A newborn female is delivered at 39 weeks’ gestation via uncomplicated spontaneous vaginal delivery. Apgar scores are 8 and 9 at 1 and 5 minutes, respectively. Shortly after arrival in the nursery, the nursing staff notes that the infant becomes cyanotic and develops significant respiratory distress when quiet. The cyanosis resolves and the respiratory effort normalizes when the infant begins to cry. On physical examination, the infant is tachypneic and has nasal flaring. An attempt to pass a 6-French nasogastric catheter through both the right and left nares is unsuccessful, meeting resistance at approximately 3 to 4 cm from the alar rim.
Which of the following is the most appropriate next step to confirm the diagnosis?
The correct answer is:
B) Computed tomography of the nasal cavity
This infant presents with clinical findings highly suggestive of choanal atresia, a congenital condition where the posterior nasal cavity fails to communicate with the nasopharynx due to a bony or membranous obstruction. Because neonates are obligate nasal breathers, complete obstruction leads to respiratory distress when the infant is at rest. When the infant cries, they switch to oral breathing, which relieves the obstruction and explains why the cyanosis improves during crying. The failure to pass a catheter through the nares is the classic initial diagnostic sign. The definitive diagnostic study for choanal atresia is a computed tomography (CT) scan of the nasal cavity. This imaging modality allows the clinician to determine whether the obstruction is bony, membranous, or mixed, and it is essential for surgical planning.
Answer choice A: Bronchoscopy, is incorrect. Bronchoscopy is utilized to evaluate the trachea and bronchi for structural anomalies like tracheomalacia or stenosis. It does not provide visualization of the posterior nasal choanae and is not indicated for the diagnosis of nasal obstruction.
Answer choice C: Flexible laryngoscopy, is incorrect. Laryngoscopy is the preferred diagnostic modality for evaluating the larynx, such as in cases of laryngomalacia or vocal cord paralysis. It does not allow for visualization of the nasopharynx or choanae.
Answer choice D: Nasal endoscopy, is incorrect. While nasal endoscopy can be used to visualize the nasal cavity, it is technically challenging in a neonate and often requires sedation or general anesthesia. It is not the gold standard for diagnosing the anatomy of the atretic plate compared to computed tomography.
Answer choice E: Plain film neck radiography, is incorrect. Plain films provide limited detail of the nasal anatomy and are not sensitive or specific enough to diagnose choanal atresia or differentiate between bony and membranous types of obstruction.
Key Learning Point
Choanal atresia should be suspected in any neonate with cyanosis that improves with crying, as newborns are obligate nasal breathers. The initial clinical step is attempting to pass a catheter through the nares. If unsuccessful, the diagnosis is confirmed by computed tomography of the nasal cavity. Clinicians should also screen these infants for associated anomalies, particularly the CHARGE syndrome association, which includes Coloboma, Heart defects, Atresia choanae, Retardation (growth and developmental delays), Genital abnormalities, and Ear abnormalities.
