Stridor VS Stertor
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Stridor vs Stertor - Differences
Stridor and Stertor are both forms of noisy breathing, but they differ significantly in their site of obstruction, mechanism, clinical significance, and associated features.
| Feature | Stridor | Stertor |
|---|---|---|
| Definition | Harsh, high pitched musical sound due to turbulent airflow through a narrowed airway | Low pitched snoring like sound due to upper airway obstruction |
| Nature of Sound | Musical, squeaky | Snoring, rumbling, gurgling |
| Pitch | High pitched | Low pitched |
| Mechanism | Turbulent airflow through partially obstructed laryngeal or tracheal airway | Vibration of soft tissues in nasopharynx or oropharynx |
| Primary Site of Obstruction | Supraglottis, glottis, subglottis, trachea | Nasopharynx or oropharynx |
| Respiratory Phase | May be inspiratory, biphasic, or expiratory depending on site of obstruction | Predominantly inspiratory |
| Effect of Crying | Worsens on crying and exertion | Usually unchanged |
| Effect of Position | Usually unaffected by position | Worse in supine position |
| Associated Cough | Usually present | Usually absent |
| Voice Changes | Hoarseness if glottis involved | Usually normal |
| Cry | May become hoarse if glottic pathology present | Muffled cry |
| Severity | Often indicates potentially life threatening airway obstruction | Usually less urgent unless severe airway compromise occurs |
| Typical Age Group | Common in infants and children but can occur at any age | Occurs at all ages; OSA more common in adults |
| Audibility | Audible even without a stethoscope | Commonly heard during sleep or relaxation |
| Site of Best Audibility | Neck or tracheal region | Nose or mouth |
| Urgency | Airway emergency until proven otherwise | Usually less acute |
| Underlying Pathology | Laryngeal or tracheal narrowing | Pharyngeal airway obstruction |
Common Causes of Stridor
- Croup
- Epiglottitis
- Laryngomalacia
- Tracheomalacia
- Subglottic stenosis
- Airway foreign body
- Laryngeal edema
- Vocal cord paralysis
Common Causes of Stertor
- Obstructive sleep apnea
- Adenoid hypertrophy
- Tonsillar hypertrophy
- Choanal atresia
- Macroglossia
- Nasopharyngeal obstruction
- Oropharyngeal obstruction
Viva Pearls
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Stridor = Laryngeal or Tracheal obstruction
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Stertor = Nasopharyngeal or Oropharyngeal obstruction
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Stridor is generally considered an airway emergency
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Stertor is classically described as a snoring type noisy breathing
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Site of best audibility helps differentiate the two:
- Neck → Stridor
- Nose/Mouth → Stertor
What does Inspiratory stridor indicate?
What does Expiratory stridor indicate?
What does Biphasic stridor indicate?
What are the different types of cough seen in different types of Stridor?
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