Pediatric Sleep Disorders Clinical Presentation

The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Text Revision (DSM-IV-TR) divides sleep disorders into the following 4 broad categories^[1] :

• Primary sleep disorders
• Sleep disorders due to a general medical condition
• Sleep disorders related to another mental disorder
• Substance-induced sleep disorders

Primary sleep disorders are further subdivided into dyssomnias, which are characterized by abnormalities in the amount, quality, or timing of sleep, and parasomnias, which are characterized by abnormal behavioral or physiologic events that occur in association with sleep stages or sleep-wake transitions.

In evaluating a child or adolescent for a sleep disorder, the importance of a thorough sleep history cannot be overemphasized. A sleep diary, usually kept for about 2 weeks, provides information on night-to-night variability over time. It can also help track patient compliance with behavioral interventions and response to treatment. Rating scales have been developed to quantify subjective sleepiness of patients. The Epstein Sleepiness Scale and the Stanford Sleepiness Scale are examples.

Issues to be addressed in the history include the following:

• Temporal history
• When the problem began
• Predisposing, precipitating, and perpetuating factors
• Review of evening activities and bedtime rituals
• Sleep environment
• Latency to sleep onset
• Arousals - When, for how long, and how often arousal occurs; behavior during awakening; and ease with which the child returns to sleep
• History of snoring, breathing pauses, sleepwalking, talking, enuresis, and nocturia
• Sleep position
• Nightmares and sleep terrors
• Seizure symptoms - Tongue biting, chewing, blood on bedclothes, and encopresis
• Time of morning awakening, sleep paralysis, and early-morning headache
• Total sleep time
• Restorative sleep
• Daytime sleepiness, fatigue, and school performance
• Questions about depression, anxiety, worries or concerns, hyperactivity, and irritability
• Frequency and duration of naps
• Existing comorbid disorders
• Substance use
• Use of caffeine, alcohol, drugs, medications (prescription or over-the-counter [OTC]), and herbal preparations
• Family history of sleep disorder or metabolic disorder
• Parents’ sleep habits^[3]
• Efforts made to control symptoms
• Overall impact of sleep disturbance on family

Primary sleep disorders

Dyssomnias

Insomnia is defined as the subjective symptom of inadequate sleep quantity and quality. Patients with primary insomnia report difficulty falling asleep or maintaining sleep. Chronic insomnia may produce poor concentration and a low level of energy. Other symptoms include a decreased sensation of well-being and poor productivity. Some patients with primary insomnia feel that the sleep was not restorative. Distress due to inability to sleep may lead to a vicious cycle of frustration and insomnia.

Patients with primary hypersomnia require more sleep despite long and good sleep (about 12 hours), usually require naps in the daytime, and are not refreshed by short naps.

Patients with narcolepsy may experience the following:

• Excessive daytime sleepiness with irresistible daytime sleep attacks
• Sleep paralysis, in which the individual awakens unable to move
• Cataplexy, which may be subtle initially (eg, wobbly knees or dizziness) but may progress to sudden falls following a strongly experienced emotion
• Hypnagogic hallucinations
• Feeling of refreshment after a sleep attack

Children with obstructive sleep apnea syndrome (OSAS) have a history significant for loud snoring, breathing pauses, mouth breathing, restless sleep, and increased perspiration at night. Snoring is the most common presenting symptom. Hyperactivity and failure to thrive are more common symptoms of childhood obstructive apnea.

Other symptoms in children with OSAS include excessive daytime sleepiness, morning headaches, and behavioral changes (paradoxical hyperactivity as children try to stay awake). These children also experience emotional lability, changes in school performance, and cardiac failure.

Of the circadian rhythm sleep disorders, delayed sleep phase syndrome (DSPS) is the most common, with a prevalence of about 7% among adolescents. It is characterized by early insomnia, little or no difficulty maintaining sleep, and difficulty waking in the morning.

Parasomnias

Nightmare disorder affects 10-50% of children aged 3-6 years. Nightmares occur during rapid eye movement (REM) sleep, usually in the second half of the night, and are well remembered in the morning. After a nightmare, the child is alert and can clearly describe scenes and frightening images in detail.

