A 3-month-old male infant is brought to the clinic by his mother because she is concerned about a persistent noisy sound her son makes when he breathes. She notes the sound has been present since he was about 2 weeks old. She describes it as a high-pitched whistling noise that occurs when he is breathing in. She reports that the sound becomes noticeably louder when he is crying or lying on his back, and seems to resolve or improve when he is sleeping on his stomach or is calm and feeding. He has had no fevers, cough, or drooling. He was born full-term without complications and has met all developmental milestones. His vaccinations are up to date. Vital signs are temperature 36.8°C (98.3°F), heart rate 120/min, respirations 30/min, and oxygen saturation 99% on room air. On physical examination, he is a well-appearing, thriving infant. Lung sounds are clear. Audible inspiratory stridor is heard when the patient is supine, which improves significantly when the infant is placed in the prone position.
Which of the following is the most appropriate next step in management?
The correct answer is:
D) Observation with parental reassurance
This patient is presenting with classic features of laryngomalacia, the most common cause of chronic stridor in infants. It is caused by the collapse of supraglottic structures, often the epiglottis, into the airway during inspiration. The hallmark clinical feature is inspiratory stridor that worsens with agitation or the supine position and improves when the infant is prone or quiet. The diagnosis is primarily clinical, and in a thriving infant with no other alarming signs, management consists of observation and parental reassurance. Most cases are self-limiting and resolve spontaneously by 18 to 24 months of age as the laryngeal cartilage matures and stiffens.
Answer choice A: Flexible laryngoscopy, is incorrect. While this is the diagnostic gold standard for visualizing the dynamic collapse of the supraglottic structures, it is reserved for infants with atypical presentations, severe symptoms, failure to thrive, apnea, or when the diagnosis is unclear. In a classic case with a thriving infant, it is an unnecessary invasive procedure.
Answer choice B: Lateral neck radiograph, is incorrect. This imaging modality is used to evaluate for causes of acute stridor, such as epiglottitis (which will show the thumbprint sign) or to identify a radiopaque foreign body. It is not indicated for the evaluation of chronic, classic laryngomalacia, as it will not visualize the dynamic collapse of the airway.
Answer choice C: Nebulized racemic epinephrine, is incorrect. This is the treatment, along with dexamethasone, for croup (laryngotracheobronchitis), which presents with acute stridor, a barking cough, and signs of viral upper respiratory infection. It has no role in the management of chronic, congenital structural airway issues.
Answer choice E: Urgent surgical supraglottoplasty, is incorrect. This surgical procedure, which involves trimming the redundant supraglottic tissue to open the airway, is reserved for severe cases of laryngomalacia. Indications include failure to thrive, severe obstructive sleep apnea, or life-threatening airway obstruction. This patient is thriving, making surgical intervention inappropriate.
Key Learning Point
Laryngomalacia is the most common cause of congenital stridor. It is characterized by inspiratory stridor that is worse when supine or agitated and improves when prone. The diagnosis is clinical, and management for typical cases is observation with reassurance, as the condition is self-limiting and resolves as the child grows.
