Stridor and Laryngomalacia in Children
Stridor is one of the common sounds that infants and toddlers can make when their airway is partially blocked. Stridor is a high-pitched sound created by turbulent airflow caused by narrowing of the airway when breathing. Stridor often occurs from narrowing of the voice box and vocal cord area (larynx) and should be differentiated from Stertor. Stertor is more nasal sounding and occurs from blockage higher up in the nose or throat. It can occur when breathing in (inspiration) or when breathing in and out (biphasic). That gives doctors a clue of the etiology of the disease process.
Causes of Stridor
Stridor is a harsh, vibratory sound of variable pitch caused by partial obstruction of the respiratory passages that results in turbulent airflow through the airway. The most common cause of stridor in an infant is laryngomalacia. Other causes of stridor include infection such as croup, swelling from gastroesophageal reflux (GER) (common in babies), vocal cord weakness, lesion on the vocal cords, scarring of the larynx from intubation (breathing tube), and of inhaled foreign objects. With so many possibilities, it is important for doctors, such as ENTs, to look at the vocal cords with a flexible fiberoptic scope in their office.
- Laryngomalacia: Laryngomalacia, a pediatric airway disorder, has been reported to account for 75% of stridor in infants and children. Laryngomalacia, the most common cause of stridor in infants, is a floppiness of the laryngeal cartilages above the vocal cords. These structures of the larynx are called the epiglottis, aryepiglottic folds, and the arytenoids. One of all three of these structures can be floppy. When these structures fall into the airway as your baby inhales it is causing noisy breathing (stridor).
(Coming soon – diagrams and video of laryngomalacia)
- GERD and laryngomalacia: Gastroesophageal reflux occur when the contents of the stomach along with gastric acid flow back into the esophagus. Laryngopharyngeal reflux (LPR) occurs when these fluids flow high enough into the back of the throat (pharynx) that they can be aspirated into the voice box (larynx) and trachea (windpipe). Reflux is common in infants, especially since they spend time lying flat. The reflux fluid cause inflammation, swelling, and narrowing of laryngeal tissues, resulting in worsening the stridor due to laryngomalacia. Allowing the reflux to resolve over time and/or medically treating it can help the symptoms.
(Coming soon – videos of GER)
- Narrowing of the airway or stenosis: Idiopathic subglottic stenosis (iSGS) is a narrowing of the trachea (windpipe) below the vocal cords (glottis) known as the subglottic area. Subglottic stenosis may occur from trauma, infection, or it may be there from birth (congenital).
- Aspirated (inhaled) foreign object: A foreign object in the airway can cause stridor by narrowing the passage of air through the trachea and creating air turbulence.
- Infections such as croup or epiglottitis: Stridor from infections is due to the turbulent flow of air past inflammatory swelling of the mucosa lining the airway.
- Vocal cord weakness or paralysis: Weak of paralyzed vocal cords do not open fully resulting in turbulent airflow.
- Lesions or masses on the vocal cords: Narrowing of the vocal cord opening (glottis) due to lesions or masses result in turbulent airflow.
(Coming soon – videos of the different types)
Diagnosis of Stridor and Laryngomalacia
The floppiness of the laryngeal structures above the vocal cords can be mild to severe producing mild symptoms of stridor to severe retractions of your baby’s chest and the inability to fully inhale.
Diagnosis of laryngomalacia in Dr. McClay’s office is by nasopharyngoscopy and laryngoscopy or “flexible scope” in an awake child. This in-office exam does not allow evaluation below the vocal cords. In this situation a laryngoscopy and bronchoscopy is recommended under general anesthesia.
(Video of endoscopy is coming soon)
Treatment for Stridor and Laryngomalacia
Treatment is based on severity of symptoms. If the symptoms are mild and the child is gaining weight, they can be watched since most babies will grow out of their problem in 8 to 12 months. If the symptoms are severe due to the floppy tissue blocking the airway resulting in difficulty breathing, turning blue (cyanosis), and inability to eat, surgery will be recommended.
Surgery for Laryngomalacia
Surgery for laryngomalacia is called a supraglottoplasty and can safely be performed under general anesthesia by a highly trained team of airway specialists. This microscopic surgical procedure is performed endoscopically through the mouth by releasing the tight aryepiglottic folds and removing the redundant and floppy tissue over the airway opening. The floppy tissue is removed from the arytenoids. The arytenoids are mobile cartilaginous structures that attach the vocal cords and allowing for movement and tightening of the cords.
Postoperative supraglottoplasty shows the floppy tissue removed from the arytenoids which is characteristic of laryngomalacia.
(Video coming soon – video before and after surgery)
This surgery can be performed with surgical microlaryngeal instruments, such as tiny, elongated scissors, or with the laser. Laser can decrease the bleeding encounter with the microlaryngeal instruments but can cause thermal injury to the area. While Laser gained popularity for this procedure when first introduced in the 1980s and 1990s, many surgeons have reverted to the non-laser techniques to avoid the thermal injury.
(Video coming soon – comparison pictures with laser and microlaryngeal instruments technique)
Dr. John McClay – Pediatric Airway Surgeon
Parents can learn more about stridor and laryngomalacia by reading an article published by Dr. John McClay, a pediatric airway surgeon. Dr McClay wrote an article for the American Academy of Pediatrics titled Stridor & Laryngomalacia: Is My Baby’s Noisy Breathing Serious? Dr. McClay is former academic professor at University of Texas at Southwestern Medical School in Dallas.