Week 23 Q&A
A mother brings to the clinic a 6-week-old girl who has a high-pitched inspiratory noise that worsens with excitement.
The girl has no respiratory distress or hoarseness. She has never turned blue or stopped breathing. She breastfeeds well and is growing normally.
What is the most likely cause of the inspiratory noise?
A. Foreign body.
B. Vocal cord paresis.
E. Aberrant right subclavian artery.
The correct answer is “C.” The most common cause of stridor in newborns is laryngomalacia. Laryngomalacia causes intermittent collapse of the supraglottic structures with inspiration. Infants are squeaky and musical sounding. It is noticed soon after birth, progressively worsens until 4 months of age, and then typically resolves by 1 year. The inspiratory stridor is (1) worse with crying, feeding, or excitement; (2) worse with viral upper respiratory tract infections; and (3) positional in nature (worse when supine). Flip the infant prone either on the bed or over your forearm; the stridor should lessen. (People will think you are a diagnostic genius.) The differential diagnosis for stridor is long but all candidate conditions cause airway obstruction typically outside of the chest (extrathoracic). (See Table 32–1.) Unilateral vocal cord paresis may be recognized by a weak cry, hoarseness, or aspiration with feeds. Bilateral disease causes stridor. Laryngomalacia does not cause hoarseness. Tracheomalacia is less common (approximately 1:2000). Tracheomalacia can cause stridor depending on the location, but more frequently is associated with cough and wheezing. Vascular rings are congenital anomalies of the aortic arch that compress the trachea or esophagus, or both, causing stridor. Complete rings fully encircle the trachea and esophagus (ie, double aortic arch). Incomplete rings (ie, pulmonary sling) do not. An aberrant right subclavian artery (incomplete ring) courses posterior to the esophagus and can cause difficulty with swallowing (dysphagia lusoria). Let’s hope this child’s older sibling did not feed her a peanut that she aspirated.