Idiopathic Hypersomnia

1 What is Idiopathic Hypersomnia?

Idiopathic hypersomnia is characterized by abnormal sleep patterns.

The main symptom of Idiopathic hypersomnia is pervasive daytime sleepiness despite adequate, or more typically, extraordinary sleep amounts (e.g., > 10 hours per night).

Additional symptoms and complaints commonly include unrefreshing or non-restorative sleep, and sleep inertia and sleep drunkenness (difficulty awakening from sleep, accompanied by feelings of grogginess and disorientation upon awakening).

Symptoms usual start in the mid-to-late teens or early twenties, although it can begin at a later age. Symptom intensity often varies between weeks, months, or years, sometimes worsen just prior to menses in women, and can spontaneously remit in 10-15% of patients.

Sleep is usually described as “deep” and arousal from sleep is usually difficult, often requiring multiple alarm clocks and morning rituals to ensure that patients arise for school or work.

In contrast to the short and generally refreshing daytime naps observed in genuine narcolepsy, those in IHS patients can be very long – on the scale of hours – and are unrefreshing.

Some patients exhibit hypersensitivity to sedating medications such as anesthetics, sleeping pills, or alcohol.

2 Symptoms

The main symptom of Idiopathic hypersomnia is pervasive daytime sleepiness despite adequate, or more typically, extraordinary sleep amounts (e.g., > 10 hours per night).

Those who suffer from idiopathic hypersomnia have recurring episodes of excessive daytime sleepiness (EDS). These occur in spite of "adequate, or more typically, extraordinary sleep amounts (e.g., greater than 10 hours per night)."

Sleep is usually deep, with significant difficulty arousing from sleep, even with use of several alarm clocks. In fact, patients with IH often must develop elaborate rituals to wake, as alarm clocks and even physical attempts by friends/family to wake them may fail.

Despite getting more hours of sleep than typically required by the human body, patients awake unrefreshed and may also suffer sleep inertia, known more descriptively in its severe form as sleep drunkenness (significant disorientation upon awakening).

Daytime naps are generally very long (up to several hours) and are also unrefreshing, as opposed to the short refreshing naps associated with narcolepsy. Sleep paralysis and hypnagogic hallucinations may also be seen, and these symptoms are as common in idiopathic hypersomnia as they are in narcolepsy without cataplexy.

Other symptoms include palpitations, digestive problems, difficulty with body temperature regulation, and cognitive problems, especially deficits in memory, attention, and concentration. Anxiety and depression are often increased in idiopathic hypersomnia, most likely as a response to chronic illness.

Peripheral vascular symptoms, such as cold hands and feet (Raynaud’s-type phenomena) are quite common. In addition to difficulty with temperature regulation and Raynaud’s type symptoms.

Symptoms associated with autonomic dysfunction include: fainting episodes (syncope); dizziness upon arising (orthostatic hypotension); and headaches (possibly migrainous in quality).

Food cravings and impotence can also be associated. In addition, some patients exhibit hypersensitivity to sedating medications such as anesthetics, sleeping pills, or alcohol.

Symptom intensity often varies between weeks, months, or years, and symptoms can worsen just prior to menses in women.

Many patients are chronically tardy to work, school or social engagements and, over time, may lose the ability to function in family, social, occupational or other settings altogether.

3 Causes

The exact cause of idiopathic hypersomnia is unknown.

IH is a disorder of the nervous system in which there often appears to be over production of a small molecule that acts like a sleeping pill (e.g., a sedative-hypnotic drug), or anesthetic (e.g., propofol).

Although the exact composition of this small molecule is yet to be determined, much is known about how it interacts with γ-aminobutyric acid (GABA), a principal player in the brain mechanisms that promote sleep.

In the presence of this substance, the inhibitory and sleep promoting actions of GABA are enhanced at the receptors at which it acts.

4 Making a Diagnosis

Because idiopathic hypersomnia is rare and has similar symptoms to other sleep disorders, properly diagnosing it can prove difficult.

Your primary care physician or sleep specialist will usually rate the severity of your EDS symptoms on the Epsworth Sleepiness Scale before asking you to partake in a sleep study. They will also want to know whether your EDS or prolonged nighttime sleep has been occurring. For an IH diagnosis the symptoms have to have been recurrent for at least 3 months.

The second step is to have an overnight polysomnogram (PSG) study performed at a sleep clinic. This sleep study is used to rule out other potential sleep disorders that may be causing EDS such as obstructive sleep apnea and periodic leg movement disorder.

During a PSG, the patient is hooked up to several electrodes that monitor brain activity, eye movement, heart rate, blood pressure, body movement, and more.

After a PSG is performed a follow up multiple sleep latency test (MSLT) is conducted, usually the next day. The MSLT measures the same functions as the PSG, but it is conducted during the day through a series of five 20 minute naps spaced 2 hours apart.

During these nap opportunities, the patient's sleep onset latency and sleep onset REM periods (SOREMPs) are measured.

Sleep onset latency is the time it takes a person to transition from wakefulness to sleep. A normal person's sleep latency is between 5-20 minutes, while a patient suffering from idiopathic hypersomnia is slightly shorter than usual at 8 minutes or less.

Sleep onset REM periods measure how fast a person transitions from wakefulness to the REM cycle of sleep. For most people, the first cycle of REM sleep takes 70-90 minutes to enter.

How is idiopathic hypersomnia distinguished from narcolepsy?

