什麼是發作性嗜睡病 (又名渴睡症、猝睡症)?

Overview

What is narcolepsy?

Narcolepsy is a sleep disorder that causes an almost overwhelming onset of falling asleep during the day. Although there is no cure for narcolepsy, lifestyle changes and medication may help . This disorder is incurable and causes serious disruptions in your life, ability to work, and social relationships. Many student patients are often mistaken as naughty students and thus do not receive the attention and treatment they deserve. Adult patients are prone to misinterpret the symptoms of this disease into stress or lack of sleep. The word "narcolepsy" comes from the French term narcolepsie , the Greek νάρκη (narkē) meaning "numbness" and λῆψις (lepsis) meaning "attack" .

What are the symptoms of narcolepsy?

There are four main symptoms of narcolepsy, but most people with the condition don't have all four. The four symptoms are:

  • Excessive daytime sleepiness . Everyone with narcolepsy experiences this symptom. People with narcolepsy and experts who study the disease often describe them as "sleep attacks." The patient suffered from severe sleep deprivation throughout his life. Patients are unable to experience the restorative deep sleep that normal people experience, and sufferers remain in a state of extreme sleep deprivation throughout their lives.
  • Sudden muscle weakness (cataplexy) . This may have a mild effect, affecting one side of the body or just mild muscle weakness.
  • Sleep-related hallucinations . These occur after falling asleep or before waking up.
  • Sleep paralysis . When you have this symptom, you wake up (sometimes fully, but not always) but find yourself unable to move.

More about cataplexy

There are two main types of narcolepsy, and whether you have cataplexy distinguishes the two types. The two types are:

  • Narcolepsy type 1 : This form involves cataplexy. About 20% of narcolepsy cases are type 1.
  • Narcolepsy type 2 : This form does not involve cataplexy. Most cases of narcolepsy (about 80%) are type 2.

Under normal circumstances, your brain shuts down most of your body's muscle control to prevent you from acting while dreaming. People with cataplexy experience sudden muscle weakness, similar to what happens when the body blocks movement during REM sleep.

Mild cataplexy may affect only your face and neck (such as your jaw dropping involuntarily) or only one side of your body. Severe cataplexy can cause you to fall to the ground, resulting in injury. These episodes usually last less than a few minutes, but you may not be able to move or speak at all during this time.

Cataplexy occurs because certain emotions cause it. Positive emotions are most likely to trigger cataplexy, especially laughter, joking, or other humor-related behaviors. Surprise, fear, and anger can also trigger cataplexy.

The form of cataplexy may be slightly different in children and in people who started experiencing symptoms within the past six months. For them, cataplexy may look like a sudden, uncontrollable grimacing or frowning, tongue sticking out, or general loss of muscle tone (making muscles feel tender and limbs "flabby"), with no mood-related cause.

More information about sleep paralysis

Your brain will shut down your body's muscle control to prevent you from achieving your dreams, but this should end when you wake up. However, if you have sleep paralysis, your body is unable to regain the muscle control it should have. You can still breathe and move your eyes, but you can't speak or move other parts of your body.

Hallucinations during sleep paralysis are common, often vivid, and downright scary. Fortunately, sleep paralysis is usually short-lived, lasting only a few minutes at most (although people with the condition often describe feeling like it lasts longer).

Other symptoms

In addition to the four main symptoms, there are a number of other symptoms or behaviors that are common in people with narcolepsy. Some of the more common or easily noticed behaviors include:

  • Automatic action . People with narcolepsy can usually fall asleep but may constantly move parts of their body, such as their hands.
  • Amnesia or forgetfulness . People with this disorder often cannot remember what they did before falling asleep.
  • Sudden onset of sleep attacks . People with narcolepsy may suddenly speak and utter words (usually words or phrases that make no sense or have nothing to do with what is going on around them). When someone with narcolepsy does this, they may wake up with a start and become fully conscious, but most people who do this also don't remember doing it.

