Narcolepsy

What is Narcolepsy?

Narcolepsy is a sleep disorder which causes sudden bouts of rapid eye movement (REM) sleep, often during the day. People with narcolepsy tend to feel extremely tired during the day, may fall asleep unexpectedly, and might have interrupted sleep. This condition can also come with other symptoms like cataplexy (sudden muscle weakness), sleep paralysis (a temporary inability to move or speak while falling asleep or waking up), and hypnagogic hallucinations (seeing, hearing, or feeling things that aren’t there when transitioning from wakefulness to sleep).

There are two kinds of narcolepsy – type 1, which includes cataplexy, and type 2 which doesn’t.

It often takes quite a long time to diagnose narcolepsy – sometimes 5 to 10 years – because its symptoms are easily misconstrued. Almost half of all people with narcolepsy start to see symptoms in their teens. This disorder can strongly affect the individual’s school and social life. However, the good news is that narcolepsy can be managed with treatment.

What Causes Narcolepsy?

Narcolepsy is a condition where people can have a sudden urge to sleep, or they might even fall asleep suddenly. There are two main types of narcolepsy: type 1 and type 2.

Narcolepsy type 1 happens when the brain loses almost all of a specific type of neuron (nerve cell) that contains orexin, which is also known as hypocretin. This chemical in your brain helps to regulate sleep. We don’t fully understand why these nerve cells disappear, but it seems to be linked to the body’s immune system, possibly because of an infection. Around 95% of people with narcolepsy type 1 have a unique pattern of particular genes (known as HLA haplotype DQB1*0602). However, this same pattern is also found in about 20% of people who don’t have narcolepsy.

The causes of narcolepsy type 2 aren’t as clear. There are a few possibilities, including fewer orexin cells being destroyed, problems with the signals these cells send out, or a process we haven’t discovered yet. Sometimes, people with type 2 narcolepsy start to develop another symptom called cataplexy, which makes them lose control of their muscles. This suggests the disease might be getting worse. In a few rare cases, physical harm or tumors can lead to narcolepsy.

In 2009 in Europe, more cases of narcolepsy type 1 were reported after people got a particular flu vaccine called Pandemrix. Initially, it was thought that the immune response to part of this vaccine, known as an adjuvant, was causing narcolepsy. The same adjuvant was used in Canada without the increase in narcolepsy cases, so this theory was questioned. Around the same time, there were also more cases of narcolepsy in people who had not been vaccinated but had caught the flu. All of this seems to suggest that narcolepsy type 1 could be an autoimmune disease, where the body mistakenly attacks its own cells.

The details surrounding how narcolepsy type 2 works are less clear, but it might be similar to type 1, just with fewer orexin cells being lost.

There are different ways to categorize narcolepsy. Some people with narcolepsy have low levels of hypocretin but don’t experience cataplexy, while others have cataplexy but normal levels of hypocretin. There are two rare types of narcolepsy linked to specific genetic conditions, one of which also involves deafness and a lack of muscle coordination, while the other also includes obesity and type 2 diabetes. Some cases of narcolepsy are triggered by a different medical condition.

Risk Factors and Frequency for Narcolepsy

Narcolepsy, a sleep disorder, can be classified into two types. Each type affects a different number of people. According to data collected between 2008 to 2010, narcolepsy type 1 affects 14 out of every 100,000 people, while type 2 of the disorder is more common, affecting 65.4 out of every 100,000 individuals. It’s important to note that narcolepsy often appears most frequently in individuals in their late teens to early twenties, and is found 50% more in women than men, especially within the U.S.

Signs and Symptoms of Narcolepsy

Narcolepsy is a sleep disorder that often starts showing signs in teenagers or those in their mid-thirties. Patients frequently experience difficulty staying awake during the day, with a progressive worsening of symptoms over a period of 15 years before diagnosis on average. The most common symptom is sudden bouts of REM sleep during the day, known as sleep attacks, that happen daily and last for at least three months.

A related symptom, cataplexy, involves a sudden weakening of muscles due to strong emotions like laughter, excitement, anger, or grief that can last a few seconds to a couple of minutes, while the patient remains conscious. However, cataplexy is not necessary for a diagnosis of narcolepsy. Another symptom called sleep paralysis happens when the patient awakes but cannot move or open their eyes, feeling like suffocating as their chest muscles are paralyzed though they can breathe normally. This can also occur in a section of the normal population.

Additionally, patients may experience hypnagogic hallucinations which are dream-like visions or feelings happening as they’re falling asleep or waking up. They often see human faces or feel like someone else is in the room. Narcolepsy patients frequently demonstrate disrupted sleep at night but find napping refreshing. Obesity, which raises the risk of developing sleep apnea, is also common amongst narcolepsy sufferers. Comprehensive physical exams are required to eliminate other possible causes of excessive sleepiness.

