatment courses are recommended for all patients with CAP, with reassessment following treatment.

From the AFP Editors

The American Thoracic Society (ATS) and the Infectious Diseases Society of America (IDSA) recently updated their recommendations on the diagnosis and treatment of community-acquired pneumonia (CAP). This guideline focuses on immunocompetent U.S. adults who have not recently traveled internationally, particularly to regions with emerging respiratory pathogens. It predates the coronavirus disease 2019 (COVID-19) pandemic.

The ATS/IDSA guideline replaces grading of CAP by care setting (e.g., outpatient, inpatient general care, intensive care unit [ICU]) because decisions about the site of care can vary widely. Instead, the updated recommendations are based on validated illness severity criteria, as shown in Table 1. Severe CAP is defined as the presence of one major criterion or at least three minor criteria.

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TABLE 1.

Criteria for Severe Community-Acquired Pneumonia

Major criteria Respiratory failure requiring mechanical ventilation Severe shock requiring vasopressors Minor criteria Blood urea nitrogen ≥ 20 mg per dL (7.14 mmol per L) Confusion or disorientation Core temperature < 96.8°F (36°C) Hypotension requiring aggressive fluid resuscitation Multilobar infiltrates Partial pressure of oxygen/fraction of inspired oxygen ratio ≤ 250 Platelet count < 100 × 103 per μL (100 × 109 per L) Respiratory rate ≥ 30 breaths per minute White blood cell count < 4,000 per μL (4.00 × 109 per L) due to infection alone (i.e., not chemotherapy induced)


Note: Diagnosis requires one major criterion or three or more minor criteria.

Adapted with permission from Metlay JP, Waterer GW, Long AC, et al. 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. Am J Respir Crit Care Med. 2019;200(7):e48.

TABLE 1.

Criteria for Severe Community-Acquired Pneumonia

Major criteria Respiratory failure requiring mechanical ventilation Severe shock requiring vasopressors Minor criteria Blood urea nitrogen ≥ 20 mg per dL (7.14 mmol per L) Confusion or disorientation Core temperature < 96.8°F (36°C) Hypotension requiring aggressive fluid resuscitation Multilobar infiltrates Partial pressure of oxygen/fraction of inspired oxygen ratio ≤ 250 Platelet count < 100 × 103 per μL (100 × 109 per L) Respiratory rate ≥ 30 breaths per minute White blood cell count < 4,000 per μL (4.00 × 109 per L) due to infection alone (i.e., not chemotherapy induced)


Note: Diagnosis requires one major criterion or three or more minor criteria.

Adapted with permission from Metlay JP, Waterer GW, Long AC, et al. 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. Am J Respir Crit Care Med. 2019;200(7):e48.

Diagnostic Testing

BLOOD AND SPUTUM CULTURES

Routine blood and sputum cultures have not been shown to improve patient outcomes in CAP. Sputum cultures are recommended before treatment initiation only if the patient has severe CAP, and particularly if he or she is intubated; if the patient has a history of methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa infection or if he or she is being empirically treated for these pathogens; or if the patient was hospitalized and received parenteral antibiotics within the previous 90 days. Lower respiratory tract samples from intubated patients with severe CAP should be sent for Gram stain and culture soon after intubation because of the higher risk of MRSA or P. aeruginosa infection, and because endotracheal aspirates have a higher yield than sputum samples. Blood cultures should be obtained if the patient has severe CAP; was previously or is currently being treated empirically for MRSA or P. aeruginosa infection, particularly respiratory infections; or if the patient was hospitalized and received parenteral antibiotics within the previous 90 days. The yield of blood cultures is low (2% to 9%) in adults without severe CAP, and empiric therapy is rarely changed based on these results.

URINARY ANTIGEN TESTING

Urinary antigen testing for Legionella or pneumococcus has not been shown to improve outcomes.

Author disclosure: No relevant financial affiliations.

Coverage of guidelines from other organizations does not imply endorsement by AFP or the AAFP.

This series is coordinated by Michael J. Arnold, MD, contributing editor.

A collection of Practice Guidelines published in AFP is available at https://www.aafp.org/afp/practguide.

 

 

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