Croup

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Objectives

Upon finishing this module, the student will be able to:

Recognize the clinical presentation of croup.
Describe the approach to the initial management of croup.
Determine the disposition based on severity of presentation and response to therapy.

Contributors

Update Authors: Samuel Dillman and Jamie Hess, MD.

Original Authors: Holly Caretta-Weyer, MD; and Jamie Hess, MD.

Update Editor: Shruti Chandra, MD, MEHP.

Last Updated: October 2024

Introduction

Laryngotracheobronchitis, better known as croup, causes subglottic inflammation and edema resulting in laryngeal obstruction and narrowing of the airways. Croup is the most common cause of upper airway obstruction in pediatrics. The swelling at the cricoid ring (narrowest part of the pediatric airway) results in symptoms of upper airflow obstruction (stridor) and subsequently respiratory distress.

Croup is most frequently seen in children ages six months-three years. The most common etiology is parainfluenza although influenza, RSV, or other viruses can also cause it. The peak incidence of croup is in the fall and winter months. In a toddler, only 1mm of edema will result in a 65% reduction of the cross-sectional area in the subglottis.

Case Study

Initial Actions and Primary Survey

As always, start by assessing the ABC’s in a child with difficulty breathing. If there is stridor at rest, the child appears ill, and you think you may need to administer IV steroids or other IV medications, obtain IV access. If stridor is not present at rest and the child is overall well-appearing and likely to tolerate oral medications, you may forgo the IV initially. Supplemental oxygen is reasonable to start on arrival if respiratory distress is present. Monitoring of pulse oximetry is also useful for repeated assessment of clinical status after interventions.

If intubation is needed for severe hypoxia, impending full airway obstruction, or clinically significant altered mental status, you may want to use an endotracheal tube that is one size smaller due to the subglottic narrowing. Paralytics should be avoided unless the patient can be adequately bag-mask ventilated prior to intubation.

Presentation

The clinical features of croup include a two-three day history of upper respiratory symptoms with progressively worsening cough, especially at night. On day three or four, the classic triad of hoarseness, stridor, and barky cough is heard. The child is usually non-toxic in appearance.

Croup severity can be classified based on the stridor. If there is no stridor at rest, the croup is mild. Croup is moderate severity if stridor is heard only with exertion or when the child is upset. If there is stridor at rest, it is considered severe and typically results in respiratory distress. Altered mental status or hypoxia in croup indicates impending respiratory failure and is a rare and late finding. The Westley Croup Severity score can also help categorize croup severity. Features of the Westley croup severity score include level of consciousness, cyanosis, stridor, air entry, and retractions.

Differential Diagnosis

Diagnostic Testing

Croup is a clinical diagnosis, and an x-ray is usually not required to make the diagnosis. However, if the diagnosis is not entirely clear or there is suspicion of an alternate etiology such as foreign body aspiration, a soft tissue x-ray of the neck can help differentiate other causes of upper airway obstruction. History of a possible choking event can raise suspicion for foreign body aspiration especially with absence of congestion and rhinorrhea. The posterior-anterior chest x-ray may show the classic steeple sign in croup, which indicates subglottic narrowing secondary to edema. Overdistention of the hypopharynx with subglottic haziness may be seen on the lateral view. The epiglottis should appear normal and without swelling.

Image 1 and 2. "Steeple Sign." Pictures courtesy of Dr. Kate Feinstein. Used with permission.

Treatment

After airway management and supplemental oxygen, initial treatment includes:

Dexamethasone: Any child who presents with croup should receive steroids. There is evidence for decreased admission rates, intubation rates, and emergency department (ED) re-visits if steroids are given. A single dose of dexamethasone is 0.6 mg/kg given as either PO, IV, or IM (effectiveness is the same across preparations). The maximum dose is 12 mg. Studies have shown 0.3 mg/kg of dexamethasone to be an effective treatment of mild-moderate croup. Repeat doses are not usually recommended.
Fever Control and Comfort: Patients with fever should receive ibuprofen and/or acetaminophen. High fevers can result in worsening tachypnea in croup. Efforts should also be made to keep the patient calm since agitation can worsen the degree of airway obstruction.
Racemic Epinephrine: Any child with severe croup should receive racemic epinephrine. This means anyone with stridor at rest or any patient with croup who appears ill or in distress. The dose is 0.5 mL of 2.25% racemic epinephrine in a 2.5 mL normal saline nebulizer. Racemic epinephrine has been shown to reduce length of stay, intubation rates, and intensive care unit (ICU) admissions. You may repeat dosing as needed.
Alternative Therapies: Alternative considerations include prednisolone, prednisone, or inhaled budesonide. Albuterol is not indicated in the treatment of croup. For persistent respiratory distress, high flow nasal cannula (HFNC) or noninvasive ventilation can also be utilized. A mixture of helium-oxygen (heliox) is used in some medical centers to treat croup. Helium's low density and viscosity help improve laminar gas flow. This mixture may prevent intubation.

