Narcolepsy is also colloquially known as "sleeping sickness." Those who are affected are unusually sleepy during the day and frequently fall asleep unexpectedly. This is more due to an organic brain disorder than a lack of sleep. Narcolepsy cannot be cured. Those affected, however, can live a better, more alert life with the help of medication.
There are two main forms of narcolepsy.
Experts distinguish two main forms of narcolepsy, related to the symptom cataplexy (sudden relaxation of muscles due to strong emotions) described below:
Type 1 narcolepsy is associated with such muscle relaxation episodes (cataplexy). This variant likely accounts for the majority of narcolepsy cases. In most cases, cataplexy does not appear until months or years after the onset of the disease's first symptom, daytime sleepiness. The defining characteristic of narcolepsy type 1 is the absence of a measurable neurotransmitter in the cerebrospinal fluid (liquor), indicating that the producing nerve cells in the brain have perished.
Type 2 narcolepsy occurs without a deficiency of this neurotransmitter and without cataplexy . In certain cases, narcolepsy type 2 is only the early stage of type 1, which means: Over time, those affected develop cataplexy - the diagnosis then changes from "narcolepsy type 2" to "narcolepsy type 1".
Narcolepsy: frequency and age
Narcolepsy is fairly common. According to studies, only 26 to 50 people out of every 100,000 in Europe are affected. However, experts believe that the number of unreported cases is high - many people likely suffer from narcolepsy without being aware of it or being treated for it.
The disease can first appear at almost any age. In most cases, however, narcolepsy begins at a young age, in adolescence or before the age of 40. Both sexes are affected roughly equally.
Narcolepsy: causes and risk factors
The loss of brain nerve cells that produce hypocretin, which regulates sleep-wake cycles by increasing wakefulness and stabilizing both wakefulness and sleep, is the cause of the neurological condition narcolepsy.
Hypocretin deficiency is caused by an autoimmune reaction in the body, disrupting the normal sleep-wake cycle, leading to frequent alternations between sleeping and waking.
Narcolepsy is caused by autoimmune processes, infections, brain damage, and a loss of hypocretin-producing nerve cells. There is rarely a family history of the disease, and it occurs as a symptom of brain damage.
Narcolepsy is essentially characterized by the following symptoms:
Daytime sleepiness: Narcoleptics are either constantly sleepy or have sudden fits of sleepiness, usually lasting only a few minutes. This daytime sleepiness is usually noticed in repetitive situations, but can also occur in more active situations such as eating or driving.
Cataplexy is the sudden, short-term loss of tension (tone) in the muscles of the face, arms and legs, usually on both sides of the body at the same time. Triggers are intense emotions such as laughter, joy, pride, surprise or anger. Cataplexy usually lasts five to 120 seconds and can vary in severity. Narcolepsy is almost always present when cataplexy occurs, but not every narcoleptic has cataplexy.
The term refers to hallucinations during the transition from wakefulness to sleep (i.e. while falling asleep) or from sleeping to wakefulness (i.e. when waking up). Some sufferers see or hear things that are not real. Tactile illusions (supposed touching) are also possible.
When falling asleep and waking up, narcoleptics are sometimes temporarily unable to move or speak. Dream perceptions and waking consciousness can mix here, so that those affected do not know whether they are awake or asleep. You feel completely paralyzed for a moment. While this feeling lasts only a few seconds to minutes and is not dangerous, it can be very frightening.
Disrupted night sleep
People with narcolepsy repeatedly wake up abruptly and for no apparent reason at night. You are then immediately wide awake. These waking phases are usually short, but can also last longer.
Daytime sleepiness and cataplexy, as well as disturbed sleep at night, are considered to be the core symptoms of narcolepsy type 1. Other symptoms, such as sleep paralysis and hallucinations, can also occur, but they do not have to.
Comorbidities of narcolepsy
There are a number of disorders that occur more frequently in narcoleptics than in people who do not suffer from the "sleep craze". These comorbidities include, for example, nightmares, sleepwalking, sleep-disordered breathing, migraines, obesity and depression.