Sleep and Insomnia

Classification of Sleeping Problems in Childhood

Sleep problems for children and adolescents can include:

• 1.

  Disorders of initiating and maintaining sleep include difficulties at sleep onset and problems occurring during sleep that may disrupt sleep or lead to awakenings. The period of wakefulness in bed that is of concern is generally longer than 30 minutes. Insomnia has been defined as an almost nightly complaint of an insufficient amount of sleep, or not feeling rested after sleep. In adults, its severity is judged by evidence of impairment of social or occupational functioning. A primary form of insomnia often arising in childhood exists. In the palliative care context, the most common form of insomnia is “Sleep Disorder Due to General Medical Condition” as per the American Psychiatric Association [DSM-IV, 780.52], or “Sleep Disorders Associated with Mental, Neurologic and Other Medical Disorders.”

• 2.

  Inability to awaken from sleep at the desired time and daytime sleepiness.

• 3.

  Sleep-related behaviors in children, which include rhythmic movement disorders such as head banging and body rocking, and parasomnias. Parasomnias are abnormal behaviors during partial arousals from non-REM (rapid eye movement) sleep. They include sleep talking, sleep walking, teeth grinding or bruxism, enuresis, and night terrors. Night terrors are the most dramatic of these and occur in approximately 6% of children. Night terrors differ from a nightmare; in that there is no memory of the sleep behavior the following morning.

• 4.

  Sleep disordered breathing is the general term used to describe obstructive sleep apnea (OSA), central sleep apnea (CSA), and hyperventilation or hypoventilation occurring in patients suffering from chronic respiratory diseases.

Growth and Development

An understanding of normal developmental changes in children's sleep patterns is helpful for both practitioners and families. Regular sleeping patterns generally become established by 12 months of age. Total sleep duration decreases from an average of 14.2 hours at 6 months of age to an average of 8.1 hours at 16 years of age ( Fig. 30-1 ). There is a decreasing trend for daytime napping beyond the age of 12 months, with the most prominent decline in napping habits occurring between 18 months and 4 years of age. There is also a trend for children, particularly adolescents, to go to sleep at a later time compared with earlier eras, and this can be attributed to academic demands and entertainment, such as the Internet and television.

Sleeping Difficulties in Healthy Children

Sleeping problems occur in healthy children. It has been found that 24% of children between 1 and 2 years still wake regularly at night. The frequency of disrupted sleep at night continues to decrease with age, with 10% of children waking at age 8. Sleeping problems are also important for adolescents, with 10% to 15% having difficulties falling asleep. Erratic sleeping patterns, partly associated with hormone secretion related to puberty, can make it difficult for some adolescents to fall asleep at bedtime. While nearly all teenagers show this tendency toward delayed sleep onset, approximately 7% will be diagnosed with delayed sleep phase syndrome in which the adolescent is typically unable to fall asleep before midnight and has extreme difficulty waking up in the morning. A national survey of 70,000 healthy children in the United States aged between 6 and 18 years showed 31.9% experienced more than one night of inadequate sleep in the week before the survey.

Children with Life-Threatening Conditions

Sleep problems are magnified in children with respiratory, metabolic, neurologic, and malignant conditions. Insomnia can be considered a symptom in this group of children rather than a diagnosis. The cause may be peripheral in origin, such as gastroesophageal reflux causing pain or adenoidal hypertrophy with nasal obstruction causing respiratory difficulty. Alternatively, the causes of poor sleep may be central in origin, related to medications, brain tumors, seizures, and syndrome abnormalities with dysfunction of central sleep systems. In particular, pain and sleep-disordered breathing are prevalent problems in this patient population. Sleeping difficulties have also been noted to be present in children receiving end-of-life care.

Sleep complaints are common in children and adolescents diagnosed with cystic fibrosis (CF) with approximately 40% of children reporting difficulty falling asleep and a similar proportion having difficulty staying asleep. Hypoxemia and nocturnal cough account for some of these difficulties. Various metabolic and genetic syndromes are also associated with sleep disturbance, including Rett syndrome and Angelmann syndrome. Approximately 90% of children diagnosed with Sanfilippo syndrome have sleep disturbance.

Structural brain lesions in infants and children are also often associated with difficulty falling asleep at night and nocturnal awakenings. States of wakefulness are regulated by brainstem nuclei, while the establishment of circadian rhythms is dependent upon the hypothalamus and its connections. Children with midline brain pathology and blindness are at high risk for sleep disorders resulting from desynchronization of the 24-hour sleep-wake rhythm. Children with hydranencephaly, in particular, can suffer from severe sleep disturbance, demonstrating the importance that intact cerebral hemispheres have in maintaining sleep-wake cycles.

Sleep-disordered breathing can occur in patients with chronic respiratory illnesses such as chest wall, neuromuscular, primary lung diseases and heart failure. Obstructive sleep apnea in children can be caused by enlarged tonsils or adenoids. Obesity, severe scoliosis, and craniofacial deformities may also contribute to sleep-related breathing problems. All of these risk factors for sleep-disordered breathing occur in children with life-threatening conditions.

Central and obstructive apneas are common and problematic for children with myopathies and other neuromuscular disease. Respiratory disorders during sleep, including apnea and hypoventilation, have been described in Duchenne muscular dystrophy and spinal muscular atrophy. Such children can experience ventilatory muscle fatigue, particularly in the latter hours of the night, resulting in disrupted sleep, daytime sleepiness, and headaches. Excessive daytime sleepiness was also a common sleep disturbance in children with brain tumors. Problems included resumption of daytime naps, difficulty waking in the morning, and inability to remain awake during daytime activities such as school.

Approximately 31% of children with cancer treated as outpatients experienced sleeping difficulties. This symptom was particularly distressing to 39% of 7- to 12-year-old children while 59% of 10- to 18-year-old children found this symptom to be particularly distressing. Children with cancer who are admitted to hospital for chemotherapy sleep for a longer duration and have more frequently disrupted sleep. One study revealed that 80% of children with cancer experienced significant pain at the time of their diagnosis. Almost 75% of children reported that this pain led to sleep disruption. The disruption of the sleep-wake pattern is a common issue adding to the fatigue that often accompanies cancer and its treatments.

A survey of children attending a chronic pain clinic found that 71% had sleep disruptions. Pain has been found to contribute to children waking from sleep and affecting the overall quality of sleep in a number of studies. Pain may interfere with the ability to sleep because it can fragment sleep with frequent awakening, activate threat-related arousal to more pain, and increase vigilance that something worse may happen. Pain and discomfort affect sleep, while poor sleep predisposes a patient to increased, pain experiences. A study of healthy young adults found that reduced sleep led to increased sensitivity to pain. A bidirectional relationship between pain and sleep may ensue such that children enter a negative downward spiral in which worsening pain disrupts sleep, which then further heightens their pain experience.

Retrospective studies of children who died found insomnia to occur in 20% to 25% of children in the terminal stage of their disease. Fatigue is the most common symptom experienced at the end of life. Fatigue in children with cancer has been found to negatively correlate with sleep quality. Although anemia and metabolic changes may contribute to fatigue, sleeping poorly at night may be another important factor. Further, medications used to treat symptoms, such as opioid analgesics, antiepileptic drugs, and benzodiazapines, and keep children comfortable can also disrupt normal sleep patterns. Assessment can be difficult in the palliative care context where fatigue and sleepiness can arise from the disease state as well as sleep disturbance.