January 15, 2020

What’s New in the 2019 Guidelines for Community-Acquired Pneumonia?

UAMS logo

By Blaze Calderon, Juliana Oguh, and Lisa C. Hutchison, PharmD, MPH, BCPS, BCGP
University of Arkansas for Medical Sciences (UAMS) College of Pharmacy

 

Several factors increase the frequency of infection and pneumonia in older adults including lowered immune function, the presence of comorbid conditions, and nursing home residence.1 Community-acquired pneumonia (CAP) is defined as an acute infection of the pulmonary tissue that is acquired outside of a health care setting.2  CAP is a leading cause of morbidity and mortality worldwide. The clinical presentation of CAP ranges from mild pneumonia, characterized by fever, cough, and shortness of breath, to severe pneumonia, characterized by sepsis and respiratory distress.2   In 2019 the American Thoracic Society (ATS) and Infectious Disease Society of America (IDSA) released an update to their 2007 guidelines on CAP.3 This marks the first update in over a decade. This update is especially important to geriatrics because CAP is one of the most common and fatal infectious diseases seen in this patient population.4

Major changes introduced in the new guidelines:

  1. Instead of defining severe CAP based on the location of treatment (inpatient or ICU), the new guidelines have introduced a validated definition in which 3 or more minor or 1 major criteria must be met in order to classify the diagnosis as severe CAP.  Minor criteria are: respiratory rate ≥ 30 breaths/min, PaO2/FiO2 ratio ≤ 250, multilobar infiltrates, confusion/disorientation, blood urea nitrogen level ≥ 20 mg/dl, leukopenia, thrombocytopenia, hypothermia, and hypotension requiring aggressive fluid resuscitation. Major criteria are septic shock with need for vasopressors and respiratory failure requiring mechanical ventilation.
  2. Sputum and blood cultures should be obtained if possible for patients with severe disease (without delaying antibiotic therapy), but the new guidelines expand this recommendation to include inpatients empirically treated for MRSA or Pseudomonas aeruginosa.
  3. Macrolide monotherapy (i.e, azithromycin, clarithromycin) may be used for outpatients, but only in areas where pneumococcal resistance to macrolides is reported to be less than 25%.
  4. The new guidelines do not recommend procalcitonin levels to decide if antibiotic therapy should be initiated.  These are reserved for identifying when to discontinue antibiotics in hospital acquired or ventilator associated pneumonia.
  5. Corticosteroids are not recommended, but may be considered in patients with refractory septic shock.
  6. The healthcare associated pneumonia (HCAP) category was introduced in 2005. The most recent recommendations are to stop using this categorization to determine if extended-spectrum antibiotics should be used. Instead, the presence of local epidemiology and risk factors decide if MRSA or P. aeruginosa coverage is needed for CAP. There is an emphasis on de-escalation of antibiotic therapy based on culture results.
  7. In the previous guidelines, empiric therapy for severe CAP was a beta lactam + macrolide or beta lactam + fluoroquinolone. Now a beta lactam + macrolide is preferred.  This is due to the increase risks identified with fluoroquinolone therapy.
  8. Finally, follow up chest imaging is not recommended for patients who are improving.1

The approach to diagnosis and management of pneumonia in older adults is generally the same as in the general population, although older adults are more often afflicted with severe disease or sepsis.1  The fact that most patients with community-acquired pneumonia can still be treated with tried-and-tested regimens like macrolides or macrolides and beta lactam antibiotics that have been used for decades is encouraging in the face of concerns over increasing antibiotic resistance. When treating older adults, the use of broader empiric treatment initially is common due to increased risk of drug resistance, and higher incidence of severe forms of pneumonia.  The new guidelines may improve tailored antibiotic use in older adults with the change in definition of severe CAP, and focus on de-escalation of therapy when possible.

 

References:

  1. Mody, L. Approach to infection in the older adult. In: UpToDate, Schmader, K.E. & Givens, J., UpToDate. Waltham, MA, 2019.
  2. Ramirez, J.A. Overview of community-acquired pneumonia in adults. In: UpToDate, File Jr., T.M. & Bond, S., UpToDate. Waltham, MA, 2019.
  3. Metlay, J. P., Waterer, G. W., Long, A. C., Anzueto, A., Brozek, J., Crothers, K., … & Griffin, M. R. (2019). 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, 200 (7), e45-e67.
  4. Niederman, M. S., & Ahmed, Q. A. (2003). Community-acquired pneumonia in elderly patients. Clinics in geriatric medicine, 19(1), 101-120.