Strep Pharyngitis Testing in Toddlers?

This is the five-hundred-fifty-first Ped EM Morsel… and on this occasion, I wanted to make it pretty simple and straight forward (in contrast to the 550th Morsel). While we are all currently “managing” the chaos conjured by COVID-19, we still must remain vigilant for the other innumerable conditions that cause patients to present to our EDs. Now that children are back in school, it is time for Strep Pharyngitis to become a common entity that we encounter. We have previously discussed several topics related to this common infection (ex, Bicillin, Rheumatic Fever, Pericarditis, Post-Strep GN), but we also need to remind our colleagues that while we are vigilant, we must also remain reasonable. Clearly, you all know this information, so please help to disseminate to those who do not, as inappropriate testing has negative consequences. Let us take a brief look at the issues with Strep Pharyngitis testing in toddlers:

Strep Pharyngitis Testing: IDSA Guidelines

  • Recall, in 2012, the Infectious Disease Society of America (IDSA) updated their published guidelines on testing for Group A Streptococcal Pharyngitis. [Shulman, 2012; 22965026]
  • Recommendations for Diagnosis of Group A Strep Pharyngitis: [Shulman, 2012; 22965026]
    • Diagnosis is made by Rapid Antigen Detection Testing and/or culture, NOT by clinical features alone.
      • The Centor Criteria are useful for their negative predictive value.
      • The Centor Criteria is better to “rule-out” the disease, not diagnosis it.
    • If Rapid Antigen Detection Testing (RADT) is negative, then throat culture should be performed.
      • The RADT is not sensitive to rule-out the illness on its own.
      • The RADT is specific enough to make the diagnosis, so a culture is not needed if the test is positive.
      • For Adults, because the risk of subsequent acute rheumatic fever is exceptionally low, a negative RADT does NOT need to have a follow-up culture.
  • Recommendations for who should NOT be tested: [Shulman, 2012; 22965026]
    • Testing is NOT recommended for those patients with features most consistent with viral etiologies:
      • Cough, rhinorrhea, hoarseness, and oral ulcers
      • It is estimated that ~20% of children are carriers of Group A Strep, so indiscriminate testing may find strep that is not the etiology of the symptoms!
    • Testing is NOT recommended for children < 3 years of age!
      • Acute rheumatic fever is rare in children < 3 years old.
      • Select children < 3 years old with other risk factors may be considered – like the symptomatic child with sibling who has KNOWN Strep pharyngitis.
    • Testing is NOT recommended for ASYMPTOMATIC household contacts.

Strep Pharyngitis Testing: Inappropriate Testing

  • Unfortunately, it is known that recommendations in the IDSA guidelines are often overlooked or disregarded. [Thompson, 2021; 34417790]
  • In recent study, it was found that ~40% of Pediatric ED encounters who received treatment for Group A Strep Pharyngitis were not compliant with the guidelines. [Thompson, 2021; 34417790]
    • The majority had inconsistent presentation for GAS (ex, viral symptoms) (67%).
    • The second most common violation of the the guidelines were for testing and treating children < 3 years of age (48%).
  • 51% of those who were tested inappropriately received antibiotics. [Thompson, 2021; 34417790]
  • Interestingly, those who were tested inappropriately were MORE likely to have return encounters (13% vs 10%, P<0.001). [Thompson, 2021; 34417790]
  • Inappropriate testing exposes children to unnecessary risk: [Thompson, 2021; 34417790]
    • Adverse and allergic reactions to antibiotics
    • Increased chance of returning to the ED
      • Additional loss of work/school
      • During which, the second visit the patient is usually appropriately diagnosed as having a viral etiology of their illness.

Moral of the Morsel

  • Less than 3, let it be. Rheumatic fever is extremely rare in this age group, so strep pharyngitis testing introduces mostly risk with very limited reward.
  • Education is the best medicine. Sometimes taking another 2 minutes to explain the differences between viral and bacterial infections and the hazards of indiscriminate testing will benefit not just the patient/family but also your colleagues and the strained medical systems.

References

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Sean M. Fox
I enjoy taking care of patients and I finding it endlessly rewarding to help train others to do the same. I trained at the Combined Emergency Medicine and Pediatrics residency program at University of Maryland, where I had the tremendous fortune of learning from world renowned educators and clinicians. Now I have the unbelievable honor of working with an unbelievably gifted group of practitioners at Carolinas Medical Center. I strive every day to inspire my residents as much as they inspire me.
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