Choanal Atresia

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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:
      LetterAnomaly
      CColoboma of the eye
      HHeart defects
      AAtresia choanae
      RRetardation of growth and/or development
      GGenital hypoplasia (males)
      EEar 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).

Choanal Atresia: Symptoms, Diagnosis, Treatment

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. Axial CT showing right choanal atresia

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.

Endoscopic Choanal Atresia Repair Steps

⭐ 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.

Practice Questions: Choanal Atresia

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Which of the following conditions is treated by laser-assisted uvulopalatoplasty?

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Flashcards: Choanal Atresia

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Clinical features of _____ polyps include unilateral nasal obstruction which becomes bilateral when it grows posteriorly and obstructs opposite choana, mucoid nasal discharge, hyponasal voice

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Clinical features of _____ polyps include unilateral nasal obstruction which becomes bilateral when it grows posteriorly and obstructs opposite choana, mucoid nasal discharge, hyponasal voice

antrochoanal

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