Almost 60% of children with Down syndrome have abnormal sleep studies by the age of 4 years. The overall incidence of obstructive sleep apnea (OSA) increases as children grow older.
Why do Individuals With Down Syndrome Have a High Incidence of OSA?
Anatomy accounts for a large part of the reason why there is a higher incidence of OSA in individuals with Down syndrome. Some of these factors include: central apnea, low muscle tone in the mouth and upper airway, poor coordination of airway movements, narrowed air passages in the midface and throat, a relatively large tongue and hypertrophy of adenoid and tonsillar tissues. Increased upper airway infections and nasal secretions and a higher incidence of obesity further contribute to collapse and obstruction of both the oropharynx and hypopharynx when the individual is sleeping.
What are the Effects of OSA?
Sleep disordered breathing affects cognitive abilities, behavior, growth rate and can lead to the more serious consequence of pulmonary hypertension (abnormally high blood pressure in the arteries of the lungs) and cor pulmonale (failure of the right side of the heart). Because of the high incidence of underlying congenital heart problems in individuals with Down syndrome, there is a higher risk of development of the more severe complications. Abnormalities in pulmonary vasculature (the circulatory system in the lungs) also increases the risk of pulmonary hypertension.
The new American Academy of Pediatrics health care guidelines published in Pediatrics in 2011 recommend a baseline sleep study or polysomnogram for all children with Down syndrome by the age of four.
What are the Symptoms of Sleep Abnormalities?
Symptoms suggestive of sleep abnormalities include: restless sleep, snoring, gasping noises, heavy breathing, apneic pauses, frequent waking during the night, trouble getting out of bed, daytime sleepiness and excessive napping. Sleep apnea can also cause behavioral changes, including irritability, poor concentration and impaired attention. Uncommon sleep positions such as sleeping sitting up, sleeping with the neck hyper-extended or sleeping bent forward at the waist in a sitting position are all suggestive of a sleep disorder or OSA.
What Causes OSA?
Enlargement of the tonsils and adenoids is one of the most common causes of OSA in children. However, other causes of obstruction such as chronic rhinorrhea and congestion, nasal septal deviation, and nasal turbinate enlargement need to be assessed and treated. If the oral exam shows edema of the posterior pharyngeal wall, thus decreasing the size of the posterior pharyngeal airway, gastro-esophageal reflux (GERD) or chronic post-nasal drainage should be considered. Treatment with anti-reflux medications and/or decongestants, nasal steroid sprays and antihistamines can sometimes be helpful.
What are the Treatments?
If there are any airway disturbances during sleep, an otolaryngologist must determine if a sleep study and/or surgical intervention is needed. Non-invasive treatment options include a continuous positive airway pressure (CPAP) machine and weight loss.
Removal of enlarged tonsils and adenoids is the first line surgical treatment. In individuals with Down syndrome, even mildly enlarged tonsils and adenoids may have a greater than expected effect on airway obstruction because of their midface hypoplasia and contracted nasopharynx.
Although tonsillectomy and adenoidectomy (T&A) is the most common initial surgical intervention, studies have shown that persistent obstructive sleep apnea after T&A is possible and more common in individuals with Down syndrome. Further interventions may be needed, both surgical and medical. All of these studies illustrate the need for post-operative evaluation of patients with Down syndrome for residual sleep apnea after T&A surgery with a post-operative sleep study. Because of the higher rate of respiratory complications after removal of the tonsils and adenoids in individuals with Down syndrome, overnight observation in the hospital after this surgery is also recommended.
If residual obstruction is present despite T&A surgery, medical treatments such as continuous positive pressure ventilation (CPAP/BiPAP) and oxygen use during sleep are still an option. Weight loss can also help to alleviate symptoms. Evaluations to determine the site or sites of residual airway obstruction include flexible nasopharyngoscopy and laryngoscopy examination in the office to rule out enlarged lingual tonsils, residual or regrowth of adenoid tissue, and possible glossoptosis. Radiographic studies using cine MRI studies have shown that the base of tongue obstruction from a combination of relative macroglossia and glossoptosis, enlarged lingual tonsils and also adenoid regrowth are some of the most common sites of residual obstruction in individuals with Down syndrome despite previous T&A.
Surgical options for persistent obstructive sleep apnea in children with Down syndrome need to be tailored to each child’s individual pattern of obstruction. Surgical approaches currently being used include lingual tonsillectomy, uvulopalatopharyngoplasty, midline posterior glossectomy, genioglossus advancement, hyoid advancement and craniofacial surgery, including mandibular and midface advancements. Dental appliances to promote mandibular stabilization have also been shown to be helpful in cases of mild residual sleep apnea. However, in cases of severe sleep apnea with associated pulmonary hypertension, severe hypoxemia and/or cardiac complications, tracheostomy may also need to be considered.