Diagnostic Features

The essential feature of Breathing-Related Sleep Disorder is sleep disruption, leading to excessive sleepiness or, less commonly, to insomnia, that is judged to be due to abnormalities of ventilation during sleep (e.g., sleep apnea or central alveolar hypoventilation) (Criterion A). This sleep disruption must not be better accounted for by a mental disorder and is not due to the direct physiological effects of a substance (including medication) or a general medical condition that produces sleep symptoms through a mechanism other than abnormal breathing (Criterion B).

Excessive sleepiness is the most common presenting complaint of individuals with Breathing-Related Sleep Disorder. Sleepiness results from frequent arousals during nocturnal sleep as the individual attempts to breathe normally. The sleepiness is most evident in relaxing situations, such as when the individual is reading or watching television. The individual’s inability to control the sleepiness can be evident in boring meetings or while attending movies, theater, or concerts. When sleepiness is extreme, the person may fall asleep while actively conversing, eating, walking, or driving. Naps tend to be unrefreshing and may be accompanied by a dull headache on awakening. However, there can be considerable variation in the intensity of the sleepiness. The impact of the sleepiness may be minimized by the individual, who may express pride about being able to sleep anywhere at any time.

Insomnia, frequent awakenings, or unrefreshing sleep are less frequent than daytime sleepiness as the presenting complaint in individuals with Breathing-Related Sleep Disorder. Some individuals may complain of difficulty breathing while lying supine or sleeping.

Abnormal respiratory events during sleep in Breathing-Related Sleep Disorder include apneas (episodes of breathing cessation), hypopneas (abnormally slow or shallow respiration), and hypoventilation (abnormal blood oxygen and carbon dioxide levels). Three forms of Breathing-Related Sleep Disorder have been described: obstructive sleep apnea syndrome, central sleep apnea syndrome, and central alveolar hypoventilation syndrome. An older term, Pickwickian syndrome, has been used to describe obese individuals with a combination of obstructive sleep apnea syndrome and waking hypoventilation as well as sleep-related hypoventilation.

Obstructive sleep apnea syndrome is the most common form of Breathing-Related Sleep Disorder. It is characterized by repeated episodes of upper-airway obstruction (apneas and hypopneas) during sleep. The central drive for respiration and respiratory movements in the chest and abdomen are preserved. It usually occurs in overweight individuals and leads to a complaint of excessive sleepiness. Obstructive sleep apnea syndrome is characterized by loud snores or brief gasps that alternate with episodes of silence that usually last 20-30 seconds. Snoring is caused by breathing through a partially obstructed airway. Silent periods are caused by obstructive apneas, with the cessation in breathing caused by complete airway obstruction. Typically the loud snoring has been present for many years, often since childhood, but an increase in its severity may lead the individual to seek evaluation. The snoring is commonly loud enough to disturb the sleep of others in close proximity. The cessation of breathing, sometimes lasting as long as 60-90 seconds and associated with cyanosis, may also be of concern to bedpartners. The termination of the apneic event can be associated with loud “resuscitative” snores, gasps, moans or mumbling, or whole-body movements. The bedpartner may have to move to a separate bed or another room as a result of the affected individual’s snoring, gasps, and movements. Most affected individuals are unaware of the loud snoring, breathing difficulty, and frequent arousals. However, some persons, particularly elderly persons, are intensely aware of the sleep disturbance and present with a complaint of frequent awakenings and unrefreshing sleep. Some individuals without frank airway obstruction may demonstrate arousals associated with increased airway resistance (sometimes referred to as upper airway resistance syndrome or respiratory event-related arousals). These individuals have many clinical characteristics in common with individuals with obstructive sleep apnea syndrome.

