Breathing sounds - abnormal (stridor)

Alternative names 

Stridor is an abnormal, high-pitched, musical breathing sound caused by a blockage in the throat or larynx, also called an extrathoracic airway obstruction. It is usually heard when inhaling (see wheezing and abnormal lung sounds). Stridor may indicate an emergency and should always be evaluated immediately by a health care provider.

Children are at higher risk of airway obstruction because they have narrower airways than adults. In young children, stridor is a significant sign of airway obstruction and must be treated immediately in order to prevent total airway obstruction.

The airway can be obstructed by an object, by swelling of the tissues of the throat or upper airway, or by spasm of the airway muscles or the vocal cords.

Common Causes

  • Inhalation of an object such as a peanut or marble (foreign body aspiration)  
  • Laryngitis (acute)  
  • Airway trauma  
  • Allergic reaction  
  • Croup  
  • Enlarged tonsils or adenoids (such as with tonsillitis)  
  • Abscess on the tonsils  
  • Inhalation injury (such as smoke inhalation)  
  • Neck surgery  
  • Neck or facial swelling  
  • Secretions, particularly phlegm (sputum)  
  • Vocal cord cancer  
  • Prolonged intubation (breathing assisted with a tube)  
  • Diagnostic tests such as bronchoscopy or laryngoscopy

Home Care
Follow prescribed therapy in treating the underlying cause. See also first-aid measures for choking.

Call your health care provider if

Call your health care provider if there is any indication of unexplained stridor, especially in a child.

What to expect at your health care provider’s office
In emergency situations, vital signs (temperature, pulse, rate of breathing, blood pressure) will be monitored, and the Heimlich maneuver may be necessary. Then the medical history will be obtained, and a physical examination performed. Intubation (insertion of a “breathing tube”) may be necessary if there is inability to breathe properly (respiratory failure).

Medical history questions documenting abnormal breathing sounds in detail may include:

  • Is the abnormal breathing sound a high-pitched sound?  
  • Did it begin suddenly?  
  • Is it possible that the child may have put something in the mouth and gotten it into the windpipe?  
  • 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 are also present?  
  • Is there nasal flaring?  
  • Is the child using chest muscles to breathe (intercostal retractions)?  
  • Does the child have blue lips, blue nailbeds, or bluish color of the skin?

The physical examination will include monitoring the vital signs and listening to the lungs.

Diagnostic tests that may be performed include:

  • Arterial blood gas analysis  
  • Bronchoscopy (using a scope to look directly at the airway)  
  • CT scan, thoracic  
  • Laryngoscopy  
  • X-ray of the chest

After seeing your health care provider:
You may want to add a diagnosis related to stridor to your personal medical record.

Johns Hopkins patient information

Last revised: December 2, 2012
by Arthur A. Poghosian, M.D.

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.