OVERVIEW

What is Idiopathic Hypersomnia?

Idiopathic hypersomnia, also known as idiopathic excessive sleepiness or idiopathic hypersomnolence, is a form of excessive sleep disorder.

It primarily manifests as an inability to stay awake and alert during daytime hours when one should remain conscious, leading to uncontrollable drowsiness or even sudden, unprovoked sleep episodes. This significantly impacts patients' daily lives and work, and may even cause severe accidents.

How Common is Idiopathic Hypersomnia?

The exact prevalence of idiopathic hypersomnia in the general population remains unknown. The average age of onset is between 16.6 and 21.2 years, with a higher occurrence among females.

SYMPTOMS

What are the characteristics of idiopathic hypersomnia?

The main features of idiopathic hypersomnia include: excessive daytime sleepiness without cataplexy, also described as "sleep drunkenness."

• It is often accompanied by prolonged difficulty waking up, recurrent sleep episodes, irritability, automatic behaviors, and confusion.

• Patients frequently struggle to wake up to alarms and require special measures for arousal.

• Over 30% of patients report total sleep time exceeding 10 hours.

• Daytime naps often last more than 60 minutes, with most patients feeling unrefreshed upon waking. These symptoms are usually subtle and may go unnoticed for weeks or months.

• Autonomic dysfunction symptoms, such as headaches and orthostatic hypotension, may also occur.

• Polysomnography (PSG) and multiple sleep latency tests (MSLT) can aid in diagnosis.

Patients with idiopathic hypersomnia may also experience emotional distress. While addressing symptoms, it's important to prioritize emotional well-being.

Lifestyle changes like meditation and exercise can help improve mood, and counseling may assist in managing emotional challenges.

Additionally, understanding and support from family can greatly aid emotional recovery.

CAUSES

What are the causes of idiopathic hypersomnia?

The exact causative factors of idiopathic hypersomnia remain unclear. Some cases may be triggered by viral illnesses; certain patients show clear familial clustering, suggesting a possible genetic correlation.

DIAGNOSIS

How is idiopathic hypersomnia diagnosed?

When experiencing prolonged naps without feeling refreshed or difficulty waking up in the morning or after naps, idiopathic hypersomnia should be considered. To diagnose idiopathic hypersomnia disorder, the following diagnostic criteria must all be met:

• Daily uncontrollable sleepiness without cataplexy, lasting ≥ 3 months;
• MSLT shows a mean sleep latency ≤ 8 minutes; or 24-hour PSG reveals a total sleep time ≥ 660 minutes; or these features are confirmed by wrist actigraphy combined with sleep logs (averaging at least 7 days of natural sleep);
• Excessive sleepiness is not caused by other factors, such as physical illness, mental disorders, insufficient sleep, sleep apnea syndrome, delayed sleep phase, substance abuse or withdrawal, narcolepsy, or other hypersomnia disorders.

Does daytime sleepiness and fatigue always indicate idiopathic hypersomnia?

Not necessarily.

Idiopathic hypersomnia disorder is an exclusionary diagnosis. Before considering idiopathic hypersomnia, other potential causes of excessive daytime sleepiness must be ruled out, such as physical illness, mental disorders, medication or drug use, insufficient sleep, sleep apnea syndrome, chronic fatigue syndrome, narcolepsy, and other hypersomnia disorders.

A detailed medical history, systematic sleep evaluation, comprehensive physical examination, necessary auxiliary tests, nocturnal polysomnography (PSG), and multiple sleep latency tests (MSLT) are essential for diagnosis. Idiopathic hypersomnia disorder is only considered after other possibilities have been excluded.

TREATMENT

Which department should patients with idiopathic hypersomnia visit?

In areas with available resources, a sleep specialist clinic is the first choice; in regions without sleep specialists but with convenient access to psychiatric or psychosomatic medicine departments, psychiatry or psychosomatic medicine can be considered. In special cases, neurology or even internal medicine may also be options.

How is idiopathic hypersomnia treated?

Currently, idiopathic hypersomnia can only be managed symptomatically, as behavioral therapy is ineffective. The primary treatment goal is to maintain daytime alertness.

• Modafinil: The first-line recommended medication for idiopathic hypersomnia, also effective for children. The dosage typically starts at 100 mg and is gradually increased. Common side effects include headaches, and slow dose titration may help reduce adverse reactions.
• Central nervous system stimulants: Such as methylphenidate, may partially alleviate symptoms, though the effects may be suboptimal.
• Melatonin receptor agonists: Such as ramelteon or agomelatine, may be effective for some patients.
• Additionally, strategies like cultivating good sleep hygiene, maintaining a healthy lifestyle, and limiting time in bed may be helpful.

How effective is the treatment for idiopathic hypersomnia?

For most patients, excessive daytime sleepiness persists; 10%–25% of patients may experience spontaneous remission. However, symptoms generally improve gradually with medication for the majority of patients.

Is spontaneous recovery possible for idiopathic hypersomnia?

Spontaneous recovery is unlikely.

Hypersomnia has a gradual onset, progressing over weeks to months. For most individuals, without treatment, the condition becomes chronic and stable.

DIET & LIFESTYLE

What should patients with idiopathic hypersomnia pay attention to in daily life?

Before hypersomnia is confirmed to be well controlled, patients should avoid participating in activities that may pose risks or significant losses due to drowsiness, including but not limited to driving vehicles, operating hazardous machinery, or precision instruments.

PREVENTION

Can idiopathic hypersomnia be prevented?

Since the cause and pathogenesis are not yet clear, prevention is currently not possible.