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Inspiratory and expiratory stridor in a 13-month child with croup
SpecialtyOtorhinolaryngology, pediatrics

Stridor (Latin for "creaking or grating noise") is a high-pitched extra-thoracic breath sound resulting from turbulent air flow in the larynx or lower in the bronchial tree. It is different from a stertor which is a noise originating in the pharynx.

Stridor is a physical sign which is caused by a narrowed or obstructed airway. It can be inspiratory, expiratory or biphasic, although it is usually heard during inspiration. Inspiratory stridor often occurs in children with croup. It may be indicative of serious airway obstruction from severe conditions such as epiglottitis, a foreign body lodged in the airway, or a laryngeal tumor. Stridor should always command attention to establish its cause. Visualization of the airway by medical experts equipped to control the airway may be needed.


Stridor may occur as a result of:


Stridor is mainly diagnosed on the basis of history and physical examination, with a view to revealing the underlying problem or condition.

Chest and neck x-rays, bronchoscopy, CT-scans, and/or MRIs may reveal structural pathology.

Flexible fiberoptic bronchoscopy can also be very helpful, especially in assessing vocal cord function or in looking for signs of compression or infection.


The first issue of clinical concern in the setting of stridor is whether or not tracheal intubation or tracheostomy is immediately necessary. A reduction in oxygen saturation is considered a late sign of airway obstruction, particularly in a child with healthy lungs and normal gas exchange. Some patients will need immediate tracheal intubation. If intubation can be delayed for a period, a number of other potential options can be considered, depending on the severity of the situation and other clinical details. These include:

In obese patients elevation of the panniculus has shown to relieve symptoms by 80%.


  1. ^ Holinger LD (1980). "Etiology of stridor in the neonate, infant and child". Ann. Otol. Rhinol. Laryngol. 89 (5 Pt 1): 397–400. doi:10.1177/000348948008900502. PMID 7436240. S2CID 20514618.
  2. ^ Wittekamp, Bastiaan HJ. Clinical review: Post-extubation laryngeal edema and extubation failure in critically ill adult patients. Crit Care. 2009; 13(6): 233.