by Ping-Ru Ko, MD, and Maida Lynn Chen, MD
Pediatric sleep disorders describe a wide range of dysfunctional sleep and, because of their often subtle and exclusive occurrence in sleep, are often under-recognized by the child, by parents and caretakers, and even by pediatricians. All pediatric healthcare providers should be generally familiar with the weighty implications on long term health and developmental potential of undiagnosed sleep disorders. Dental providers, by virtue of being able to carefully and thoroughly inspect a child’s oral cavity and external craniofacial features, have a unique and crucial opportunity to identify and notify children and their caretakers about potential sleep problems, and particularly sleep disordered breathing. This review is not meant to be an exhaustive overview of pediatric sleep disorders, but aims to portray the wide variety of disorders seen in a pediatric sleep medicine clinic. For the purposes of this review, however, a larger emphasis will be placed on sleep disordered breathing.
Pediatric sleep disorders encompass sever- al categories of diseases and derangements in sleep. These include the following:
- Sleep-Disordered Breathing (SDB)
The majority of patients seen by sleep medicine physicians have sleep disordered breathing. The classic example is obstructive sleep apnea (OSA), in which the patient experiences intermittent partial or complete blockage of their airway during sleep, sometimes with caretakers or roommates observing prolonged breathing pauses, labored breathing, or snoring in sleep, which leads to impaired ventilation and gas exchange. Patients may experience transient or prolonged oxygen desaturations, rises of arterial PCO2, or both, leading to central nervous system arousals and a systemic stress response with marked elevations in heart rate and blood pressure, and repetitive sleep disruption. These lead to poor sleep quality, and daytime symptoms such as excessive sleepiness, behavioral problems such as hyperactivity, and long-term cognitive problems such as poor academic performance. Milder formers of SDB including upper airway resis- tance syndrome (UARS), in which there are subtle disturbances of respiration during sleep which may not be associated with gas exchange abnormalities but is associated with increased respiratory effort with or without snoring, and may lead to daytime symptoms such as sleepiness or behavioral problems. An even milder form is primary snoring, in which snoring by itself is observed during sleep; however, even in these children, there may be evidence of subtle pathology in sleep and wakefulness.
The prevalence of sleep disordered breathing in children is estimated to be 4-11%, and obstructive sleep apnea constitutes a large portion of SDB with estimated prevalence of 1-4%. Habitual snoring is reported to occur in about 5-12% of children, though there are reports as high as ~30%. Boys, obesity, African American ethnicity, and atopy are all associated with higher prevalence. SDB can occur at any age; in infants and young children, large tonsils and adenoids, large body habitus, and craniofacial abnormalities play a larger role in SDB. In older teenagers, large body habitus and oral airway crowding are more prominent risk factors, similar to their adult counterparts. Adenotonsillar hypertrophy may be exacerbated by recurrent or chronic upper airway infections, and can continue to grow, sometimes up to 12 years of age or more. Genetic syndromes such as Pierre-Robin sequence, Treacher- Collins syndrome, achondroplasia, and other craniofacial dysplasia syndromes which lead to midface hypoplasia, micrognathia, retrognathia, or dental malocclusion, are all risk factors for OSA. Children with Down’s syndrome have high prevalence of OSA due to maxillary hypoplasia, small nose, hypotonia, and relative macroglossia. Other genetic syndromes leading to visceromegaly or hypotonia, such as lysosomal storage diseases, Prader-Willi syndrome, and neuromuscular disorders, also impart a higher risk of OSA.
Screening for symptoms of SDB can be helpful but cannot be used to definitively diagnose SDB. The classic triad for pediatric OSA is snoring, labored breathing in sleep, and witnessed apnea in sleep; together, these three symptoms are thought to have the highest sensitivity and specificity for OSA. In addition, restlessness in sleep, recurrent nocturnal awakenings, diaphoresis, mouth-breathing, drooling in sleep, and nocturnal enuresis may also suggest SDB. Given that most parents do not sleep in the same room as their children and therefore cannot provide a complete observational history of their children’s sleep characteristics, daytime symptoms may be more prominent or more disturbing. These symptoms may include vague behavioral problems such as hyperactivity, difficulty focusing at school or at home, poor academic performance, mood lability, aggressiveness, poor appetite, and daytime sleepiness. In young infants with severe OSA, growth failure may occur. Overall, however, subjective symptom reporting by the patient and their caretakers is not completely sensitive or specific for SDB, and additional data, including a careful physical examination and especially objective data in the form of poly-somnography, are crucial for diagnosing this common pediatric disorder.
