What is narcolepsy with cataplexy

Psychiatry, Psychosomatics & Psychotherapy

25.10.2018

Causes of the rare sleeping sickness narcolepsy revealed

Narcolepsy causes fatigue and sudden sleep attacks, among other things. The latest research shows that certain immune cells react to the body's own tissue, which leads to a loss of certain nerve cells.

A research team from Switzerland, with the participation of Dr. Ulf Kallweit from the University of Witten / Herdecke (UW / H) identified the cause of the chronic disease narcolepsy. The results of this study were recently published in the renowned journal "Nature".

Narcolepsy is a rare neurological disease and affects around 40,000 people in Germany. The first symptoms often appear during puberty or young adulthood, but small children can also be affected. The main symptoms of the disease are chronic and severe daytime sleepiness, attacks of falling asleep and cataplectic attacks, i.e. a sudden loss of muscle tension caused by an emotion. Neuropsychiatric, motor and metabolic disorders can also occur. Narcolepsy is associated with a severe reduction in performance or work ability and quality of life.

Late diagnosis and only symptomatic treatment options

So far, it has taken an average of ten years from the onset of the first symptoms to the diagnosis. The diagnosis is usually made on the basis of anamnesis, sleep laboratory examinations and a nerve fluid examination in which the so-called hypocretin value is examined.
The treatment of narcolepsy is purely symptomatic; a cure is not yet possible. In addition to behavioral measures such as planning a daily structure in which sleep times are also planned during the day, drug treatment primarily targets the main symptoms of the disease. Daytime sleepiness can be treated with various stimulants or drugs that promote wakefulness, while other drugs can alleviate the cataplexy.

Mechanism of nerve cell loss previously unknown

Narcolepsy is caused by the gradual loss of nerve cells in the hypothalamus (a specific region of the brain) that make hypocretin. Hypocretin is a neuropeptide that is essential for maintaining sleep and wakefulness, but also relevant for emotional, nutritional and rewarding behavior. So far it has been known that both a certain genetic predisposition and environmental factors, such as certain infections or individual vaccines, must be present together. The mechanism that led to the destruction of the neurons was previously unknown.

With the help of a special method, the research group has now been able to clarify that T lymphocytes of the CD4 subtype (and in some cases also those of the CD8 subtype) react to hypocretin, among other things. They cause inflammation, thereby destroying neurons, or they may also directly destroy the neurons in which hypocretin is produced specifically.

Hope for new treatment options

The study author and sleep specialist Dr. Kallweit emphasizes that this study could contribute to the fact that in the future narcolepsy could possibly be diagnosed more easily and quickly using a blood test for autoreactive T lymphocytes against hypocretin. This would also help to start treatment earlier, for example in order to successfully graduate from school or to be able to go to university. He also emphasizes the importance of the study for new treatment options.

The loss of hypocretin-producing neurons in narcolepsy is slow and presumably irreversible. Knowing the exact cause, the autoreactive T cells, can now possibly suppress these cells at the beginning of the disease, so that the further cell death is slowed down or even stopped. This could affect the severity of narcolepsy or even the overall progression of the disease. Kallweit: "In the next step, appropriate therapies must now be developed."

Source and further information: University of Witten / Herdecke