Excessive Daytime Sleepiness (Idiopathic Hypersomnia)

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KEY POINTS

• Excessive daytime sleepiness, called idiopathic hypersomnia (HIS), is a sleep disorder that causes you to be very drowsy during the day, even after getting 10 or more hours of sleep at night.
• Your healthcare provider may give you medicine to decrease your symptoms and help you feel more alert.
• Follow the full course of treatment prescribed by your healthcare provider. Ask your provider if there are activities you should avoid and how to take care of yourself at home.

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What is excessive daytime sleepiness?

Excessive daytime sleepiness is a sleep disorder that causes you to be very drowsy during the day, even after getting a normal amount of sleep at night or more. You often doze, nap, or fall asleep when you need or want to be awake and alert. This can be dangerous when you are driving a car or operating machinery. This disorder is also called idiopathic hypersomnia (IHS).

What is the cause?

The cause of this disorder is not completely known. It may be linked to having too much of a chemical in the brain that promotes sleep.

IHS is most common in teenagers and young adults. Your risk may be greater if another family member has it.

What are the symptoms?

Symptoms may include:

• Constant sleepiness
• Taking naps regularly and still feeling sleepy
• Long nighttime sleeping, often more than 10 hours
• Trouble waking from a long sleep and trouble waking up in the morning
• Feeling groggy and confused when you wake up
• Trouble focusing and remembering things

How is it diagnosed?

Your healthcare provider will ask about your symptoms and medical history and examine you. You may have tests to check for other possible causes of your symptoms, such as medicines or medical conditions such as narcolepsy, restless leg syndrome, or sleep apnea.

You will be asked to visit a sleep center to have tests such as:

• An overnight sleep study or polysomnogram. This test records brain waves, muscle activity and leg movements, heartbeat, and breathing while you sleep.
• Multiple sleep latency test (MSLT). This test shows how quickly you fall asleep during the daytime. For the MSLT, you will be asked to take several short naps during the daytime test period.

How is it treated?

Your healthcare provider may give you medicine to decrease your symptoms and help you feel more alert.

How can I take care of myself?

Follow the full course of treatment prescribed by your healthcare provider. In addition:

• Keep regular sleep times, including scheduled naps.
• If you are sleepy, then you should not drive.
• Avoid medicines such as sedatives or some antihistamines that may cause sleepiness, including nonprescription and prescription sleeping pills.
• Avoid alcohol.
• Ask your provider:
  • How and when you will get your test results
  • If there are activities you should avoid
  • How to take care of yourself at home
  • What symptoms or problems you should watch for and what to do if you have them

Make sure you know when you should come back for a checkup. Keep all appointments for provider visits or tests.

You can get more information from:

• National Sleep Foundation
  703-243-1697
  https://sleepfoundation.org/