Central sleep apnea syndrome is characterized by episodic cessation of ventilation during sleep (apneas and hypopneas) without airway obstruction. Thus, in contrast to obstructive apnea events, central apneas are not associated with continued chest wall and abdominal breathing movements and occur more commonly in elderly persons as a result of cardiac or neurological conditions that affect ventilatory regulation. Individuals most often present with complaints of insomnia due to repeated awakenings, which they may or may not associate with breathing difficulties. Individuals with central sleep apnea may have mild snoring, but it is not a prominent complaint.

The central alveolar hypoventilation syndrome is characterized by an impairment in ventilatory control that results in abnormally low arterial oxygen levels further worsened by sleep (hypoventilation without apneas or hypopneas). The lungs in individuals with this disorder have normal mechanical properties. This form most commonly occurs in very overweight individuals and can be associated with a complaint of either excessive sleepiness or insomnia.

Associated Features and Disorders

Associated descriptive features and mental disorders. The individual with Breathing-Related Sleep Disorder may complain of nocturnal chest discomfort, choking, suffocation, or intense anxiety in association with apneic events or hypoventilation. Body movements associated with breathing difficulties can be violent, and individuals with Breathing-Related Sleep Disorder are often described as restless sleepers. Individuals with this disorder typically feel unrefreshed on awakening and may describe feeling more tired in the morning than when they went to sleep. They may also describe sleep drunkenness (i.e., extreme difficulty awakening, confusion, and inappropriate behavior). Severe dryness of the mouth is common and often leads the person to drink water during the night or on awakening in the morning. Nocturia occurs more often with the progression of symptoms. Dull, generalized morning headaches can last for 1-2 hours after awakening.

The sleepiness can lead to memory disturbance, poor concentration, irritability, and personality changes. Mood Disorders (particularly Major Depressive Disorder and Dysthymic Disorder), Anxiety Disorders (particularly Panic Disorder), and dementia are commonly associated with Breathing-Related Sleep Disorder. Individuals can also have reduced libido and erectile ability. Rarely, erectile dysfunction is the presenting complaint of the obstructive sleep apnea syndrome. Children with Breathing-Related Sleep Disorder may have failure to thrive, developmental delay, learning difficulties, poor attention, and hyperactive behavior. Excessive daytime sleepiness can result in injuries (e.g., falling asleep while driving a vehicle) and can also cause severe social and occupational impairment resulting in job loss, marital and family problems, and decreased school performance.

Associated laboratory findings. Each of the major Breathing-Related Sleep Disorder syndromes produces specific abnormalities. In the obstructive sleep apnea syndrome, nocturnal polysomnography shows apneic episodes longer than 10 seconds in duration (usually 20-40 seconds), with rare episodes lasting up to several minutes. Hypopneas are characterized by a reduction of airflow. Both types of events are associated with a reduction in oxyhemoglobin saturation. Generally, more than 10-15 apneas or hypopnias per hour of sleep in the presence of symptoms is considered to be clinically significant. The central sleep apnea syndrome may include Cheyne-Stokes respiration (i.e., a pattern of periodic breathing consisting of an apnea, a 10- to 60-second episode of hyperventilation following the apnea, and a gradual decrease in ventilation culminating in another apnea). In the central alveolar hypoventilation syndrome, periods of decreased respiration lasting up to several minutes occur, with sustained arterial oxygen desaturation and increased carbon dioxide levels. Other features of nocturnal polysomnography in individuals with Breathing-Related Sleep Disorder include short sleep duration, frequent awakenings, increased amounts of stage 1 sleep, and decreased amounts of slow-wave sleep and rapid eye movement (REM) sleep. The arousals that occur at the termination of the apneic and hypoventilation events may be quite brief (several seconds).

Apneas, hypopneas, and hypoventilation may produce other disturbances: oxyhemoglobin desaturation, ECG abnormalities, elevated pulmonary and systemic arterial pressure, and transient arousals as the individual terminates an episode of breathing disturbance. Cardiac arrhythmias commonly occur during sleep in individuals with Breathing-Related Sleep Disorder and may include sinus arrhythmias, premature ventricular contractions, atrioventricular block, or sinus arrest. Bradycardia followed by tachycardia is commonly seen in association with apneic episodes. Frequent nocturnal awakenings and oxyhemoglobin desaturation can result in excessive sleepiness that may be detected by the Multiple Sleep Latency Test (MSLT) or other tests of daytime sleepiness. Mean sleep latency on the MSLT is often less than 10 minutes and can be less than 5 minutes (normal is 10-20 minutes).