Having a high suspicion for SDB during evaluation of any child is important, as the clinical consequences of untreated sleep centers. In general, an obstructive apnea-hypopnea index (AHI) of 1.0 or above is diagnostic of obstructive sleep apnea in children, although adolescents can use the adult criteria of AHI or respiratory disturbance index (RDI) of
5.0 or higher with clinical symptoms.
Treatment can be curative or near-curative for some children with adenotonsillectomy. Polysomnography is often done several weeks after adenotonsillectomy to document resolution of respiratory events, especially given the subtlety of signs and symptoms of residual disease in children. If the child is not a candidate for adenotonsillectomy, or if the procedure does not prove to be non-curative, positive airway pressure can be trialed, although this therapy is difficult to tolerate especially in children with developmental delay or other behavioral problems. Additionally, long-term usage of PAP masks can lead to abnormal development of the midface in growing children. In children OSA can be profound. Untreated SDB can lead to pulmonary hypertension due to chronic hypoventilation, leading to right heart strain. In one study of 27 children, right ventricular dysfunction and impaired cardiac wall motion in children with OSA improved after adenotonsillectomy as evi- denced by radionuclide ventriculography.1 Children with OSA and tonsillar hypertrophy were shown to have increased 24-hour blood pressure loads, and significant reductions in DBP were seen after adenotonsil- lectomy. 2 Failure to thrive and growth fail- ure, as previously mentioned, may occur in children with OSA due to a combination of with significant craniofacial dysmorphisms for whom our various PAP mask interfaces are not suitable, significant air leak can render PAP therapy unfeasible. In these cases, skeletal advancement procedures may be more beneficial. Mandibular distraction osteogenesis may be used in children with micrognathia or retrognathia. In children with maxillofacial dysmorphisms or dental malocclusion, rapid maxillary expansion (RME) or maxilla-mandibular advancement (MMA) can be used. Alternatives to the above procedures include oral appliances that gradually change maxillomandibular alignment using a series of removable acrylic mouthpieces. If the obstruction occurs lower decreased appetite, impaired growth hormone secretion, and high energy expenditure due to increased work of breathing. In young children, OSA was shown to be a risk factor for community acquired pneumonia.3 Elevated serum inflammatory markers such as Creactive protein and various pro-coagulation proteins have been observed suggesting increased oxidative stress and systemic inflammation. Several studies have demonstrated lower IQ scores in children with SDB compared to controls, although these scores are typically still within normal range.4 In other studies, lower grades in mathematics, spelling, reading, and science; impaired memory recall; and lower performance on a phonological processing test were seen in children with SDB compared to controls.
As in adults, diagnosis of pediatric OSA is through polysomnography, which is largely still in the laboratory setting in most pediatric down in the airway, tongue reduction, genio-glossal advancement, or hyoid myotomy and suspension can be used. Sleep endoscopy, in which flexible endoscopy of the pharynx and hypopharynx is done while the child is under propofol to simulate sleep, can be a useful procedure to determine the level of obstruction and to direct surgical therapy. Adjunctive therapies include optimization of the nasal airway to nasal saline or corticosteroid sprays, positional therapy. Treatment of exacerbating conditions such as obesity, gastroesophageal reflux, asthma, and other chronic cardiopulmonary conditions can also be helpful. When other therapies have failed or are not available, supplemental oxygen may ameliorate hypoxemia, but should be used in caution in children with chronic hypercapnia due to potential decrease in central respiratory drive. Oral appliances are not generally used in children due to concerns for misalignment of permanent dentition in this age group. A Cochrane Review in 2007 regarding the use of oral appliances in children 15 years old or younger concluded that there is not enough evidence about their efficacy in the treatment of OSA in this age group.5
Insomnia
These can include difficulties falling or staying asleep, or both. They may be behaviorally induced, such as when children grow used to having a parent stay with them, sometimes in the same bed with them, until they fall asleep; these children have difficulties achieving on their own and require excessive effort from the parents each night to get to sleep. These can occur secondary to other sleep disorders, such as restless legs syndrome or obstructive sleep apnea. They occur in high prevalence in certain neuropsychiatric conditions such as autism spectrum disorder.