Who does narcolepsy affect?

Healthcare providers typically diagnose narcolepsy in people between the ages of 5 and 50. However, the disease is most likely to appear in young people in their late teens and early 20s. Men who are male are at higher risk of developing narcolepsy.

How common is narcolepsy?

The National Organization for Rare Disorders reports that approximately 1 in 2,000 people may have narcolepsy. Other researchers estimate that about 20 to 55 people per 100,000 people worldwide may have the disease. . However, due to the hidden nature of the disease, many patients are not diagnosed , or it often takes years to be diagnosed, so the actual number of patients is difficult to estimate.

How does narcolepsy affect my body?

Understanding narcolepsy requires understanding more about how the human sleep cycle works. This cycle involves the following stages:

  • Stage one : light sleep. This brief phase begins immediately after you fall asleep and accounts for about 5% of your total sleep time.
  • Stage 2 : deep sleep. This stage is deeper and takes up about 45 to 50 percent of your sleep time (this number rises as you age).
  • Stage 3 : Slow wave sleep. This stage accounts for about 25% of your sleep time (this number decreases with age). Waking someone from stage 3 sleep is very difficult, and waking directly from stage 3 sleep often results in "sleep inertia," a state of "mental fog" and slowed thinking. This is also the stage where sleepwalking or sleep talking often occurs.
  • REM sleep : REM stands for “rapid eye movement.” This stage is when you are dreaming. When a person is in REM sleep, you can see their eyes moving under their eyelids.

If you don't have narcolepsy, you'll usually enter stage one as you fall asleep, then move on to stages two and three. You will cycle between these stages, eventually entering REM sleep and starting to dream. After the first REM cycle, you start a new cycle and return to phase 1 or 2. One cycle usually takes about 90 minutes before another cycle can begin. Most people experience four to five cycles per night (assuming they have a full eight hours).

If you have narcolepsy, your sleep cycle doesn't work this way. Instead, you enter the REM stage shortly after you fall asleep. During the rest of the night, you only sleep for short periods of time and typically don't go through a typical sleep cycle.

With narcolepsy, no matter how well you sleep at night, you will feel extremely sleepy during the day. The urge to fall asleep is often overwhelming, but daytime sleep is short (about 15 to 30 minutes). Once you wake up, you'll feel well-rested and ready to continue whatever you were doing. However, this can happen several times during the day, which is why narcolepsy is so devastating.

symptoms and causes

What are the causes of narcolepsy?

The cause of narcolepsy depends on the type of narcolepsy itself. However, they are all related to the hypothalamus, a specific region of the brain that helps regulate sleep and wake times.

narcolepsy type 1

In 1998, researchers discovered orexin, a chemical molecule produced by certain neurons (brain cells) and used for communication. The neurons that use orexin are located in a part of the brain called the hypothalamus, and these neurons are key to keeping you awake.

Orexin (sometimes called hypocretin) is a molecule produced by neurons that is typically detected in cerebrospinal fluid (CSF), the thin layer of fluid that surrounds and cushions the brain and spinal cord. However, orexin levels in the cerebrospinal fluid of patients with narcolepsy are very low or even undetectable. This means that the cells that produce orexin have stopped working or have been damaged by something.

Based on further research, the most likely reason these neurons stop working is an autoimmune issue. This means your immune system attacks the neurons that produce and use orexin, the orexin itself, or both.

About 90 to 95 percent of people with narcolepsy type 1 have a specific genetic mutation that affects the immune system (the mutation's identifier is HLA-DQB1*06:02). However, about 25% of people also have this mutation but do not have narcolepsy. As a result, experts rarely test the mutation, and they aren't sure what role it plays. There is also some evidence that the disorder runs in families, as having a first-degree relative (parent, sibling, or child) with narcolepsy puts you at higher risk of developing narcolepsy.

