Tuesday, November 30, 2010

Narcolepsy and Excessive Daytime Sleepiness

Narcolepsy and Excessive Daytime Sleepiness
Narcolepsy is a serious, but relatively uncommon, disorder characterized by sudden and uncontrollable attacks of sleep. These attacks can be brief - lasting just 30 seconds - or longer, lasting as long as 30 minutes or more. Sometimes the attacks are accompanied by hallucinations and/or temporary paralysis. Narcolepsy can be quite debilitating, causing lack of muscle control and dream experiences occurring at inappropriate times.

Sufferers often unexpectedly fall asleep in the middle of important activities, including driving and while playing sports. This can be quite dangerous for themselves and others. In addition, they can fall asleep during conversations and at work, harming their personal and professional relationships.

Those with Narcolepsy often experience a temporary paralysis, which can be physically harmful if they fall down, and also very frightening when it occurs.

Research to date reveals that Narcolepsy appears to affect the part of the central nervous system that controls sleep and wakefulness and that it is not a psychological disorder. While there is no "cure" yet, recent advances in medicine, technology and pharmacology allow those with Narcolepsy to lead nearly normal lives. The finding that the Brain Protein called Orexin or Hypocretin is deficient in patients with Narcolepsy by leading researchers, including our own, is bringing hope of a cure. The doctors at the Sleep Medicine group of sleep centres are actively pursuing this research.

Diagnosing Narcolepsy needs to be done in a clinic that is familiar with sleep medicine. The patient's complete medical history is considered and the patient is given a thorough physical examination. Most often, patients are also given two tests, a polysomnogram and a multiple sleep latency test (MSLT) to confirm a suspected diagnosis and also to determine the extent of the Narcolepsy.

Excessive Daytime Sleepiness (EDS) is an essential part of the diagnosis of Narcolepsy but may have a variety of other causes including Obstructive Sleep Apnoea (OSA), Restless Legs Syndrome (RLS), Circadian Rhythm Disorder and the syndrome of Primary Hypersomnolence.

The symptom of EDS is important because it is associated with feeling drowsy and tired; having an overwhelming need to sleep during the day, being unable to stay awake in the daytime, even after getting a good night's sleep and falling asleep at times you need to be fully awake and alert.

It could mean ineffective work performance or dangerous levels of driving or other activities and, interference with a person's ability to concentrate or perform daily tasks or routines. Some people affected by EDS often feel frustration and anger about being misunderstood and being regarded as unintelligent or not interested in personal growth or learning. They often have low self-esteem and/or poor personal relationships as a result.

Narcolepsy

Narcolepsy

Narcolepsy is characterized by the classic tetrad of excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis. Note that this tetrad is seen only rarely in children. The term "narcolepsy" is derived from Greek, "seized by somnolence." Gelineau was the first to delineate the syndrome in 1880.

Narcolepsy frequently is unrecognized, with a typical delay of 10 years between onset and diagnosis. Approximately 50% of adults with the disorder retrospectively report symptoms beginning in their teenage years. This disorder may lead to impairment of social and academic performance in otherwise intellectually normal children. The implications of the disease are often misunderstood by patients, parents, teachers, and health care professionals.


Narcolepsy is treatable. However, a multimodal approach is required for the most favourable outcome.

Narcolepsy is thought to result from genetic predisposition, abnormal neurotransmitter functioning and sensitivity, and abnormal immune modulation. Current data implicate certain human leukocyte antigen (HLA) subtypes and abnormalities in monoamine synaptic transmission, particularly in the pontine reticular activating system.

Understanding of the neurochemistry of narcolepsy stems primarily from research involving narcoleptic dogs (eg, special laboratory-bred Dobermans and Labradors). In these animal models, the disorder is transmitted in an autosomal recessive fashion with full penetrance and is characterized mainly by cataplexy.

Excessive daytime sleepiness (EDS) is the primary symptom of narcolepsy.

Sleepiness is a normal experience that cycles and invariably occurs after prolonged wakefulness. In healthy persons, mild sleepiness is apparent only during boring situations (eg, falling asleep while watching TV).
In patients with narcolepsy, severe EDS leads to involuntary somnolence during more active conditions such as eating and talking. Sleepiness in narcolepsy may be severe and constant, with paroxysms during which patients may fall asleep without warning (ie, sleep attacks).
Patients with narcolepsy tend to take short and refreshing naps (ie, REM type naps) during the day.
Several questionnaires evaluate sleepiness. The most commonly used is the 8-question Epworth Sleepiness Scale (1991).
Patients respond to each question on a scale from 0 (not at all likely to fall asleep) to 3 (very likely to fall asleep).
The resulting total score is between 0 and 24.
Although what score constitutes abnormal sleepiness is controversial, total scores above 10 generally warrant investigation.
Cataplexy (Latin, "to strike down with fear") is an abrupt attack of muscle weakness.

