One of the most characteristic symptoms of narcolepsy is episodes of cataplexy, in which muscles suddenly relax and weaken, Sometimes resulting in 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 these “cataplexy” or “cataplexy” transient episodes of muscle weakness that occur in some people. It is considered to be an intrusion of the processes that regulate sleep in the waking state, although during cataplexy the person retains consciousness.
Usually these symptoms occur as a result of intense emotions; for example, it is common for muscle loss to occur when the person laughs a lot, is afraid, or cries.
Cataplexy episodes they occur almost exclusively against the background of narcolepsyWe can therefore consider them as a cardinal symptom of this disease. It is very rare for cataplexy to occur without narcolepsy.
What is narcolepsy?
Narcolepsy is a sleep disorder characterized by the appearance of elements of REM sleep (rapid eye movement) while awake. Its most characteristic symptom is the sleep attacks that occur despite having rested properly.
In addition to sleep seizures and cataplexy, other common symptoms of narcolepsy are daytime hypersomnolence, disturbed sleep during the REM phase, and the onset of hypnagogic hallucinations and sleep paralysis while awake. .
Cases of narcolepsy do not always include cataplexyBut these episodes occur in 70% of narcoleptic people. When there is cataplexy, there is almost always a deficiency of the hormone hypocretin, another of the basic signs of narcolepsy.
The episodes of cataplexy are brief; most often last less than two minutes. They are usually the result of physical exertion or strong emotions, especially if they arise unexpectedly.
Muscle weakness is variable and may be limited to a loosening of the knees or jaws or lead to transient paralysis of the whole body. This can lead to falls or accidents, for example if the person is driving.
Cataplexy episodes should not be confused with sleep seizures, which are also characteristic of narcolepsy: during cataplexy, the person remains aware, even if they are in a comfortable position, they may feel drowsy and even sleepy. fall asleep as a result of relaxation.
Other symptoms that commonly occur during episodes of cataplexy 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 cerebrospinal fluid. Orexin plays a key role in maintaining wakefulness and alertness; its deficit has been linked to the REM intrusions typical of narcolepsy.
More specifically, the episodes of cataplexy would be a consequence of the sudden and generalized inhibition of motor neurons in the spinal cord, which leads to a loss of muscle control.
Any change that lowers orexin levels is likely to cause narcoleptic symptoms such as cataplexy. This way, these episodes can occur as a result of injuries, deformities and brain tumors.
Brain infections, strokes, or diseases such as multiple sclerosis can also cause episodes of cataplexy. Damage to the hypothalamus, which secretes hypocretin, is frequently involved in the development of this alteration.
In many cases, both narcolepsy and cataplexy have a genetic component. In this regard, many experts consider narcolepsy to be an autoimmune disease linked to so-called “human leukocyte antigens” (HLA).
Treatment and prevention
Cataplexy it is treated mainly with drugs. The treatment of choice is sodium oxybate, a very safe drug that is also effective in combating daytime sleepiness. Gammahydroxybutyrate has similar effects.
Other drugs used for cataplexy and narcolepsy in general are stimulants, such as modafinil, and antidepressants, In particular tricyclics and venlafaxine, a selective serotonin and norepinephrine reuptake inhibitor.
Psychology can also help in the treatment of cataplexy. In this sense, the interventions focus on prevention of these episodes from the identification of symptoms that precede them: Learning to detect cataplexy prodromes is useful in order to be able to react to them when they start to occur in the future.
To reduce the symptoms of narcolepsy, including cataplexy and drowsiness, it is recommended that you schedule short naps during the day and maintain healthy sleep habits.
- Seigal, Jérôme (2001). Narcolepsy. American scientist: 77.
- van Nues SJ, van der Zande WL, Donjacour CE, van Mierlo P, Jan Lammers G. (2011). Clinical features of cataplexy: a questionnaire study in patients with narcolepsy with and without hypocretin-1 deficiency. Sleep medicine.