However, people can also develop narcolepsy type 1 after certain viral and bacterial infections, especially the H1N1 influenza strain and the bacteria that cause strep throat. Experts suspect this is because infections sometimes trigger changes and dysfunction in the immune system.

narcolepsy type 2

While experts know a lot about what causes narcolepsy type 1, that's not the case with narcolepsy type 2. Experts still don't fully understand why narcolepsy type 2 occurs. But they suspect it happens for similar reasons. These include less severe losses of neurons that use orexin or problems with how orexin travels through the brain.

secondary narcolepsy

In rare cases, damage to the hypothalamus may cause narcolepsy. Head injuries (such as concussions and traumatic brain injuries), strokes, brain tumors, and other conditions can cause this damage.

Narcolepsy may also be a feature of an unrelated condition that you inherit. Examples of this include:

  • Autosomal dominant cerebellar ataxia, narcolepsy, and deafness (ADCADN).
  • Autosomal dominant narcolepsy, type 2 diabetes, and obesity.

Is narcolepsy contagious?

Narcolepsy is not contagious.

Diagnosis and testing

How is narcolepsy diagnosed?

Healthcare providers can suspect narcolepsy based on your symptoms. However, narcolepsy shares symptoms with several other brain and sleep-related disorders. Therefore, the only way to conclusively diagnose narcolepsy is with specialized diagnostic testing.

Before doing most major tests for narcolepsy, your healthcare provider will first make sure you're getting enough sleep. This often involves simple sleep-wake pattern tracking methods, such as actigraphy. This typically uses a watch-like device worn on your wrist to track movement patterns (for example, when you sleep versus when you get up and move around).

What tests are needed to diagnose narcolepsy?

Some possible tests to diagnose narcolepsy include:

  • Sleep study (polysomnography).
  • Multiple Sleep Latency Test (MSLT).
  • Sustained sobriety test.
  • Spinal tap (lumbar puncture).

Sleep study (polysomnography)

Sleep studies involve many types of sensors to track your sleep. A key part of a complete sleep study (formally called a polysomnogram) is that it includes an electroencephalogram (EEG) sensor. These sensors track your brain waves, allowing healthcare providers to know which stage of sleep you are in at any time.

A sleep study can help diagnose narcolepsy because people with the disorder enter the REM sleep stage much faster than people without the disorder. Their sleep can also be interrupted by periods of wakefulness, which can also be detected and recorded by sleep studies.

Another key reason to do a sleep study is that excessive daytime sleepiness is also a primary symptom of sleep apnea. A sleep study can rule out sleep apnea.

Multiple sleep latency tests

This test involves testing whether you fall asleep easily during the day. The test involves timed naps that occur within a specific time frame. This test can help determine whether a person has excessive daytime sleepiness, which is a necessary symptom of narcolepsy. This test is usually performed the day after an overnight sleep study.

Sobriety test

This test determines whether you can stay awake during the day, even if you fall asleep easily. While it's less common in narcolepsy testing, it's still possible and can rule out other problems. It is also useful for testing whether stimulant treatments are helpful.

spinal tap (lumbar puncture)

This test can help determine if orexin levels are low in the cerebrospinal fluid. This is the key to diagnosing narcolepsy type 1. Low orexin levels may also indicate that someone with narcolepsy may experience cataplexy, even if they are not yet exhibiting symptoms. Unfortunately, orexin levels don't change in people with narcolepsy type 2, so it's not always a helpful test to diagnose.

Other tests

Many other tests are also common for people with narcolepsy. An example of this happening is in the symptoms of cataplexy. Cataplexy is similar to several other motor (movement-related) symptoms of brain disorders, such as atonic seizures (also called fall attacks).

Therefore, health care providers may test for more serious conditions, such as seizures and epilepsy, first, which means it may take longer for providers to recognize and diagnose narcolepsy. Other tests are possible, and your healthcare provider is the best person to explain which tests they recommend and why.

Management and Treatment

How is narcolepsy treated? Is there a cure?

