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.