Stridor is a medical term for "noisy breathing". It is a high-pitched sound caused by an obstruction or narrow area in your child's airway.
The audio clip demonstrates the sound of a child with stridor. You'll hear the pitch and rhythmic nature of the noise that occurs when the child breathes. Although many children with stridor sound like this, not all stridor sounds the same. If you think your child has developed stridor, seek medical attention immediately.
Are there different types of stridor?
Yes. The specific type of stridor depends on the location of the obstruction. Usually, the stridor is heard when the child breathes in, but can also be heard when the child breathes out. If the stridor is best heard when the child breathes in, the obstruction is typically at the level of the vocal cords or above. If the stridor is heard when the child breathes both in and out, the obstruction is at the level of the vocal cords or just below the vocal cords in the upper trachea (subglottis). If the stridor is best heard when the child breathes out, the obstruction is in the lower trachea or the bronchi. Often, stridor heard on exhalation (breathing out) is called wheezing.
What are the causes of stridor?
There are many different causes of stridor. Some of the causes are diseases, while others are problems with the anatomical structure of the child's airway. The upper airway in children is shorter and narrower than that of an adult, and, therefore, more likely to lead to problems with obstruction. The following are some of the common causes of stridor in newborns, infants, and children:
Laryngomalacia: Laryngomalacia is a congenital (present at birth) condition where floppy tissue above the vocal chords falls into the airway when a child breathes in, causing stridor. The child will usually outgrow this condition by the time he or she is 18 months old. Some children need surgery to treat laryngomalacia.
Vocal cord paralysis: If one or both of the vocal cords does not move properly, the child may have stridor. Some children are born with a paralyzed vocal cord(s) and others may develop a paralyzed vocal cord(s) after neck, esophageal, or heart surgery. Treatment depends on the child's symptoms. Frequently a "watch and wait" plan is adopted, but sometimes surgery is needed. The chance of recovery depends on the cause of the paralysis.
Subglottic stenosis: The larynx (voice box) may be too narrow below the vocal cords. Often, but not always, the child required a breathing tube as a newborn. Although breathing tubes are life-saving, they can also lead to narrowing of the airway. If the stenosis is mild the child may be able to outgrown the problem without treatment. Most children will need a surgical procedure if the obstruction is severe.
Subglottic hemangioma: A hemangioma is an abnormal growth of blood vessels. Hemangiomas grow quickly in the child's first few months of life. If the growth is just below the vocal cords the child may have stridor, typically both when breathing in and out, and a baby with a hemangioma may have a barking cough. Some children may outgrow this problem, as the hemangioma will begin to get smaller after the first year of life. Others may require medication to control the hemangioma or may require surgery.
Mass lesions of the larynx: A fluid-filled sac or abnormal growth on the vocal cords (such as a papilloma) may cause partial airway obstruction and stridor.
Vascular rings: The trachea, or windpipe, may be compressed by one of the body's large blood vessels (an artery or vein). Surgery may be required to alleviate this condition.
The video above shows a dynamic CT scan demonstrating vascular compression of the child's airway, which may be associated with stridor.
Infectious causes of stridor:
Croup: Croup is an infection caused by a virus that leads to swelling in the airway just below the level of the vocal cords and causes breathing problems and a barking cough. Croup is caused by a variety of different viruses, most commonly the parainfluenza virus.
Bacterial Tracheitis: Sometimes a viral infection in the trachea such as croup can lead to a bacterial infection of the trachea. The stridor is typically heard when breathing both in and out. The patient typically requires treatment with intravenous antibiotics.
Epiglottitis (also called supraglottitis): Epiglottitis is an acute life-threatening bacterial infection that results in swelling and inflammation of the epiglottis. The epiglottis is an elastic cartilage structure at the root of the tongue that prevents food from entering the windpipe when swallowing. Epiglottitis causes breathing problems that can progressively worsen, potentially leading to airway obstruction. Epiglottitis was historically caused by the bacteria Haemophilus influenzae, and now is rare because infants are routinely vaccinated against this bacteria.
Foreign Bodies: Foreign bodies, such as a peanut, in the trachea or bronchi may cause stridor to occur. The foreign body will need to be removed in the operating room.
How is stridor diagnosed?
Stridor is diagnosed first by listening to your child. It is important to remember that stridor is a symptom of some underlying problem or condition. If your child has stridor, your child's doctor may order some of the following tests to help determine the cause of the stridor:
Flexible laryngoscopy: A small flexible scope is passed through the child's nose and used to view the larynx. This is typically done in the clinic with the child awake.
Bronchoscopy: If the airway below the level of the vocal cords needs to be visualized, a flexible or rigid bronchoscope can be used. This procedure is typically performed in the operating room with the child under anesthesia.
Chest and/or neck X-rays: X-rays of the chest and/or neck are used to help determine the source of stridor.
What is the treatment for stridor?
Specific treatment of stridor will be determined based on your child's age, overall health and medical history. You child's doctor will take into consideration the cause and severity of the condition, your child's tolerance for specific medications, procedures and therapies, and your opinions and preferences for treatment options.
Treatments may include:
Referral to an ear, nose, and throat specialist (otolaryngologist) for further evaluation
Medications by mouth or injection
Hospitalization and emergency surgery may be necessary depending on the severity of the stridor.