Medication Summary
As previously mentioned, current treatment approaches for patients with croup are corticosteroids and nebulized epinephrine; steroids have proven beneficial in severe, moderate, and even mild cases of croup. The anti-inflammatory action of corticosteroids reduces laryngeal mucosal edema and decreases the need for salvage nebulized epinephrine. In moderate to severe disease, corticosteroids improve croup scores within 12-24 hours and decrease hospitalization rates. Most trials have used dexamethasone at 0.6 mg/kg (intramuscular or oral), but oral doses as low as 0.15 mg/kg are effective. [46]
Nebulized racemic epinephrine (mixture of dextro isomers and levo isomers) or L-epinephrine is typically reserved for patients in moderate to severe distress. Epinephrine constricts the precapillary arterioles through adrenergic stimulation, thereby decreasing capillary hydrostatic pressure. This leads to fluid resorption from the interstitium and improves the laryngeal mucosal edema. Because of the potential adverse effects of tachycardia and hypertension, it is reserved for children with moderate to severe disease. [23]
Corticosteroids
Class Summary
Steroids are thought to decrease airway edema via their anti-inflammatory effect. Although a subject of controversy throughout the 1980s and 1990s, corticosteroids have since become a routine part of ED management of croup. Corticosteroids have been shown to reduce hospitalization rates by 86%, and in mild disease, they have been proven to reduce the number of children returning to the ED for further treatment.
In moderate to severe disease, corticosteroids improve croup scores within 12-24 hours and decrease hospitalization rates. Most trials have used dexamethasone at 0.6 mg/kg (intramuscular or oral), but oral doses as low as 0.15 mg/kg are effective. Oral and intramuscular routes appear equally beneficial. Prednisolone (1 mg/kg) has been proven effective but may be associated with a greater return of children to the ED.
Inhaled corticosteroids also have demonstrated efficacy, with most trials using budesonide. According to most authors, however, the relative ease, speed, and cost of administration make systemic corticosteroids preferable to nebulized formulations.
Dexamethasone (Baycadron)
Several studies have shown improvement in clinical symptoms and croup score in hospitalized and ED patients who received dexamethasone. The drug exerts a beneficial effect via anti-inflammatory action that decreases laryngeal mucosal edema. The onset of action occurs within 6 hours after oral or intramuscular administration. Dexamethasone has a long pharmacodynamic effect of 36-56 hours. No studies have evaluated the effect of multiple doses of the drug.
Prednisone
Several studies have shown improvement in clinical symptoms and croup score in patients who were treated while hospitalized or in the ED. Corticosteroids exert beneficial effect via anti-inflammatory action in which laryngeal mucosal edema is decreased. In calculating an appropriate prednisone dose, it is important to know that dexamethasone is 6.67 times more potent and has a long half-life of 36-56 hours, versus a median half-life of 18-36 hours for prednisone.
Prednisolone (Prelone, Pediapred, Millipred)
Corticosteroids exert beneficial effect via anti-inflammatory action in which laryngeal mucosal edema is decreased. Like with prednisone, in calculating an appropriate prednisolone dose, it is important to know that dexamethasone is 6.67 times more potent and has a long half-life of 36-56 hours, versus a median half-life of 18-36 hours for prednisolone.
Budesonide inhaled (Pulmicort Respules, Pulmicort Flexhaler)
Clinical studies have documented improvement in symptoms and decrease in hospital admissions with nebulized budesonide in children with croup. Inhaled budesonide has been shown in several studies to be equivalent to oral dexamethasone.
Corticosteroids exert beneficial effect via anti-inflammatory action in which laryngeal mucosal edema is decreased.
Nebulized Vasoconstrictors
Class Summary
Epinephrine stimulates alpha receptors and beta2 receptors. It constricts the precapillary arterioles, thus decreasing airway edema. Because of the potential adverse effects of tachycardia and hypertension, it is reserved for children with moderate to severe disease.
The effects of epinephrine are transient, and most trials show alleviation of symptoms for no longer than 2 hours. In the 1980s and early 1990s, a rebound phenomenon was thought to occur, necessitating admission of all children who received the drug. However, patient discharge after 3-4 hours of observation has since become acceptable, as long as the patient has no stridor at rest, normal air entry, normal color, and normal consciousness and has received a dose of steroids.
Epinephrine (Adrenalin)
This agent is a levo isomer. It stimulates alpha-, beta1-, and beta2-adrenergic receptors, which results in bronchodilatation, increased peripheral vascular resistance, hypertension, increased chronotropic cardiac activity, and positive inotropic effects. Epinephrine causes alpha-adrenergic receptor–mediated vasoconstriction of edematous tissues, thus reversing upper airway edema.
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Child with croup. Note the steeple or pencil sign of the proximal trachea evident on this anteroposterior film. Courtesy of Dr. Kelly Marshall, CHOA at Scottish Rite.
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Steeple sign on radiograph.
