Cataplexy: causes, symptoms, prevention and treatment
One of the most characteristic symptoms of narcolepsy are episodes of cataplexy, during which the muscles relax and weaken suddenly , sometimes causing 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" 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 the 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, feels fear or cries.
Episodes of cataplexy they occur almost exclusively in the context of narcolepsy , so that we can consider them a cardinal symptom of this disease. Cataplexy without narcolepsy is very infrequent.
- 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 are the sleep attacks that occur despite having rested properly .
In addition to sleep access and cataplexy, other common symptoms of narcolepsy are daytime hypersomnolence, sleep disturbance during the REM phase, and the appearance of hypnagogic hallucinations and sleep paralysis during wakefulness.
Cases of narcolepsy do not always include cataplexy , but these episodes occur in 70% of narcoleptic people. When there is cataplexy there is almost always a deficit of the hormone hypocretin, another of the fundamental signs of narcolepsy.
Episodes of cataplexy are brief; most times they last less than two minutes . They are usually the result of physical efforts or strong emotions, especially if they occur unexpectedly.
The muscular weakness is variable, being able to be limited to the relaxation of the knees or the jaws or to imply a transitory paralysis of all the body. This can lead to falls or accidents, for example if the person is driving.
Do not confuse episodes of cataplexy with sleep attacks also characteristic of narcolepsy: during cataplexy the person maintains consciousness, although in case he is in a comfortable position can feel drowsy and even fall asleep as a result of the relaxation.
Other symptoms that occur regularly during episodes of cataplexy are pronunciation difficulties and visual disturbances, particularly blurred or double vision.
Causes of these alterations
It is considered that the main cause of narcolepsy and cataplexy is the presence of low levels of the hormone orexin or hypocretin in the cerebrospinal fluid. Orexin has a fundamental role in the maintenance of wakefulness and alertness; its deficit has been related to REM intrusions typical of narcolepsy.
In particular, it is believed that episodes of cataplexy are a consequence of the sudden and generalized inhibition of motor neurons at the level of the spinal cord, which causes a loss of control of the muscles.
Any alteration that reduces orexin levels is likely to cause narcoleptic symptoms such as cataplexy. In this way, these episodes can occur as a result of injuries, malformations and brain tumors .
Brain 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 alteration.
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
The cataplexy it is mainly treated by 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 the tricyclics and venlafaxine, a selective inhibitor of the reuptake of serotonin and noradrenaline.
Psychology can also contribute to the treatment of cataplexy. In this sense, the interventions focus on the prevention of these episodes from the identification of the symptoms that precede them: learn to detect the prodrome of the cataplexy is useful to be able to react to them when they begin to produce in the future.
To reduce the symptoms of narcolepsy, including cataplexy and drowsiness, it is recommended to schedule brief daytime naps and maintain healthy sleep habits.