Cataplexy: causes, symptoms, prevention and treatment

One of the most characteristic symptoms of narcolepsy is cataplexy episodes, during which the muscles suddenly relax and weaken, sometimes 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 "cataplexy" or "cataplexy" the transient episodes of muscle weakness that occur in some people. They are considered an intrusion of the processes that regulate sleep in the waking state, although during cataplexy the person maintains consciousness.

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

episodes of cataplexy occur almost exclusively in the context of narcolepsy, so that we can consider them a cardinal symptom of this disease. It is very rare for cataplexy to occur without narcolepsy.

• Related article: "Narcolepsy: Types, Causes, Symptoms, and Treatment"

What is narcolepsy?

Narcolepsy is a sleep disorder characterized by the appearance of elements of REM (rapid eye movement) sleep during wakefulness. Its most characteristic symptom is sleep attacks that occur despite having adequately rested.

In addition to sleep spells and cataplexy, other common symptoms of narcolepsy include daytime hypersleepiness, sleep disturbance during REM sleep and the appearance of hypnagogic hallucinations and sleep paralysis during wakefulness.

Narcolepsy cases do not always include cataplexy, but these episodes occur in 70% of narcoleptic people. When there is cataplexy, there is practically always a deficit of the hypocretin hormone, another of the fundamental signs of narcolepsy.

Symptoms

Cataplexy episodes are brief; most of the time they last 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 involve temporary 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, also characteristic of narcolepsy: during cataplexy the person maintains consciousness, although if you are in a comfortable position you may feel drowsy and even fall asleep as a result of the relaxation.

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

Causes of these alterations

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

Specifically, it is believed that cataplexy episodes are the consequence of sudden inhibition and of motor neurons at the level of the spinal cord, causing a loss of control of the muscles.

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

Brain infections, vascular accidents or diseases such as multiple sclerosis can also cause episodes of cataplexy. The damage in the hypothalamus, which secretes hypocretin, are frequently implicated in the development of this disorder.

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

treatment and prevention

cataplexy It is mainly treated with drugs.. The treatment of choice is sodium oxybate, a very safe medication that is also effective in combating daytime sleepiness. Gammahydroxybutyrate 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 and venlafaxine, a selective serotonin and norepinephrine reuptake inhibitor.

Psychology can also contribute to the treatment of cataplexy. In this sense, interventions focus on the prevention of these episodes from the identification of the symptoms that precede them: learning to detect the prodromes of cataplexy is useful 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 is 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.