Arterial blood gas measurements while the person is awake are usually normal, but some individuals with severe obstructive sleep apnea syndrome or central alveolar hypoventilation syndrome can have waking hypoxemia or hypercarbia. Cephalometric X rays, magnetic resonance imaging (MRI), computed tomography (CT), and fiber-optic endoscopy can show obstruction of the upper airway. Cardiac testing may show evidence of impaired right ventricular function. Individuals may also have elevated hemoglobin or hematocrit values due to repeated nocturnal hypoxemia. Polysomnographic findings in children differ from those in adults in that most children demonstrate labored breathing, partial obstructive hypoventilation with cyclical desaturations, hypercapnia, paradoxical movements, and snoring.

Associated physical examination findings and general medical conditions. The majority of individuals with the obstructive sleep apnea syndrome and the central alveolar hypoventilation syndrome are overweight and notice an increase in the severity of symptoms with increasing body weight. Upper-airway narrowing can occur due to excessive bulk of soft tissues. In particular, individuals with larger neck sizes (e.g., neck circumference greater than 17 inches in men and greater than 16 inches in women) are at higher risk for obstructive sleep apnea. Obstructive sleep apnea syndrome occurring in individuals of normal or below-normal body weight suggests upper-airway obstruction due to definable, localized structural abnormality, such as a maxillomandibular malformation or adenotonsillar enlargement. Nasal airway obstruction may also be present. Individuals may have noisy breathing even while awake. Gastroesophageal reflux with severe “heartburn” pain may occur in the obstructive sleep apnea syndrome in association with the effort to reestablish breathing during sleep. Individuals with central sleep apnea syndrome less frequently are overweight or have demonstrable upper-airway obstructions.

Systemic hypertension with elevated diastolic pressure is commonly associated with Breathing-Related Sleep Disorder. Some individuals, particularly those with chronic obstructive pulmonary disease or alveolar hypoventilation, have continuously low oxygen saturation values during sleep and are predisposed to developing pulmonary hypertension and associated right-sided cardiac failure (cor pulmonale), hepatic congestion, and ankle edema.

Individuals with Breathing-Related Sleep Disorder may have an underlying abnormality in the neurological control of the upper-airway musculature or ventilation during sleep. Disorders affecting neurological control of ventilation usually manifest as the central sleep apnea syndrome. Some individuals with neurological conditions have a specific lesion affecting the control of pharyngeal muscles, which may lead to the obstructive sleep apnea syndrome.

Breathing-Related Sleep Disorder can be associated with systemic general medical or neurological conditions. For instance, obstructive sleep apnea may result from tongue enlargement due to acromegaly, lingual thyroid tissue or cysts, or vocal cord paralysis as seen in Shy-Drager syndrome. Impaired cardiac function due to reduced cardiac output can result in central sleep apnea, as can neurological conditions that affect the brain stem control of respiration, such as syringobulbia or brain stem tumors.

Specific Age and Gender Features

In young children, the signs and symptoms of Breathing-Related Sleep Disorder (almost exclusively the obstructive sleep apnea syndrome) are more subtle than those in adults and the diagnosis is more difficult to establish. In children, polysomnography is useful in confirming the diagnosis. Snoring, which is characteristic of adult obstructive sleep apnea syndrome, might not be present. Agitated arousals and unusual sleep postures, such as sleeping on the hands and knees, commonly occur. Nocturnal enuresis is also common and should raise the suspicion of obstructive sleep apnea syndrome if it recurs in a child who was previously dry at night. Children may also manifest excessive daytime sleepiness, although this is not as common or pronounced as in adults. Daytime mouth breathing, difficulty in swallowing, and poor speech articulation are also common features in children. In children younger than 5 years, nighttime symptoms such as observed apneas or labored breathing are more often the presenting symptoms. In children over the age of 5, daytime symptoms such as sleepiness and behavioral problems, attention and learning difficulties, and morning headaches are more often the focus of concern. On physical examination, pectus excavatum and rib flaring can be seen. If associated with adenotonsillar enlargement (the most common cause of obstructive sleep apnea in children), typical “adenoid facies” can be seen with a dull expression, periorbital edema, and mouth breathing.

