Laryngomalacia

Other Names: Laryngomalacia congenital; Congenital laryngomalacia; Congenital laryngeal stridor

Laryngomalacia is an abnormality of the voice box (larynx) that leads to the inward collapse of the airway when air is drawn into the lungs (inspiration). It usually becomes apparent at birth or shortly after birth.

Epidemiology

The incidence of laryngomalacia in the general population is relatively unknown but has been estimated to be anywhere from 1 in 2000 to 3000. This figure may be an underestimation, as mild laryngomalacia is often clinically followed by pediatricians and never diagnosed endoscopically. While previous evidence has suggested a male predominance, recently published literature suggests that it is equally common in females. Black and Hispanic infants may be at an increased risk compared to White infants. Low birth weight has also been suggested to be a correlating factor.

Cause

The reason that laryngomalacia occurs is not known. Various theories regarding its cause have been proposed, including anatomic abnormalities, impaired neuromuscular coordination or low muscle tone of laryngeal structures, pharyngo-laryngeal reflux (when stomach acid travels up through the esophagus and reaches the larynx), and abnormalities in the amount of air displaced when breathing (tidal volume).

The development of symptoms of laryngomalacia may result from variable combinations of these factors in each infant. Regardless of the underlying causes(s), the symptoms are due to the cartilage being "floppy," and prolapsing (collapsing) over the larynx when inhaling. This in turn causes the noises generated when breathing.

Inheritance

Laryngomalacia may be inherited in some instances. Only a few cases of familial laryngomalacia (occurring in more than one family member) have been described in the literature. In some of these cases, autosomal dominant inheritance has been suggested.

Laryngomalacia has also been reported as being associated with various syndromes. In cases where these specific syndromes are inherited, a predisposition to being born with laryngomalacia may be present. However, even within a family, not all people affected with one of these syndromes will have the exact same signs and symptoms (including laryngomalacia). Syndromes that have been associated with laryngomalacia include diastrophic dysplasia, alopecia universalis congenital, XY gonadal dysgenesis, Costello syndrome, DiGeorge syndrome, and acrocallosal syndrome. The inheritance pattern depends upon the specific syndrome present.

Signs and symptoms

Signs and symptoms of laryngomalacia typically begin at or shortly after birth, with the average age at presentation approximately 2 weeks. The condition is primarily characterized by noisy breathing (stridor) that may be worse when the baby is agitated, feeding, crying or sleeping on his/her back. However, in severe cases, inward pulling of the chest muscles (sternal or intercostal retraction), apnea, cyanosis or significant respiratory distress may be the initial symptom. Feeding difficulties are also common in infants with laryngomalacia and may result in poor weight gain or lead to failure to thrive. Many infants with laryngomalacia are also diagnosed with gastroesophageal reflux. The baby's cry is generally normal, unless laryngitis is present due to reflux.

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Abnormality of the voice(Voice abnormality)
• Laryngomalacia(Softening of voice box tissue)

30%-79% of people have these symptoms

• Cleft palate(Cleft roof of mouth)
• Non-midline cleft lip

Diagnosis

A diagnosis of laryngomalacia is often suspected based on the presence of characteristic signs and symptoms. Additional testing can then be ordered to confirm the diagnosis, evaluate the severity of the condition, and rule out other disorders that can be associated with similar features. These tests may include:

• Flexible fiberoptic laryngoscopy (nasolaryngoscopy)
• Airway fluoroscopy
• Direct laryngoscopy
• Bronchoscopy

Treatment

Treatment of the majority of patients with laryngomalacia is conservative. In cases of mild or moderate stridor without feeding difficulties, observation is recommended after making a diagnosis. It is important to monitor for appropriate weight gain and development of any severe symptoms outlined above. Positional feeding and thickening feed may help those infants with feeding difficulties. Symptoms abate in the majority of patients by the age of 12 to 18 months without the need for surgical intervention.

Nearly 10 to 20% of infants with laryngomalacia will have severe symptoms. These patients often require surgical intervention. A supraglottoplasty has become the initial treatment of choice for patients with severe symptoms. Multiple techniques for this procedure exist, including the use of a laser, cold steel, laryngeal microdebrider, or coblator. The most frequent reasons for surgical intervention are worsening airway symptoms and failure to thrive. Supraglottoplasty has been shown to decrease the duration of symptoms of laryngomalacia significantly.Patients generally tolerate the procedure well and are observed in the hospital postoperatively. Steroid administration during surgery and in the postoperative period to decrease airway inflammation is typically the recommended pharmaceutical therapy.

Prognosis

While traditional thought says symptoms resolve in the majority of patients by the age of 12 to 18 months, a recent article suggested there is limited evidence from this and that the age range at resolution may be much wider. Conservative management with feeding upright, antireflux therapy, and close observation of respiratory symptoms are generally all that is necessary for the majority of infants. The minority of patients who require surgical treatment with a supraglottoplasty have reliable outcomes, with some studies showing as high as 95% success rates.

NIH genetic and rare disease info

• NIH info on Laryngomalacia

Laryngomalacia is a rare disease.

Laryngomalacia Resources
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