If severe and generalized, it may cause a fall.
More subtle forms exist with only partial loss of tone (eg, head nod).
The most characteristic feature of cataplexy is that it usually is triggered by emotions (usually laughter and anger).
Cataplexy is seen in about 70% of patients with narcolepsy, and its presence with EDS strongly suggests the diagnosis of narcolepsy. Specific historical questions concerning cataplexy are required.
Sleep paralysis is the inability to move upon falling asleep or awakening with consciousness intact.

It often is accompanied by hallucinations.
Sleep paralysis occurs during REM sleep in healthy subjects.
Sleep-related hallucinations may occur at sleep onset (ie, hypnagogic) or awakening (ie, hypnopompic) and are usually vivid (dreamlike) visual, auditory, or tactile in nature.

The classic picture of narcolepsy may be somewhat different in young children.

Children may deny EDS because of embarrassment.
Sometimes restlessness and motor overactivity may predominate.
Academic deterioration, inattentiveness, and emotional lability are common.
In one study of 51 prepubertal patients with narcolepsy, the following initial complaints were noted:
Children younger than 5 years presented with unexplained falls and "drop attacks," aggressive behavior, abrupt irritability, sleep terrors, and abrupt dropping of objects.
In children aged 5-10 years, the most common initial complaint was repetitive sleepiness, followed by difficulty with morning arousal associated with aggressive behavior and abrupt falls in school. These children often were misdiagnosed as having attention deficit hyperactivity disorder (ADHD), learning disability, or another neurologic disorder.
In children aged 10-12 years, poor academic performance was a common complaint. Other presenting symptoms included inappropriate low level of alertness, falling asleep in class, and inability to wake up in the morning.

Sleep Disorders


OVERVIEW

Excessive daytime sleepiness, difficulty sleeping, and abnormal sleep behaviors are common problems that can have large impacts on a person's overall health, safety and quality of life. With accurate diagnosis, however, most sleep disorders can be effectively treated.


Sleep Disorders Treated by Dr Yacoob Omar Carrim - Sleep Medicine Specialist

Sleep-related breathing disorders

Insomnia
Hypersomnias
Circadian rhythm disorders
Parasomnias
Sleep-related movement disorders

Narcolepsy TREATMENT

Narcolepsy
Overview

TREATMENT

Treatment plans for narcolepsy usually combine lifestyle modifications and medication. Plans need to be highly individualized and may require adjustment over time.

Lifestyle modifications
A patient's treatment team works with him or her to develop a daily plan to increase wakefulness. Elements of the plan may include:

Having a regular nighttime sleep schedule and adhering to it even on weekends
Taking naps at strategic times
Avoiding nicotine and alcohol
Getting regular exercise
Making changes at work or school to break up monotonous tasks. The Americans with Disabilities Act prohibits discrimination against workers with narcolepsy and requires employers to provide reasonable accommodation to qualified employees.
Avoiding driving if drowsy. If patients with narcolepsy must drive a long distance, they'll need to work with their treatment team to establish a medication schedule that ensures the greatest likelihood of wakefulness during the drive, and will need to stop for naps and exercise breaks whenever they feel drowsy. Patients should not drive if their sleepiness is not well controlled.

Medications
The best medication for a given patient depends on whether the patient experiences cataplexy, other medications being taking for other conditions, the patient's age, and response to particular drugs. Some medications often prescribed include:

Stimulants: Stimulate the central nervous system to help stay awake during the day. They include:
Modafinil (Provigil): Newer stimulant that isn't as addictive and doesn't produce the highs and lows often associated with older stimulants.

Methylphenidate (Ritalin)

Various amphetamines: Although effective, they may cause side effects, such as nervousness and heart palpitations.

Antidepressants: Suppress REM sleep to help alleviate the symptoms of cataplexy, hypnagogic (the boundary state between sleep and wakefulness) hallucinations, and sleep paralysis. Options include selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants.

Sodium oxybate (Xyrem): Controls cataplexy, sleep paralysis and hallucinations, helps improve nighttime sleep, and in high doses may also help control daytime sleepiness (though taken only at night). Associated with possible serious side effects, however, such as trouble breathing during sleep, sleepwalking and bed-wetting, and therefore strictly regulated by the Food and Drug Administration.