Stridor

Stridor (from Latin stridere 'to grate, screech') is an extra-thoracic high-pitched breath sound resulting from turbulent air flow in the larynx or elsewhere in the upper respiratory tract. It is different from stertor, which is a snoring noise originating in the pharynx, and wheezing, which originates in the bronchi. 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.