Narcolepsy

Narcolepsy

Overview

Narcolepsy is a condition that makes people very sleepy during the day and can cause them to fall asleep suddenly. Some people also have other symptoms, such as muscle weakness when they feel strong emotions.

The symptoms can have serious effects on daily life. People with narcolepsy have trouble staying awake for long periods of time. When narcolepsy causes a sudden loss of muscle tone, it is known as cataplexy (KAT-uh-plek-see). This can be triggered by a strong emotion, especially one that causes laughter.

Narcolepsy is divided into two types. Most people with type 1 narcolepsy have cataplexy. Most people with type 2 narcolepsy don't have cataplexy.

Narcolepsy is a lifelong condition and does not have a cure. However, medicines and lifestyle changes can help manage the symptoms. Support from family, friends, employers and teachers can help people cope with the condition.

Symptoms

The symptoms of narcolepsy may get worse during the first few years. Then they continue for life. Symptoms include:

Extreme daytime sleepiness. Daytime sleepiness is the first symptom to appear, and the sleepiness makes it hard to focus and function. People with narcolepsy feel less alert and focused during the day. They also fall asleep without warning. Sleep can happen anywhere and at any time. It may happen when they are bored or while doing a task. For example, people with narcolepsy can suddenly fall asleep while working or talking with friends. It can be especially dangerous to fall asleep while driving. Sleep may last only a few minutes or up to a half-hour. After waking, people with narcolepsy feel refreshed but get sleepy again.

Automatic behaviors. Some people with narcolepsy continue doing a task when they fall asleep briefly. For example, they may fall asleep while writing, typing or driving. They might continue to perform that task while asleep. After waking, they can't remember what they did, and they probably didn't do it well.

Sudden loss of muscle tone. This condition is called cataplexy. It can cause slurred speech or complete weakness of most muscles for up to a few minutes. It's triggered by intense emotions — often positive emotions. Laughter or excitement may cause sudden muscle weakness. But sometimes fear, surprise or anger can cause the loss of muscle tone. For example, when you laugh, your head may drop without your control. Or your knees may suddenly lose strength, causing you to fall. Some people with narcolepsy experience only one or two episodes of cataplexy a year. Others have several episodes a day. Not everyone with narcolepsy has these symptoms.

Sleep paralysis. People with narcolepsy may experience sleep paralysis. During sleep paralysis, the person can't move or speak while falling asleep or upon waking. The paralysis is usually brief — lasting a few seconds or minutes. But it can be scary. You may be aware of it happening and can recall it afterward. Not everyone with sleep paralysis has narcolepsy.

Hallucinations. Sometimes people see things that aren't there during sleep paralysis. Hallucinations also may happen in bed without sleep paralysis. These are called hypnagogic hallucinations if they happen as you fall asleep. They're called hypnopompic hallucinations if they happen upon waking. For example, the person might think they see a stranger in the bedroom who isn't there. These hallucinations may be vivid and frightening because you may not be fully asleep when you begin dreaming.

Changes in rapid eye movement (REM) sleep. REM sleep is when most dreaming happens. Typically, people enter REM sleep 60 to 90 minutes after falling asleep. But people with narcolepsy often move more quickly to REM sleep. They tend to enter REM sleep within 15 minutes of falling asleep. REM sleep also can happen at any time of the day.

Other sleep symptoms

People with narcolepsy may have other sleep conditions. They might have obstructive sleep apnea, in which breathing starts and stops during the night. Or they may act out their dreams, known as REM sleep behavior disorder. Or they may have trouble falling asleep or staying asleep, called insomnia.

Causes

The exact cause of narcolepsy is not known. People with type 1 narcolepsy have low levels of hypocretin (hi-poe-KREE-tin), also called orexin. Hypocretin is a chemical in the brain that helps control being awake and entering REM sleep.

Hypocretin levels are low in people who have cataplexy. Exactly what causes the loss of hypocretin-producing cells in the brain isn't known. But experts suspect it's due to an autoimmune reaction. An autoimmune reaction is when the body's immune system destroys its own cells.

It's also likely that genetics plays a role in narcolepsy. But the risk of a parent passing this sleep condition to a child is very low — only about 1% to 2%.

Narcolepsy may be linked to exposure to the H1N1 flu, sometimes called the swine flu. It also may be linked to a certain type of the H1N1 vaccine that was given in Europe.

Typical sleep pattern vs. narcolepsy

The typical process of falling asleep begins with a phase called non-rapid eye movement (NREM) sleep. During this phase, brain waves slow. After an hour or so of NREM sleep, brain activity changes and REM sleep begins. Most dreaming occurs during REM sleep.

In narcolepsy, you may suddenly enter REM sleep after going through minimal NREM sleep. This can happen both at night and during the day. Cataplexy, sleep paralysis and hallucinations are similar to changes that occur in REM sleep. But in narcolepsy, these symptoms happen while you're awake or sleepy.

Risk factors

There are only a few known risk factors for narcolepsy, including:

Age. Narcolepsy typically begins between ages 10 and 30.

Family history. Your risk of narcolepsy is 20 to 40 times higher if you have a close family member who has it.

