Congenital Anomalies of the Larynx
Introduction to Congenital Anomalies of the Larynx
Congenital anomalies of the larynx are structural abnormalities present at birth that affect the larynx (voice box) and its surrounding structures. These conditions can range from mild to severe and may impact breathing, swallowing, and vocalization. Understanding these anomalies is crucial for pediatricians, otolaryngologists, and neonatologists to ensure proper diagnosis and management.
Key points:
- Incidence: Varies by specific anomaly, but collectively affects approximately 1 in 2,000 live births
- Etiology: Multifactorial, including genetic factors, environmental influences, and developmental abnormalities
- Clinical presentation: Stridor, feeding difficulties, voice abnormalities, and respiratory distress
- Long-term impact: Can affect speech, swallowing, and respiratory function if not properly managed
Laryngomalacia
Laryngomalacia is the most common congenital laryngeal anomaly, accounting for 60-70% of congenital stridor cases in infants.
Pathophysiology
- Characterized by floppiness of the supraglottic structures, particularly the epiglottis, aryepiglottic folds, and arytenoids
- During inspiration, these structures collapse inward, causing airway obstruction
Clinical Features
- Inspiratory stridor, typically worse when supine or during feeding
- Symptoms usually worsen over the first few months of life, then improve by 12-18 months
- Feeding difficulties and failure to thrive in severe cases
Management
- Conservative management in most cases, with close monitoring and reassurance
- Surgical intervention (supraglottoplasty) in severe cases with feeding difficulties or respiratory compromise
- Gastroesophageal reflux management, as it can exacerbate symptoms
Congenital Vocal Cord Paralysis
Congenital vocal cord paralysis is the second most common laryngeal anomaly, accounting for 10-20% of congenital laryngeal lesions.
Etiology
- Unilateral: Often idiopathic, can be associated with birth trauma or cardiovascular anomalies
- Bilateral: Frequently associated with neurological conditions (e.g., Arnold-Chiari malformation, hydrocephalus)
Clinical Features
- Unilateral: Weak cry, aspiration, and feeding difficulties
- Bilateral: Severe respiratory distress, stridor, and cyanosis
Management
- Unilateral: Often conservative management, speech therapy
- Bilateral: May require tracheostomy, consideration of vocal cord lateralization procedures
- Regular follow-up to assess for spontaneous recovery, which can occur in up to 50% of cases
Laryngeal Webs
Laryngeal webs are membranous connections between the vocal cords, resulting from incomplete recanalization of the laryngeal lumen during embryonic development.
Classification
- Type 1: Anteriorly located, involving less than 35% of the glottic aperture
- Type 2: Involving 35-50% of the glottic aperture
- Type 3: Involving 50-75% of the glottic aperture
- Type 4: Complete glottic obstruction
Clinical Features
- Weak or absent cry
- Biphasic stridor
- Respiratory distress, severity depending on the extent of the web
Management
- Endoscopic lysis for thin webs
- Open laryngoplasty for thicker webs or those associated with subglottic stenosis
- Postoperative stenting and mitomycin C application to prevent recurrence
Subglottic Stenosis
Congenital subglottic stenosis is a narrowing of the subglottic airway, often defined as a diameter less than 4 mm in a full-term newborn.
Classification (Myer-Cotton grading system)
- Grade I: ≤50% obstruction
- Grade II: 51-70% obstruction
- Grade III: 71-99% obstruction
- Grade IV: Complete obstruction
Clinical Features
- Biphasic stridor
- Recurrent croup-like episodes
- Respiratory distress, especially during upper respiratory infections
Management
- Conservative management for mild cases
- Endoscopic techniques: balloon dilation, laser resection
- Open surgical techniques: laryngotracheal reconstruction, cricotracheal resection for severe cases
Laryngeal Cysts
Congenital laryngeal cysts are rare anomalies that can cause airway obstruction and feeding difficulties.
Types
- Saccular cysts: Arise from the laryngeal saccule
- Ductal cysts: Result from obstruction of mucous gland ducts
- Thyroid cartilage foramina cysts: Develop through a defect in the thyroid cartilage
Clinical Features
- Stridor, often present at birth
- Respiratory distress
- Feeding difficulties
- Cyanotic episodes in severe cases
Management
- Endoscopic marsupialization for small cysts
- External approach for larger cysts or those extending into the neck
- Complete excision to prevent recurrence
Laryngeal Clefts
Laryngeal clefts are rare congenital anomalies characterized by a failure of fusion of the posterior cricoid lamina and interarytenoid muscles.
