A neonate presents with respiratory distress at birth that worsens during feeding and improves with crying. Examination shows inability to pass a nasal catheter bilaterally. What is the embryological basis of this condition?

• A Failure of rupture of the oropharyngeal membrane
• B Failure of fusion of the lateral nasal and maxillary processes
• C Persistence of the bucconasal membrane (failure of the nasal fin to dissolve) ✓
• D Failure of development of the posterior choanae from the nasal sac

Explanation

Choanal atresia results from persistence of the bucconasal membrane (nasal fin/oronasal membrane) — the thin membrane separating the primitive nasal cavities from the nasopharynx at 7-8 weeks gestation. Normally it ruptures to form the posterior choanae. Bilateral choanal atresia causes neonatal respiratory distress (neonates are obligate nasal breathers) that worsens with feeding. 90% are bony/mixed, 10% membranous. Diagnosed by inability to pass a 6 Fr catheter 3.5 cm past the nasal sill.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.