What are the symptoms of laryngeal hypoplasia?

Generally, laryngomalacia occurs mostly in infants and young children. It is a condition caused by insufficient cartilage support in the larynx, with main symptoms including inspiratory stridor, abnormal breathing, feeding difficulties, hoarseness, and symptom changes related to body position. A detailed analysis is as follows:

1. Inspiratory stridor: This usually appears within several weeks after birth. During inspiration in infants, the narrowing of the laryngeal cavity causes airflow vibrations that produce a high-pitched stridor sound. The stridor worsens during crying, feeding, or physical activity, but improves when the infant is calm or lying on their side.

2. Abnormal breathing: Some affected infants may experience mild inspiratory breathing difficulty, manifested as slight flaring of the nostrils and mild retractions of the suprasternal or supraclavicular fossae during inhalation. The severity varies—symptoms are often noticeable only after activity, but in severe cases, labored breathing can occur even at rest.

3. Feeding difficulties: Insufficient laryngeal cartilage support may disrupt the coordination between swallowing and breathing. Infants may choke or cough while feeding, swallow slowly, or even stop feeding voluntarily due to breathing effort. Prolonged feeding difficulties can lead to poor weight gain.

4. Hoarseness: In a small number of infants, underdeveloped laryngeal cartilage affects vocal cord vibration, resulting in hoarseness and a weak, low cry. If accompanied by laryngeal mucosal congestion, hoarseness may temporarily worsen.

5. Symptoms vary with body position: Symptoms are closely related to body posture. When lying supine, gravity narrows the laryngeal cavity, worsening stridor and breathing difficulty. When lying on the side or held upright, the laryngeal space becomes relatively wider, significantly relieving symptoms—this positional variation is one of the distinguishing features from other laryngeal disorders.

Laryngomalacia typically improves gradually as the infant grows. Parents should take care to prevent colds and respiratory infections, hold the baby upright during feeding, and control milk flow to reduce choking. Daily supplementation with vitamin D and calcium, as directed by a physician, may help promote maturation of the laryngeal cartilage.