Disposition

The observation period varies by study and by provider. Depending on the parents’ comfort level, many children with minimal symptoms who are tolerating PO and have no respiratory distress can be safely discharged home with careful return precautions. In moderate croup, the child should be observed for two-four hours after steroids to determine disposition. After the observation period, asymptomatic children may be discharged but persistently symptomatic children require admission. If croup is severe and racemic epinephrine is administered, you should observe the child for three-four hours for recurrence of resting stridor. If stridor recurs after racemic epinephrine or the child requires three or more doses, you should admit the child to the hospital. Other considerations for admission are patients with unreliable social situations/caregivers, children who live far away from the hospital, persistent stridor at rest, previous intubation, other significant comorbid conditions, or clinically significant dehydration. Criteria for discharge often include:

No stridor at rest.
Normal pulse oximetry.
Normal color.
Normal level of alertness.
Demonstrated ability to tolerate PO fluids.
Careful return precautions and reliable caregivers.

If the child is going home, discuss home management with parents. They may sit by an open window or outside in the cool air to alleviate symptoms. Humidity by way of sitting in the bathroom with a hot shower running may also help.

Pearls and Pitfalls

Croup is a clinical diagnosis and is treated with dexamethasone.
When in doubt about severity, give racemic epinephrine and observe for three-four hours for recurrence of stridor. The biggest pitfall is not observing long enough and discharging the child only to see them back in several hours with recurrent stridor.
History should include risk factors for possible foreign body aspiration.
Be sure to discuss what to expect with parents if the child is to be discharged home.

Case Study Resolution

The 18-month-old female received one dose of racemic epinephrine with only transient improvement. The patient received ibuprofen, one additional dose of racemic epinephrine and 0.6 mg/kg of dexamethasone. The patient showed significant clinical improvement after the second dose of racemic epinephrine. The patient was observed an additional three hours prior to meeting discharge criteria.

References

Bjornson CL, Johnson DW. Croup. Lancet. 2008.
Cherry JD. Clinical Practice: Croup. New England Journal of Medicine. 2008.
Fleisher GR, Ludwig S, Henretig FM. Infectious Disease Emergencies: Textbook of Pediatric Emergency Medicine. Lippincott, Williams & Wilkins. 2006.
Kaditis AG, Wald ER. Viral Croup: Current Diagnosis and Treatment. Pediatric Infectious Disease Journal. 1998.
Kairys SW, Olmstead EM, O'Conner GT. Steroid Treatment of Laryngotracheitis: A Meta-Analysis of the Evidence from Randomized Trials. Pediatrics. 1989.
Ledwith CA, Shea LM, Mauro RD. Safety and Efficacy of Nebulized Racemic Epinephrine in Conjunction with Oral Dexamethasone and Mist in the Outpatient Treatment of Croup. Annals of Emergency Medicine. 1995.
Peltola V, Heikkinen T, Ruuskanen O. Clinical Courses of Croup Caused by Influenza and Parainfluenza Viruses. Pediatric Infectious Disease Journal. 2002.
Rizos JD, DiGravio BE, Sehl MJ, Tallon JM. The Disposition of Children with Croup Treated with Racemic Epinephrine and Dexamethasone in the Emergency Department. Journal of Emergency Medicine. 1998.
Siebert JN, Salomon C, Taddeo I, Gervaix A, et al. Outdoor Cold Air Versus Room Temperature Exposure for Croup Symptoms: A Randomized Controlled Trial. Pediatrics. 2023 Sep 1.