Stridor

Definition

• Inspiratory stridor suggests obstruction at or above the glottis.
• Expiratory stridor suggests intrathoracic tracheal obstruction.
• Biphasic stridor suggests a fixed obstruction at glottic or subglottic level.
  Textbook of Family Medicine, p. 436; ROSEN's Emergency Medicine, p. 3165.

Causes of stridor

• Laryngomalacia, the commonest cause in infancy
• Vocal-cord paralysis
• Subglottic stenosis
• Laryngeal web or cleft
• Subglottic haemangioma
• Tracheomalacia, complete tracheal rings
• Vascular ring or other mediastinal vascular compression

• Viral croup, acute laryngotracheobronchitis
• Acute epiglottitis or supraglottitis
• Bacterial tracheitis
• Retropharyngeal abscess
• Peritonsillar abscess
• Laryngeal oedema due to allergy or anaphylaxis

• Inhaled foreign body
• Post-intubation laryngeal oedema
• Laryngeal or tracheal trauma, burns, caustic ingestion
• Acquired subglottic or tracheal stenosis after intubation

• Laryngeal tumour, especially in adults with smoking/alcohol history
• Laryngeal papillomatosis or polyps
• Goitre, neck mass, mediastinal mass causing external compression

Management of a patient with stridor

1. Immediate measures: ABC approach

• Call for senior help immediately: anaesthetist, ENT surgeon, paediatrician where relevant.
• Keep the patient calm and sitting upright. In a child, allow the child to remain with the parent.
• Avoid unnecessary handling, upsetting the patient, forcing the patient supine, or examining the throat with a tongue depressor if epiglottitis is suspected.
• Give high-flow humidified oxygen if tolerated.
• Monitor pulse, respiratory rate, oxygen saturation, level of consciousness, work of breathing, and ECG.
• Obtain IV access only if it does not distress an unstable child. Do not delay airway treatment for investigations.

2. Secure the airway

• Prepare for a difficult airway: experienced operator, suction, bag-mask ventilation, appropriately sized endotracheal tubes, video/fibre-optic equipment, and emergency surgical airway equipment.
• If severe distress, hypoxia, exhaustion, reduced consciousness, or rapidly worsening obstruction occurs, perform controlled endotracheal intubation by the most experienced clinician.
• If intubation fails and oxygenation cannot be maintained, proceed to emergency front-of-neck airway, such as surgical cricothyrotomy in adults or tracheostomy according to age and expertise.
• Once stable, flexible fibre-optic laryngoscopy is useful to identify the lesion. Textbook of Family Medicine, p. 436.

3. Treat the cause

• Croup: corticosteroid such as dexamethasone; nebulised adrenaline for moderate/severe disease; observe for recurrence.
• Epiglottitis or bacterial tracheitis: controlled airway management first, then IV broad-spectrum antibiotics. Avoid throat examination in an unstable patient.
• Anaphylaxis/angioedema: immediate IM adrenaline, oxygen, IV fluids as needed, and repeat adrenaline if symptoms persist. The Resuscitation Council UK guidance advises ABCDE assessment and early IM adrenaline for airway, breathing, or circulatory involvement.
• Foreign body: if complete obstruction, give age-appropriate choking first aid; if partial obstruction and stable, avoid blind finger sweeps and arrange urgent rigid bronchoscopy.
• Retropharyngeal/peritonsillar abscess: IV antibiotics, ENT assessment, and drainage when indicated.
• Tumour, stenosis, vocal-cord paralysis, or congenital lesion: ENT referral for definitive endoscopic or surgical treatment.

4. Further evaluation after stabilisation

• Focused history: sudden onset/choking, fever, allergy exposure, trauma, prior intubation, voice change, feeding difficulty, and positional variation.
• Neck and chest radiographs or CT only in a stable patient and only if they will not delay airway control.
• Admit patients with stridor at rest, significant retractions, hypoxia, uncertain diagnosis, poor response to treatment, or need for repeated nebulised adrenaline.

Stridor

Definition (2 marks)

• Inspiratory: obstruction at or above the glottis
• Expiratory: intrathoracic tracheal obstruction
• Biphasic: fixed glottic/subglottic or tracheal obstruction

Causes (4 marks)

1. Congenital causes

• Laryngomalacia, commonest cause in infants
• Vocal-cord paralysis
• Subglottic stenosis
• Laryngeal web/cleft
• Subglottic haemangioma
• Tracheomalacia or vascular ring

2. Infective/inflammatory causes

• Croup (acute laryngotracheobronchitis)
• Acute epiglottitis
• Bacterial tracheitis
• Retropharyngeal or peritonsillar abscess
• Laryngeal oedema due to allergy/anaphylaxis

3. Mechanical/traumatic causes

• Inhaled foreign body
• Trauma to larynx or trachea
• Post-intubation laryngeal oedema
• Acquired subglottic/tracheal stenosis

4. Neoplastic/extrinsic compression

• Laryngeal papilloma, polyp, or carcinoma
• Thyroid swelling, neck mass, mediastinal mass

Management of a case with stridor (4 marks)

A. Immediate airway measures

• Call for help: senior clinician, anaesthetist and ENT surgeon.
• Keep patient calm and sitting upright. Do not force a distressed child to lie down.
• Give high-flow oxygen if tolerated.
• Monitor pulse, respiratory rate, SpO₂, blood pressure, ECG and consciousness.
• Avoid unnecessary examination, especially throat examination with a tongue depressor if epiglottitis is suspected.
• Assess for danger signs: cyanosis, severe chest retractions, drooling, exhaustion, altered consciousness, silent airway, or decreasing stridor.

B. Secure airway if severe or worsening

• Prepare difficult-airway equipment, suction, bag-mask ventilation, endotracheal tubes and emergency surgical-airway facilities.
• Controlled endotracheal intubation should be done by the most experienced available clinician.
• If intubation fails with inability to oxygenate, perform emergency front-of-neck airway/tracheostomy as appropriate.

C. Treat the underlying cause

• Croup: dexamethasone ± nebulised adrenaline.
• Epiglottitis/bacterial tracheitis: secure airway first, then IV broad-spectrum antibiotics.
• Anaphylaxis: immediate IM adrenaline, oxygen and IV fluids where needed.
• Foreign body: age-appropriate choking manoeuvres if complete obstruction; rigid bronchoscopy for removal.
• Abscess/tumour/stenosis: urgent ENT referral for drainage, endoscopic assessment or definitive surgery.

D. Investigations after stabilisation

• Flexible fibre-optic laryngoscopy is useful for diagnosis.
• Neck/chest radiograph or CT only in a stable patient and never if it delays airway management.