Nightmares are common during stressful times or after frightening events, such as frightening movies. If nightmares are severe and frequent, they may affect daytime functioning. In posttraumatic stress disorder (PTSD), nightmares may be associated with flashbacks, numbing, reenacting the events, and avoidance.

Night terrors typically occur in the first 3 hours of sleep. The child is not awake but appears agitated. Abrupt, usually agitated, arousal from slow-wave sleep takes place. Night terrors are associated with autonomic arousal (eg, tachypnea, tachycardia, and diaphoresis) and screaming. The child is often inconsolable during the episode. After about 3-5 minutes, the episode terminates spontaneously, and the child quickly returns to sleep. Recall of the event in the morning is poor. This type of disturbance may be associated with an ongoing illness or fever.

In sleepwalking disorder (somnambulism), the patient is difficult to arouse and usually has no recollection of the event in the morning. Actions taking place during sleepwalking frequently vary.

In primary nocturnal enuresis (bed wetting), no period of nighttime dryness occurs for more than 6 months. In secondary enuresis, a relapse of bed wetting occurs after a period of at least 6 months of dryness. This sleep disturbance may be associated with shame and low self-esteem.

Sleep disorders related to general medical condition

A wide variety of medical and psychiatric disorders may result in sleep disruption. The clinician must first establish the presence of a general medical condition. Furthermore, the clinician must determine whether the sleep disturbance is causally related to the medical illness through a physiologic mechanism. Cluster headaches occur more frequently during the night than in the daytime. Sleep-related headaches usually awaken the patient and fragment sleep.

Diagnostic criteria for sleep disorders caused by a general medical condition include the following:

• A prominent disturbance in sleep that is sufficiently severe to warrant independent clinical attention
• Evidence from the history, physical examination, or laboratory findings that the sleep disturbance is the direct physiologic consequence of a general medical condition
• Disturbance that is not better accounted for by another mental disorder (eg, an adjustment disorder in which the stressor is a serious medical illness)
• Disturbance that does not occur exclusively during the course of a delirium
• Disturbance that does not meet the criteria for breathing-related sleep disorder or narcolepsy
• Sleep disturbance that causes clinically significant distress or impairment in social, occupational, or other important areas of functioning

In pediatric populations, epilepsies occurring during sleep account for 30% of seizure disorders. Epilepsy appears to fragment sleep and causes impairment in daytime functioning.^[4] The sleep disturbances associated with developmental central nervous system (CNS) disorders generally reflect fragmentation with frequent awakenings, difficulty in initiating sleep, and early morning awakenings. Blind individuals experience cyclic disorders because of the lack of cues that continually reset the internal clock to fit the 24-hour day-night cycle.

Kleine-Levin syndrome comprises a constellation of symptoms that include episodes of excessive somnolence, overeating, and sexual disinhibition; it is 3 times more frequent in boys than in girls.^[5] Behavioral disturbances, such as irritability and confusion, are associated with this syndrome, and occasional hallucinations have been reported.

Symptoms of Kleine-Levin syndrome typically begin during adolescence, either gradually or abruptly. Onset follows a flulike illness or injury with loss of consciousness in half the cases. The course of the syndrome is characterized by remissions and relapses, with relapses occurring at intervals of weeks to months. Symptoms may last from 12 hours to 3 weeks. Kleine-Levin syndrome usually resolves spontaneously during late adolescence or early adulthood.

In Down syndrome, airway hypotonia leads to obstructive apnea that is not associated with obesity, age, or congenital heart disease. Central apnea also is common and is associated with significant desaturation.

Paradoxical hyperactivity in children with attention deficit hyperactivity disorder (ADHD) encourages them to stay awake. Emotional lability may be observed. Children with ADHD tend to have fewer and shorter arousals than adults. They also tend to have obstructive hypopnea, with relatively few complete apneic events. Children with ADHD have a strong tendency to fall asleep during the day. They have high rates of restless legs syndrome (RLS) and periodic limb movement in sleep (PLMS) and a higher prevalence of OSAS.