In children, narcolepsy may cause restlessness and motor overactivity. Parents and teachers often report inattentiveness, and some children might show symptoms like drop attacks, aggressiveness, irritability, and falling, which can be incorrectly associated with seizures.

• Experiencing symptoms at least three times weekly over the past 3 months is a prerequisite for a narcolepsy diagnosis.
• Additionally, one of the following should be present:
  • A deficiency in hypocretin, a brain chemical
  • Cataplexy episodes occurring several times monthly
  • Less than 15 minutes of REM sleep latency or, alternatively, two or more instances of sleep onset occurring in REM periods and a mean sleep latency of fewer than 8 minutes.

Testing for Narcolepsy

The first step in diagnosing narcolepsy requires you to maintain a minimum of 6 hours of sleep consistently every night for two weeks. This can be tracked using a sleep log, where you record your sleeping habits. However, research has shown that people often overestimate how much they sleep. For this reason, it’s recommended to use a device known as an actigraph, which objectively records sleep patterns, along with your sleep log. If you’re averaging less than 6 hours of sleep per night over two weeks, then narcolepsy isn’t typically considered as a possible diagnosis.

If your sleep logs and actigraph data show that you’re getting at least 6 hours of sleep per night, the next step is a sleep study known as a polysomnogram (PSG). This test is used to rule out other sleep disorders, like sleep apnea. If you get enough sleep during this test and no other sleep disorders are identified, another test called the Multiple Sleep Latency Test (MSLT) is performed the next day. During this test, you’re given four to five chances to nap, each lasting 20 minutes and spaced 2 hours apart. If you show a quick onset of REM (dream) sleep — in less than 15 minutes — at least twice during the test and fall asleep on average in less than 8 minutes, this would suggest narcolepsy. In some cases, even if this test doesn’t suggest narcolepsy, but your doctor still suspects that you have the condition based on other symptoms, the test might be repeated at a later date.

It’s crucial that before the MSLT, you’re allowed to sleep until you wake up naturally the night before during the PSG. This prevents possible misleading test results. For example, if you’re sleep-deprived the night before or the test is started too early in the day, you might fall into REM sleep quickly even though you don’t have narcolepsy. People who consistently don’t get enough sleep or shift workers who are tested during their usual sleep hours can also have similar misleading results. Therefore, thorough initial tracking of your sleep patterns using log and actigraphy is important.

Narcolepsy type 1 can also be diagnosed by checking the levels of a protein called hypocretin-1 in your brain’s spinal fluid. If the levels are low, it may suggest narcolepsy. And while most people with narcolepsy type 1 carry a specific gene called HLA DQB1*0602, testing for this gene is not typically useful because it’s also found in people without narcolepsy.

Treatment Options for Narcolepsy

Changing your behavior can help manage excessive sleepiness during the day. This can include taking quick, planned naps throughout the day and ensuring you get enough sleep at night. The first-line medical treatment for excessive sleepiness during the day involves a medication called modafinil or armodafinil. If these do not work, amphetamines might be used.

For a symptom known as cataplexy (sudden loss of muscle control), sodium oxybate is the first-line treatment. It’s important to take this medication in bed because it can make you feel sleepy very quickly (usually in 5 to 15 minutes). A second dose is taken about 2.5 to 4 hours later. Sodium oxybate is a controlled substance, but research has shown the concerns about misuse and dependency are largely unfounded. Other types of medications, such as tricyclic antidepressants and certain types of SSRIs, have also been beneficial in treating cataplexy.

Non-drug treatments may also be beneficial, like maintaining good sleep hygiene, emotional support, mental health counseling, assistance with disability forms and medications, and education about the harmful effects of alcohol and illicit drug use.

Common drugs used to treat narcolepsy include central nervous system (CNS) stimulants, though no drug is 100% effective for all patients. Methylphenidate can improve sleep, though it may also cause side effects like anxiety, headaches, and irritability. Modafinil can also help with wakefulness, but its safety for children hasn’t been established. Sodium oxybate, approved by the FDA, is the only treatment for cataplexy, but it mustn’t be mixed with other CNS depressants or alcohol. Recently, the FDA approved pitolisant for treating narcolepsy. Early studies indicate that it can improve sleep. However, so far, no medication has been approved by the FDA for use in children with narcolepsy.

What else can Narcolepsy be?

