COMMUNITY-ACQUIRED PNEUMONIA (CAP) is one of hospitalists’ bread-and-butter diagnoses and one of the most common infectious diseases they treat. Given the prevalence of CAP—and the fact that if it’s winter, it’s CAP season—do you know the latest recommendations for testing for viruses when you suspect community-acquired pneumonia? Other key questions include whether (and how long) you should treat community-acquired pneumonia with steroids and antibiotics?
At a recent conference on the management of the hospitalized patient at the University of California, San Francisco, Bradley Sharpe, MD, the former UCSF hospital medicine division chief, reviewed the latest guidance on testing and treatment for community-acquired pneumonia.
In this article
THIS ARTICLE will review the latest recommendations for testing to detect community-acquired pneumonia (CAP) in hospitalized patients and when to treat CAP with steroids and antibiotics. This article will answer the following questions:
• When is community-acquired pneumonia caused by viruses like influenza, RSV or rhinovirus?
• Can procalcitonin levels help determine if the cause of community-acquired pneumonia is viral or bacterial?
• When should community-acquired pneumonia be treated with steroids?
• What do study data say about treating community-acquired pneumonia with antibiotics?
• How long do clinical guidelines suggest treating community-acquired pneumonia with antibiotics?
• Which community-acquired pneumonia patients need extended spectrum coverage with antibiotics?
Viral causes of CAP
Virus vs. bacteria: What studies have found. Over the past decade, Dr. Sharpe said, it’s become apparent “that viruses are common and that maybe as many as 20% or 30% of patients we admit with community-acquired pneumonia have viral causes such as influenza, RSV or rhinovirus.”
“Doing a whole respiratory viral panel doesn’t impact management or outcomes.”
Bradley Sharpe, MD
University of California, San Francisco
The bad news is that clinical features—symptoms, exam, chest X-rays—aren’t sensitive or specific enough to determine what is viral and what is bacterial. “You need to test for viruses,” he added. That’s particularly true for influenza, and particularly during flu season.
Here’s why it matters: In patients with influenza pneumonia, treatment with a neuraminidase inhibitor can reduce overall mortality by 29%. Mortality benefits are even more substantial (51%) if treatment for community-acquired pneumonia is started within 48 hours of symptom onset. Treatment also lowers patients’ length of stay.
In fact, evidence so strongly supports treating influenza pneumonia that “you should consider starting that treatment even before test results are back, if you suspect the flu,” Dr. Sharpe said.
Should you run a respiratory viral panel? As for running an entire respiratory viral panel (RVP), a systematic review and meta-analysis in the May 1, 2024, issue of JAMA Internal Medicine looked at testing such panels in the ED vs. no testing at all. The authors found that while running a full virus panel may cut down on the use of other diagnostic tests including labs and chest X-rays (at least among patients treated in the ED and discharged home), it didn’t affect the number of patients who went on to receive antibiotics. It also, importantly, didn’t change clinical outcomes.
One of the challenges is that studies have found that potentially more than 10% of patients with community-acquired pneumonia are co-infected with both a virus and bacteria. As a result, providers treat for bacterial pneumonia even if the respiratory viral panel is positive.
“This confirms other studies that doing that whole respiratory viral panel doesn’t impact management or outcomes,” Dr. Sharpe pointed out. Moreover, he added, testing is expensive. Researchers at UCSF did a quality improvement project in 2018 and found that their hospital spent about $3 million a year on RVPs.
“That was basically wasted money,” he said. “Either no one looked at the results, or people didn’t use them to change their management.”
Dr. Sharpe noted, however, that guidelines issued in 2021 by the American Thoracic Society do recommend considering a full viral panel in two scenarios: for someone in the ICU with severe pneumonia and in patients who are immunocompromised.
Procalcitonin levels in community-acquired pneumonia
What studies say about testing procalcitonin in CAP. When you suspect community-acquired pneumonia, can testing patients’ procalcitonin levels help you determine if the cause is viral or bacterial?
According to a meta-analysis published in Clinical Infectious Diseases in 2020, “sadly, the answer is no,” said Dr Sharpe. Data found that the sensitivity of the test is only 55%, while specificity is 76%. “We cannot use procalcitonin to decide to initiate antibiotics if you think a patient has pneumonia,” he noted.
He did add that he sometimes uses procalcitonin testing if he’s on the fence about whether or not a patient has community-acquired pneumonia. “I may not really think the patient is infected,” he explained, “but I really don’t know. If the procalcitonin is low, that can be helpful.”
Steroids and community-acquired pneumonia
What do studies say about treating CAP with steroids? Recommendations on whether or not to treat patients with community-acquired pneumonia with steroids have followed a pendulum, Dr. Sharpe explained, going from “not at all” to “a definite yes.” That’s where the answer is right now, particularly for patients who have severe pneumonia, are in the ICU or are on high-flow nasal cannula, among other indications.
“We know that from a pathophysiology standpoint, the cause of the respiratory failure isn’t the bacteria itself but the inflammatory response,” he pointed out. You could expect corticosteroids to reduce respiratory failure and improve outcomes.
Studies have weighed in on this question for years, with conflicting analyses showing inconsistent mortality benefits. But research in the May 25, 2023, issue of the New England Journal of Medicine was “incredibly rigorous and well-designed,” Dr. Sharpe noted. The randomized, double-blind study enrolled ICU patients with severe pneumonia to receive either IV hydrocortisone (200 mg daily for either four or seven days as determined by clinical improvement) or placebo. Patients in both arms of the study received antibiotics and standard care.
