There are serious repercussions for infants, teenagers, and adults who suffer from narcolepsy, a sleep disease characterized by excessive daytime sleepiness (EDS).
Both narcolepsy kinds, NT1 and NT2, are quite uncommon. Fewer than 100 out of every 100,000 persons are affected by both categories, according to most estimates.
Since narcolepsy is relatively uncommon, it is possible that many cases go untreated or are discovered years after the onset of symptoms. A patient’s safety and quality of life may be jeopardized if they do not receive treatment in a timely manner following a delayed diagnosis.
Medical testing and sleep studies are just two of the many tools doctors use in the diagnostic process for narcolepsy. When a person with narcolepsy symptoms has a better idea of what to expect from their doctor, they will be better able to collaborate with them.
What is narcolepsy?
The inability of people with narcolepsy to regulate their sleep and wake times is a hallmark of the chronic neurological condition. Those who suffer from narcolepsy may feel refreshed upon rising, but subsequently become overly sleepy for the better part of the day. Uneven and disrupted sleep, including frequent wakings at night, is a common symptom of narcolepsy.
Narcolepsy can greatly affect daily activities. People may unwillingly fall asleep even if they are in the middle of an activity like driving, eating, or talking. Other symptoms may include sudden muscle weakness while awake that makes a person go limp or unable to move (cataplexy), vivid dream-like images or hallucinations, and total paralysis just before falling asleep or just after waking up (sleep paralysis).
If left undiagnosed or untreated, narcolepsy can interfere with psychological, social, and cognitive function and development and can inhibit academic, work, and social activities.
Who Diagnoses Narcolepsy?
Without proper diagnosis and treatment, narcolepsy can have serious negative effects on a person’s mental health and wellbeing, including on their ability to learn, work, and interact socially.
Sleep specialists, neurologists, and/or psychiatrists may be consulted in some circumstances to provide additional diagnostic and therapeutic information.
What are the symptoms?
Narcolepsy is a chronic condition that does not improve with age. There may be some amelioration of symptoms over time, but they will never entirely disappear. Common signs include difficulty staying awake during the day, sleep paralysis, cataplexy, and hallucinations. In spite of the fact that every patient suffers from extreme drowsiness throughout the day, only about 10–25% of those who are afflicted will experience all of the other symptoms.
- Excessive drowsiness during the day (EDS). EDS is present in everyone who suffers from narcolepsy and is frequently the most noticeable symptom. With EDS, daytime sleepiness is always a problem, even if you get enough of shut-eye at night. In narcolepsy, however, fatigue is more akin to a “sleep attack,” in which a sudden and severe feeling of tiredness strikes. The individual’s regular level of alertness returns between bouts of sleepiness, especially if they engage in activities that demand their whole concentration.
- Cataplexy. Weakness and a lack of control over one’s muscles are the results of this sudden decrease of muscular tone that occurs while the person is awake. Sudden, intense feelings like joy, terror, rage, worry, or excitement might set it off. Cataplexy symptoms may not show up until months or even years after the first diagnosis of EDS. While others may have several attacks every single day, some people may only have one or two in their whole career. Cataplexy is the first symptom to occur in roughly 10% of patients of narcolepsy and might be mistaken for a seizure disease. Milder attacks may just cause a temporary feeling of weakness in a few muscles, like a drooping of the eyelids. A total collapse of the body occurs in the most severe bouts, making it impossible for the victim to do anything, including move, speak, or keep their eyes open. However, even during the most severe attacks, sufferers maintain full consciousness, setting cataplexy apart from conditions like fainting and epilepsy. Cataplexy’s decrease of muscular tone parallels the paralysis of muscle action that happens during REM sleep. Incidents typically last no more than a few minutes and clear up on their own without any intervention. Scary as they may seem, these episodes pose little threat so long as the victim can locate a safe location to collapse.
- Lack of movement during sleeping. Similar to REM-induced inhibitions of voluntary muscular action, the incapacity to move or talk during sleep or awakening often only lasts for a few seconds or minutes. Sleep paralysis is quite similar to cataplexy, however it happens in the twilight stages of sleep. Affected individuals retain complete awareness, as is the case with cataplexy. When episodes of cataplexy or sleep paralysis end, sufferers typically regain full motor and verbal function very quickly.
- Hallucinations. Sleep paralysis often occurs at the onset or cessation of a sleep state, and is accompanied by extremely vivid and, at times, terrifying imagery. In most cases, visuals take the stage, but any sense can play a role.
Included in the list of narcolepsy symptoms are:
- The inability to sleep or only sleeping in small increments. Those who suffer from narcolepsy often have trouble falling asleep at night and staying asleep during the night, while being extremely sleepy during the day. Insomnia, vivid dreams, sleep apnea, disruptive behavior in dreams, and REM sleep behavior disorder are among sleep disorders that can cause disruptions.
- Automatic behaviors. Individuals with narcolepsy may experience temporary sleep episodes that can be very brief, lasting no more than seconds at a time. A person falls asleep during an activity (e.g., eating, talking) and automatically continues the activity for a few seconds or minutes without conscious awareness of what they are doing. This happens most often while people are engaged in habitual activities such as typing or driving. They cannot recall their actions, and their performance is almost always impaired. Their handwriting may, for example, degenerate into an illegible scrawl, or they may store items in bizarre locations and then forget where they placed them. If an episode occurs while driving, individuals may get lost or have an accident. People tend to awaken from these episodes feeling refreshed, finding that their drowsiness and fatigue has temporarily subsided.
What are the types of narcolepsy?
