Choanal atresia

Choanal atresia is a congenital condition characterized by a bony and/or membranous obstruction of the posterior nasal passage. This obstruction may occur either unilaterally or bilaterally. Unilateral choanal atresia often presents late with chronic inflammation (e.g., rhinorrhea, congestion) of the affected nasal passage. Bilateral choanal atresia manifests as obstructed nasal breathing with intermittent cyanosis immediately after birth; breathing improves when crying, as it allows the infant to breathe through his or her mouth. The diagnosis is confirmed with contrast rhinography or CT imaging. The definitive treatment is surgery, in which the obstructive membrane or bony portion is perforated.

• Congenital condition; characterized by a bony (90% of cases) and/or membranous (10%) obstruction of the posterior nasal passage

References:^[1]

• Sex: ♀ > ♂ (∼ 2:1)
• Unilateral choanal atresia is twice as common as bilateral choanal atresia.
• Frequently associated with other anomalies (“CHARGE syndrome” - coloboma, heart defects, atresia choanae (also known as choanal atresia), retardation of growth, genital abnormalities, and ear abnormalities)

References:^[2]

Epidemiological data refers to the US, unless otherwise specified.

Choanal atresia has a positive association with periconceptional maternal exposure to:

• Thyroid medications (methimazole, carbimazole)
• Cigarette smoking
• Caffeine (≥ 3 cups per day)
• Elevated levels of vitamin B12, zinc, and vitamin B3 (niacin)

References:^[2]

• It has been hypothesized that the condition is due to ^[3]
  • Persistence of the buccopharyngeal membrane during the embryonic period
  • Persistence of the oronasal membrane beyond the embryonic period
  • Outgrowth of the palatine bone
  • Atypical mesodermal adhesions
  • Incomplete mesodermal resorption
  • Altered local growth factors
  • Abnormal neural crest cell migration

• Bilateral choanal atresia
  • Early presentation
  • Infants are only able to breathe through the mouth (immediately postpartum)
  • Cyanosis that worsens when feeding and improves when crying
  • Upper airway obstruction (e.g., noisy breathing, dyspnea)
  • Food intake impossible: Complete airway obstruction is a life-threatening condition immediately following birth because of the worsening dyspnea associated with feeding.
• Unilateral choanal atresia
  • Typically presents later in life
  • Chronic rhinitis in the affected nasal passage with purulent nasal discharge over several weeks

References:^[2][4]

• The inability to pass the catheter through the nasal cavity is an indication of choanal atresia.
• Confirmatory tests: contrast rhinography in the supine position or CT scan
  • Unilateral or bilateral narrowing of the posterior nasal passage
  • Airway width < 3 mm

References:^[2][5][6]

• Bilateral choanal atresia
  • Urgent insertion of an oropharyngeal airway (or even intubation) as a temporary airway until surgery
  • Surgical perforation (e.g., endoscopic resection of the posterior nasal septum)
  • Local use of chemotherapeutic agents (e.g., mitomycin C) may reduce the need for stenting, dilatations, and second surgery.
• Unilateral choanal atresia
  • Observation and subsequent surgery when the infant is 1–2 years old

In suspected cases of bilateral choanal atresia, do not feed. A feeding tube is required due to the increased risk of aspiration.
References:^[4][7]

• With appropriate management, full recovery occurs in most cases.
• Periodic dilatations may be needed, as stenosis can recur postoperatively.