Narcolepsy is a chronic sleep disorder characterized by overwhelming daytime drowsiness and sudden attacks of sleep. It is a neurological disorder that affects the control of sleep and wakefulness. People with this often experience excessive daytime sleepiness and intermittent, uncontrollable episodes of falling asleep.
It is a rare disease which occurs equally in men and women and is thought to affect roughly 1 in 2000 people.
In a typical sleep cycle, we initially enter the early stages of sleep followed by deeper sleep stages of sleep followed by deeper sleep stages and ultimately rapid eye movement (REM) sleep (after about 90min). For people suffering from this, REM sleep occurs almost immediately in the sleep cycle, as well as periodically during the waking hours. It is in REM sleep that we can experience dreams and muscle paralysis- which explains some of the symptoms.
Sometimes narcolepsy can be accompanied by a sudden loss of muscle tone(cataplexy), which can be triggered by strong emotion. Narcolepsy that occurs with cataplexy is called type 1 & without cataplexy, it is called type 2 narcolepsy.
The exact cause of it is unknown. Hypocretin is an important neurochemical in the brain that helps in the regulation of wakefulness and REM sleep. People with type 1 narcolepsy have low levels of these of Hypocretin chemical. Hypocretin levels are particularly low in those who experience cataplexy. Some experts say that genetic plays an important role in the development of narcolepsy.
Research also indicates that a possible association with exposure to the swine flu (H1N1 flu) virus and certain form of H1N1 vaccine.
There are only few risk factors for narcolepsy –
AGE– Narcolepsy usually begins in people between ages of 10 and 30yrs.
Family history– Risk of narcolepsy increases to 20 to 40 times if you have a family history of narcolepsy.
The symptoms of narcolepsy are often referred as the “tetrad of narcolepsy” are cataplexy, sleep paralysis, hypnagogic hallucinations, and excessive daytime sleepiness.
Type 2 CATAPLEXY
Cataplexy is an episodic loss of muscle function ranging from sagging facial muscles, weakness at the knees, inability to speak clearly to a complete body collapse. Cataplexy is uncontrollable and is triggered by intense emotions. Usually positive ones such as laughter or excitement, but sometimes fear, surprise or anger.
Some people with narcolepsy experience only one or two episodes of cataplexy a year, while others have numerous episodes daily.
Hypnagogic hallucinations are often vivid and frightening, dreamlike experiences that occur while dozing or falling sleep. These hallucinations may manifest in the form of visual or auditory sensations.
This is an inability to move or speak while falling asleep, sleeping or walking. Episodes last only a few minutes. Sleep paralysis mimics the type of temporary paralysis that normally occurs during a period of sleep called rapid eye movement(REM) sleep.
EXCESSIVE DAYTIME SLEEPINESS
Patients fall asleep without warning anytime. They may also experience decreased alertness and focus throughout the day.
Many people with narcolepsy also suffer from insomnia for extended periods of time.
The excessive daytime sleepiness and cataplexy often become severe enough to cause serious problems in persons social, personal and professional life.
Your doctor may make a preliminary diagnosis based on your excessive daytime sleepiness and sudden loss of muscle tone(cataplexy).
A physical exam and exhaustive medical history are essential for proper diagnosis of narcolepsy. Two tests that are essential for proper diagnosis of narcolepsy are the POLYSOMNOGRAM(PSG) and the multiple sleep latency test (MSLT).
A PSG can help reveal weather REM sleep occurs at abnormal times in the sleep cycle and can eliminate the possibility that an individual’s symptoms result from another condition.
MSLT is performed during the day to measure a person’s tendency to fall asleep and to determine whether isolated elements of REM sleep intrude at inappropriate times during the waking hours.
There is no cure for narcolepsy, but medications and lifestyle modifications can help you manage the symptoms.
STIMULANTS – Drugs that stimulate CNS (Central nervous system) are the primary treatment to help people stay awake during the day. Doctors often try modafinil(Provigil) or armodafinil(Nuvigil) first for narcolepsy.
Modafinil and armodafinil aren’t as addictive as older stimulants and don’t produce the highs and lows often associated with older stimulants. Some people need treatment with methylphenidate (Addwize, Inspiral, Concerta 18mg)
Side effects include- Headache
– Nausea & Anxiety
Selective serotonin reuptake inhibitor(SSRIs) or Serotonin and norepinephrine reuptake inhibitors(SNRIs) –
Doctors prescribe these medications, which suppress the REM sleep, to help alleviate the symptoms of cataplexy, hypnogogic hallucinations and sleep paralysis. They include Fluoxetine (FLUDAC, FLUNIL, PRODEP) and Venlafaxine (VENLOR XR 75, VENIZ XR 75)
Side effects are- Weight gain
– Digestive problems
Tricyclic Antidepressants – These older antidepressants such as Protriptyline, Imipramine (DEPSOL, ANTIDEP 25) and Clomipramine (CLONIL 10) are effective for cataplexy.
– These older antidepressants such as Protriptyline, Imipramine (DEPSOL, ANTIDEP 25) and Clomipramine (CLONIL 10) are effective for cataplexy.
Side effects include- Dry mouths
Sodium Oxybate(XYREM) – This medication is highly effective for cataplexy. Sodium oxybate helps to improve nighttime sleep, which is often poor in people with Narcolepsy. It must be taken in two doses, one at bedtime and one upto 4hrs later.
Side effects are- Nausea
– Worsening of sleepwalking
– Bed Wetting