In the spring of 2022, the Pediatric Academic Society meeting sponsored an informative "Hot Topic" session reviewing practitioner dilemmas when diagnosing and treating community-acquired pneumonia (CAP).
The CAP Diagnosis
One of the first challenges is deciding whether a child has bacterial CAP. A 2017 review article provided guidance, noting that in children, there's a great deal of overlap in the clinical features between CAP caused by bacteria, CAP caused by viruses, or even other lung diseases. That review identified hypoxemia and increased work of breathing as the two indicators that outperform other clinical examination findings, even more than auscultation and vital sign abnormalities.
Developing evidence published in 2022 suggests that clinical features such as prolonged fever, tachypnea, and (most importantly) increasing age and focally decreased breath sounds correlated best with bacterial pneumonia, whereas rhinorrhea and wheezing negatively correlated with bacterial causes. Although the model suggested in this study requires additional validation, it provides some useful clinical guidance. The bottom line is that there is not yet a validated scoring approach or model to predict CAP in children, but work is ongoing. Finally, a multinational study is underway to try to develop a more comprehensive CAP risk model that will help pediatricians refine which clinical features correlate best with bacterial CAP.
Chest imaging really does not provide a gold standard for diagnosing patients with pneumonia, and certainly most children are diagnosed with CAP in clinicians' offices without the benefit of radiographs. In fact, a Cochrane review from 2008 notes that radiography does not routinely correlate with outcomes of pneumonia. Chest radiographs can be helpful, nevertheless, if the diagnosis is unclear. Alveolar, focal infiltrates on radiographs have the best agreement in the setting of CAP when multiple examiners reviewed the radiographs. Alternatively, a negative chest radiograph can be very helpful. Many of us were taught conventional wisdom that "radiographic changes lag clinical findings," so that a negative radiograph does not mean the patient does not have pneumonia. However, Lipsett and co-authors followed a group of patients seen for pneumonia-like symptoms who had a negative radiographs and demonstrated a negative predictive value of 98.8%, indicating that very few patients with a negative radiograph will go on to develop CAP.
A meta-analysis from 2021 demonstrated that biomarkers can be helpful in diagnosing children with bacterial CAP. C-reactive protein level performs better than procalcitonin, both of which perform better than white blood cell count or erythrocyte sedimentation rate in predicting patients with bacterial pneumonia. Just as a negative radiograph can be helpful, data from 2018 demonstrated that procalcitonin < 0.25 essentially eliminated the risk for bacterial pneumonia. It was emphasized that procalcitonin, however, is really not discriminating enough to be used alone.
In summary, for diagnosing children with bacterial CAP, clinicians can consider using published decision rules to assist with deciding whether to obtain a chest radiograph, deciding on disposition, and even antibiotic decisions, but all of those decision rules require additional validation. Chest radiographs aren't always indicated, but they can be helpful if they are either totally clear or if there is a focal alveolar infiltrate. Finally, absence of elevated procalcitonin may help practitioners identify particularly low-risk patients for developing bacterial CAP.
Current CAP Treatment Recommendations
Antibiotic selection recommendations have not changed much since guidelines were published in 2011, but a few points are worth emphasizing. Treatment for bacterial pneumonia for children aged 5 years or younger should focus on Streptococcus pneumoniae, whereas mycoplasma and other atypical bacteria become more common after age 5 years. That said, if the examination or radiographic pattern suggest pneumococcus (ie, focal sounds or radiographic changes), treat for pneumococcus. Amoxicillin is still recommended as the first-line antibiotic and performs better than cephalosporins for pneumococcus. Macrolide antibiotics should not considered first-line, single-agent therapy for pneumococcus because of variable resistance, depending on where a clinician practices. In addition, data from 2021 suggest that up to 23% of amoxicillin-susceptible pneumococci are not sensitive to cefdinir.
How long to treat childhood CAP is often a dilemma for clinicians, but there is rapidly developing evidence that short-course therapy is appropriate and safe for the outpatient treatment of CAP. The current guidelines note that 10 days of treatment is the best studied, but data from a succession of double-blind, placebo-controlled clinical trials studies have suggested that 5 days was not inferior to 10 days of treatment (SAFER study), and 3 days was not inferior to 7 days treatment (CAP-IT study). Certainly, the fact that many pediatric pneumonias are viral in origin biases toward finding no difference between treatment durations, but the recent studies were well-designed, randomized, and double-blind. In summary, clinicians can consider 5 days of treatment to be adequate for the majority of immunocompetent patients with uncomplicated, ambulatory CAP. Pending revisions of the CAP diagnosis and treatment guidelines will probably offer more specific guidelines for ages and scenarios with which providers can consider short-course antibiotic therapy for childhood CAP.
William T. Basco, Jr, MD, MS, is a professor of pediatrics at the Medical University of South Carolina and director of the Division of General Pediatrics. He is an active health services researcher and has published more than 60 manuscripts in the peer-reviewed literature.
Lead image: The National Institutes of Health
Image 1: William T. Basco, Jr, MD, MS
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Cite this: William T. Basco. The Latest on Community-Acquired Pneumonia in Kids: Diagnosis and Treatment - Medscape - Jul 26, 2022.