Key Points
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Although pediatric obstructive sleep apnea gets the majority of clinical attention, nonobstructive sleep disorders are also common and can have a significant negative effect on sleep in children.
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A dyssomnia is a primary sleep disorder characterized by an abnormality in the amount, quality, or timing of sleep that causes difficulty in initiating or maintaining sleep.
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A parasomnia is an undesirable event that occurs during entry into sleep, within sleep, or during arousals from sleep.
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Neuropsychiatric conditions such as attention-deficit/hyperactivity disorder and pervasive developmental disorders can also lead to sleep disturbance.
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Common dyssomnia conditions include insomnia, narcolepsy, primary hypersomnia, limb movement disorders, limit-setting sleep disorder, insufficient sleep disorder, and circadian rhythm disorders.
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Insomnia, limit-setting sleep disorder, insufficient sleep disorder, and circadian rhythm disorders are often a result of poor sleep hygiene.
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Narcolepsy is a rapid eye movement (REM)-related dyssomnia associated with a tetrad of irresistible daytime somnolence, cataplexy, sleep onset paralysis, and hypnagogic hallucinations. It may be treated with a combination of behavioral and pharmacologic therapy.
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Hypersomnia is a dyssomnia associated with excessive sleepiness.
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Limb movement disorders such as restless leg syndrome and periodic limb movement disorder may be associated with other neuropsychiatric conditions and may require pharmacologic therapy.
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Non-REM parasomnias include events that occur during slow-wave sleep and include sleep terrors, somnambulism (sleepwalking), and confusional arousals.
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REM parasomnias are events that occur later in the night and include nightmares, sleep paralysis, and REM sleep behavior disorder.
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Additional parasomnias have been defined that do not fall clearly into a REM or non-REM category such as bruxism, somniloquy (sleeptalking), nocturnal enuresis, and rhythmic movement disorders.
* The views herein are the private views of the authors and do not represent official views of the Department of Defense or the Department of the Army.
Pediatric obstructive sleep apnea syndrome has appropriately been the focus of significant attention and medical study. However, lesser-known nonobstructive pediatric sleep disorders can also be a disturbing problem that can negatively affect children and their families. Disturbances in the normal sleep architecture of a pediatric patient from any source may significantly impact their development and emotional and behavioral well-being. Multiple factors that include nighttime awakenings, sleep latency, longest sleep period, and daily naps affect how a caretaker perceives the quality of sleep a child is achieving nightly. These features of sleep will naturally change in healthy children as they get older; however, progression of these factors may result in development of nonobstructive pediatric sleep disorders, which can be categorized as either dyssomnias or parasomnias ( Table 4-1 ). Although not categorized directly as a dyssomnia or parasomnia, neuropsychiatric disorders such as attention-deficit/hyperactivity disorder (ADHD) or pervasive developmental disorders have also been regularly associated with sleep disturbance in pediatric patients.| Dyssomnias | Parasomnias |
|---|---|
| Primary idiopathic insomnia | Sleep terrors |
| Narcolepsy | Somnambulism |
| Primary idiopathic hypersomnia | Confusional arousal |
| Limb movement disorders | Nightmares |
| Limit-setting sleep disorder | Sleep paralysis |
| Insufficient sleep syndrome | REM sleep behavior disorder |
| Circadian rhythm sleep disorder | Bruxism |
| Somniloquy | |
| Nocturnal enuresis | |
| Rhythmic movement disorders |
Dyssomnias
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V), defines a dyssomnia as a primary disorder of sleep or wakefulness characterized by insomnia or hypersomnia as the major presenting symptoms and are disorders of the amount, quality, or timing of sleep.
Primary Idiopathic Insomnia
Primary pediatric insomnia comprises the inability to initiate or maintain sleep despite being provided the age-appropriate opportunity to sleep and results in a daytime impairment for the child and family. The prevalence, although varied, ranges from 1% to 6% in the general population and up to 75% in pediatric patients with comorbid neurocognitive disorder such as ADHD or pervasive developmental disorders. These children often present with paradoxic hyperactivity and restlessness as opposed to daytime hypersomnolence in response to their sleep disorder. Difficulties in making a proper wake-to-sleep transition in pediatric patients has often been attributed to poor sleep hygiene practices or the inability for a parent to withdraw comfort measures in a fashion that allows the child to self-soothe and initiate sleep. The treatment for insomnia traditionally focuses on providing a more consistent routine for the child and enforcing good practices such as caffeine avoidance, limit setting, and an age-appropriate schedule. If a child has persistent issues once the appropriate sleep hygiene practices have been addressed, the child should be evaluated for additional neurocognitive comorbidities, which may require pharmaceutical or behavioral therapy. These more complicated patients have commonly been prescribed clonidine, mood stabilizers, antidepressants, hypnotics, or antihistamines based on anecdotal evidence; however, no consensus has been reached on pharmacologic management of these patients because of a lack of randomized clinical data.