The MSLT is used to differentiate narcolepsy from IH. Narcolepsy type I is usually easily distinguishable because it often has cataplexy associated with it. When cataplexy is not present (as with narcolepsy type II), the MSLT helps distinguish between the two primarily by sleep onset latency and sleep onset REM periods.

In patients with narcolepsy and idiopathic hypersomnia, sleep onset latency occurs quicker than in most other people. However, most patients with narcolepsy (about 80%) have a much shorter sleep onset latency of 5 minutes or less.

Patients with narcolepsy also experience rapid sleep onset REM periods. Often, if the patient also has sleep paralysis this can occur almost immediately, but generally narcoleptics enter REM in under 15 minutes. Sufferers of IH however, usually have normal sleep onset REM periods of 70-90 minutes.

If the results do not paint a clear picture (e.g., there is a compelling history of excessive sleep, sleepiness, or slowed reaction times, but a normal or ambiguous MSLT result), diagnosis can be clarified with a lumbar puncture to obtain cerebrospinal fluid (CSF) in order to measure hypocretin (to test for narcolepsy with cataplexy), and determine to what extent a patient’s CSF might enhance GABA receptor function in human cells grown in a petri dish in the laboratory (thought to underlie many cases of idiopathic hypersomnia and narcolepsy without cataplexy).

5 Treatment

Currently there is no cure for idiopathic hypersomnia. While IH is similar in some aspects to narcolepsy and some of the treatments for narcolepsy can be used for IH, there are no FDA approved prescription medications for IH. Many of the prescription medications for narcolepsy are used "off label."

Most of the treatments focus on the symptom of EDS, and there is no prescribed treatment for other symptoms such as sleep drunkenness or cognitive dysfunction.

Management of symptoms of IH usually involves sleep hygiene techniques and some medications.

Sleep Hygiene:

Sleep hygiene are general practices that are encouraged for nearly all people to avoid sleep difficulty. While not exactly a treatment for IH, many of the practices of sleep hygiene can still prove helpful.

  • Keep a consistent sleep schedule. Go to sleep and wake up at the same times every day, including weekends.
  • Avoid caffeine and alcoholic beverages if taking amphetamine based medications.
  • Talk to others about your condition. Having the love and support from those close to you can go a long way in treatment. Furthermore, your coworkers, employers, and teachers should also be aware of your condition to help accommodate your needs. Support groups can also be helpful in connecting with others suffering from the same condition. At support groups you can also learn about the latest developments in medicine, get coping tips from others, other practical help, and even emotional support.
  • Don't over extend yourself. The best advice for sufferers of IH is to ""not extend yourself too much or push yourself to do more than is realistic. We should all listen to our bodies and sleep when we know we should. The only difference for someone with IH is that we are not capable of achieving as much in a day as an average person.""

Drug Treatments:

Stimulant medications used to treat narcolepsy are often used to treat IH. These stimulants include adderall, modafinil, nuvigil, armodafinil, dextroamphetamine, and methylphenidate (Ritalin). These stimulants help promote wakefulness during the day to combat the symptoms of EDS.

The largest problem for sufferers of IH is that they live in a near constant state of never feeling completely awake. Constantly feeling sedated can negatively impact lives. Performances at work and school, troubles with social and family lives, and even the dangers of driving or operating machinery, are all hardships for sufferers of IH.

6 Prevention

Because the cause of idiopathic hypersomnia is unknown, it is not known how to prevent the condition from occurring.

If you suspect that you have idiopathic hypersomnia, you should contact your doctor and follow your doctor’s treatment plan.

Your doctor can help identify safety precautions for your lifestyle to help prevent injury during your daily activities.

7 Lifestyle and Coping

In some cases, you can help yourself with your idiopathic hypersomnia by making some simple changes in your lifestyle. Always check with your doctor first, but here are some tips:

  • Changes in behavior (for example avoiding night work and social activities that delay bed time) and diet may offer some relief. Patients should avoid alcohol and caffeine.
  • Go to bed at a set time each night and get up at the same time each morning.
  • Try to exercise 20 to 30 minutes a day.
  • Daily exercise often helps people sleep, although a workout soon before bedtime may interfere with sleep. For maximum benefit, try to get your exercise about four to five hours before going to bed.
  • Smokers tend to sleep very lightly and often wake up in the early morning due to nicotine withdrawal. Alcohol robs people of deep sleep and REM sleep and keeps them in the lighter stages of sleep.
  • A warm bath, reading, or another relaxing routine can make it easier to fall sleep. Sleep until sunlight.
  • Maintain a comfortable temperature in the bedroom. Extreme temperatures may disrupt sleep or prevent you from falling asleep.
  • If you have trouble falling asleep night after night, or if you always feel tired the next day, then you should see a physician.

8 Risks and Complications

There are several risks and complications associated with idiopathic hypersomnia.

Accidents may occur as a result of individuals falling asleep while driving. Individuals deprived of sleep may eat more and exercise less, which can lead to obesity.

A rise in the pressure inside the blood vessels of the lungs (pulmonary hypertension) can develop in individuals with sleep apnea.

Higher carbon dioxide and lower oxygen levels in the blood at night may increase the risk of high blood pressure, stroke, heart attack, heart failure, diabetes, and kidney failure.

Sleep apnea may affect higher brain functions such as memory and concentration. It may also cause headaches and irregular menstrual periods in females.

Psychological and social dysfunction in all aspects of life is common in individuals with narcolepsy.

Other complications include depression, headaches, injury caused by sudden falls, and stimulant dependence or abuse.

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