Welcome to the Rare Classroom, a new series from Patient Worthy. Rare Classroom is designed for the curious reader who wants to get informed on some of the rarest, most mysterious diseases and conditions. There are thousands of rare diseases out there, but only a very small number of them have viable treatments and regularly make the news. This series is an opportunity to learn the basics about some of the diseases that almost no one hears much about or that we otherwise haven’t been able to report on very often.

Eyes front and ears open. Class is now in session.

The disease that we will be learning about today is:

Idiopathic Hypersomnia

What is Idiopathic Hypersomnia?

• Idiopathic hypersomnia is characterized by excessive sleep and excessive daytime sleepiness
• It is considered a neurological disorder
• Many patients live with the symptoms of the condition long before diagnosis
• Symptoms usually become apparent in early adulthood
• The sleepiness patients experience can severely disrupt daily life
• Prevalence of idiopathic hypersomnia is unknown, but may range from 1 in 10,000 to 1 in 100,000 people

How Do You Get It?

• An idiopathic condition by definition has no clear cause
• Some possible explanations include:
  • An abnormal hypersensitivity to GABA, the primary brain chemical responsible for sedation
  • Malfunction of the norepinephrine system
  • Decreased cerebrospinal fluid histamine levels

What Are the Symptoms?

• The principal symptoms of idiopathic hypersomnia include:
  • Excessive daytime sleepiness
    • Persistent urgent need to sleep through the day coupled with fatigue, despite getting a full night of sleep. Patients may nap multiple times during the day and have a strong urge to sleep even while driving, eating, working, or socializing
  • Excessive sleep
    • This is defined as 9 or more hours of sleep in a 24-hour period without feeling energized or refreshed
  • Brain fog
    • Inattention, trouble with cognitive processing, language, and thought processing
    • Memory, learning, and other basic function may be impacted
  • Sleep inertia, or sleep drunkeness
    • Severe difficulty waking up, often with a strong desire to sleep again

How Is It Treated?

• Xywav is an FDA-approved treatment for idiopathic hypersomnia
• Stimulant drugs of the amphetamine class, such as Ritalin, may also be used
• Non-stimulant medications that promote wakefulness, such a modafinil, are also used
  • Pitolisant, another medication of this class, was FDA-approved in 2019
• While these treatments can be effective, some patients may need to adjust their lifestyle in order to avoid potentially dangerous scenarios while facing the urge to sleep, such as high-risk work or driving

Where Can I Learn More???

• Check out our cornerstone on this disease here.
• Learn more from the Sleep Foundation.