Choanal Atresia

Definition & Embryology - Blocked Backdoor

• Definition: Congenital blockage of the posterior nasal aperture (choana), which connects the nasal cavity to the nasopharynx. This obstruction can be unilateral or bilateral, bony or membranous.
• Embryology: Primarily due to:
  • Failure of the bucconasal membrane (posterior choanal membrane) to rupture during the 6th-7th week of fetal development.
  • Other proposed mechanisms:
    • Persistence of the fetal nasobuccal membrane.
    • Abnormal persistence or migration of mesenchymal cells forming a blockage.

⭐ Choanal atresia is the most common congenital anomaly of the nose. oka

Epidemiology & Associations - Unlucky Draw

• Incidence: 1 in 5000-8000 live births.
• Sex predilection: Females > Males (F:M ≈ 2:1).
• Laterality: Unilateral more common.
  • Right side typically affected in unilateral cases.
• Type: Bony atresia (~90%) more common than membranous (~10%).
• Associated Syndromes:
  • 📌 CHARGE syndrome is a key association. The components are:

    Letter	Anomaly
    C	Coloboma of the eye
    H	Heart defects
    A	Atresia choanae
    R	Retardation of growth and/or development
    G	Genital hypoplasia (males)
    E	Ear anomalies and/or deafness

  ⭐ CHARGE syndrome is associated with choanal atresia in up to 50% of bilateral cases.

Clinical Presentation - Can't Breathe Easy

• Bilateral (Neonates - Obligate Nasal Breathers):
  • Immediate, severe respiratory distress; noisy breathing.
  • Cyclical cyanosis: worsens with feeding/sleep (mouth closed), dramatically improves with crying (mouth open) (📌 Cyanosis Relieved By Crying - CRBC).
  • Choking/gagging during feeds; failure to thrive.
• Unilateral (Older Children/Adults - Often Missed):
  • Presents later; may be asymptomatic for years.
  • Chronic, persistent unilateral purulent nasal discharge (mucoid/mucopurulent).
  • Nasal stuffiness/obstruction; anosmia on the affected side.

⭐ Bilateral choanal atresia is a neonatal emergency, often requiring immediate airway management (e.g., oral airway, intubation).

Diagnosis - Spotting the Block

• Clinical Suspicion: Arises from symptoms like cyclical cyanosis, especially during feeding.
• Catheter Test: Key initial step. Inability to pass a #6 or #8 French catheter more than 3-4 cm from the anterior nares into the oropharynx.
• Confirmatory Tests:
  • Mirror Test: Lack of fogging on the affected side when a cold mirror is held under the nostril.
  • Nasal Endoscopy (Flexible/Rigid): Allows direct visualization of the atretic plate.
• Imaging (Gold Standard):
  • CT Scan (Axial & Coronal views): Defines bony/membranous nature, thickness of the atretic plate, and narrowing of posterior choanae. Essential for surgical planning.

  ⭐ CT scan is the gold standard for diagnosis and surgical planning.

Management - Opening Airways

• Immediate Airway (Bilateral):
  • Oral airway, McGovern nipple crucial; intubation if distress.
• Surgical Correction:
  • Timing: Early for bilateral (obligate nasal breathers); elective for unilateral.
  • Approaches:
    • Transnasal Endoscopic: Most common, preferred.
    • Transpalatal: For thick bony atresia or revision cases.
  • Techniques: Drilling, puncture, or laser to create opening.
  • Adjuncts:
    • Stenting: Controversial, duration varies; aims to prevent restenosis.
    • Mitomycin C: Topical application to reduce granulation and restenosis.

⭐ Transnasal endoscopic approach is currently the preferred surgical method for choanal atresia repair due to better visualization and lower morbidity.

High‑Yield Points - ⚡ Biggest Takeaways

• Congenital obstruction of the posterior nasal aperture; predominantly bony (90%) over membranous.
• More frequent in females (2:1); strong association with CHARGE syndrome.
• Bilateral atresia presents as neonatal respiratory distress and cyclic cyanosis, relieved by crying.
• Unilateral atresia often presents later with chronic unilateral nasal discharge or obstruction.
• Diagnosis confirmed by failure to pass a catheter and CT scan (gold standard).
• Definitive treatment is surgical correction, typically via transnasal endoscopic approach.