Sleep-disordered breathing and PLMS have been frequently found in children with ADHD who have symptoms and complaints of disturbed sleep. Routine assessment of the sleep habits of patients with ADHD is important; consider objective sleep assessment, including polysomnography (PSG).

Approximately 50% of children with Tourette syndrome have sleep disturbances. Nocturnal awakenings and movements increase when tics persist into sleep. Comorbidity exists with obsessive-compulsive signs, traits associated with increased sleep latency, decreased REM sleep, and deceased REM sleep latency. Children and adolescents with this movement disorder are at risk for parasomnias. Patients with Tourette syndrome have a higher incidence of enuresis.

Rett syndrome is associated with prolonged sleep latency. Short and fragmented sleep results in low sleep efficiency.

In Prader-Willi syndrome, obesity, hyperphagia, and developmental delay are the most common features. Obesity can cause obstructive sleep apnea. An increased frequency of apneas, a decreased nadir of oxygen saturation, an increased maximum heart rate, and a blunted respiratory response to hypercapnia during non-REM (NREM) sleep all may occur in patients with Prader-Willi syndrome. Sleep time and slow-wave sleep increase during the day and at night.

Upper airway resistance syndrome results in REM fragmentation and extra daytime sleep (EDS).

Menstrual-associated periodic hypersomnia is another cyclic sleep disorder, noted during the first few years after menarche. Attacks generally last 1-2 weeks after ovulation, with sudden resolution occurring at the time of menses.

Sleep-related gastroesophageal reflux disease (GERD) is characterized by regurgitation of stomach contents into the esophagus during sleep. It is very common in patients using theophylline as a respiratory stimulant for apnea of prematurity or asthma.

Nighttime exacerbations of childhood asthma are common and may lead to significant sleep disruption.

Children with atopic dermatitis tend to have increased sleep-onset difficulty, night awakenings, and decreased sleep duration as a result of pruritus and medications, such as antihistamines and corticosteroids.

Children with chronic illnesses, such as juvenile rheumatoid arthritis (JRA) or sickle cell disease, can experience sleep difficulties.

Sleep disorders related to another mental disorder

Insomnia related to another mental disorder is the most frequent diagnosis (35-50%) among individuals who present to sleep disorder facilities for evaluation of chronic insomnia. In young children, separation anxiety, stress, and trauma may result in nighttime awakening, nightmares, or resistance to going to bed.

Insomnia related to another mental disorder is characterized by reports of difficulty falling asleep, frequent awakenings during the night, or a marked feeling of nonrestorative sleep that has lasted for at least 1 month and is associated with daytime fatigue or impaired daytime functioning. Hypersomnia related to another mental disorder is characterized by reports of either prolonged nighttime sleep or repeated daytime sleep episodes for at least 1 month.

In both insomnia related to another mental disorder and hypersomnia related to another mental disorder, the sleep symptoms cause significant distress or impairment in social, occupational, or other important areas of functioning.

Patients who have major depressive disorder or dysthymic disorder often report difficulty in falling asleep or staying asleep or early morning awakening with inability to return to sleep. Hypersomnia can be a feature of depression, especially major depression with atypical features. Children and adolescents with major depressive disorder generally present with less subjective sleep disturbance and fewer PSG changes than do older adults with a similar degree of depression.

Prepubertal children with depression are more likely to experience insomnia (75%) than hypersomnia (25%); after puberty, hypersomnia predominates. Hypersomnia is a common feature of depressive disorders in adolescents and young adults, and insomnia is more common in older adults.

Individuals with generalized anxiety disorder often report difficulty in falling asleep and may awaken with anxious thoughts in the middle of the night. Panic attacks can arouse patients and cause insomnia. Significant insomnia is often observed during exacerbations of schizophrenia and other psychotic disorders but rarely is a predominant symptom. Other mental disorders that may be related to insomnia include adjustment disorders, somatoform disorders, and personality disorders.

Substance-induced sleep disorders

Substance-induced sleep disorder most commonly occurs during intoxication with substances such as alcohol, amphetamine and related substances, caffeine, cocaine, opioids and sedatives, hypnotics, or anxiolytics. Substance-induced sleep disorder can also occur in association with withdrawal from these same classes of substances.

