Introduction
Congenital disorder in which nasal choanae, (paired openings that connect nasal cavity with nasopharynx), are occluded by soft tissue (membranous), bone, or a combination of both, due to failed recanalization of the nasal fossae during fetal development.
- Acute otolaryngologic emergency (since newborns are obligate nasal breathers, establishing an airway is of utmost importance in bilateral choanal atresia)
Aetiology
Embryology:
Nasal choanae develop between the 3rd and 7th embryonic weeks, following the rupture of the vertical epithelial fold between olfactory groove and roof of primary oral cavity (stomodeum).
Choanal atresia occurs due to the following reasons:
- Persistence of buccopharyngeal membrane
- Persistence of nasobuccal membrane of Hochstetter
- Incomplete resorption of nasopharyngeal mesoderm
- Local misdirection of neural crest cell migration
Associated conditions:
- CHARGE syndrome (M/C associated condition): Coloboma, heart disease, atresia choanae, growth, and mental retardation, genital hypoplasia, and ear anomalies
Clinical features
Varies from acute life-threatening airway obstruction to chronic recurrent nasal discharge on the affected side, depending on a unilateral or bilateral nature of the abnormality.
Bilateral choanal atresia:
- Acute respiratory distress with paradoxical cyanosis (cyanosis that is relieved with crying and with the return of cyanosis with rest/breastfeeding)
- Feeding difficulty: Progressive airway obstruction and choke episodes during feeding because of their inability to breathe and feed at the same time
Unilateral choanal atresia:
Rarely present with infant respiratory distress. In some cases, the correct diagnosis is not reached until adulthood due to the non-specific symptoms of unilateral nasal obstruction.
- Purulent nasal discharge and obstruction on the affected side
- History of chronic sinusitis.
Diagnosis
Clinical diagnosis:
The diagnosis of this condition should be done immediately after birth.
- Laryngeal mirror under nostril to check for fogging
- Introducing suction catheter through each nostril and into child’s oral cavity.
Flexible nasal endoscopy:
Done with proper preparation, such as nasal decongestion and mucous suctioning, allowing direct visualization of the possible obstruction in the nasal passage.
CT scan (confirmatory):
Delineates characteristics of malformation, such as the anatomy of the atretic area, including the thickness of the atretic plate and the presence and thickness of a bony plate. CT is also useful in differentiating other causes of nasal obstruction from choanal atresia.
Differential diagnoses:
- Pyriform aperture stenosis
- Nasolacrimal duct cysts
- Turbinate hypertrophy
- Septal dislocation and deviation
- Antrochoanal polyp
- Nasal neoplasm
Management
Objectives are to restore choanal patency, not to interfere with the patient normal craniofacial development, to minimize invasiveness, and to avoid recurrences.
Acute management:
For infants with bilateral choanal atresia in asphyxia to maintain an adequate oral airway
- Endotracheal intubation
- McGovern nipple: Intraoral nipple with a large opening by cutting its end off, secured in the mouth with ties around the infant’s occiput, followed by perforation of the atresia plate.
Surgical management:
The treatment of choanal atresia is essentially surgical. Unilateral choanal atresia does not require surgical treatment as urgently as the bilateral case and can be postponed until school-age when the anatomy of the region is more similar to that in adults.
- Transpalatal surgical approach (M/C, before endoscopic surgery came to use)
- Other surgical approaches: Transeptal, sublabial, transantral, and transnasal
Endoscopic sinus surgery:
Currently most preferred surgical technique
- Endoscopic endonasal technique: For the repair of choanal atresia
Adjunct therapy:
Administered with surgery to prevent restenosis
- Choanal stenting
- Mitomycin C