Apnea Due to Gastroesophageal Reflux
Gastroesophageal reflux may produce apnea by causing a laryngospasm or by a reflex mechanism that involves the esophageal mucosa, the superior laryngeal nerve, and the respiratory centers in the brainstem.
Laryngospasm should be suspected in an awake or asleep neonate with an obstructive episode within one hour of feeding. The episode consists of staring, rigid or opisthotonic posturing, and plethora followed by hypotonia and cyanosis or pallor. There is no coughing, choking, or gagging during the episode. The reflex-mediated apnea produced by gastroesophageal reflux is central, occurs during swallowing, and is associated with bradycardia.
Diagnosis of gastroesophageal reflux-induced apnea requires polysomnogram and pH probe. It is established by documenting pathological gastroesophageal reflux by pH probe recordings temporally associated with the apnea or by documenting that apnea only occurs during periods of low esophageal pH. A decrease in frequency of apnea after successful gastroesophageal reflux treatment confirms the diagnosis. Treatment consists of positioning the neonate upright while feeding, administering oral antacids, and using sphincter-augmenting agents (metoclopramide). Thickening formula and frequent feeding are of questionable value in neonates. Surgical treatment may be warranted.

Apnea Due to Upper Airway Abnormality
Air on its way to the alveoli travels through the nose, pharynx, larynx, and trachea. A structural obstruction at any level in this trajectory may produce apnea. Choanal atresia is an infrequent cause of apnea. It is easily diagnosed by finding no mist on the surface of a glass held close to the nostrils. Narrowing of the upper airway produces increased airflow turbulence resulting in excessive negative pressure that may collapse the pharynx. Narrowing of the upper airway occurs with micrognathia (Figure 34.1).

Figure 34.1.— Micrognathia.

Other condition that produces narrowing of the upper airway are macroglossia, or even by mild anatomical upper-airway abnormalities (Figure 34.2). Plexiform neuroblastoma should be considered in neonates with narrow upper airway if café au lait spots are present.

A	B

Figure 34.2.1.—A. Vallecular cyst. B. Vallecular cyst removed. Patients apneas disapeared after surgery.

The typical clinical presentation consists of noisy or laborious respirations preceding apnea. Facial dysmorphism may be present. Apnea due to upper airway abnormalities is obstructive, except for apnea due to choanal atresia which is central.