Sleep and Sleep-Wake Disorders

Question 1

REM Sleep

Answer 1

REM sleep is associated with loss of muscle movements.

The brain is highly active and it accounts for about 20% of sleep.

External sensory input is inhibited.

Motor systems that control body movements and muscle tone are inhibited. The result is a set of paradoxes, in which people see things in their dreams but are paralyzed.

Question 2

International classification of sleep disorders

Answer 2

Dyssomnias: disorders of initiating and maintaining sleep and disorders of excessive sleepiness.

Parasomnias: undesirable phenomena that occur primarily during sleep; do not disturb the sleep-wake cycle.

Question 3

Periodic Limb Movement Disorder (PLMD)

Answer 3

Episodes or repetitive large toe movement with flexion of the ankle, knee, and hip during sleep.

Cause if PLMD is largely known. A person must experience both periodic leg movements in sleep and a disruption in daytime functioning for diagnosis.

Question 4

Restless Leg Syndrome

Answer 4

Approximately 7 out of 10 people may experience. RLS can occur as a primary or secondary disorder. There is a high familial incidence of primary RLS, suggesting a genetic disorder.

Secondary causes of RLS include iron deficiency, neurologic disorders, pregnancy, uremia, and medications.

Diagnosis of RLS is based on a history of a compelling urge to move the legs, usually associated with unpleasant sensations; motor restlessness, as seen by activities such as pacing, tossing and turning in bed, or rubbing the legs; symptoms that become worse at rest are relieved by activity; and symptoms that are worse in the evening or night.

Because RLS may be a symptom of iron deficiency, serum ferritin and iron saturation should be addressed.

Question 5

Obstructive Sleep Apnea (OSA)

Answer 5

Apnea = cessation of airflow for a period of time (10 secs or longer)

A critical pathophysiologic feature of OSA is sleep-related partial or full collapse of the upper airway at the pharynx level.

Risk factors include increasing age, family history, obesity. Alcohol and other drugs can make it worse but not give the cause.
Large neck girth (greater than 40 cm) correlates with OSA, more telling than body mass index.

Noisy snoring, insomnia, abnormal movements during sleep, systemic hypertension.