Narcolepsy: The Most Common Cause of Hypersomnia

What is narcolepsy?

Do you feel excessive sleepiness during the daytime? Do you get sleepy easily in a calm environment at any time of the day? If the answer to these questions is yes then you may be suffering from hypersomnia and the most common cause of this condition is narcolepsy.

Narcolepsy is the most common neurological disorder that disrupts sleep/wake pattern leading to hypersomnia.

We will examine what causes narcolepsy and how to cure it.

   Narcolepsy: the commonest cause of hypersomnia

What is narcolepsy?

Narcolepsy is defined by ICSD as irresistible urges to sleep occurring on a daily basis for at least three months with the following laboratory findings present…

  • On the multiple sleep latency test (MSLT), mean sleep latency is ≤8 minutes and two or more sleep-onset rapid eye movement (REM) periods are found in patients who have had at least 6 hours of sleep the night before the test
  • CSF hypocretin-1 levels ≤110 pg/mL (or one-third of mean control values) are also considered to be diagnostic

The DSM criteria for narcolepsy includes:

  • Irresistible attacks of refreshing sleep that occur daily over at least three months
  • The presence of cataplexy and/or recurrent rapid eye movement intrusions in the transition between sleep and wakefulness as manifested by sleep paralysis and hypnopompic or hypangogic hallucinations

Narcolepsy may be associated with cataplexy. This is defined as a transient loss of muscle tone that occurs suddenly in response to strong emotion. That is, during sleep, a paralysis-like condition may occur.

What are the types of narcolepsy?

Your narcolepsy may be one of three types.

These are:

1.Narcolepsy with cataplexy

This is the most frequent neurological cause of hypersomnia. The classic tetrad of symptoms (described later) is seen in this type of patient

2. Narcolepsy without cataplexy

The occurrence of EDS (excessive daytime sleepiness) and irresistible episodes of sleep without associated cataplexy. Other features may also be present, eg automatic behavior, hypnic hallucinations or sleep paralysis. Nocturnal sleep is usually less disturbed than in narcolepsy with cataplexy

3. Narcolepsy due to a medical condition

A consistent chronological link with the presumed underlying causative medical condition is found

What causes narcolepsy?

To understand narcolepsy, you need to have some idea about normal sleep cycles. Human sleep pattern cycles through two stages: REM (rapid eye movement) sleep and non-REM sleep. When you fall asleep, sleep is light and gradually become deeper. Both light and deep stages are part of non-REM sleep. The first stage of REM sleep comes after 90 minutes of sleeping. This is the dreaming portion. With narcolepsy, the REM pattern of sleep starts immediately after sleeping and even occurs randomly in the  daytime. This means that the normal sleep/wake pattern is disrupted.

The exact mechanism is not clear but there are some known causes. Narcolepsy with cataplexy is linked to a loss of hypothalamic neurons that contain hypocretin. An underlying autoimmune process may lead to the elimination of the hypocretin cells. Several studies show that narcolepsy with cataplexy is associated with human leukocyte antigen (HLA) subtypes DR2/DRB1*1501 and DQB1*0602. First-degree relatives of patients with these subtypes have a 10- to 40-fold increased risk for narcolepsy with cataplexy

What are the symptoms of narcolepsy?

The classical ‘tetrad’ of symptoms are helpful for diagnosis but suffered by only a minority of patients with narcolepsy.

These are: 1) excessive sleepiness; 2) cataplexy; 3) sleep paralysis; 4) hypnagogic hallucinations.

  • Excessive daytime sleepiness and associated cataplexy (sudden bilateral loss of muscle tone with preserved consciousness triggered by a strong emotional reaction such as laughter or anger) are by far the most common complaints. More often a cataplectic attack will be partial, eg involving jaw muscles (difficulty with articulation), facial muscles (grimacing), or thigh muscles (brief unlocking of the knees). Attacks vary from seconds to minutes, with a frequency of a few a year to several a day, and (very rarely) repeated ‘status cataplecticus’.
  • Other REM sleep phenomena also occur but are not necessary for the diagnosis to be made. These include sleep paralysis (sometimes up to 10 minutes long) and vivid hallucinations on falling asleep (hypnagogic) or, less commonly, waking up (hypnopompic).
  • Sleep may also be disturbed due to frequent awakenings, disturbing dreams, sleep-talking and REM-related sleep behaviors (from phasic muscle twitching to more dramatic dream enactment).
How does it affect people?

Narcolepsy may  impact seriously on your education, work, relationships, ability to drive or recreational activities and can have negative effects on self-esteem and mood.

How to cure narcolepsy?

There are, fortunately, effective treatments available for narcolepsy.

  • Daytime somnolence can be treated with stimulants (modafinil, methylphenidate, dexamfetamine). It’s possible, also, to use sodium oxybate.
  • Cataplexy is treated with TCAs (clomipramine 10–75mg/day is licensed) or SSRIs (and possibly other antidepressants: venlafaxine, nefazodone, mirtazapine, atomoxetine). These drugs may also improve your REM-related symptoms, hypnagogic/hypnopompic hallucinations and sleep paralysis. Note: abrupt withdrawal of antidepressants may potentially cause cataplectic episodes or even status cataplecticus. So, never discontinue your drugs, without consulting your physician. Sodium oxybate is newly licensed for cataplexy, is not associated with a rebound cataplexy on withdrawal but can cause significant side-effects (nausea, nocturnal enuresis, confusional arousals, headache) and there is also a danger of abuse.
  • Other treatments for poor sleep and REM-related symptoms are benzodiazepines (e.g. clonazepam) and possibly sodium oxybate are helpful.

Be aware that these drugs are not for over the counter use. Consult your doctor and he will choose the best suitable drug for you.

Besides drug treatment, some behavioral treatments are also worthwhile. The following advice may be helpful for you:

Establish good sleep habits for narcolepsy:

  1. Maintain a regular sleep schedule. Estimate how long you need to sleep and try to follow that. Most adults require 6-8 hours and teens 9-10 hours per day
  2. Develop a consistent sleep schedule
  3. Take regular daytime naps. It will help you to improve mood and alertness. A short sleep of 15-20 minutes will refresh you but don’t make it much longer. Find out the best time for a nap and stick to it
  4. Make your bedroom comfortable for sleeping. Keep TVs, computers and cell phones out of your bedroom
  5. If you wake up at night, don’t engage with your smartphone or TV. Restrict yourself from social media like Facebook
  6. Avoid caffeine in the evening
  7. Don’t take any medication without consulting your doctor. Many drugs are associated with sleep cycle interruptions

Stay active:

A boring, inactive period will make anyone sleepy. It is more harmful when you have narcolepsy. Try to keep yourself busy. Do some interesting work in your leisure time

Control your diet:

A heavy meal stimulates sleep. When you have narcolepsy, this may also provoke cataplexy. Try to keep you meal size smaller. You may increase your frequency of eating to compensate.

Get help from your family:

If your cataplexy is related to specific stimulations like laughing, joking or crying, try to avoid these situations. Discuss with your friends and family.

Remember that for any neurological disorder the success of treatment depends mostly on the patient. The doctor can only prescribe you but cure depends on your compliance to treatment.

So, try to follow any prescriptions and advice. Most importantly, establish good sleeping habits.

Have a nice sleep!

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