Introduction to narcolepsy Paroxysmal sleeping sickness is a disease characterized by an irresistible short-term sleep attack. It is a syndrome with unclear etiology, which is characterized by abnormal sleep tendencies, including excessive daytime sleepiness, nocturnal restlessness and pathological REM sleep. More than children or youth onset, the incidence of men and women is similar, some patients may have a history of encephalitis or craniocerebral trauma. Its pathogenesis is not yet clear, which may be related to the decreased function of the ascending activation system of the brainstem reticular formation or the hyperfunction of the caudal pontine reticular nucleus. Most patients are accompanied by other symptoms such as cataplexy, sleep paralysis, sleep hallucination, and so on, which is collectively called the tetralogy of narcolepsy. Basic knowledge Prevalence rate: 0.003% Susceptible population: mostly in children or youth Mode of infection: non infectious Complications: neurasthenic autism


Causes of narcolepsy

Functional lesions (25%):

It is related to the decreased function of the ascending activation system of the brainstem reticular formation or the hyperfunction of the caudal pontine reticular nucleus. Some studies also believe that it is an autosomal dominant hereditary disease. Although the incidence rate is high in some races, such as the Japanese, there are reports of cases in various races and around the world. In various populations, their genetic characteristics are closely related to human HLA minimal tissue related genes (DR and DQ loci), The pathogenesis is the disorder of REM sleep regulation. The loss of control over REM sleep immediately after the NREM sleep cycle increases the tendency to enter REM sleep, whether at the beginning of sleep or in the waking period.

Trauma factors (25%):

Sandyk (1995) believed that the dysfunction of the pineal gland and its melatonin secretion might be related to the occurrence of this disease, and others believed that it might be related to brain trauma, viral infection, immune dysfunction, brain tumors, multiple sclerosis and other diseases. The occurrence of normal REM sleep depends on the triggering of the 5-hydroxytryptamine system in the brain stem raphe nucleus to other transmitter systems, This triggered dysrhythmia can lead to this disease.

Genetic factors (20%):

Yoss reported in 1960 that there were 12 cases (7 men and 5 women) in three generations of a family. Animal experiments showed that when both parents of dogs were narcolepsy, all litter of dogs were affected, while those dogs bred by mating with unrelated or distant dogs were not affected. The transmission mode might be autosomal recessive inheritance, but it was also found that, Not all kinds of dogs show that the genetic transmission of sleeping sickness may be caused by different causes.

Environmental factors (15%):

Honda and others reported that 100% of Japanese narcolepsy patients showed positive HLA-DR2. Scholars in Europe and America also confirmed that most Caucasian narcolepsy patients were HLA-DR2, DQWl and DW2 positive, but Guilleminault and others believed that the transmission of narcolepsy was multifactorial, and environmental factors also played an important role.


Prevention of narcolepsy

In order to avoid accidents, it is necessary to take a series of prevention and control measures in daily life to reduce attacks. Patients should consciously arrange their lives in a colorful way, participate in recreational and sports activities, do some interesting work, try to avoid monotonous activities, and drink tea or coffee properly in the daytime to increase brain excitability.

Keep an optimistic mood, establish confidence in overcoming diseases, avoid depression and sadness, but also not be too excited, because the loss of excitement can induce a sudden attack, it is better not to travel alone, do not engage in high-altitude, underwater operations, not to be engaged in driving vehicles, managing various signals and other work with great responsibility, so as to avoid accidents.


Complications of narcolepsy complication Neurasthenic autism

In addition to sleep attacks, some patients complain of fatigue and sleepiness, low alertness all day long, poor memory, low work efficiency, affecting physical health and work efficiency, and reducing the quality of life. Long term lack of sleep can lead to irritability, depression, autonomic nervous dysfunction, digestive dysfunction, reduced immune function, and can also be accompanied by hypertension and arrhythmia, Cerebrovascular disease, diabetes, kidney disease, etc.


Symptoms of narcolepsy common symptom Irregular breathing, anxiety, palpitation, palpitation, fatigue, sleep apnea Hallucinatory asthenia, sleep paralysis, lethargy

The onset age is generally from childhood to early adulthood, but it is generally not detected before adolescence. The most common age is 10-20 years old. The incidence rate is the same for men and women. A few patients have a history of encephalitis or brain injury, but the relationship with this disease has not been confirmed.

The first symptoms are mostly in adolescence, and narcolepsy, cataplexy, sleep paralysis and hallucination before falling asleep are the four main symptoms of the disease.

1. Episodic somnolence : When patients wake up, they are generally in a state of frequent and fluctuating low alertness level, which is more obvious in the afternoon. When the degree of drowsiness increases, short sleep occurs. Most patients feel more sleepy before the onset, and only a few patients suddenly fall into sleep from their relative waking state. The monotonous environment, such as reading and listening to lectures, is easy to induce, Typical cases can occur in various activities, such as eating, speaking, operating machines, driving vehicles, etc. Each attack lasts from a few seconds to several hours, most of which last for tens of minutes. Most of them do not sleep deeply, and are easy to wake up. After waking up, they generally feel temporarily awake, which can occur several times a day.

2. Suddenness: Cataplexy is a transient, completely reversible attack of exercise inhibition, which is characterized by sudden loss or reduction of voluntary muscle strength. It can occur in 50%~70% of patients, often induced by laughter, anger, emotional excitement, tension, fatigue or satiety.

