Stridor is an abnormal, high-pitched, musical breathing sound. It is caused by a blockage in the throat or voice box (larynx). It is most often heard when taking in a breath.
Breathing sounds - abnormal; Extrathoracic airway obstruction; Wheezing
Children are at higher risk of airway blockage because they have narrower airways than adults. In young children, stridor is a sign of airway blockage. It must be treated right away to prevent the airway from becoming completely closed.
The airway can be blocked by an object, swollen tissues of the throat or upper airway, or a spasm of the airway muscles or the vocal cords.
Common causes of stridor include:
- Abscess on the tonsils
- Airway injury
- Allergic reaction
- Diagnostic tests such as bronchoscopy or laryngoscopy
- Epiglottitis, inflammation of the cartilage that covers the trachea (windpipe)
- Inhaling an object such as a peanut or marble (foreign body aspiration)
- Neck surgery
- Use of a breathing tube for a long time
- Secretions such as phlegm (sputum)
- Smoke inhalation or other inhalation injury
- Swelling of the neck or face
- Swollen tonsils or adenoids (such as with tonsillitis)
- Vocal cord cancer
Follow your doctor's advice to treat the cause of the problem.
When to Contact a Medical Professional
Stridor may be a sign of an emergency. Call your health care provider right away if there is unexplained stridor, especially in a child.
What to Expect at Your Office Visit
In an emergency, the health care provider will check the person's temperature, pulse, breathing rate, and blood pressure, and may need to do the Heimlich maneuver.
A breathing tube may be needed if the person can't breathe properly.
After the person is stable, the health care worker may ask questions about the patient's medical history, and perform a physical exam. This includes listening to the lungs.
Parents or caregivers may be asked the following medical history questions:
- Is the abnormal breathing a high-pitched sound?
- Did the breathing problem start suddenly?
- Could the child have put something in the mouth?
- Has the child been ill recently?
- Is the child's neck or face swollen?
- Has the child been coughing or complaining of a sore throat?
- What other symptoms does the child have? (For example, nasal flaring or a bluish color to the skin, lips, or nails)
- Is the child using chest muscles to breathe (intercostal retractions)?
Tests that may be done include:
- Arterial blood gas analysis
- CT scan, thoracic
- Laryngoscopy (examination of the voice box)
- Pulse oximetry to measure blood oxygen level
- X-ray of the chest or neck
O'Handley JG, Tobin EJ, Shah AR. Otorhinolaryngology In: Rakel RE, ed. Textbook of Family Medicine. 8th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 19.
Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.