Complications

Narcolepsy can cause complications, such as:

Misbeliefs about the condition. Narcolepsy can affect work, school or your personal life. Others might see people with narcolepsy as lazy or sluggish.

Effects on intimate relationships. Intense feelings, such as anger or joy, can trigger cataplexy. This can cause people with narcolepsy to withdraw from emotional interactions.

Physical harm. Falling asleep suddenly may result in injury. You're at increased risk of a car accident if you fall asleep while driving. Your risk of cuts and burns is greater if you fall asleep while cooking.

Obesity. People with narcolepsy are more likely to be overweight. Sometimes weight goes up quickly when symptoms start.

Diagnosis

Your healthcare professional may suspect narcolepsy based on your symptoms of daytime sleepiness and sudden loss of muscle tone, known as cataplexy. Your healthcare professional likely will refer you to a sleep specialist. Formal diagnosis usually requires staying overnight at a sleep center for an in-depth sleep analysis.

A sleep specialist will likely diagnose narcolepsy and determine how serious it is based on:

Your sleep history. A detailed sleep history can help with a diagnosis. You'll likely fill out the Epworth Sleepiness Scale. The scale uses short questions to measure your degree of sleepiness. You'll answer how likely it is that you would fall asleep in certain times, such as sitting down after lunch.

Your sleep records. You may be asked to write down your sleep pattern for a week or two. This allows your healthcare professional to compare how your sleep pattern may relate to how alert you feel. You might wear a device on your wrist, known as an actigraph. It measures periods of activity and rest, along with how and when you sleep.

A sleep study, known as polysomnography. This test measures signals during sleep using flat metal discs called electrodes placed on your scalp. For this test, you must spend a night at a medical facility. The test measures your brain waves, heart rate and breathing. It also records your leg and eye movements.

Multiple sleep latency test. This test measures how long it takes you to fall asleep during the day. You'll be asked to take four or five naps at a sleep center. Each nap needs to be two hours apart. Specialists will observe your sleep patterns. People who have narcolepsy fall asleep easily and enter into rapid eye movement (REM) sleep quickly.

Genetic tests and a lumbar puncture, known as a spinal tap. Occasionally, a genetic test may be performed to see if you're at risk of type 1 narcolepsy. If so, your sleep specialist may recommend a lumbar puncture to check the level of hypocretin in your spinal fluid. This test is only done in specialized centers.

These tests also can help rule out other possible causes of your symptoms. Extreme daytime sleepiness also could be caused by not getting enough sleep, medicines that make you sleepy and sleep apnea.

Treatment

There is no cure for narcolepsy, but treatment to help manage the symptoms include medicines and lifestyle changes.

Medicines

Medicines for narcolepsy include:

Stimulants. Medicines that stimulate the central nervous system are the main treatment to help people with narcolepsy stay awake during the day. Your healthcare professional may recommend modafinil (Provigil) or armodafinil (Nuvigil). These medicines aren't as habit-forming as older stimulants. They also don't produce the highs and lows related to older stimulants. Side effects are not common but may include headache, nausea or anxiety.

Solriamfetol (Sunosi) and pitolisant (Wakix) are newer stimulants used for narcolepsy. Pitolisant also may be helpful for cataplexy.

Some people need treatment with methylphenidate (Ritalin, Concerta, others). Or they may take amphetamines (Adderall XR 10, Desoxyn, others). These medicines are effective but can be habit-forming. They may cause side effects such as nervousness and a fast heartbeat.

Serotonin and norepinephrine reuptake inhibitors (SNRIs) or selective serotonin reuptake inhibitors (SSRIs). These medicines suppress REM sleep. Healthcare professionals prescribe these medicines to help ease the symptoms of cataplexy, hallucinations and sleep paralysis.

They include venlafaxine (Effexor XR), fluoxetine (Prozac), duloxetine (Cymbalta, Drizalma Sprinkle) and sertraline (Zoloft). Side effects can include weight gain, insomnia and digestive problems.

Tricyclic antidepressants. These older antidepressants can treat cataplexy. But they can cause side effects such as dry mouth and lightheadedness. These medicines include protriptyline, imipramine and clomipramine (Anafranil).

Sodium oxybate (Xyrem, Lumryz) and oxybate salts (Xywav). These medicines work well at relieving cataplexy. They help improve nighttime sleep, which is often poor in narcolepsy. They also may help control daytime sleepiness.

Xywav is a newer formulation with less sodium.

These medicines can have side effects, such as nausea, bed-wetting and sleepwalking. Taking them together with other sleeping tablets, narcotic pain relievers or alcohol can lead to trouble breathing, coma and death.

If you take medicines for other health conditions, ask your healthcare professional how they may interact with narcolepsy medicines.

Certain medicines that you can buy without a prescription can cause drowsiness. They include allergy and cold medicines. If you have narcolepsy, your healthcare professional may recommend that you don't take these medicines.

Researchers are studying other potential treatments for narcolepsy. Medicines being studied include those that target the hypocretin chemical system. Researchers also are studying immunotherapy. Further research is needed before these medicines become available.

Type of Doctor Department : Sleep medicine specialists and neurologists