A concerned mother brings her previously healthy 10-month-old daughter to the urgent care with a 24-hour history of “shortness of breath.” The child is tolerating oral intake and has 8 wet diapers per day. Vital signs are significant for a respiratory rate of 36 breaths/min, a 101.4°F axillary temperature, and a pulse ox of 95%. The mother is concerned about respiratory syncytial virus (RSV), as the daycare has notified parents that RSV has been reported.
Of the following, what initial diagnostic tests should be considered for this patient?
- A COVID-19 and influenza antigen test
- Chest x-ray
- An RSV molecular test from a reference laboratory
- None, as a diagnostic test will not change the treatment plan
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Correct Answer: a. A COVID-19 and influenza antigen test
While the mother is concerned about RSV, your primary concern is whether the patient has influenza. Because she is aged <2 years, she is in the highest risk category for complications and antiviral treatment is recommended. COVID-19 is also in the differential diagnosis, but antivirals for COVID-19 are not approved for this age range. Your clinic has POC antigen influenza and COVID-19 testing, so to assess for COVID-19 and influenza, you test for both. If RSV testing is warranted, it requires send out to a reference laboratory. You discussed with the mother that RSV is a virus that causes an acute respiratory illness with associated fever and wheezing in pediatric patients, with the highest prevalence in children aged <1 year. You told her that the 2 main complications that would warrant further management in an inpatient setting are dehydration and difficulty breathing. If the patient is stable, outpatient management with supportive care measures is recommended. You further discussed with the mother that bronchiolitis is a clinical diagnosis, and that there are other viruses besides RSV that can cause the exact same symptoms.
Thankfully, the antigen influenza and COVID-19 tests are negative. Because your clinical index of suspicion is high for RSV and low for influenza, the negative predictive value is sufficient to not initiate antiviral influenza medications. Based on the recent exposure and the patient’s symptoms, you determined that she most likely has RSV. Mom agreed to withhold testing for RSV since it would not change treatment and was comfortable monitoring at home for worsening symptoms and providing supportive care.
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Tracey Davidoff, MD, FACP, FCUCM, has practiced Urgent Care Medicine for more than 15 years. She is Board Certified in Internal Medicine. Dr. Davidoff is a member of the Board of Directors of the Urgent Care Association and serves as Co-Editor-in-Chief of the College of Urgent Care Medicine’s “Urgent Caring” publication. She is also the Vice President of the Southeast Regional Urgent Care Association and a member of the editorial board of the Journal of Urgent Care Medicine. At EB Medicine, Dr Davidoff is Editor-In-Chief of Evidence-Based Urgent Care, and co-host of the Urgentology podcast.
