Narcolepsy is explained in the International Classification of Sleep Disorders as "a disease of unknown etiology distinguished by severe sleepiness during the day, poor night sleep, cataplexy and pathological manifestations of REM sleep, such as the appearance of short episodes of REM sleep in an awake person or sleep attacks", "microsleep", sleep paralysis, and sleep-related hallucinations”.
The prevalence of this sleep disorder in the population ranges from 0.03 to 0.16%. The disease is equally common among men and women, most likely its onset before the age of 20. There is a fairly close correlation of narcolepsy with certain histocompatibility antigens HLA DR2.
The classic manifestation of the disorder is attacks of falling asleep during the day, which are difficult to resist. Patients can fall asleep while sitting in the theater, in transport, and even while talking. Another important manifestation is attacks of sudden muscle tone drop, especially in emotional situations (laughing till "knee buckling" is a fairly accurate metaphor), which can lead to falls. When falling asleep or on awakening, indidivuals with the disorder may feel or see strange, often threatening images called hypnagogic and hypnapompic hallucinations. These sensations can be accompanied by an equally unpleasant phenomenon a drop in the tone of the muscles of the body (the patient at this time cannot move either an arm or a leg). 40% of individuals with the disorder suffer form of frequent night awakenings.
The above clinical manifestations in narcolepsy are associated with disintegration syndrome, manifested by the untimely onset of sleep stages, especially REM sleep.
A polysomnographic study reveals changes in the form of rapid falling asleep (less than 10 minutes) and early onset of REM sleep (within 20 minutes). A large number of nocturnal awakenings are also recorded.
As mentioned in the definition, the causes of the disorder are unknown. Recent research data suggest the leading role of hypothalamic peptides, hypocretins or orexins, in regulating the correct alternation of slow and REM sleep. In narcolepsy, the level of these substances in the cerebrospinal fluid is reduced.
Treatment for narcolepsy includes behavioral and medicinal treatments.
Behavioral include the prevention of industrial and domestic injuries (organization of a safe environment and schedule) and the method of planned falling asleep (short periods of sleep 15-20 minutes with 2-3 hour intervals during the day).
Medicinal methods are aimed at eliminating drowsiness and cataplexy. In the first case, drugs with a psychostimulating effect (Modafinil, Armodafinil, methylphenidate) are effective, in the second, antidepressants of various groups (Imipramine, Fluoxetine). For the correction of sleep disorders, modern hypnotic drugs Zopiclone and Zolpidem are used.
Narcolepsy is pathology of the central nervous system, in which the patient constantly feels an irresistible desire to sleep in the daytime, falls asleep suddenly, has a sleep disorder, may lose muscle tone while his consciousness is working, and is faced with hallucinations during awakening and/or falling asleep.
In such patients, after awakening, short-term paralysis is often noted. It is worth noting that all symptoms do not need to be present for a diagnosis of narcolepsy. For this, the presence of sudden falling asleep and one or two other symptoms is enough.
Symptoms typical of narcolepsy are as follows: attacks of severe sleepiness that happen at any time of the day; short-term sleep anytime and anywhere (1-10 minutes); easy awakening on their own or after external influence; constant feeling of tiredness; memory impairment; decreased concentration of attention; sudden loss of muscle tone and strength (catalepsy); the occurrence of hallucinations; sleep paralysis; involuntary muscle twitching.
According to statistics, 20-40 out of 100 thousand people have narcolepsy.
Narcolepsy is slightly more common in men than in women. Moreover, almost all patients are young. At the moment, scientists are of the opinion that narcolepsy is inherited, however, to start the development of pathology in most cases, an unfavorable factor is necessary.
The reason for the development of the disorder is the disruption of the part of the brain that is responsible for the process of changing REM and NREM sleep. Thousands of chemical reactions occur in the human brain every second. The transmission of a nerve impulse from one part of the brain to another is due to special substances neurotransmitters.
In some cases, this well-established mechanism malfunctions and the nerve impulse cannot be transmitted normally. In this case, the person develops pathological drowsiness. The neurotransmitter responsible for keeping people awake is called orexin. It is its deficiency in the body that causes narcolepsy.
