Stridor in children

A 6 month old presents to the general practitioner’s surgery with his mother. She is concerned because he has a runny nose and makes a “funny” loud noise when breathing in, which you diagnose as stridor. Stridor is caused by partial upper airway obstruction and is typically heard in inspiration, although it can also be heard on expiration if the obstruction is below the larynx. It sounds different from wheeze , which is a high-pitched whistling expiratory sound, and from stertor , a snoring sound. ### How long has the stridor been present? ### Associated features