Narcolepsy
Narcolepsy is a rapid eye movement (REM) sleep disorder that often starts in adolescence and is classically defined as a combination of irresistible daytime somnolence; cataplexy, or sudden loss of muscle tone associated with emotional triggers; sleep onset paralysis; and hypnagogic hallucinations, or vivid hallucinations on sleep onset. The condition affects approximately .02% to .05% of the U.S. population, but only about 50% of individuals will exhibit the classic tetrad of symptoms. Narcolepsy animal models show deficient neurotransmitter hypocretin (orexin), which is a regulator in non-REM (NREM) versus REM sleep. Patients with suspected narcolepsy should be further evaluated by overnight polysomnogram (PSG) data to rule out other sleep disorders, followed by a daytime multiple-sleep latency test (MSLT). The MSLT is an objective test that measures the speed of falling asleep during 20 minute napping intervals with a faster onset of sleep indicating greater level of sleepiness. A child with narcolepsy will often exhibit spontaneous onset of REM sleep during at least two of these naps, whereas normal subjects will exhibit no REM sleep. Additionally, a child with narcolepsy will exhibit a mean sleep latency during the MSLT of 6 minutes, whereas normal sleep latency is more in the range of 15 minutes.
Pediatric patients with narcolepsy may first start having symptoms as early as age 5 but may not be diagnosed until much later in adolescence because of confounding emotional and behavioral disturbances. Symptoms are often characterized by roughly 10- to 20-minute sleep attacks in which irresistible urges to sleep invade normal daily activities such as eating, driving, or walking. Cataplexy, the sudden but brief bilateral loss of muscle tone, in addition to the intense hypersomnia is pathognomonic for narcolepsy. Adequate treatment of children with narcolepsy is important because these children often express increased emotional lability, adjustment difficulty, and problems in school. In addition to promoting good sleep hygiene and establishing healthy sleep-wake schedules, treatment includes stimulants to decrease daytime sleepiness, modafinil to promote wakefulness, and suppression of REM sleep with agents such as tricyclic antidepressants or serotonin reuptake inhibitors. Additional studies are also looking at agents such as sodium oxybate, which acts as an agonist on the γ-aminobutyric acid B receptor to specifically address the cataplexy component of narcolepsy.
Primary Idiopathic Hypersomnia
Primary idiopathic hypersomnia is characterized by excessive sleepiness that lasts for at least four weeks. These children are excessively sleepy for no obvious reason and have no evidence of cataplexy that would be concerning for a narcolepsy diagnosis. Additionally, aside from prolonged sleep duration, these patients have adequate age-appropriate sleep time and will often exhibit normal PSG data. The lack of REM sleep during their individual, often prolonged naps further separates this diagnosis from narcolepsy. As in primary insomnia, it is important to differentiate this diagnosis from common differential diagnoses such as poor sleep hygiene, neuropsychiatric comorbidities, or even OSA. Treatment for hypersomnia may include stimulant therapy; however, this has been shown to be less effective for hypersomnia than for narcolepsy patients.
Kleine-Levin Syndrome is a rare, nonfamilial hypersomnia subcategorization that affects adolescents and presents with compulsive hyperphagia and indiscriminate hypersexuality in addition to hypersomnia. Other symptoms such as confusion, depression, memory deficits, irritability, and hallucinations can confound the diagnosis. The condition is episodic and self-limited and occurs over a period of weeks to years and may be associated with completely symptom-free intervals. A 2 : 1 to 3 : 1 male to female predominance is apparent, and the median age of onset is 15. Precipitating viral infections or head trauma have been reported. Consistent with hypersomnia, the PSG data for Kleine-Levin Syndrome is significant for increased sleep time and short REM sleep latency that does not meet criteria for narcolepsy. Use of modafinil, amphetamines, and methylphenidate are reported; however, no consensus on pharmacotherapy exists as a result of the extremely sporadic nature of the condition.
Limb Movement Disorders
The diagnosis of limb movement disorders such as restless leg syndrome (RLS) and periodic limb movement disorder (PLMD) in pediatric patients should not go unrecognized, lest associated pain, sleep disturbances, and possible comorbid neuropsychiatric conditions go untreated. RLS is defined as the subjective complaint of uncomfortable tingling sensation in the lower extremities around bedtime with relief of symptoms with movement, whereas PLMD is the repetitive contraction of the anterior tibialis muscle evaluated objectively in the sleep laboratory. Most patients with RLS will also have periodic limb movements on PSG; however, the converse is not always true. Approximately 2% of the pediatric population surveyed in one study of over 10,000 families met the criteria for diagnosis of RLS. No gender differences were observed, and 70% reported a family history of RLS ( Table 4-2 ). Sleep disturbances were common in children with RLS, as was the complaint of “growing pains;” therefore, RLS should at least be considered and appropriately treated in children with sleep difficulty and unexplained pain. It has been well documented that iron deficiency plays a role in adult RLS and must also be considered in pediatric RLS. A central nervous system iron deficiency along with dopaminergic dysfunction are thought to contribute to symptoms. When ferritin levels are below 50 ug/L, supplemental iron therapy should at least be considered. Additionally, PLMD may not be a wholly benign finding because it has been found that many children exhibit daytime symptoms associated with ADHD; therefore, these individuals deserve further neuropsychiatric evaluation if clinical suspicion is present. Treatment for both conditions centers around dopaminergic therapy, gabapentin, benzodiazepines, and possibly iron therapy.
