Evidence Based Strategies for Common Clinical Questions

When Life Gives You Croup, Give Steroids and Maybe Racemic Epinephrine

Author: Maya Gibson, MD | Pediatric Resident

Column Editor: Kathleen Berg, MD | Co-Director, Department of Evidence Based Practice | Pediatric Hospitalist, Division of Pediatric Hospital Medicine | Associate Professor of Pediatrics, UMKC School of Medicine 

It is a cool day when an otherwise healthy 3-year-old patient enters your office with upper respiratory symptoms over the past few days. Mother noticed a barky cough that prompted her to bring the patient in. You can hear inspiratory stridor from the door. When you enter the exam room, your patient appears mildly distressed. You consider the most likely diagnosis and next steps.

Croup, or viral laryngotracheitis, is an upper airway inflammatory process most commonly due to parainfluenza virus type 1 affecting children from 3 months to 6 years of age. Croup accounts for 10% to 15% of respiratory tract diseases and an estimated 300,000 emergency room visits annually.^1,2 Roughly 8% of patients who present with croup will be admitted to the hospital.³

The characteristic barky cough and presence of inspiratory stridor are classic physical exam findings in croup.⁴ Inflammation impedes the typical laminar flow through the larynx and trachea. The increase in resistance creates turbulent air flow which contributes to the high-pitched inspiratory sound appreciated during the physical exam.

The diagnosis of croup and assessment of the severity of symptoms are based on clinical evaluation. Neither imaging nor laboratory studies are generally needed. Treatment for croup depends on the severity of symptoms.

Humidified air has often been used to treat mild croup. For decades, parents have used humidifiers or steamy showers and reported relief in symptoms. However, there is currently no evidence that humidified air treats croup.⁵ Even so, it is hypothesized that humidified air is comfortable in the airway, calming the patient down, and bringing comfort to both patient and parent.⁶

Systemic steroids have been used to treat croup since the 1980s.³ They work to reduce local inflammation thus decreasing air flow resistance. As steroids work at the intracellular level, it may take six hours before the effects can be clinically appreciated. There is no difference between one dose of dexamethasone or three daily doses of prednisone.⁷ However, for better compliance and lower cost, a single dose of dexamethasone is recommended.

Racemic epinephrine is an alpha-1 agonist with rapid onset causing vasoconstriction and thus leading to decreased airway inflammation.⁸ Racemic epinephrine is used in patients with moderate to severe symptoms, specifically stridor at rest. Effects are noticeable within 30 minutes and last one to two hours.^3,9,10 Following administration of racemic epinephrine, the patient should be observed for two hours. Several doses of racemic epinephrine may be needed until the steroid takes effect. 

Heliox is reserved for patients with severe croup. It is most commonly a blended mixture of 80% helium/20% oxygen or 70% helium/30% oxygen.¹¹ Helium is a less dense air molecule, thereby improving oxygen delivery by promoting laminar flow.¹² Heliox is not commonly used and is often reserved for use in the intensive care unit, as these patients are at high risk of respiratory failure.

In the outpatient setting, it can be difficult to determine which patients will benefit from admission. Unnecessary hospitalizations are a burden to patients, patients’ families and the hospital system. However, not hospitalizing may lead to clinical deterioration and return visits. This dilemma has been addressed by evaluating clinical characteristics of patients who go on to require additional interventions while inpatient versus those who require observation only, suggesting they may have been safely discharged home. Two cohort studies found that neither age nor the presence of stridor were predictive of additional inpatient treatment (such as racemic epinephrine, heliox or intensive care). The same studies found that one or two doses of racemic epinephrine were not predictive either. However, they found that children who require three or more doses of racemic epinephrine have increased odds (OR = 1.78, 95% CI [1.18, 2.69], p = .006) of needing additional interventions while inpatient.^13,14

With the arrival of fall and winter, the need increases for evidence-based management of croup. Although it takes time to provide additional doses of racemic epinephrine with observation following each administration in the emergency department or urgent care setting, this strategy may allow time for systemic steroids to take effect and decrease unnecessary hospitalizations. The Department of Evidence Based Practice is currently updating the Children’s Mercy care process model for the diagnosis and management of croup in inpatient and outpatient settings. View this clinical decision support tool (updated version will be available by 11/25/22).

References:

1. Retzke J. Croup (acute laryngotracheobronchitis). American Academy of Pediatrics Quick References. 2021. doi:10.1542/aap.ppcqr.396247
2. Hanna J, Brauer PR, Morse E, Berson E, Mehra S. Epidemiological analysis of croup in the emergency department using two national datasets. Int J Pediatr Otorhinolaryngol. 2019;126:109641. doi:10.1016/j.ijporl.2019.109641
3. Marchese A, Langhan ML. Management of airway obstruction and stridor in pediatric patients. Pediatr Emerg Med Pract. 2017;14(11):1-24.
4. Bagwell T, Hollingsworth A, Thompson T, et al. Management of croup in the emergency department: the role of multidose nebulized epinephrine. Pediatr Emerg Care. 2020;36(7):e387-e392. doi:10.1097/PEC.0000000000001276
5. Moore M, Little P. Humidified air inhalation for treating croup: a systematic review and meta-analysis. Fam Pract. 2007;24(4):295-301. doi:10.1093/fampra/cmm022
6. Henry R. Moist air in the treatment of laryngotracheitis. Arch Dis Child. 1983;58(8):577. doi:10.1136/adc.58.8.577
7. Russell KF, Liang Y, O’Gorman K, Johnson DW, Klassen TP. Glucocorticoids for croup. Cochrane Database Syst Rev. 2011;(1):CD001955. Published January 19, 2011. doi:10.1002/14651858.CD001955.pub3
8. Westley CR, Cotton EK, Brooks JG. Nebulized racemic epinephrine by IPPB for the treatment of croup: a double-blind study. Am J Dis Child. 1978;132(5):484-487. doi:10.1001/archpedi.1978.02120300044008
9. Bjornson CL, Johnson DW. Croup in children. CMAJ. 2013;185(15):1317-1323. doi:10.1503/cmaj.121645
10. Petrocheilou A, Tanou K, Kalampouka E, Malakasioti G, Giannios C, Kaditis AG. Viral croup: diagnosis and a treatment algorithm. Pediatr Pulmonol. 2014;49(5):421-429. doi:10.1002/ppul.22993.
11. Duncan PG. Efficacy of helium--oxygen mixtures in the management of severe viral and post-intubation croup. Can Anaesth Soc J. 1979;26(3):206-212. doi:10.1007/BF03006983
12. Gupta VK, Cheifetz IM. Heliox administration in the pediatric intensive care unit: an evidence-based review. Pediatr Crit Care Med. 2005;6(2):204-211. doi:10.1097/01.PCC.0000154946.62733.94
13. Asmundsson AS, Arms J, Kaila R, et al. Hospital course of croup after emergency department management. Hosp Pediatr. 2019;9(5):326-332. doi:10.1542/hpeds.2018-0066
14. Hester G, Barnes T, O’Neill J, Swanson G, McGuinn T, Nickel A. Rate of airway intervention for croup at a tertiary children’s hospital 2015-2016. J Emerg Med. 2019;57(3):314-321. doi:10.1016/j.jemermed.2019.06.005