Narcolepsy can be managed with treatment, but it cannot be cured. Treatment usually starts with medication, but daily routine and lifestyle changes can also help.

What medications or therapies are used to treat narcolepsy?

Medication is the mainstay of treatment for narcolepsy. Most medications target excessive daytime sleepiness, but some target other symptoms as well. Possible medications for this condition include:

  • Sobriety drugs . These are usually the first line of treatment. Examples of these drugs include modafinil and armodafinil. These medications stimulate your nervous system and help reduce the severity or frequency of daytime sleepiness.
  • Amphetamines and amphetamine-type stimulants . Drugs such as methylphenidate (better known by several trade names, including Ritalin®, Concerta®, or Qullivant®) or the amphetamine/dextroamphetamine combination (better known by the trade name Adderall®).
  • Antidepressants . Medications, such as serotonin norepinephrine reuptake inhibitors (SNRIs), such as venlafaxine (commonly known by the trade name Effexor®), selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine (better known as Prozac®), or a tricyclic antidepressant such as clomipramine or protriptyline (but these are less common).
  • Sodium oxybate . This medication can help you sleep and may also reduce the frequency of cataplexy. Due to its effects, this drug is tightly controlled in most countries, but it is still frequently used to treat narcolepsy type 1.
  • Drugs that affect histamine . An example of such a drug is pitolisant, a histamine receptor antagonist. Receptor antagonists are drugs that prevent specific chemicals in the body from attaching to cells. This slows down or prevents cells from doing certain things.

While there are many treatment options for narcolepsy in adults, treatment options for children are very limited. Your child's pediatrician or specialist is the best person to tell you about the treatment options available or what they recommend.

Complications/side effects of narcolepsy treatment

Many medications used to treat narcolepsy or its symptoms are more likely to interact with other medications. High blood pressure and irregular heartbeats are just two complications that can arise from any stimulant medication. Sodium oxybate is especially dangerous if combined with other drugs that depress the work of the central nervous system, and it should never be mixed with alcohol.

Generally speaking, your healthcare provider is the best person to tell you what side effects, complications, or drug interactions to watch out for or avoid. They can tailor messages to your specific circumstances and circumstances, taking into account your health history and personal circumstances.

How can I take care of myself or manage my symptoms?

You should not try to self-diagnose and self-treat narcolepsy. This is because symptoms of this disease often occur at the same time as other conditions, such as sleep apnea or epilepsy, which can also be dangerous. This condition can also make certain activities, such as driving or swimming, dangerous, so you should always see a health care provider for diagnosis and treatment.

How soon after treatment will I feel better and how long will it take to recover from treatment?

Recovery time, or the time it takes to feel the effects of narcolepsy treatment, depends on many factors. Your healthcare provider is the best person to tell you what to expect in your case, including a timetable for when you should see effects of the medication or changes in symptoms.

Other possible treatments

prevention

How can I reduce my risk of narcolepsy or prevent narcolepsy?

In almost all cases, the onset of narcolepsy is unpredictable. Therefore, it is not possible to reduce the risk of developing the disease or prevent it from occurring.

Outlook/Forecast

What happens to me if I have narcolepsy?

Narcolepsy itself is usually not dangerous, but the sudden, irresistible need to sleep can be very disruptive. People with this condition may be unable to drive (either temporarily or permanently, depending on their specific symptoms and circumstances).

While narcolepsy is not usually dangerous, narcolepsy type 1 does increase the risk of injury from falls when cataplexy is severe. Narcolepsy can also cause dangerous situations while driving, using power tools or heavy equipment, swimming, and more.

narcolepsy in children

Children with narcolepsy often struggle with the effects of the condition. Daytime sleepiness can make it difficult to concentrate in school, maintain social relationships, and participate in school and non-school activities.