The obstructive sleep apnea syndrome is most common in middle-aged, overweight males and prepubertal children with enlarged tonsils. Aging leads to an increase in the frequency of both obstructive and central apnea events, even among asymptomatic healthy individuals. Because some degree of apnea may be normative with aging, polysomnographic results must be interpreted within this context. On the other hand, significant clinical symptoms of insomnia and hypersomnia should be investigated regardless of the individual’s age, and a diagnosis of Breathing-Related Sleep Disorder should be made if a breathing disturbance best explains the symptoms.

In adults, the male-to-female ratio of obstructive sleep apnea syndrome ranges from 2:1 to 4:1. There is no sex difference among prepubertal children. In adults, central apneic events appear to be more prevalent in males than in females, although this difference is less apparent after menopause.

Prevalence

The prevalence of Breathing-Related Sleep Disorder associated with obstructive sleep apnea is estimated to be approximately 1%-10% in the adult population but may be higher in elderly individuals. The prevalence of Breathing-Related Sleep Disorder also varies considerably as a function of the threshold for the frequency of apnea events. The prevalence of central sleep apnea syndrome is not precisely known but is estimated to be 10% of the rate of obstructive sleep apnea syndrome.

Course

The obstructive sleep apnea syndrome can occur at any age, but most individuals present for evaluation when they are between ages 40 and 60 years (with females more likely to develop obstructive sleep apnea after menopause). Central sleep apnea is more commonly seen in elderly individuals with central nervous system or cardiac disease. The central alveolar hypoventilation syndrome and central sleep apnea syndrome can develop at any age.

Breathing-Related Sleep Disorder usually has an insidious onset, gradual progression, and chronic course. Most often, the disorder will have been present for years by the time it is diagnosed. Spontaneous resolution of the obstructive sleep apnea syndrome has been reported with weight loss, but usually the course is progressive and can ultimately lead to premature death due to cardiovascular disease or arrhythmia. The central sleep apnea syndrome also has a chronic unremitting course, although management of underlying medical conditions may improve the breathing disturbance. Adults with the central alveolar hypoventilation syndrome have a slowly progressive course.

Familial Pattern

A familial tendency for obstructive sleep apnea syndrome has been described.

Differential Diagnosis

Breathing-Relating Sleep Disorder must be differentiated from other causes of sleepiness, such as Narcolepsy, Primary Hypersomnia, and Circadian Rhythm Sleep Disorder. Breathing-Related Sleep Disorder can be differentiated from Narcolepsy by the absence of cataplexy, sleep-related hallucinations, and sleep paralysis and by the presence of loud snoring, gasping during sleep, or observed apneas or shallow breathing in sleep. Daytime sleep episodes in Narcolepsy are characteristically shorter, more refreshing, and more often associated with dreaming. Breathing-Related Sleep Disorder shows characteristic apneas or hypoventilation during nocturnal polysomnographic studies, and Narcolepsy results in multiple sleep-onset REM periods during the MSLT. Some individuals have concurrent Narcolepsy and Breathing-Related Sleep Disorder. Breathing-Related Sleep Disorder may be distinguished from Primary Hypersomnia and Circadian Rhythm Sleep Disorder based on the presence of clinical or laboratory findings of obstructive sleep apnea, central sleep apnea, or central alveolar hypoventilation syndromes. Definitive differential diagnosis between Primary Hypersomnia and Breathing-Related Sleep Disorder may require polysomnographic studies.

