Inspiratory stridor is a syndrome of upper airway obstruction, characterized by a harsh sound on inspiration. Etiologic factors include croup, epiglottitis, retropharyngeal abscess, peritonsillar abscess, foreign body, extrinsic laryngeal compression (tumor, cyst, hematoma), angioedema, laryngeal webs, vascular rings, bacterial tracheitis, acquired or congenital subglottic stenosis, and laryngomalacia.
Viral croup, often considered synonymous with laryngotracheobronchitis, is the most common form of upper airway obstruction in children aged 6 months to 6 years. It is caused by inflammation and edema of the subglottic region of the larynx. Epiglottitis is a bacterial infection of the epiglottis that causes acute upper airway obstruction. It is usually caused by Haemophilus influenzae
type b infection and has been nearly eradicated since the introduction of routine immunization with H. influenzae
vaccine (see Chapter 1.1
A. Clinical presentation.
The mean age of children presenting with croup is 18 months, with age ranging from 3 months to 6 years. Croup is most common in early fall and winter, and usually, but not always, is preceded by a couple of days of upper respiratory symptoms followed by hoarseness, low-grade fever, and a “croupy” or barking cough (1
Illness may progress no further or may go on to cause inspiratory stridor, flaring of the ala nasi, and suprasternal and intercostal retractions. The lungs are generally clear but about 5% of the time there is associated wheezing.
B. Diagnostic studies.
Usually no diagnostic studies are needed, and the diagnosis of croup can be made on clinical grounds. White blood cell (WBC) counts are usually normal or mildly elevated but are greater than 15,000/mm3 approximately 20% of the time. Lateral neck radiography shows widening of the hypopharynx. Posteroanterior radiographs may show a narrowed subglottic region known as a steeple sign. Classic signs of croup on radiography are seen only about half the time.
The first decision in the treatment of croup is whether a child should be treated on an outpatient or inpatient basis. This decision is made based on the degree of stridor, severity of retractions, pulse rate, respiratory rate, and evidence of cyanosis. Many physicians believe that stridor at rest is an indication for hospital admission. A helpful algorithm for treatment is shown in Figure 4.3-1
FIG. 4.3-1. An algorithm for the treatment of croup. *, dosage 0.6 mg/kg; ‡, dosage l-epinephrine 1:1,000, see text for dose. (From Skolnik NS. Croup. J Fam Pract 1993; 37:168, with permission.)
Humidified air. Provision of humidified air, either by having the parent hold the child in his or her arms in the bathroom at home with the shower turned on to generate steam or by using a croup tent in the hospital, is reasonable, although the efficacy of this time-tested treatment is unproved and varies a great deal.
(1:1,000) at a dose of 0.5 mL/kg diluted in 3 mL normal saline (maximum doses: <4 yrs: 2.5 mL/dose; >4 yrs: 5 mL/dose) administered by nebulizer can be given to acutely decrease the upper airway obstruction seen in croup. l-Epinephrine has been shown to have equivalent potency and safety when compared to the much less available racemic epinephrine (2
). Epinephrine works through α-adrenergic effects, which lead to mucosal vasoconstriction that results in decreased edema in the subglottic region of the larynx. Time of onset of action is less than 10 minutes and duration of action is less than 2 hours. Treatment is very effective, but all children who receive racemic epinephrine must be observed for at least 2 hours because of the possibility of rebound stridor, and all such children should receive corticosteroid treatment (3
Dexamethasone, 0.6 mg/kg IM or PO, is effective in decreasing airway obstruction, but it has a slow onset of action and often does not take effect for up to 6 hours. Prednisone, 3 mg/kg PO, is also probably effective but has not been studied as extensively. Adrenal corticosteroids should be administered to all children with severe croup, and many children with moderate croup (3
Budesonide is a highly potent topical steroid that can be administered by nebulizer. It has a short onset of action and is effective in decreasing inspiratory stridor (4
). It is not yet available in the United States.
A. Clinical presentation.
Epiglottitis tends to occur in children who are older (3–7 years) than the croup age group with no history of a preceding upper respiratory infection. The disease is of sudden onset, and there is a high fever. The child is often sitting up, leaning forward and drooling without a cough, and appears toxic (6
B. Diagnostic studies.
Lateral neck radiography shows a swollen epiglottis, classically referred to as the “thumb sign.” If the clinical presentation of a child suggests epiglottitis, the physician should not waste time getting a lateral neck radiograph. Visualization of the epiglottis should be performed as soon as possible in a controlled setting with facilities available for intubation and tracheotomy. Epiglottitis is confirmed by visualizing a cherry-red epiglottis. Blood cultures should be obtained because this is usually a bacteremic disease.
Treatment is twofold. First, the airway must be secured to ensure adequate ventilation. This is usually accomplished through endotracheal intubation done in a controlled setting where tracheostomy can be performed if necessary. Second, intravenous antibiotics effective against H. influenzae type b should be started (cefuroxime, 75 mg/kg per day divided into q8h, or ceftriaxone, 100 mg/kg per day divided into ql2h).