Uinumine ja naer: mis on narkolepsia ja kuidas seda tavalisest unisusest eristada

Narcolepsy can significantly affect a person’s quality of life, making daily tasks and social interactions difficult. Together with an expert, we find out what this disease is and how to distinguish it from ordinary drowsiness.

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What is narcolepsy?

neurologist at the Hadassah branch of the Hadassah Clinic in the Skolkovo International Medical Cluster

“Narcolepsy is characterized by chronic pathological daytime sleepiness, often combined with episodes of sudden loss of muscle tone (cataplexy).”

The term “Narcolepsy” was coined in 1880 by Jean-Baptiste-Edouard Gelineau (J. B. E. Gelineau), who observed a patient with sudden falling asleep during the day, accompanied by loss of muscle tone. Prevalence figures vary widely but average one patient per 1000 population.

In 50% of cases, the disease debuts before the age of 15.

Causes of narcolepsy

For a long time, various conditions such as schizophrenia, epilepsy, hysteria and encephalitis were considered to be the cause of narcolepsy. Now, however, research shows that this disease disrupts the regulation of the periodicity of the onset of rapid eye movement sleep phase (REM phase, or rapid eye movement sleep phase).

The REM phase can occur suddenly during wakefulness, as well as during the transition from wakefulness to sleep. This observation is supported by the fact that during the onset of an episode of narcolepsy, the patient has vivid dreams, and muscle tone is maximally reduced at this time, which is characteristic of the REM phase.

At the heart of such changes is the incorrect functioning or decreased concentration of the neurotransmitter orexin (hypocretin-1). It provides cortical activation and keeps us awake throughout the day. It is its deficiency that is now considered a key factor in the development of narcolepsy.

The question of whether there is a genetic factor in the development of this disease is still open. Studies examining identical twins have shown a low level of coincidence (concordance). Meanwhile, some scientific work has revealed the autoimmune nature of the disease: after immunization or streptococcal upper respiratory tract infection.

What is the difference between narcolepsy and ordinary sleepiness?

The fundamental difference between narcolepsy and ordinary increased daytime sleepiness is the pathological nature of falling asleep. That is, the patient can have a conversation, walk down the street, passionately watch a movie – and the next moment suddenly plunge into sleep, and in the phase of REM sleep with dreams.

This may be preceded by bright emotions, laughter, followed by a sharp decrease in muscle tone, which is often accompanied by a fall of the patient.

It is impossible to resist such sleepiness: a person is not able to cheer himself up, distract himself with something interesting. Such sleepiness is called imperative.

The number of attacks during the day can vary significantly, and their duration can range from a few minutes to several hours. In this case, waking the patient is often no more difficult than in normal sleep.

Patients may experience sleep attacks – sudden repeated sleep attacks without warning. The patient may feel awake after waking up, but after a few minutes may fall asleep again.

There are two types of narcolepsy: the first type is accompanied by cataplexy (momentary muscle weakness), the second type – without cataplexy. In the second type, it becomes more difficult to distinguish narcolepsy from normal sleepiness, especially in people with severe obstructive sleep apnea syndrome, who also suffer from increased daytime sleepiness and may even fall asleep at the wheel.

However, patients with narcolepsy always have additional sleep-related symptoms. Thus, there are hallucinations that occur at the moment of falling asleep or immediately after awakening, similar to normal vivid dreams. Also characterized by sleep paralysis – the inability to move for a few seconds after waking up. All this is accompanied by a feeling of anxiety or fear, a feeling of squeezing in the chest.

How is the diagnosis made?

Polysomnography with multiple sleep latency test (MTLS) is used to diagnose narcolepsy. During this technique, doctors monitor the patient’s sleep with special sensors during the night and for several hours after waking up.

Several criteria must be met to make a diagnosis of narcolepsy:

• the REM sleep phase is recorded during at least 2-5 episodes of daytime falling asleep;
• the average time of falling asleep and the onset of REM sleep is less than eight minutes;
• absence of other changes according to polysomnography, such as epilepsy, pronounced sleep breathing disorders (apnea).

Also to exclude other possible causes of abnormal sleepiness may require blood tests, urinalysis and MRI of the brain.

How is narcolepsy treated?

It is impossible to completely get rid of narcolepsy, but it is possible to reduce the severity of the symptoms of the disease. In therapy, both medication and non-medication methods are used.

Patients with narcolepsy are recommended to follow the rules of sleep hygiene: a long night’s sleep, it is also recommended to sleep during the day up to 30 minutes (daily and preferably at approximately the same time). People who have episodes of decreased muscle tone should avoid provoking emotional reactions: laughter, anger, fright.

As for medications, they should be selected only by a doctor based on the individual characteristics of the patient and the type of narcolepsy.