Croup is a very common upper respiratory infection in children characterized by stridor, hoarseness, and a barking cough. The age range is 6 months to 6 years of age, with one to two years old being the most common range. Glucocorticoids and racemic epinephrine are the cornerstones of therapy, with humidified air/cool mist being used less than in the past. Croup, also known as laryngotracheitis, is caused by the parainfluenza virus. Upper airway inflammation and edema impedes airflow, leading to the stridor, hoarseness, and that classic barking cough we have all come to know and love. The Westley score is commonly used to determine the severity of croup, as many studies looking at treatments use improvements in this score as a primary outcome. The score ranges from 0 to 17, with 17 being the most severe. The elements of the score are listed below.
- Level of consciousness: Normal, including sleep = 0; disoriented = 5
- Cyanosis: None = 0; with agitation = 4; at rest = 5
- Stridor: None = 0; with agitation = 1; at rest = 2
- Air entry: Normal = 0; decreased = 1; markedly decreased = 2
- Retractions: None = 0; mild = 1; moderate = 2; severe = 3
Mild croup is equal or less than 2, moderate is 3 to 7, and severe is 8 or higher. The admission rate ranges from 1% to 30%. In the past, these children were admitted to the hospital and given humidified air, usually in the form of cool mist. The management of this disease has changed over the last thirty years with glucocorticoids and racemic epinephrine being added as interventions. Luckily for us, the Cochrane database looked at these interventions and gave recommendations.
A Cochrane review found that glucocorticoids resulted in a statistically significant improvement in the Westley score at 6 hours (improvement of 1.2 points) and 12 hours (improvement of 1.9 points), although there was no improvement at the 24 hour time point. As this disease is self-limited, glucocorticoids are thought to decrease enough inflammation and edema in the short-term to allow self-resolution. The effects start working at 6 hours and last around 12 hours. Glucocorticoids were also associated with a decrease return rate to the ED and a decreased readmission rate (RR of 0.5, with a NNT of 17 to avoid return/readmission). Length of stay in the ED and hospital was also reduced. The above body of data is why glucocorticoids are now one of the cornerstones of therapy. The usual medication given in dexamethasone orally at 0.6 mg/kg (max is 10 mg), although many are starting to use a 0.15 mg/kg dose. More studies need to be performed to determine the optimal dose. If the child is not PO tolerant, IM works well.
Nebulized racemic epinephrine was found to reduce symptoms at the 30 minute time period compared to placebo. Two small studies found no difference between racemic epinephrine and placebo at 120 minutes and 6 hours. However, when the effects of the nebulized racemic epinephrine had dissipated, the symptoms were not worse than before treatment. One inpatient study found at 32 hour shorter hospital stay in children treated with nebulized racemic epinephrine. It’s difficult to accept results from just one study, but the results were significant. No statistical significance has been found between racemic epinephrine and L-epinephrine. The standard dose of racemic epinephrine is 0.5 ml of 2.25% nebulized.
A Cochrane review also looked at heliox. Only two small RCTs were included. One compared heliox 70/30 to humidfied oxygen and the other compared heliox 70/30 to 100% oxygen. They found a small but statistically insignificant improvement in the heliox group. At this time, the Cochrane group does not recommend heliox based on these studies.
The major controversial treatment for croup is humidified air/cool mist, which was the treatment of choice for years. Of the three studies the Cochrane group analyzed, the pooled 20 minute to 60 minute improvement in the Westley score with humidified air was only 0.14, which was not significant. Cool mist fared a little better, with a 0.4 Westley score improvement at 20-30 minutes. However, overall the Cochrane group found no statistical improvement in these treatments and they do not recommend the use of humidified oxygen/cool mist in the emergency department.
Despite the prior common use of humidified air as treatment for croup, the current evidence supports glucocorticoids and nebulized racemic epinephrine for the treatment of moderate croup. Nebulized racemic epinephrine (o.5 ml of 2.25% nebulized) improves the Westley score at 30 minutes, and glucocorticoids improve the score at 6 to 12 hours, allowing time for self-resolution. Supportive care is always indicated.
Moore M, Little P. Humidified air inhalation for treating croup (Review). The Cochrane Library. 2010. Issue 9.
Vorwerk C, Coats T. Heliox for croup in children (Review). The Cochrane Library. 2010. Issue 2.
Bjornson C, Russell KF, Vandermeer B, Durec T, Klassen TP, Johnson DW. Nebulized epinephrine for croup in children (Review). The Cochrane Library. 2011. Issue 2.
Russell KF, Liang Y, O’Gorman K, Johnson DW, Klassen TP. Glucocorticoids for croup (Review). The Cochrane Library. 2012. Issue 2.
Woods C. Approach to the management of croup. Uptodate.com. Updated July 16, 2012.