Stridor: Symptoms, Complaints, Signs

The following symptoms and complaints may indicate Stridor:

Leading symptom

  • Whistling respiratory sound (whistling breathing) that occurs during inspiration and/or expiration (inspiratory/expiratory stridor)

Stridor can be differentiated according to its localization:

  • Stridor nasalis – mostly audible as “sniffing”.
  • Stridor pharyngealis – mostly audible as “snoring“.
  • Stridor laryngealis – mostly audible as “whistling”.
  • Stridor trachealis – mostly audible as “humming”.

Cave (Attention)!

  • Immediate hospitalization if the following symptoms also occur: Child with increased pulse and increased respiratory rate with increasing intercostal (“between the ribs“) retractions, possibly also signs of drowsiness.

Note: In inspiratory stridor (breathing sound on inspiration), the main distinction is between:

  • viral croup (formerly: pseudocroup): laryngitis (inflammation of the larynx), which leads mainly to swelling of the mucosa below the vocal cords (stenosing laryngitis); this is usually manageable without invasive measures; DD (differential diagnoses; diseases with similar or almost identical symptoms): Tracheitis(tracheitis), diphtheria; symptoms and complaints that may indicate pseudocroup:
    • Acute onset of hoarseness (dysphonia), barking cough, and inspiratory stridor (predominantly at night).
    • Occasional fever (< 38.5 °C).
    • Usually only mild dyspnea (shortness of breath); transition to a severe course with pronounced dyspnea is possible
    • Occasionally restlessness, anxiety
  • Epiglottitis (epiglottitis): laryngitis supraglottica: Acute, purulent inflammation of the epiglottis, occurring almost exclusively in infants, due to infection with Haemophilus influenzae type b (Hib) (made rare by Hib vaccination); acute emergency requiring rapid hospitalization for intubation (insertion of a tube (hollow probe) through the mouth or nose between the vocal folds of the larynx into the trachea) (leads to death in 24-48 hours if untreated! ); DD: Retropharyngeal abscess: collection of pus (abscess) in the spatium retropharyngeum (retropharyngeal space/area between the posterior pharyngeal wall and the spine), angina, tracheitis, EBV infection; the following symptoms must be concerning:
    • Child sits bent forward with mouth open.
    • Dysphagia (difficulty swallowing) and severe pain
    • Aphonia (voicelessness; disturbances in the formation of sound up to the loss of voice).
    • Pronounced salivation
    • High fever (> 39 °C)
    • Cherry-red, balloon-like distended epiglottis (per laryngoscopy/throatoscopy).

Warning signs (red flags) in children

  • Medical history:
  • High fever + low-frequency stridor + dysphagia (dysphagia) → think of: Epiglottis (inflammation of the epiglottis) Caveat. Pharyngeal examination may provoke airway obstruction.
  • Inspiratory stridor + acute dyspnea → think of: Upper airway obstruction (dyspnea may increase to asphyxia (impending asphyxia); retractions in the jugulum (small depression in the front of the neck) and epigastrium (abdominal region between the costal arch and the navel) and increasing cyanosis).
  • Expiratory stridor + acute dyspnea → think of: Bronchospasm (cramping of the muscles surrounding the airways); if in addition skin symptoms (redness, wheals, etc.), hypotension (drop in blood pressure) and tachycardia (heartbeat too fast: > 100 beats per minute) → think of: anaphylactic reaction