Stridor is an abnormal, high-pitched, musical breathing sound. It is caused by a blockage or narrowing in the upper airways. It is more often heard during inspiration, frequently without the aid of a stethoscope.
In children, croup, a viral respiratory infection, has stridor as a symptom. When a child has swallowed a foreign object and it becomes lodged in the upper airways, stridor sounds can be heard.
In adults, stridor breath sounds are often due to vocal cords problems. Vocal cord dysfunction can cause partial upper airways blockage resulting in stridor sounds. It occurs in 10-20% of extubated patients.
Causes of stridor are pertussis, croup, epiglottis, aspirations.
Stridor will be heard as a loud, high-pitched breath sound typically heard during inspiration. It can also occur throughout the respiratory cycle particularly as a patient's condition worsens. In children, stridor may become louder in the supine position.
Stridor Audio Recording
The waveform of stridor sounds is not typically used in clinical practice. However it can be a useful tool for learning auscultation of lung and heart sounds.
Respiratory Sounds Reference Guide
Our auscultation reference guide provides quick access to stridor as well as many other adventitious sounds. Each sound is described also with an audio recording and waveform.