Choanal Atresia

Choanal atresia is a congenital defect in which the openings that connect the nasal cavity to the nasopharynx (choanae) are occluded, either by soft tissue, bone, or both. (90% bony, 10% membranous and 5% mixed)

It is more common in females. Most cases are unilateral (65%, right-side predominance). It is associated with prenatal use of carbimazole and methimazole, cigarette smoking, caffeine (> 3 cups a day), and elevated vitamin B12, vitamin B3 and zinc levels.

• Pathophysiology
  • Persistence of the bucconasal membrane or Abnormal migration of neural crest cells into the nasal vault
  • Results in complete bony (30%), mixed bony-membranous (70%), or membranous (rare) obstruction of the posterior nasal cavity
  • The bony components are from the pterygoid plate and vomer
• What are the theories behind the development of choanal atresia?
  • Persistence of buccopharyngeal membrane during the embryonic period
  • Persistence of the oronasal membrane beyond the embryonic period
  • Outgrowth of the palatine bone
  • Abnormal persistence of the mesoderm leading to atypical mesodermal adhesions
  • Incomplete mesodermal resorption
  • Altered local growth factors
  • Abnormal neural crest cell migration
• Signs and symptoms
  • Unilateral: may be asymptomatic
    • Rhinorrhoea
    • Nasal obstruction
  • Bilateral
    • Cycles of apnoea and cyanosis followed by crying (neonates are obligate nose breathers)
    • Blue baby (central cyanosis)
    • Color relieved when the neonate cries and worsens when feeding
• Investigations and bedside tests
  • Cotton wisp test
  • Metallic spatula test/ mirror test to detect condensation
  • Attempt transnasal passage of a 6 Fr catheter
  • Put blue dye through nostril
  • Attempt nose blowing with an occluded nostril
  • Nasal endoscopy
  • CT scan
  • EKG
• Associated syndromes
  • CHARGE syndrome (most common concurrent syndrome with bilateral atresia in 50%)
    • Coloboma Idris
    • Heart Defects
    • Atresia (Choanal)
    • Retardation (Mental)
    • Genital Hypoplasia
    • Ear defects
  • Apert, Treacher Collins, Crouzon, Trisomy 21, and 22q11 deletion
• Treatment of bilateral atresia
  • Establish an oral airway with McGovern Airway (cut the end of a bottle nipple and secure it around the mouth) or Oropharyngeal airway. Intubation is rarely required
  • Feeding through an orogastric tube
  • Oxygen supplementation using a mask
  • Arrange for repair as early as possible
• Treatment of unilateral atresia
  • Repair electively
• Repair options
  • Surgical repair via Transnasal, Transantral, Transseptal, or Transpalatal approach → drill + stent
    • The transnasal approach is usually endoscopic
    • Transantral approach can create a large cavity for recurrent cases
    • The transpalatal approach is a classical approach that may disrupt orthodontic growth