Stridor

This page is for adult patients. For pediatric patients, see: stridor (peds)

Background

• Stridor refers to harsh upper airway sounds caused by turbulent airflow through a narrowed airway
• Classically inspiratory, indicating extrathoracic obstruction
• A true airway emergency — rapidly assess for need for definitive airway management
• In adults, the differential differs significantly from pediatrics due to larger airway caliber
• Most common adult causes: anaphylaxis, foreign body, angioedema, infection (peritonsillar/retropharyngeal abscess, epiglottitis), post-extubation edema, and malignancy

Clinical Features

Phase of Respiration

• Inspiratory stridor: extrathoracic obstruction (supraglottic or glottic level)
  • Pressure_trach < Pressure_atm causes dynamic collapse
  • Examples: epiglottitis, angioedema, foreign body, laryngeal mass
• Expiratory stridor (vs. wheezing): intrathoracic obstruction (subglottic/tracheal level)
  • Pressure_trach < Pressure_pleura
  • Examples: tracheal mass, goiter, tracheomalacia
• Biphasic stridor: fixed obstruction (critical narrowing at glottis or subglottis)
  • Examples: subglottic stenosis, bilateral vocal cord paralysis, large foreign body

Associated Features

• Drooling, dysphagia, muffled voice (supraglottic process)
• Hoarseness (glottic or recurrent laryngeal nerve involvement)
• Fever (infectious etiology)
• Facial/lip/tongue swelling (angioedema, anaphylaxis)
• History of intubation, neck surgery, or radiation (subglottic stenosis, recurrent laryngeal nerve injury)
• Preceding choking event (foreign body)

Differential Diagnosis

Stridor

Trauma

• Larynx fracture
• Tracheobronchial tear/injury
• Thyroid gland injury/trauma
• Tracheal injury
• Electromagnetic or radiation exposure
• Burns, inhalation injury

Infectious Disorders

• Bacterial tracheitis
• Diphtheria
• Tetanus
• Tracheobronchial tuberculosis
• Poliomyelitis, paralytic, bulbar, or acute
• Fungal laryngitis

Abscesses

• Retropharyngeal abscess
• Epiglottitis, acute
• Peritonsillar abscess
• Laryngotracheobronchitis (croup)
• Retropharyngeal abscess

Neoplastic Disorders

• Neoplasms/tumors

Allergic and Auto-Immune Disorders

• Spasmodic/tracheobronchitis
• Angioedema/Angioneurotic edema

Metabolic, Storage Disorders

• Cerebral Gaucher's of infants (acute)
• Tracheobronchial amyloidosis

Biochemical Disorders

• Tetany

Congenital, Developmental Disorders

• Angioedema/Angioneurotic edema, hereditary

Psychiatric Disorders

• Somatization disorder

Anatomical or Mechanical

• Foreign body aspiration
• Acute gastric acid/aspiration syndrome
• Airway obstruction
• Neck compartment hemorrhage/hematoma
• Paradoxical vocal fold motion

Vegetative, Autonomic, Endocrine Disorders

• Esophageal free reflux/GERD syndrome
• Laryngospasm, acute
  • Bilateral vocal cord paralysis
• Hypoparathyroidism

Poisoning

• Smoke inhalation
• Chemical burn/esophagus

Chronic Pediatric Conditions

• Laryngotracheomalacia
• Subglottic stenosis or prior intubation
• Vascular ring (double aortic arch)
• Vocal cord dysfunction/paroxysmal vocal fold movement

Evaluation

Immediate

• Assess airway stability — if in extremis, proceed directly to airway management
• Pulse oximetry (may be normal until late stages)
• Allow patient to maintain position of comfort
• Do NOT agitate the patient if concern for supraglottic infection (epiglottitis)

Workup

• Stable patient:
  • Lateral soft tissue neck radiograph (thumbprint sign in epiglottitis, retropharyngeal widening)
  • CT neck with contrast if mass, abscess, or deep space infection suspected
  • Nasopharyngoscopy or fiberoptic laryngoscopy for direct visualization (if available and safe)
• Unstable patient:
  • Defer imaging — proceed to airway management
  • Consider calling anesthesia, ENT for surgical airway backup

Laboratory

• Generally not helpful acutely
• Consider CBC, blood cultures if infectious etiology suspected
• Tryptase if anaphylaxis suspected

Management

Airway Management

• Prepare for difficult airway — have backup equipment ready including surgical airway kit
• Intubation with a smaller-than-expected endotracheal tube (due to narrowed airway)
• Consider awake fiberoptic intubation if expertise available
• Surgical airway (cricothyrotomy) if unable to intubate/ventilate
• Call for help early (anesthesia, ENT)

Condition-Specific

• Anaphylaxis: epinephrine IM 0.3-0.5mg, repeat q5-15min; adjuncts per anaphylaxis protocol
• Angioedema: distinguish allergic vs. ACE inhibitor-induced vs. hereditary
  • Allergic: epinephrine, antihistamines, corticosteroids
  • ACE inhibitor-induced: epinephrine if severe, consider icatibant or C1-esterase inhibitor concentrate
  • Hereditary angioedema: C1-esterase inhibitor concentrate, icatibant, or ecallantide
• Epiglottitis: IV antibiotics (ceftriaxone + vancomycin), airway management in OR if possible
• Peritonsillar/retropharyngeal abscess: IV antibiotics, surgical drainage, ENT consultation
• Foreign body: direct laryngoscopy or bronchoscopy for removal
• Post-extubation stridor: racemic epinephrine nebulized, IV dexamethasone, consider Heliox
• Malignancy: ENT/oncology consultation, dexamethasone for tumor-related edema

Disposition

• All patients with stridor should be closely monitored
• Most require admission for airway observation
• ICU admission for: tenuous airway, requiring repeated treatments, post-intubation
• Discharge is rare — only if complete resolution of mild post-procedural or allergic stridor after observed treatment and monitoring

See Also

• Stridor (Peds)
• Difficult Airway Algorithm
• Anaphylaxis
• Angioedema
• Epiglottitis