Cataplexy: causes, symptoms, prevention and treatment

This curious phenomenon causes the muscles of the body to suddenly relax and weaken.

One of the most characteristic symptoms of narcolepsy is cataplexic episodes, during which the muscles relax. episodes of cataplexy, during which the muscles suddenly relax and weaken, sometimes leading to falls.sometimes even leading to falls and accidents.

In this article we will explore the causes of cataplexy and the treatments that prevent its symptoms, both pharmacological and psychological.

Definition of cataplexy

We call "cataplexia" or "cataplexy" to the transient episodes of Muscle weakness that occur in some people.. They are considered to be an intrusion of the processes that regulate sleep into the waking state, although during cataplexy the person maintains consciousness.

These symptoms usually occur as a result of intense emotions; for example, it is common for loss of muscle tone to occur when the person laughs a lot, feels afraid or cries.

Episodes of cataplexy occur almost exclusively in the context of narcolepsyso that they can be considered a cardinal symptom of this disease. Cataplexy without narcolepsy is very rare.

What is narcolepsy?

Narcolepsy is a sleep disorder characterized by the appearance of elements of REM (rapid eye movement) sleep in wakefulness. Its most characteristic symptom is sleep attacks that occur despite adequate rest. despite adequate rest.

In addition to sleep onset and cataplexy, other common symptoms of narcolepsy are daytime hypersomnolence, sleep disturbance during REM sleep, and the occurrence of hypnagogic hallucinations and sleep paralysis during wakefulness.

Cases of narcolepsy do not always include cataplexy.but these episodes occur in 70% of narcoleptic persons. When cataplexy is present, there is almost always a deficit of the hormone hypocretin, another key sign of narcolepsy.

Symptoms

Episodes of cataplexy are brief; most often lasting less than two minutes.. They are usually the result of physical exertion or strong emotions, especially if they occur unexpectedly.

Muscle weakness is variable and may be limited to relaxation of the knees or jaws, or may involve transient paralysis of the entire body. This can lead to falls or accidents, for example if the person is driving.

Cataplexy episodes should not be confused with sleep attacks, which are also characteristic of narcolepsy: during cataplexy, the person remains conscious, but if he or she is in a comfortable position, he or she may feel drowsy or even fall asleep as a result of the relaxation.

Other symptoms that commonly occur during episodes of cataplexy are pronunciation difficulties and visual disturbances, particularly blurred or double vision.

Causes of these disturbances

The main cause of narcolepsy and cataplexy is considered to be the presence of low levels of the hormone orexin or hypocretin in the cerebrospinal fluid. in the cerebrospinal fluid. Orexin plays a key role in the maintenance of wakefulness and alertness; its deficit has been linked to the REM intrusions typical of narcolepsy.

In particular, cataplexy episodes are thought to result from the sudden and generalized inhibition of motor neurons at the spinal cord level, causing a loss of muscle control.

Any alteration that reduces orexin levels is likely to cause narcoleptic symptoms such as cataplexy. Thus, these episodes can occur as a consequence of lesions, malformations and brain tumors..

Encephalic infections, vascular accidents or diseases such as multiple sclerosis can also cause episodes of cataplexy. Damage to the hypothalamus, which secretes hypocretin, is frequently implicated in the development of this disorder.

In many cases narcolepsy and cataplexy have a genetic component. In this regard, many experts consider narcolepsy to be an autoimmune disorder related to the so-called "human leukocyte antigens" (HLA).

Treatment and prevention

Cataplexy is primarily treated with drugs. The treatment of choice is sodium oxybate, a very safe drug that is also effective in combating daytime sleepiness. Gamma-hydroxybutyrate has similar effects.

Other drugs that are used in cases of cataplexy and narcolepsy in general are stimulants, such as modafinil, and antidepressants, particularly tricyclics, have similar effects.particularly tricyclics and venlafaxine, a selective serotonin and norepinephrine reuptake inhibitor.

Psychology can also contribute to the treatment of cataplexy. In this regard, interventions are focused on prevention of these episodes by identifying the symptoms that precede them. learning to detect the prodromes of cataplexy is useful in order to be able to react to them when they begin to occur in the future.

To reduce the symptoms of narcolepsy, including cataplexy and drowsiness, scheduling short daytime naps and maintaining healthy sleep habits are recommended.

Bibliographic references:

• Seigal, Jerome (2001). Narcolepsy. Scientific American: 77.
• van Nues SJ, van der Zande WL, Donjacour CE, van Mierlo P, Jan Lammers G. (2011). The clinical features of cataplexy: A questionnaire study in narcolepsy patients with and without hypocretin-1 deficiency. Sleep Medicine.