Narcolepsy: what is it?
Narcolepsy is a chronic disease characterized by excessive daytime sleepiness and sudden sleep attacks. The episodes or sleep attacks usually last from a few seconds to several minutes and can occur at any time, thus significantly affecting all daily activities. These people may fall asleep involuntarily at work, at school, while talking to someone, playing games, eating, or, most dangerously, while driving a car or operating potentially dangerous equipment or machinery.
Symptoms of narcolepsy to identify risk
Symptoms of narcolepsy can appear at any age (from infancy to 45-55 years of age), although most often the first symptoms occur between 10 and 25 years of age.
Typical symptoms of narcolepsy (they need not all be present) are:
– Excessive daytime sleepiness (first and most frequent symptom). People with narcolepsy fall asleep without warning, anywhere and at any time.
– Cataplexy or sudden loss of muscle tone. Cataplexy is considered the only specific sign of narcolepsy, although not all people with narcolepsy have cataplexy (it occurs in 60-70% of narcoleptics). These episodes are not associated with loss of consciousness; they are episodes that the patient usually remembers and can describe later. Sometimes they consist only of a kind of subjective feeling of uncontrollable weakness that is usually triggered by intense emotions such as laughter, fear, surprise, etc….
– Sleep paralysis, at sleep onset or on awakening from sleep: This is a temporary inability to move or speak. They are usually brief episodes of 1-2 minutes, but very distressing.
– Hypnagogic hallucinations (falling asleep) or hypnapompic hallucinations (waking up). They are usually visual, like a kind of very real and very vivid dreams.
– Nocturnal sleep disturbances, with sleep disruption or fragmentation. Approximately half of the patients with narcolepsy have problems sleeping during the night.
– Other accompanying symptoms: recurrent naps throughout the day, automatic behaviors, memory lapses, etc.
Causes of narcolepsy
Narcolepsy is currently considered to be a disease of autoimmune origin, although the exact cause remains unknown. The immune system in response to an infection (e.g., influenza virus) may mistakenly attack a group of neurons (located in a region of the brain called the hypothalamus) that produce a neurotransmitter called hypocretin or orexin, a neurotransmitter that usually helps regulate wakefulness and REM sleep.
How to diagnose narcolepsy
Despite the frequent early onset of the disease, most patients with narcolepsy remain undiagnosed for many years (it is usually not definitively diagnosed until 10 to 15 years after the first symptoms.
A thorough clinical examination and medical history are essential for diagnosis. However, this lack of specificity of symptoms in narcolepsy generally makes other more specialized diagnostic tests (which can be performed in any Sleep Disorders Unit) necessary to help establish the diagnosis definitively.
There are two tests that are considered essential to confirm the diagnosis of narcolepsy:
– The Polysomnography (PSG) or Sleep Study: this consists of an overnight test that takes measurements of several variables throughout the night to see if it is a normal sleep or there is some type of sleep disturbance.
– The Test of Multiple Sleep Latencies (TLMS): is performed during the day, the next morning, and consists of four or five short 20-minute naps, usually scheduled 2 hours apart, to measure the level of sleepiness during the day. It assesses a person’s ease of falling asleep or sleep latency (a latency period of 5 minutes or less is considered highly suggestive of narcolepsy) and whether there are REM sleep intrusions (if a person goes into REM sleep during at least two of these scheduled naps, it is also considered a positive sign of narcolepsy).
Although rarely used (only to confirm difficult to diagnose cases) determination of CSF hypocretin levels by lumbar puncture may also be useful.
If a person tends to fall asleep, is it always due to narcolepsy or can there be other problems that prevent rest?
Excessive daytime sleepiness, the most common symptom of narcolepsy, is not exclusive to this disease and can also appear in other diseases, such as infections, depression, cranioencephalic trauma, central nervous system tumors, etc. or in other sleep disorders such as, for example:
– Sleep apnea
– Circadian rhythm disorders
– Restless legs syndrome
– Any other disorder with the capacity to disrupt normal sleep patterns.
Various drugs or substances of abuse can also cause increased sleepiness that clinically simulates narcolepsy.
Beforehand, it should always be ruled out that there is no chronic sleep deprivation, a fact that has now become one of the most frequent causes of excessive daytime sleepiness.
Narcolepsy treatment and results
There is no cure for narcolepsy, but it is a manageable condition with medication and some lifestyle changes. Excessive daytime sleepiness and cataplexy (the most disabling symptoms of the disorder) can be controlled in most patients with drug treatment.
The most commonly used drugs are usually methylphenidate, modafinil or sodium oxabate. However, none of the currently available drugs allows people with narcolepsy to maintain a completely normal state of alertness on a sustained basis. Therefore, pharmacological therapy is usually complemented by non-pharmacological measures consisting of behavioral techniques and education to understand the disease, which is necessary for both the patient and the people with whom he or she interacts (as these patients can benefit greatly from the support of family, friends, teachers, co-workers, etc.).
Among the most important common sense measures patients can take to improve sleep quality are maintaining a regular sleep schedule, avoiding tobacco, alcohol and caffeine-containing beverages, and making some lifestyle changes (which may also include scheduled short naps of less than 20 minutes duration so that they do not interfere with nighttime sleep).
Children and adolescents with narcolepsy can try to adjust their school schedules as much as possible by informing school personnel of their needs.
Adults can try to discuss and reach an agreement with their employers or company about the possibility of modifying their work schedules to allow them to take short naps if necessary, or to perform the most demanding tasks when they are most alert.
These patients are also advised to take some safety precautions. Actions that are usually safe, such as walking down a flight of stairs or driving, can become potentially very dangerous if you suddenly fall asleep or lose muscle control. People with untreated narcoleptic symptoms are about 10 times more likely to have a traffic accident than the general population. In contrast, the frequency of accidents among patients who have received adequate pharmacological treatment is similar to the rest of the population.
People with narcolepsy are often unfairly judged as lazy, unintelligent, undisciplined or unmotivated. Such stigma often increases the tendency toward isolation, so joining support groups with other people with narcolepsy can provide important practical and emotional help.
Short Self-Test to find out if you suffer from narcolepsy
– Have you had sleep attacks during the day even if you had enough sleep the night before?
– Have you ever fallen asleep while working, eating or talking to someone?
– Have you felt alert after a short nap but soon afterward the drowsiness quickly returned?
If you answered yes to these three questions, you probably have narcolepsy. Consult a physician specializing in Clinical Neurophysiology and/or Sleep Medicine.