- Hypersomnia
These involve an increased sleep drive, sometimes manifesting as longer sleep times at nighttime, unusually fast onset of sleep, and excessive sleepiness during the daytime. Narcolepsy is the classic hypersomnia, where the central nervous system’s regulation of sleep, especially rapideye movement (REM) sleep, and wakefulness become dysregulated. Other types of hypersomnias exist, including those that follow traumatic brain injury, sedatives and other psychotropic medications, and idiopathic forms.
- Circadian Rhythm Disorders
These involve differences in each individual’s circadian rhythm, which is dictated by natural biological rhythms in the body, as well as melatonin release from the pineal gland which is influenced by light exposure in the eyes. In advanced sleep phase syndrome, the individual has a natural tendency to fall asleep early in the evening and wake up early the next morning; in contrast, in delayed sleep phase syndrome, the child has a natural tendency to fall asleep later and wake up later. This is, essentially, a characterization of the so-called “morning lark” versus the “night owl.” Young children tend to have an earlier sleep phase compared to their parents (i.e, they go to bed earlier and wake up earlier). However, adolescents naturally develop a tendency toward a delayed sleep phase, which can become pathologic in the setting of early school start times. Another
Dental providers are often on the front line in assessing children for potential sleep problems. Dental providers have a distinct advantage compared to pediatricians and many other healthcare providers in this regard as they are afforded a long and careful look in the oral cavity, and can assess for signs of bruxism, enlarged tonsils, and craniofacial features that may predispose to SDB including micrognathia, retrognathia, a high arched palate, macro-glossia, and other signs of oral airway crowding. Dental providers can inspect the oral cavity when the child is laying supine, which mimics the normal sleeping position and may bring out features suggestive of sleep disordered breathing, whereas most pediatricians often must make do with inspecting the child’s nose and mouth in an upright position. Similarly, from their vantage point, dental providers may also be able to detect abnormalities of the nose such as nasal septal deviation, asymmetry of the nostrils, and wide columella with relatively narrow nostrils, or the presence of audible and obligate mouth-breathing, or labored breathing in the supine position. Helpful screening question to ask the child’s caretakers are:
S: Does your child snore or have loud breathing when asleep?
N: Does your child have nasal congestion or breathe mostly through his or her mouth?
O: Have you ever observed your child pause in his or her breathing during sleep, even for just a few seconds?
R: Is your child restless in sleep? Does your child move around a lot, sweat a lot, wake up frequently at night, or seem to be uncomfortable in sleep?
E: Is your child excessively sleepy, hyperactive, aggressiveness, or inattentive during the daytime?
If any of the above questions are answered positively, directing the child to his or her pediatrician and getting a referral to a sleep medicine specialist is highly advised.
In conclusion, pediatric sleep disorders encompass sleep disordered breathing, parasomnias, and movement disorders, insomnias, hypersomnias, and circadian rhythm disorders. Similar to their adult counterparts, children with SDB may suffer from cardiovascular complications, systemic inflammation and stress response with untreated SDB; compared to adults however, children can have misleading daytime symptoms of inattentiveness, hyperactivity, aggressiveness, and other behavioral problems, and as well as poor academic performance. These can negatively impact the quality of life of both the child and the family, and have long-term cognitive implications. Dental providers can help assess for pediatric sleep disorders by closely inspecting the oral cavity as well as the cranio-facial structure of the child, and using a short set of questions inquiring about snoring, nasal symptoms, witnessed pauses in breathing, restless sleep, and daytime behavioral symptoms. A referral to pediatric sleep medicine specialist should be made promptly assess for the presence of sleep disorders; in the case of SDB, treatment can impact cardiovascular and cognitive complications.
References
Tal A, et Ventricular dysfunction in children with obstructive sleep apnea: radionuclide assessment. Pediatr Pulmonol. 1988;4(3):139-43.
Ng DK, et Ambulatory blood pressure before and after adenotonsillectomy in children with obstructive sleep apnea. Sleep Med. 2010 Aug;11(7):721-5
Goldbart AD, et Sleep-disordered breathing is a risk factor for community-acquired alveolar pneumonia in early childhood. Chest. 2012 May;141(5):1210-5.
Sheldon SH, et Principles and Practice of Pediatric Sleep Medicine. London: Elsevier Saunders, 2014. Print.
Carvalho FR, et Oral appliances and functional orthopaedic appliances for obstructive sleep apnoea in children. Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.: CD005520.