Does This Febrile Neonate Need a CXR?

Written by Caitlin Nicholson

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This prospective study identified a handful of clinical features associated with radiographic pneumonia in young febrile infants, including elevated procalcitonin and/or absolute neutrophil count, respiratory distress, and positive viral testing.

A little more clarity for when to x-ray
This was a secondary analysis of data from a prospective observational cohort study that included 568 febrile infants aged 60 days or younger in 18 EDs.  All patients received chest x-rays (CXRs), of which 19 (3.3%) had definite pneumonia, and 34 (6%) had possible pneumonia, as determined by an attending radiologist or stratified by study investigators. The primary objective was to identify demographic and clinical factors associated with radiographic pneumonia in febrile infants.

In patients with possible or definite radiographic evidence of pneumonia, there was a significant association with respiratory distress (p=0.02; including increased work of breathing and tachypnea), elevated ANC and procalcitonin (p= 0.01; 0.007, respectively), and detection of a viral illness (p < 0.001). Limitations included a small patient population, variability in labs obtained, and lack of auscultatory findings.

How will this change my practice?
While this study was interesting, I do not think it will change my practice. Currently, the infants I am ordering chest x-rays on are patients that do not fit the “classic virus” pattern. This is primarily based on my clinical gestalt, but objective findings that would push me to get an x-ray would include severe hypoxemia, high or prolonged fevers, focal findings on exam, and elevated procalcitonin. While this study aligns with my decision making, larger studies will be needed if the ultimate goal is to establish a clinical decision tool for CXRs in febrile infants.

Source
Radiographic pneumonia in young febrile infants presenting to the emergency department: secondary analysis of a prospective cohort study. Emerg Med J. 2023;41(1):13-19. Published 2023 Dec 22. doi:10.1136/emermed-2023-213089.