However, narcolepsy is a disease. Because of this, children with narcolepsy are often protected by law, which requires schools to provide suitable accommodation. Some examples include adjusting class schedules, scheduling naps or breaks, and taking medications during school hours. Your child's pediatrician or other specialist can help you address this issue and find solutions that can help your child.

Sleepiness in working adults

Just as there are legal protections for children in schools, adults with narcolepsy are often protected by the law for this reason. The Americans with Disabilities Act prohibits discrimination against someone in the United States because of a medical condition, including narcolepsy.

This legal protection means people with narcolepsy can often enter into accommodation agreements with their employers, allowing them to have a career while managing their condition.

How long does narcolepsy last?

Once you have narcolepsy, it is permanent, making it a lifelong condition. However, it doesn't get worse as time goes on.

What’s the future for narcolepsy?

Narcolepsy itself is not dangerous, but it can make it difficult to go to certain places or do certain activities. It can also disrupt school, work and other common parts of life. Although treatment is not always completely effective, most cases of narcolepsy respond to treatment.

Living with narcolepsy

How do I take care of myself?

If you suffer from narcolepsy, there are a number of things you can do to help control the condition and make treatment more effective. Most of these relate to maintaining good sleep hygiene or otherwise adjusting your schedule and daily routine, including actions such as:

  • Be consistent with your sleeping habits . Sticking to a sleep schedule can improve the quality of your sleep.
  • Make time for sleep . Set a bedtime that allows you to get the recommended amount of sleep for your age. You should also schedule some time to relax before bed.
  • Limit time in bright lights or using electronics . Light that is too close to bedtime can disrupt the body's natural sleep-wake function.
  • Avoid alcohol or caffeine, smoking, or eating before bed . If you feel hungry before bed, eating a snack is your best option. You should avoid alcohol altogether if you take certain medications (your healthcare provider can tell you if they have prescribed any of these medications for you). Experts also strongly recommend quitting smoking cessation products (including e-cigarettes and smokeless tobacco) altogether.
  • Stay physically active . Staying active, even just for a walk, can help improve the quality of your sleep.
  • Take a nap People with narcolepsy often feel better after taking a nap. Once you figure out the times of day when you're sleepiest, adjust your schedule so that naps at these times can help.

Avoid hazardous activities or take precautions when performing these activities

Narcolepsy can lead to serious or even fatal car accidents. To ensure your own safety and the safety of those around you, you should never drive unless your health care provider specifically gives you permission to drive.

If you notice narcolepsy while driving, you should stop driving completely and contact your healthcare provider. While this can be an inconvenience under the best of circumstances, it is also critical to avoiding the fatal or life-changing consequences of a car accident caused by falling asleep at the wheel.

Another key area where narcolepsy poses specific dangers is in the water. If you suffer from narcolepsy, it is important to wear a life jacket when swimming or on any boat or vessel where life jackets are recommended. Without a life jacket or life jacket, sleep attacks in the water can have fatal consequences.

When should I see my health care provider?

Falling asleep suddenly for no expected reason is a sign that you need to see a health care provider. All of these are symptoms of many conditions, not just narcolepsy, and some of them are serious. As with many of these conditions, the longer you wait for diagnosis and treatment, the more likely you are to face complications or that treatment will be less effective.

When should I go to the emergency room?

If you collapse or pass out unexpectedly, you should seek medical care at a hospital or emergency room. This is a key symptom of many illnesses, including heart attacks, strokes, irregular heartbeats, and more. These situations are medical emergencies and require immediate attention.

Falling or passing out unexpectedly can also put you at risk for injury from a fall. If you have a possible injury to your head, neck, or any part of your back and spine, you should seek medical attention immediately. Fractures and injuries to the spinal cord of any degree can result in permanent damage, paralysis, or even death.

You should also seek medical attention if you fall and are taking any type of blood-thinning medication, especially if you hit your head. Falls and injuries pose a dangerous risk of internal bleeding, and you'll need medical attention to make sure you don't suffer injuries that could lead to life-threatening complications.

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