neurologic disorders
Narcolepsy
Symptoms and Signs of Narcolepsy
The main symptoms of narcolepsy are Excessive daytime sleepiness (EDS) Cataplexy Hypnagogic and hypnopompic hallucinations Sleep paralysis Disturbed nocturnal sleep (due to increased arousals) About 10% of patients have all 5 of these symptoms. Symptoms usually begin in adolescents or young adults without prior illness, although onset can be precipitated by an illness, a stressor, or a period of sleep deprivation. Once established, narcolepsy persists throughout life; life span is unaffected. EDS is the primary symptom and can occur anytime. Sleep episodes vary from few to many per day, and each may last minutes or hours. Patients can resist the desire to sleep only temporarily but can be roused as readily as from normal sleep. Sleep tends to occur during monotonous conditions (eg, reading, watching television, attending meetings) but may also occur during complex tasks (eg, driving, speaking, writing, eating). Patients may also experience sleep attacks—episodes of sleep that strike without warning. Patients may feel refreshed when they awaken yet fall asleep again in a few minutes. Nighttime sleep may be unsatisfying with frequent arousals and interrupted by vivid, frightening dreams. Consequences include low productivity, breaches in interpersonal relationships, poor concentration, low motivation, depression, a dramatic reduction in quality of life, and potential for physical injury (particularly due to motor vehicle collisions). Momentary episodes of muscular weakness or paralysis occur without loss of consciousness and usually last < 2 minutes;they are evoked by sudden emotional reactions, such as laughter, anger, fear, joy, or, often, surprise. Weakness may be confined to the limbs (eg, patients may drop the rod when a fish strikes their line) or may cause a limp fall during hearty laughter (as in “weak with laughter”) or sudden anger. Cataplexy can also affect other muscles: The jaw may droop, facial muscles may flicker, eyes may close, the head may nod, and speech may be slurred. Vision may be blurred. These attacks resemble the loss of muscle tone that occurs during REM sleep. Clinically significant cataplexy occurs in about 20% of patients. Patients are momentarily unable to move as they are just falling asleep or immediately after they awaken. These episodes may be very frightening. They resemble the motor inhibition that accompanies REM sleep. Sleep paralysis occurs in about 25% of patients but also in some healthy children and, less commonly, in healthy adults. Particularly vivid auditory or visual illusions or hallucinations may occur when just falling asleep (hypnagogic) or, less often, immediately after awakening (hypnopompic). They are difficult to distinguish from intense reverie and are somewhat similar to vivid dreams, which are normal in REM sleep. Hypnagogic hallucinations occur in about 30% of patients, are common among healthy young children, and occasionally occur in healthy adults. Sleep is often also disturbed by increased arousals in patients with narcolepsy, potentially worsening EDS. 