Scientists have not been able to establish the exact reasons for the decrease in the level of this substance. It is speculated that this may result from: the presence of an autoimmune response when the immune system attacks the cells of its body; violation of carbohydrate tolerance; brain damage from trauma; damage to the nervous system as a result of infectious processes in the body; traumatic situations; depletion of the body.
Classification of narcolepsy
At the moment, it is customary to distinguish 2 forms of narcolepsy:
- Narcolepsy combined with cataplexy;
- Narcolepsy without cataplexy.
Cataplexy is a pathological condition in which a person's muscle tone decreases sharply, despite the fact that he is conscious. Most often this occurs at times when the patient is experiencing strong emotions. In this state, a person can easily fall into a stupor, drop an object that he was holding in his hands, or even fall to the floor himself. As a rule, cataplexy is replaced by severe drowsiness, which lasts for several minutes.
Based on the cause of the pathological process, the following types of narcolepsy are distinguished: genetic a tendency to it is inherited, but it develops independently, without the presence of provoking factors; symptomatic a tendency to it is transmitted genetically, however, for the appearance of symptoms of the disease, the presence of adverse factors is necessary (in 35% of cases, these are head injuries).
The prognosis for narcolepsy is not very good. At the moment, this disease is incurable. Throughout the patient's life, the symptoms of pathology can constantly increase or, on the contrary, decrease. Often, after some time, the person's condition stabilizes.
As a rule, drowsiness accompanies these people all their lives, although cataplexy with age may decrease or disappear altogether.
To improve the quality of life, patients should regularly visit a neurologist, take medications prescribed by a doctor, and observe wakefulness and sleep regime.
To determine how to treat narcolepsy, a neurologist conducts a series of tests and studies, including:
- Clinical blood test;
- General urine analysis;
- Multiple sleep latency test (MTLS);
- Magnetic resonance imaging of the brain;
- CT scan.
The treatment needed for narcolepsy is aimed at relieving symptoms and includes:
- Stimulants that reduce daytime sleepiness (first-line Modafinil or Armodafinil, second-line amphetamines);
- Sleeping pills.
Narcolepsy requires constant use of certain medications because they do not cure the disease but rather suppress the symptoms.
Effect/for what used
First-line medications are Modafinil and Armodafinil sold under the brand names Provigil, Nuvigil, and generic names Artvigil, Waklert, Modalert, and others.
Second-line: Methylphenidate sold under the names Concerta, Ritalin, and others, amphetamines (a combination of dextroamphetamine or amphetamine and dextroamphetamine or amphetamine sulfate) sold under the names Adderall, Dexedrine, and others.
These groups of drugs promote wakefulness stimulating the brain areas and the release or maintenance of the level of natural wakefulness-promoting substances in the brain. Modafinil and Armodafinil promote wakefulness for 10-12 hours, while amphetamines for 2-3 hours and should be taken repeatedly. It is preferable to start treatment with Modafinil or Armodafinil and use amphetamines only if the first-line drugs provide insufficient effect or are poorly tolerated.
Doxepine (Silenor), Eszopiclone (Lunesta ), Ramelteon (Rozerem)
Sleeping pills are not always used for narcolepsy. They can be prescribed only if an individual suffers from severe sleep disturbances such as trouble falling asleep or night awakenings. Based on the problem, different drugs are used as they render different effects and affect different phases of sleep.
CNS depressants and antidepressants (selective serotonin reuptake inhibitors)
Sodium oxybate sold under the brand Xyrem
These drugs are used only in the presence of cataplexy attacks.
They help preventing cataplexy attacks caused by intense emotions by regulating the level of neurotransmitters in the brain and central nervous system.
Lack of timely treatment increases the risk of injury, as the patient can fall asleep in any position, even driging. Patients are contraindicated in work related to transport management, fire and moving mechanisms.
At risk are:
- People with a genetic predisposition (family history of narcolepsy);
- Pregnant women;
- People with brain injuries;
- People with autoimmune diseases.
To prevent the disease, patients are recommended:
- Normalize sleep routine;
- Exercise regularly;
- Avoid emotional and physical overload;
- Limit consumption of coffee, strong tea, heavy food, especially, in the second half of a day;
- Avoid taking medications that affect sleep quality;
- See a doctor in the first signs of sleep disorder.
Post by: John Johansson, M.D., Amsterdam, Netherlands