Diagnostic criteria for substance-induced sleep disorder include the following:

• Prominent disturbance in sleep that is sufficiently severe to warrant independent clinical attention
• Evidence from the history, physical examination, or laboratory findings of either (1) symptoms that developed during or within 1 month of substance intoxication or withdrawal or (2) medication use that is etiologically related to the sleep disturbance
• Disturbance that is not better accounted for by a sleep disorder that is not substance induced

Evidence that the symptoms are better accounted for by a sleep disorder that is not substance induced might include the following:

• Symptoms preceding the onset of the substance use (or medication use).
• Symptoms persisting for a substantial period (eg, about 1 month) after the cessation of acute withdrawal or severe intoxication
• Symptoms that are substantially in excess of what would be expected from the type or amount of the substance used or the duration of use, or the presence of other evidence suggesting an independent non–substance-induced sleep disorder
• Disturbance that does not occur exclusively during the course of an episode definable as delirium
• Sleep disturbance that causes clinically significant distress or impairment in social, occupational, or other important areas of functioning

Alcohol-induced sleep disorder typically occurs as the insomnia type. Alcohol, which often facilitates sleep onset, can lead to decreased REM sleep and sleep disruption. Acute intoxication initially results in increased sleepiness and reduced wakefulness for 3-4 hours.

An increase in stages 3 and 4 of NREM sleep is a typical feature of this initial stage. After these initial effects, the individual experiences increased wakefulness, restless sleep, and, often, vivid and anxiety-laden dreams during the second half of the night. In addition, alcohol can increase the number of obstructive sleep apnea events and result in fragmented sleep. With continued habitual use, alcohol continues to show a short-lived sedative effect for several hours, followed by sleep continuity disruption for several hours.

During alcohol withdrawal, sleep architecture is grossly disturbed. Sleep tends to be fragmented and accompanied by an increase in the amount and intensity of REM sleep. Vivid dreams often accompany this stage of sleep.

During the period of acute intoxication, amphetamines produce sleep disruption associated with increased sleep latency, reduced total sleep time, fragmented sleep, an increase in body movements, and a decrease in REM sleep. Slow-wave sleep tends to be reduced. During withdrawal from long-term amphetamine use, hypersomnia with prolonged nocturnal sleep duration and excessive daytime sleepiness tends to be the rule.

Caffeine-induced sleep disorder is characterized by insomnia during intoxication and by hypersomnia and excessive daytime sleepiness during withdrawal. Caffeine is known to result in increased wakefulness and sleep fragmentation, which may be documented on PSG as prolonged sleep latency, multiple arousals, and a decrease in slow-wave sleep.

Use of cocaine results in increased sleep latency, reduced total sleep time, and fragmentation of sleep architecture during intoxication. Cocaine withdrawal is associated with hypersomnia.

Short-term use of opioids produces increased sleepiness and reduced REM sleep. Insomnia and frequent arousals become common with prolonged use. Opioid withdrawal generally produces symptoms and signs of CNS hyperactivity, though some patients may report hypersomnia.

Use of sedative-hypnotic medications produces an increase in sleepiness and PSG findings of decreased REM sleep and an increase in sleep-spindle activity. On the other hand, long-term use of sedatives may be accompanied by symptoms of insomnia and tolerance to these medications.

Withdrawal from sedative-hypnotics and anxiolytics is associated with anxiety and insomnia. The manifestation of withdrawal symptoms depends on the half-life of the drug used. Withdrawal from drugs with short half-lives typically produces insomnia. Medications with long half-lives are associated with symptoms of excessive sedation during their use.

A full physical examination, focusing on the causes and consequences of sleep-related disorders, is warranted. Significant things to look for in a physical examination include the following:

• level of consciousness
• Physical features - Head circumference, weight and indicators of failure to thrive, features suggestive of congenital anomalies, and size of the posterior pharynx
• Physical causes of airway blockage (eg, enlarged tonsils or adenoids)
• Obesity and neck circumference
• Systemic signs of heart failure (eg, clubbing or cyanosis)
• Signs indicative of seizure activity
• Tooth injuries on tongue
• Incontinence
• Postictal changes in sensorium