The typical hair is jaw relaxation, head drooping forward, arms falling to one side and knees opening, and complete loss of muscle strength can lead to trauma or even fracture, but the severity of the attack is not all so serious, and it can only be a temporary, local or systemic sense of weakness. The patient can complain of blurred vision (palpebral muscle involvement), language interruption (arytenoid muscle involvement), Irregular breathing (involvement of abdominal muscles or diaphragm), slight bending of knee or sudden falling of holding objects (involvement of upper and lower limb muscles) may be accompanied by involuntary movements, such as head and eyelid tremor, facial spasm, and also accompanied by autonomic nervous symptoms such as palpitation and pallor. These atypical attacks are often ignored by doctors and should be paid special attention.

Symptoms often disappear after the emotion returns to normal or the body is touched. Sudden attacks are accompanied by inhibition of tendon reflex, but always remain conscious. The frequency of attacks can occur once every few days or months, or four to five times a day. Each attack lasts for several seconds to 30 minutes (Zancone, 1973).

The relationship between cataplexy and other symptoms is 50% at the same time, 25% 1~5 years after the onset of narcolepsy, and 15% 10 years after the onset of narcolepsy. It is extremely rare that cataplexy occurs before the onset of narcolepsy.

3. Sleeping paralysis : About 20%~30% of narcolepsy patients may also appear alone, either in the afternoon or at night when they wake up or fall asleep.) Occasionally, flaccid paralysis of the limbs occurs. The patient is conscious, but cannot speak or act, often accompanied by anxiety and hallucination, which usually subsides in seconds to minutes, occasionally for hours, When someone touches the patient's body or speaks to him, the attack can often be stopped, but it may recur if he does not act after remission.

4. Hallucination during sleep : It can appear in about 30% of patients, often at the same time with sleep paralysis. Hallucinations mainly occur in the sleepy period, mainly visual and auditory hallucinations, and may also be tactile, pain and other somatosensory hallucinations. Most of the contents are bright, and most of them are patients' daily experiences.


Examination of narcolepsy

1. Multiple sleep latency test (MSLT) is a test to assess the degree of sleepiness. Subjects in a comfortable, quiet and dimly lit room are allowed to nap for 20 minutes every 2 hours for 5 to 6 times, usually at 10:00, 12:00, 14:00, 16:00 and 18:00. At the same time, PSG is used for monitoring, Record the time from turning off the light to the beginning of sleep (according to EEG), the presence or absence of REM period and the time of its occurrence. It is generally believed that the sleep latency of normal people should be more than 10 minutes, if the average is less than 8 minutes, it is pathological; The REM phase occurs during the nap and is within 15 minutes of the beginning of sleep (normal people occur about 90 minutes after the beginning of sleep), which is considered to be a sleep that starts in REM phase. If there are more than two times of sleep that starts in REM phase in MSLT, and the overnight polysomnography excludes other diseases that can cause sleepiness, then paroxysmal sleeping sickness can be diagnosed.

2. Polysomnography (PSG) examination: SAS can be distinguished from narcolepsy. SAS has typical respiratory events, and a few narcolepsy patients also have sleep apnea (Zancone, 1973). When distinguishing from OSAS, attention should be paid to whether there is pathological REM sleep.

3. PSG examination with anterior tibial electromyography: PLMS can be diagnosed, which is characterized by periodic burst activity of anterior tibial electromyography, lasting 0.5~5s, with 15~60s intervals.

On the basis of inquiring medical history and key nervous system examination, other necessary and selective auxiliary examination items include:

1. CT and MRI.

2. Routine blood test, blood electrolyte, blood sugar, urea nitrogen.

3. ECG, abdominal B-ultrasound, chest X-ray, thyroid function examination.


Diagnosis and differentiation of narcolepsy

It is generally believed that if there is a typical history of narcolepsy attacks and cataplexy symptoms, it can be diagnosed. Others believe that only the typical history of narcolepsy can be diagnosed. With the continuous development of sleep medicine, people have realized that many diseases can cause daytime narcolepsy attacks, such as sleep apnea syndrome (SAS), periodic leg movement syndrome (PLMS), etc, A distinction should be made.

It must be differentiated from the following diseases

1、 Seizures are mostly found in children or adolescents. The main symptom is the disturbance of consciousness. They often suddenly lose consciousness, stare directly, stand still, and do not fall; Or suddenly stop the ongoing action, such as holding the object to the ground, unable to continue the original action, lasting for several seconds, EEG can have a 3Hz spike slow complex wave,

2、 Faint, transient loss of consciousness caused by cerebral blood circulation disorder, most of which have transient omens such as dizziness, weakness, nausea, blackness in front of the eyes, followed by loss of consciousness and fainting, often accompanied by autonomic nervous symptoms, such as pale face, cold sweat, weak pulse, low blood pressure, which last for several minutes,

3、 Kleine Levin syndrome, also known as periodic somnolence and pathological hunger syndrome, is usually seen in male adolescents. It presents periodic attacks (several weeks or months apart), lasting for 3 to 10 days each time. It is characterized by somnolence, gluttony and abnormal behavior. The etiology and pathogenesis are still unclear, and may be caused by abnormal function of the diencephalon, especially the hypothalamus, or focal encephalitis.

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