Hypersomnia related to a Major Depressive Episode can be distinguished from Breathing-Related Sleep Disorder by the presence or absence of other characteristic symptoms (e.g., depressed mood and loss of interest in a Major Depressive Episode and snoring and gasping during sleep in Breathing-Related Sleep Disorder).

Individuals with Breathing-Related Sleep Disorder must also be differentiated from otherwise asymptomatic adults who snore. This differentiation can be made based on the presenting complaint of insomnia or hypersomnia, the greater intensity of snoring, and the presence of the characteristic history, signs, and symptoms of Breathing-Related Sleep Disorder. For individuals complaining of insomnia, Primary Insomnia can be differentiated from Breathing-Related Sleep Disorder by the absence of complaints (or reports from bedpartners) of difficulty breathing during sleep and the absence of the history, signs, and symptoms characteristic of Breathing-Related Sleep Disorder.

Nocturnal Panic Attacks may include symptoms of gasping or choking during sleep that may be difficult to distinguish clinically from Breathing-Related Sleep Disorder. However, the lower frequency of episodes, intense autonomic arousal, and the lack of excessive sleepiness differentiates nocturnal Panic Attacks from Breathing-Related Sleep Disorder. Polysomnography in individuals with nocturnal Panic Attacks does not reveal the typical pattern of apneas, hypoventilation, or oxygen desaturation characteristic of Breathing-Related Sleep Disorder.

Attention-Deficit/Hyperactivity Disorder in children may include symptoms of inattention, academic impairment, and hyperactivity, all of which may also be symptoms of childhood sleep apnea. The presence of other symptoms and signs of childhood sleep apnea (e.g., labored breathing or snoring during sleep and adenotonsillar hypertrophy) would suggest the presence of a Breathing-Related Sleep Disorder.

The diagnosis of Breathing-Related Sleep Disorder is appropriate in the presence of a general medical condition that causes insomnia or hypersomnia through the mechanism of impaired ventilation during sleep. For example, an individual with tonsillar hypertrophy who has sleep difficulty related to snoring and obstructive sleep apneas should receive a diagnosis of Breathing-Related Sleep Disorder on Axis I and tonsillar hypertrophy on Axis III. In contrast, Sleep Disorder Due to a General Medical Condition is appropriate if a general medical or neurological condition causes sleep-related symptoms through a mechanism other than breathing disturbance. For instance, individuals with arthritis or renal impairment may complain of insomnia or hypersomnia, but this does not result from breathing impairment during sleep.

The use of, or withdrawal from, substances (including medications) can produce insomnia or hypersomnia similar to that in Breathing-Related Sleep Disorder. A careful history is usually sufficient to identify the relevant substance, and follow-up shows improvement of the sleep disturbance after discontinuation of the substance. In other cases, the use of a substance (e.g., alcohol, barbiturates, benzodiazepines, or tobacco) has been shown to be associated with Breathing-Related Sleep Disorder. An individual with symptoms and signs consistent with Breathing-Related Sleep Disorder should receive that diagnosis, even in the presence of concurrent substance use that is exacerbating the condition.

Relationship to the International Classification of Sleep Disorders

Breathing-Related Sleep Disorder is identified as three more specific syndromes in the International Classification of Sleep Disorders (ICSD): Obstructive Sleep Apnea Syndrome, Central Sleep Apnea Syndrome, and Central Alveolar Hypoventilation Syndrome.

Diagnostic criteria for 780.59 Breathing-Related Sleep Disorder

A. Sleep disruption, leading to excessive sleepiness or insomnia, that is judged to be due to a sleep-related breathing condition (e.g., obstructive or central sleep apnea syndrome or central alveolar hypoventilation syndrome).

B. The disturbance is not better accounted for by another mental disorder and is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or another general medical condition (other than a breathing-related disorder).

Coding note: Also code sleep-related breathing disorder on Axis III.