Narcolepsy: History and Symptoms



2009, there was a nation-wide vaccination in Sweden which resulted in hundreds of children getting narcolepsy. Even 10 years later, there are cases that can be connected with the Pandemrix vaccine, but this sleeping disorder can also occur as a result of especially vicious forms of tonsillitis.


Ever since it was first described in the 1800s, it has been known that the majority of people getting narcolepsy are teenagers. Constantin von Economo was a neurologist who identified in the 1910-1920s that some people require more sleep than others, referred to as hypersomnia. This, as well as narcolepsy, is categorized by daytime sleepiness and a need to sleep abnormally much. Economo realised, also, that these sleeping disorders are from a disruption in the middle brain, especially the anterior tegmentum, nucleus raphe and locus coeruleus, and the associated neurotransmitters. In the case of narcolepsy, it is notably a lack of hypocretin (also referred to as orexin), that is normally released from hypothalamus, that are at the basis for the disease.


One of the most distinct symptoms of narcolepsy is that of cataplexies. Triggered by a strong emotion, often a positive one, but also those of anger, surprise, or fear, cataplexies causes, in their most extreme form, the muscles to weaken, leading to the person falling to the floor. Cataplexies are, however, in its weaker forms, more common that one might think with around 25 % of people able to experience some form of it. In Swedish, there are idioms that convey these more ordinary forms of cataplexies, e.g. “Skratta så att knäna viker sig” (Laugh so that the knees buckle) and “Tappa hakan” (Lose the chin). However, in people with narcolepsy, this loss of muscle-control can happen more frequently and more extreme than among others. For us not to fall to the ground every time someone tells us a joke, a signal that would go from the amygdala to the sublaterodorsal nucleus to the spinal cord and eventually to the muscles, must be inhibited. For this to occur, hypocretin must activate the nucleus raphe that in turn signals to the sublaterodorsal nucleus via nerve fibres to disrupt the signal that would otherwise lead to cataplexies. Because people with narcolepsy lack the necessary hypocretin, the signal is carried to its final destination, leading to a cataplexy.

Other symptoms caused by the lack of hypocretin are those referred to as hypothalamic symptoms. These include a worse memory, a decreased ability to concentrate (“ADHD”-symptom), weight gain, impaired motivation/reward system. In their combined effect, these symptoms have a tendency to lead to procrastination and strong emotional responses.


Also, because narcolepsy is a disorder strongly tied to that of a great need for sleep, there are many symptoms that have been identified and that are connected to just sleep. Sleep paralysis is something not too uncommon, but instead of just getting it when waking up, some patients with narcolepsy can get paralysed when they are about to fall asleep. This is because instead of following the normal stages of sleep, they enter directly into REM-sleep which is when the body needs to be still for us to not act out our dreams, for instance by swinging a broom around as if it were the sword we are fighting the fire-spitting dragon with in our dream. Also hallucinations and illusions are created more frequently among those with narcolepsy because of the brain’s fast transition from a half-awake state to that of entering into dream-land.


Source:

Lecture by specialist physician Attila Szakacs and specialist physician Pontus Wasling

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