Stridor (Latin, plural stridores, literally “hissing,” “whistling”; synonyms: whistling breathing; whistling breath sound; stertor; ICD-10 R06.1: Stridor) is a whistling breath sound that occurs during inspiration and/or expiration (inspiratory/expiratory stridor):
- Inspiratory stridor: breathing sound on inspiration, typical of stenosis (narrowing) or obstruction (blockage) of the upper airway (larynx, trachea, main bronchi)
- Expiratory stridor: breathing sound on exhalation, typical of obstructive lung disease
Furthermore, stridor can be distinguished according to the localization:
- Stridor nasalis – at the level of the nose; mostly audible as “sniffing”.
- Stridor pharyngealis – at the level of the throat; mostly audible as “snoring“.
- Stridor laryngealis – at the level of the larynx; mostly audible as “whistling”.
- Stridor trachealis – at the level of the trachea; mostly audible as “humming”.
In contrast to stridor is sertor, which refers to a rasping breathing caused by accumulation of mucus in the airways.
The etiology (causes) can be varied. A distinction is made between congenital (congenital) and acquired causes. In children, a sudden onset of stridor must always be associated with the presence of an inhaled foreign body (see Foreign Body Aspiration below).
Stridor can be a symptom of many diseases (see “Differential diagnoses” below).
Course and prognosis: In the case of stridor, the situation can always quickly deteriorate drastically. As soon as dyspnea (shortness of breath) occurs in addition to the whistling breathing sound, a physician should be consulted immediately. If stridor is accompanied by a high-grade obstruction of the airway, it is called a medical emergency!