What research says about steroids and mortality. The authors found that in patients given hydrocortisone, “steroids cut mortality in half,” said Dr. Sharpe, dropping from 11.9% for those taking placebo to 6.2% for those on hydrocortisone. Other benefits included less intubation and vasopressor use, as well as lower rates of respiratory failure and shock. “The only side effect of giving patients steroids was more hyperglycemia, so patients got more insulin.”
Another meta-analysis—this from the August 2023 Journal of General Internal Medicine—confirmed those findings, analyzing the data from 18 randomized controlled trials. Moreover, different studies among those looked at different steroid durations.
“I’ll typically do five days, but you could do seven, and there’s no need to taper,” Dr. Sharpe said. Often, steroids are administered through IV, “but they can be switched to PO. For me, steroids in severe pneumonia are now the standard of care, and the evidence is good enough.”
He did offer this caveat: “Patients with non-severe pneumonia didn’t have a mortality benefit.” As a result, you shouldn’t use steroids in patients with non-severe pneumonia.
Antibiotics for community-required pneumonia
What do data say about the duration of antibiotic therapy for CAP? Studies dating back to 2007 have weighed in on antibiotic duration in community-acquired pneumonia patients. Research has consistently backed shorter courses of antibiotics (seven days or fewer) over longer ones (10 days).
According to Dr. Sharpe, “the study that changed practice for many of us was published in 2016.” Appearing in the September 2016 issue of JAMA Internal Medicine, that study randomized about 300 hospitalized patients who were afebrile after 48 hours. “It ended up essentially being a study of five vs. 10 days, and there was no difference in the many outcomes tracked, including cure rates and mortality.”
A 2023 systematic review and meta-analysis in the British Medical Journal on the benefits of shorter courses (between three and nine days) vs. 10 days or longer looked at nine studies. It found that “three to five days of antibiotics is equal to longer courses.”
The number that Dr. Sharpe said he sticks to is five. “Five days is what I start with as long as a patient is getting better,” he pointed out. “But if you’re worried because, for example, your patient is frail, 80 years old and has stage 4 CKD, it’s OK to give antibiotics a bit longer, although I wouldn’t do more than seven days.”
What about an even shorter course of three days? “I’m not convinced the data are good enough to do only three days,” he said. “But I think it’s likely that in the coming years, we will identify a subset of patients for whom three days is probably enough.”
What bacteria in CAP should antibiotic therapy target? With aspiration pneumonia, Dr. Sharpe noted that medical students are still being taught that these patients need coverage against anaerobes.
But studies that support that message “are 50 years old,” he added. More recent studies have found that the bacteria present in true aspiration pneumonia are “mainly gram-negative rods and typical pneumonia organisms. Most patients with aspiration don’t need anaerobic coverage.” He considers adding anaerobic coverage when patients with pneumonia have signs of lung abscess, cavitation or empyema.
Standard antibiotics coverage for CAP
What do clinical guidelines suggest for treating community-acquired pneumonia with antibiotic therapy? As for what constitutes standard antibiotic treatment, “we should all be following the guidelines,” Dr. Sharpe stated. “If you’re not following the guidelines, you’re killing people. That’s because guideline-recommended regimens have a mortality benefit compared to other regimens.” The guidelines endorse three choices for hospitalized patients with non-severe pneumonia who are not in the ICU.
Those are a beta-lactam plus a macrolide; fluoroquinolone monotherapy; or a beta-lactam plus doxycycline. As for which of the three is better, studies have found that they all have similar outcomes. At UCSF, Dr. Sharpe said that he and his colleagues typically choose ceftriaxone for the beta-lactam plus doxycycline: “One, doxycycline is equivalent,” he noted. “And two, it’s cheap.”
Moreover, a study published in September 2012 in Clinical Infectious Diseases found that hospitalized patients given doxycycline had a 20% to 30% lower risk of developing C. diff.
For patients in the ICU, guidelines recommend either a beta-lactam plus macrolide or a beta-lactam plus a fluoroquinolone.
Who needs extended spectrum coverage?
Which CAP patients do clinical guidelines say should be covered against MRSA and P. aeruginosa? Then there’s the question of who with community-acquired pneumonia needs extended spectrum coverage against MRSA and P. aeruginosa.
“This was previously described as HCAP, health care-associated pneumonia,” Dr. Sharpe explained. But the standard criteria for HCAP didn’t predict resistant organisms. Guidelines single out two scenarios in which providers should consider broader spectrum coverage: in patients who previously had MRSA or Pseudomonal infection, and in those who have been hospitalized within the last 90 days and received IV antibiotics. “In general, using vancomycin and pip-tazo or cefepime should be rare in community-acquired pneumonia.”
When you do use extended-spectrum antibiotics, he noted, get blood and sputum cultures if possible—and de-escalate to standard CAP treatment within 48 hours if those cultures are negative and the patient is improving.
Phyllis Maguire has been Executive Editor of Today’s Hospitalist since 2006. Based in Bucks County, Pa., her health care interests are hospital medicine and long-term care options. She also likes zydeco, hiking, and reading memoirs and romances.