Classification (Benjamin and Inglis)
- Type I: Supraglottic interarytenoid cleft
- Type II: Partial cricoid cleft
- Type III: Total cricoid cleft extending into cervical trachea
- Type IV: Cleft extending into thoracic trachea
Clinical Features
- Aspiration and recurrent pneumonia
- Chronic cough
- Stridor and respiratory distress
- Feeding difficulties
Management
- Conservative management for Type I clefts: thickened feeds, anti-reflux measures
- Endoscopic repair for Type I and some Type II clefts
- Open surgical repair for Type III and IV clefts
- Multidisciplinary approach involving otolaryngology, pulmonology, and gastroenterology
Diagnosis and Management of Congenital Laryngeal Anomalies
Diagnostic Approach
- Detailed history and physical examination
- Flexible fiberoptic laryngoscopy: Often the initial diagnostic tool
- Direct laryngoscopy and bronchoscopy: Gold standard for definitive diagnosis
- Imaging studies:
- Neck and chest X-rays
- CT or MRI for complex cases or associated anomalies
- Swallow studies for suspected aspiration
General Management Principles
- Multidisciplinary approach involving otolaryngology, neonatology, pulmonology, and speech therapy
- Airway management: Priority in severe cases, may require intubation or tracheostomy
- Feeding management: Thickened feeds, gastrostomy tube placement in severe cases
- Regular follow-up to monitor growth, development, and respiratory status
- Surgical intervention tailored to the specific anomaly and severity
- Long-term speech and swallowing therapy as needed
Prognosis
Prognosis varies widely depending on the specific anomaly, severity, and associated conditions. Early diagnosis and appropriate management are crucial for optimizing outcomes. Many children with congenital laryngeal anomalies can achieve normal or near-normal function with proper care.
Congenital Anomalies of the Larynx
- Q: What is laryngomalacia? A: A condition where the laryngeal structures are soft and floppy, causing airway obstruction
- Q: What is the most common congenital anomaly of the larynx? A: Laryngomalacia
- Q: At what age do symptoms of laryngomalacia typically appear? A: Within the first 2 weeks of life
- Q: What is the characteristic sound associated with laryngomalacia? A: Inspiratory stridor
- Q: How is laryngomalacia typically diagnosed? A: Flexible laryngoscopy
- Q: What percentage of laryngomalacia cases resolve spontaneously? A: Approximately 90%
- Q: What is a laryngeal web? A: A thin membrane of tissue connecting the vocal cords
- Q: What is the most common location for a laryngeal web? A: The anterior commissure of the glottis
- Q: What is the primary symptom of a complete laryngeal web in newborns? A: Aphonia (inability to produce voice)
- Q: What is laryngeal atresia? A: Complete obstruction of the laryngeal lumen
- Q: What is the embryological cause of laryngeal atresia? A: Failure of recanalization of the laryngotracheal tube
- Q: What is the most severe form of laryngeal cleft? A: Type 4, extending into the thoracic trachea
- Q: What is the primary concern with laryngeal clefts? A: Aspiration and recurrent respiratory infections
- Q: What is subglottic stenosis? A: Narrowing of the subglottic airway
- Q: What percentage of subglottic stenosis cases are congenital? A: Approximately 5%
- Q: What is the Cotton-Myer classification used for? A: Grading the severity of subglottic stenosis
- Q: What is vocal cord paralysis? A: Immobility of one or both vocal cords
- Q: What is the most common cause of congenital vocal cord paralysis? A: Central nervous system abnormalities
- Q: What is the characteristic breathing pattern in bilateral vocal cord paralysis? A: Inspiratory stridor with a normal cry
- Q: What is the treatment for severe laryngomalacia? A: Supraglottoplasty
- Q: What is a laryngocele? A: An abnormal dilation of the laryngeal saccule
- Q: What is the primary symptom of an external laryngocele? A: A compressible neck mass that enlarges with Valsalva maneuver
- Q: What is the most common type of congenital subglottic cyst? A: Ductal cysts
- Q: What is the potential complication of untreated laryngeal hemangioma? A: Airway obstruction
- Q: What is the first-line treatment for infantile laryngeal hemangiomas? A: Propranolol
- Q: What is the characteristic triad of CHARGE syndrome? A: Coloboma, heart defects, and choanal atresia
- Q: What laryngeal anomaly is commonly associated with CHARGE syndrome? A: Laryngomalacia
- Q: What is the primary concern with congenital high airway obstruction syndrome (CHAOS)? A: Fetal hydrops and pulmonary hypoplasia
- Q: What imaging modality is most useful for evaluating laryngeal anomalies prenatally? A: Fetal MRI
- Q: What is the EXIT procedure? A: Ex utero intrapartum treatment, used to secure the airway in fetuses with known airway obstruction
Further Reading
- Congenital Anomalies of the Larynx - Comprehensive review article in Otolaryngologic Clinics of North America
- Congenital Malformations of the Larynx - Medscape article with detailed information on various laryngeal anomalies
- Congenital Laryngeal Anomalies - In-depth discussion in Otolaryngologic Clinics of North America
- Congenital High Airway Obstruction Syndrome (CHAOS) - Children's Hospital of Philadelphia resource on severe laryngeal obstruction
