What Is Narcolepsy?
The Oxford language dictionary explains narcolepsy as a condition characterized by an extreme tendency to fall asleep in relaxing surroundings. It is a neurological condition that affects the sleep, and wake cycle of an individual. A person with narcolepsy tends to sleep excessively during the daytime, people with this disorder can fall asleep suddenly during any activity. This disorder affects an individual's life severely as these people feel sleepy throughout the day.
Individuals with narcolepsy also have an unusual sleep cycle, which means during a sleep cycle. Normal people go through early, deeper, and lastly, rapid eye movement sleep, whereas in people with narcolepsy, the first two stages of sleep are skipped, and they enter the stage of rapid eye movement as soon as they fall asleep and sometimes even when they are awake.
How Is Narcolepsy Classified?
According to the international journal of sleep disorders, Narcolepsy can be classified into two types, mainly based on cataplexy, which means loss of muscle tone, for a fraction of seconds or a few minutes but can cause accidents.
Type 1: Involves cataplexy and causes a sudden loss of muscle tone, muscle control, and weakness. People with this type usually lack a neurotransmitter called hypocretin. Occurrence of type I is relatively more common than type 2.
Type 2: Does not involve cataplexy. It is most commonly caused as a result of injury or a lesion compressing the hypothalamus.
How Does a Person With Narcolepsy Present?
The most common symptoms of the disease are as follows:
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Significant daytime sleepiness.
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Cataplexy.
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Poorly regulated rapid eye movement (REM) sleep.
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Fragmented sleep.
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Hallucinations when falling asleep.
Significant Daytime Sleepiness: Significant daytime sleepiness, also called excessive daytime sleepiness, is the first and most complicated symptom of narcolepsy. A person tends to dose off at any time in the middle of any activity generally that is monotonous. The nap lasts for a few minutes to around half an hour, after which a person feels refreshed for a few minutes or hours. During sleep attacks, many life-threatening accidents can occur, thus making it a serious problem. Daytime sleepiness affects daily activities as well, as a person is disoriented, tired, and feels lazy throughout the day.
Cataplexy: Most commonly known as loss of muscle tone, a characteristic feature of type 1 narcolepsy. This is usually seen after the incidents with a positive emotional response like excitement. It leads to sudden muscle weakness or loss of tone that lasts for a few minutes and affects bilaterally. Though the condition lasts for a few minutes still can end up in a life-threatening situation as a person can be at risk of sudden fall or losing balance, can lose control when driving, etc.
The episodes of cataplexy vary from 2 to 3 episodes annually to the same number of episodes per day.
Poorly Regulated REM Sleep: As mentioned above, people with narcolepsy tend to enter immediately or within a few minutes of falling asleep into the REM sleep, skipping the first two stages of a normal sleep cycle. This is due to disturbance in the brain where the sleep-wake cycle is regulated.
Sleep Paralysis: It is characterized by difficulty in speaking and movement when sleeping or immediately after waking up.
Fragmented Sleep: people with narcolepsy mostly have difficulty sleeping calmly
throughout the night. Narcolepsy also includes other sleep problems like sleep apnea, hallucinations, and excessive sleep movements.
The signs and symptoms of narcolepsy are severe at the onset of the disease and continue further lifelong, the intensity and the severity of the disease remains the same, but individuals learn to cope with it.
What Causes Narcolepsy?
The definitive cause of the disease is not known as the researchers have found some relation between narcolepsy with loss of neurons producing a chemical in the brain called hypocretin, it has also been found that loss of neurons is most likely in people infected with viral most likely H1N1. The other causes of narcolepsy are thought to be hereditary. Injury, trauma to the brain that affects the hypocretin-secreting neurons is considered one of the reasons for the disease, and narcolepsy caused due to trauma to the brain is termed secondary narcolepsy.
How Is Narcolepsy Diagnosed?
A standardized criterion is followed for the diagnosis of narcolepsy, as it helps in accurate diagnosis and differentiation of NT1, NT2, and other sleep disorders.
Following are the criteria for diagnosis of the disease:
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A person with narcolepsy must have significant daytime sleepiness that lasts for more than 2-3 months.
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A person with NT1 must have low hypocretin levels, cataplexy, tendency to enter into the REM stage shortly after sleeping when monitored on MSLT (multiple sleep latency test)
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People with NT2 report the same results when they undergo MSLT (multiple sleep latency test), but they have normal levels of hypocretin and lack cataplexy.
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Differentiating narcolepsy from other sleep disorders is difficult as they have similar pictures but narcolepsy can be ruled out from other sleeping disorders by its characteristic symptoms of short refreshing naps and fragmented night sleep.
Diagnostic Test:
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Multiple sleep latency tests (MSLT).
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Polysomnogram (PSG).
These tests confirm the diagnosis of the disease that is carried out in sleep disorder centers where a person is made to stay overnight to monitor sleep patterns and cycles.
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Lab Test: A blood test is carried out to trace or rule out a genetic marker in the blood called HLA DQB * 0602, which is associated with Narcolepsy.
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Epworth Sleepiness Scale: It is a set of eight questions related to the sleeping tendency that a person has to answer on a scale of 0-3. The scores are obtained between 0-24, and further evaluations are done based on the above scores. Scores between 0-10 are considered to be normal. Any scores above 10 undergo further evaluations and tests to rule out the disease.
This test can be taken at home, and a person does not need to be admitted overnight.
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CSF Evaluation: CSF is obtained from the spine through a lumbar puncture needle and is evaluated for the amount of brain chemical hypocretin.
How Can We Prevent Narcolepsy?
Narcolepsy being a rare disorder, is difficult to diagnose and doesn't have any definitive cure available. When a person is diagnosed with narcolepsy, experts advise measures like planning short naps, having a balanced diet, exercising, and driving with caution to prevent the progress of the disease and avoid accidents by reducing sleep attacks. Measures are taken to help overcome the problem of fragmented sleep that can help a person be more oriented and socially active during the day. Some medications that can be prescribed to reduce the symptoms are Modafinil and armodafinil, Methylphenidate, etc but Sodium oxybate (Xyrem®) is the only FDA-approved drug used to regulate EDS in patients with narcolepsy, patients who are on Xyrem are advised to have low sodium diet.
Conclusion:
Narcolepsy is a difficult-to-diagnose sleep disorder caused mainly due to a deficiency of a chemical in the brain called hypocretin that regulates sleep and wake mechanisms. A person with narcolepsy has a difficult time as he experiences sleep attacks anytime, anywhere.No definitive treatment is available to treat this disorder; thus, symptomatic measures help a person lead a better life.
