Sleep Disorders Overview

Sleep Disorders Definition

• Sleep is a recurring state characterized by a loss of responsiveness to the external environment.
• It's now known as an active physiologic state involving changes in neural, metabolic, and cardiorespiratory function.
• Sleep disorders encompass a wide array of conditions categorized in the International Classification of Sleep Disorders (ICSD-2).
• The ICSD-2 lists over 80 distinct sleep disorders, grouped into categories like insomnia, sleep-related breathing disorders, hypersomnias, circadian rhythm disorders, parasomnias, and sleep-related movement disorders.

Sleep Pathophysiology

• Normal sleep and wake cycles are generated by a complex neuronal network in the brain, regulated by homeostatic and circadian mechanisms.
• Sleep stages include REM (rapid eye movement) and NREM (non-REM) sleep.
• REM sleep is characterized by desynchronized EEG activity, REM bursts, and dreaming.
• NREM sleep features synchronized EEG activity and muscle relaxation.
• Sleep homeostasis regulates the intensity and duration of sleep, with deprivation leading to increased sleep pressure.
• Sleep physiology varies with age, showing a decrease in deep sleep and increased awakenings in older adults.

Sleep Signs and Symptoms

• A practical approach to assessing sleep-related disturbances involves eliciting symptoms.
• Common symptoms include difficulty falling asleep, maintaining sleep, or experiencing non-refreshing sleep leading to daytime fatigue.
• Chronic insomnia, often due to medical or psychological factors, can impair social and occupational functioning.
• Excessive daytime sleepiness is the inability to stay alert and results in falling asleep inappropriately.
• Abnormal movements or behaviors during sleep can include sleepwalking, sleep terrors, nightmares, and REM sleep behavior disorder.

Insomnia

• Difficulty falling asleep, maintaining sleep, or experiencing non-refreshing sleep are common complaints.
• Chronic insomnia impacts daytime functioning, quality of life, and can be associated with medical, psychiatric conditions, and pain.
• Inadequate sleep hygiene such as excessive caffeine, alcohol, or mentally/ physically arousing activities before bedtime can contribute to problems.
• Psychophysiological insomnia is characterized by a heightened arousal state, while adjustment insomnia stems from a temporary stressor.

Excessive Daytime Sleepiness

• Difficulty staying alert during the major waking period is described as excessive daytime sleepiness.
• It’s more likely in monotonous situations.
• Associated with increased risks of accidents, quantified using the Epworth Sleepiness Scale.

Abnormal Movements or Behavior in Sleep

• NREM parasomnias: Disorders of arousal seen in children (confusional arousals, sleepwalking, and sleep terrors).
• REM parasomnias: Include nightmare disorder and REM sleep behavior disorder.
• Restless legs syndrome (RLS): Characterized by an urge to move the legs due to uncomfortable sensations, particularly at rest. Periodic limb movement disorder (PLMD): Leg movements during sleep, not usually associated with symptoms during wakefulness.
• Sleep-related epilepsy: Difficulty differentiating from related behaviors without proper documentation (EEG).

Diagnosis

• Comprehensive history gathering is crucial for sleep disorder diagnosis, including sleep habits, environment, daytime activities, and collateral information from others.
• Sleep logs, questionnaires & scales (like the Epworth Sleepiness Scale), are often useful.
• Pattern recognition of clinical characteristics from the history and physical examination are critical parts of the diagnostic procedure.

Sleep Disorders Manifesting with Excessive Daytime Sleepiness

• Excessive daytime sleepiness can be caused by multiple factors, including sleep deprivation, obstructive sleep apnea (OSA), narcolepsy, and shift work disorder.
• OSA is diagnosed using polysomnography (PSG) which measures multiple physiologic parameters, like EEG (electroencephalography), EMG (Electromyography), EOG (Electrooculography), airflow, respiratory effort, and pulse oximetry in a sleeping patient.

Sleep Disorder Testing

• Polysomnography (PSG) monitors multiple physiologic parameters during sleep to assess sleep quality, breathing patterns, and other related disturbances.
• The Multiple Sleep Latency Test (MSLT) is a gold standard for assessing daytime sleepiness.
• The Maintenance of Wakefulness Test (MWT) measures the ability to stay awake in quiet situations.

Sleep Disorder Treatment

• Lifestyle modifications, such as good sleep hygiene, are often recommended.

• Stimulus control & sleep restriction techniques are part of these modifications.

• Drug therapies may include sedative hypnotics, anxiolytics, antidepressants, and others, as indicated and monitored.

• Stimulant medications can also be used in instances of excessive daytime sleepiness.

• Positive airway pressure (PAP) therapy (CPAP, autoPAP, or BiPAP) is a mainstay for obstructive sleep apnea (OSA).

This quiz covers the definition and pathophysiology of sleep disorders. It explores various types of sleep disorders listed in the ICSD-2 and explains the complexities of sleep cycles, including REM and NREM stages. Test your knowledge on how sleep is regulated and the physiological changes that occur during sleep.