Cataplexy can often be mistaken for several other conditions, these include:

• Seizures, especially atonic seizures
• Periodic paralysis
• Syncope, caused by heart issues (cardiogenic), changes in body position (orthostatic) or nerve problems (neurogenic)
• Psychogenic conditions (mental health-related)

Excessive sleepiness during daytime can be a symptom of several disorders such as:

• Insufficient sleep syndrome or poor sleep hygiene
• Idiopathic hypersomnia (excessive sleepiness without a known cause)
• Sleep apnea syndromes (disorders causing abnormal pauses in breathing during sleep)
• Chronic fatigue syndrome
• Sleep-related movement disorders like periodic limb movement disorder, and restless leg syndrom
• Disorders affecting the body’s natural sleep-wake cycle like jet lag, shift work disorder, and non-24 hour sleep-wake disorder
• Long sleepers, who naturally need more sleep than the average person to feel well-rested
• Psychiatric conditions like depression, malingering, conversion disorder, or factitious disorder
• Substance-induced sleep disorders from drugs like narcotics, benzodiazepines, antihistamines, beta-blockers, etc.
• Kleine-Levin syndrome, a rare disorder characterized by intermittent episodes of excessive sleep
• Menstrual-related hypersomnia (excessive sleep associated with a woman’s menstrual cycle)

Hypersomnia, or excessive sleepiness, can also be a symptom of other medical conditions like Parkinson’s disease and Multiple Sclerosis.

Idiopathic hypersomnia is another condition that can be mistaken for narcolepsy. Patients with this disorder exhibit excessive daytime sleepiness and decrease in mean sleep latency (time to fall asleep), but they do not enter REM (rapid eye movement) sleep abnormally quickly. Unlike patients with narcolepsy, individuals with idiopathic hypersomnia typically fall asleep quickly, stay asleep throughout the night, do not find naps refreshing, and often experience significant sleep inertia (difficulty waking up and shaking off sleepiness in the morning).

Sleep apnea may coexist with narcolepsy in up to a third of patients. However, narcolepsy can only be diagnosed once sleep apnea has been adequately treated, usually with a therapy called CPAP (Continuous Positive Airway Pressure) for an appropriate amount of time.

What to expect with Narcolepsy

Some people diagnosed with narcolepsy type 2, a sleep disorder that causes excessive daytime tiredness, might eventually start exhibiting ‘cataplexy’ – sudden muscle weakness triggered by strong emotions. And thus, their diagnosis may change to narcolepsy type 1. Some people find their symptoms getting worse as time goes on. Though it’s rare for symptoms to get better on their own, they can usually be managed efficiently with a mix of healthy habits and prescribed medications.

Currently, medical researchers are exploring new treatments, which might include immunomodulation – changes to the body’s immune response – or usage of medications small enough to pass from the bloodstream into the brain. These medications, known as ‘orexin agonists,’ could potentially help regulate sleep.

Children with this condition often struggle with school performance and social interactions. It’s not uncommon for adults with narcolepsy to have trouble maintaining a job. Despite these challenges, many people with narcolepsy lead fulfilling lives with appropriate management of their condition.

Possible Complications When Diagnosed with Narcolepsy

People with narcolepsy frequently experience mood disorders like depression and anxiety. However, it’s not clear whether these mood issues are a direct result of the disease itself or due to the effect it has on the person’s life quality.

Preventing Narcolepsy

It’s important to talk about driving safety at each doctor’s visit, especially for people with narcolepsy, because they have a much greater chance of getting into car accidents. Staying alert during boring tasks can be extra difficult for these individuals, and this means that long drives on the highway or during heavy traffic could become dangerous. Working out guidelines for driving based on symptoms might be a good start. For example, advice might include not driving at night, keeping drives to less than 30 minutes, and taking planned naps before or during certain trips.

If sleepiness continues to be a problem, or if there has been an accident caused by sleepiness, a test known as a Maintenance of Wakefulness Test (MWT) can be done. This test measures how well you can stay awake during unstimulating situations. It involves four to five sessions of 40 minutes each where you take your usual medications, sit still in a quiet room, and try to stay awake. The results can help decide if your medications need to be changed, and give further advice about driving safely.

Additionally, people with narcolepsy should also follow these guidelines:

• Avoid taking medications that can make you more sleepy, like painkillers and allergy medications. You should also avoid eating heavy meals and drinking alcohol.
• Stick to a regular sleep schedule, mostly sleeping at night.
• Think about taking short, scheduled naps throughout the day. For example, 15 minutes at noon and another 15 minutes at 5 PM before driving home from work.
• Always take your medication as prescribed.
• Keep regular check-ups with your doctor to make sure your symptoms are being managed properly.