Bacterial tracheitis is a rare but serious superinfection of the trachea that may follow viral croup and is most commonly caused by S. aureus. Spasmodic croup describes sudden onset of croup symptoms, usually at night, but without a significant upper respiratory tract prodrome. These episodes may be recurrent and severe but usually are of short duration. Spasmodic croup has a milder course than viral croup and responds to relatively simple therapies, such as exposure to cool or humidified air. The etiology is not well understood and may be allergic.
Oral or intramuscular dexamethasone for children with mild, moderate, or severe croup reduces symptoms, the need for hospitalization, and shortens hospital stays. Dexamethasone
Onset of illness Gradual Acute Acute Sudden (at night)
Quality of stridor Harsh Mild Harsh Harsh
Drooling, neck – ++ + – hyperextension
From Bell LM: Middle respiratory tract infections. In Jenson HB, Baltimore RS: Pediatric Infectious Diseases: Principles and Practice, ed 2, Philadelphia, 2002, Saunders, p 772.
+, frequently present; –, absent; ±, may or may not be present; ++, present and usually pronounced.
Figure 107-1 Croup (laryngotracheobronchitis). A, Posteroanterior view of the upper airway shows the so-called steeple sign, the tapered narrowing of the immediate subglottic airway (arrows). B, Lateral view of the upper airway shows good delineation of the supraglottic anatomy. The subglottic trachea is hazy and poorly defined (arrow) because of the inflammatory edema that has obliterated the sharp undersurface of the vocal cords and extends down the trachea in a diminishing manner. (From Bell LM: Middle respiratory tract infections. In Jenson HB, Baltimore RS: Pediatric Infectious Diseases: Principles and Practice, ed 2, Philadelphia, 2002, Saunders, p 774.) phosphate (0.6 to 1 mg/kg) may be given once intramuscularly or dexamethasone (0.6 to 1 mg/kg) once orally. Alternatively prednisolone (2 mg/kg per day) may be given orally in two to three divided doses. For significant airway compromise, administration of aerosolized racemic (Dand L-) epinephrine reduces subglottic edema by adrenergic vasoconstriction, temporarily producing marked clinical improvement. The peak effect is within 10 to 30 minutes and fades within 60 to 90 minutes. A rebound effect may occur, with worsening of symptoms as the effect of the drug dissipates. Aerosol treatment may need to be repeated every 20 minutes (for no more than 1 to 2 hours) in severe cases.
Children should be kept as calm as possible to minimize forceful inspiration. One useful calming method is for a child with croup to sit on the parent’s lap. Sedatives should be used cautiously and in the intensive care unit only. Cool mist administered by face mask may help prevent drying of the secretions around the larynx.
Hospitalization is often required for children with stridor at rest. Children receiving aerosol treatment should be hospitalized or observed for at least 2 to 3 hours because of the risk of rebound airway obstruction. Decreased symptoms may indicate improvement or fatigue and impending respiratory failure.
The most common complication of croup is viral pneumonia, which occurs in 1% to 2% of children. Parainfluenza virus pneumonia and secondary bacterial pneumonia are more common in immunocompromised persons. Bacterial tracheitis may also be a complication of croup.
The prognosis for croup is excellent. Illness usually lasts approximately 5 days. As children grow, they become less susceptible to the airway effects of viral infections of the middle respiratory tract.
There is no vaccine for parainfluenza.