Habitual actions. Sleep episodes in people with narcolepsy may be extremely brief, lasting only a few seconds at a time. When a person nods off while engaged in a task (eating, conversing), they may unknowingly carry on with their actions for several seconds or minutes. As a rule, this occurs when the victim is performing a routine task, such typing or driving. They have no idea what they did, and they are virtually always less effective because of it. For example, their handwriting may deteriorate into an unreadable scrawl, or they may start putting things in odd places and then forget where they put them. Some people may become disoriented or even crash their cars if they experience an episode while driving. After one of these events, people often report feeling invigorated, with their exhaustion and lethargy having temporarily vanished.
- Disorder characterized by recurrent episodes of sleepiness known as narcolepsy, type (previously termed narcolepsy with cataplexy). Cataplexy and excessive daytime sleepiness on a particular nap test or low levels of a brain hormone (hypocretin) are the two main criteria for making this diagnosis.
- Definition of Narcolepsy, Type 2 (previously termed narcolepsy without cataplexy). People with this illness are typically affected by daytime sleepiness but do not typically suffer from emotional-triggered muscle weakness. They also tend to have normal levels of the hormone hypocretin in the brain and have milder symptoms. Secondary narcolepsy develops when the hypothalamus, a deep brain area responsible for regulating sleep, is damaged. Some people with narcolepsy have significant neurological issues and sleep for more than 10 hours a night, in addition to experiencing the classic narcolepsy symptoms.
What causes narcolepsy?
There is no one clear cause for narcolepsy. Hypocretin, a naturally occurring hormone that encourages wakefulness and controls rapid eye movement (REM) sleep, is absent or present in extremely low amounts in nearly all patients with narcolepsy who experience cataplexy. People with narcolepsy who do not experience cataplexy typically have normal levels of hypocretin.
Although the cause of narcolepsy is not completely understood, current research suggests that narcolepsy may be the result of a combination of factors working together to cause a lack of hypocretin. The following are some of these elements:
- Illnesses caused by the body’s immune system. Hypocretin-producing brain cells are particularly vulnerable to death, which makes their demise a common underlying cause of cataplexy. Despite the fact that the underlying cause of this cell death is still unknown, evidence suggests that it is connected to immune system disorders. Diseases of the immune system are called autoimmune diseases because they manifest when the body’s defenses start attacking its own cells and tissue instead of the harmful invaders. Scientists believe that a combination of hereditary and environmental variables drive the immune system to target and destroy hypocretin-containing brain cells in people with narcolepsy.
- A look back in time. The vast majority of narcolepsy instances develop “in the wild,” or in people who have no known relatives who suffer from the illness. However, there can be familial clusters; up to 10% of people with a diagnosis of narcolepsy with cataplexy also report a close family with the disorder.
- Traumatic brain damage. Injury or disease to the brain regions responsible for controlling wakefulness and rapid eye movement (REM) sleep are rare causes of narcolepsy.
How Is Narcolepsy Diagnosed?
Talking to a primary care doctor or family doctor should be the first step for anyone experiencing symptoms of narcolepsy or EDS. The diagnostic procedure, which often consists of numerous stages, might begin with this initial point of contact.
The first step in diagnosing any medical condition is for the doctor to learn more about your symptoms, go over your medical history, and perform a thorough physical examination.
The doctor may inquire as follows to better understand your symptoms:
- Typically, how many hours do you snooze each night?
- When trying to go to sleep at night, do you find it hard to relax?
- What’s your nocturnal waking experience like?
- Do you feel sleepy and/or take naps during the day?
- Is daytime sleepiness a problem for you?
- Do you find it difficult to concentrate during the day?
- Did you get a good night’s sleep? In the event that you are rousing yourself from a nap?
- In your slumber, do you ever dream?
- Is weekend sleep longer than weekday sleep for you?
- Do you feel like you can’t move or have hallucinations right before you fall asleep or wake up?
- Have you ever suffered a cataplexy attack, in which you suddenly lose control of your muscles?
- Do you produce loud gasping or choking noises when you sleep, or do you snore?
There are numerous potential causes of EDS, and your responses to these questions will be very helpful to the doctor in determining the most likely cause. Other potential causes of your symptoms can be ruled out with a thorough physical examination and evaluation of your medical history and current medications.
The doctor may have you take the brief Epworth Sleep Scale to learn more about your sleeping habits (ESS). The doctor can use your impressions of how sleepy you feel from these survey questions.
In addition, your doctor may have you keep a sleep log, a chronicle of your sleep patterns, for a week or more. Actigraphy, which utilizes a tracker in a watch-like device, is yet another method of quantifying sleep quality.
While this is helpful, a diagnosis of narcolepsy requires more than just a patient’s symptoms. However, a diagnosis of narcolepsy cannot be made without first ruling out all other possible explanations for the patient’s symptoms.
Polysomnography and the Multiple Sleep Latency Test
Two types of sleep investigations are commonly recommended by doctors who suspect narcolepsy or another sleep disorder:
- Overnight in a sleep lab, a polysomnogram (PSG) records your vital signs and monitors your eye and muscle activity as well as your brain’s electrical activity. A polysomnogram (PSG) records your sleep patterns and awakenings, and can detect conditions including sleep apnea.
- The Multiple Sleep Latency Test (MSLT) typically follows the polysomnogram (PSG) first thing in the morning. You will keep your PSG sensors attached throughout the duration of the exam. The MSLT tracks how quickly you drift off to sleep and how quickly you enter rapid eye movement (REM) sleep at five distinct intervals during your sleep study.
Both polysomnography (PSG) and multiple sleep latency testing (MSLT) are elaborate procedures that require a sleep clinic’s expert personnel. Due to a lack of brain activity monitoring, narcolepsy cannot be diagnosed using at-home testing.
The PSG and MSLT findings may be decisive in making a narcolepsy diagnosis. Narcoleptics with both types of the disorder have a substantially faster average time to sleep (less than eight minutes) and enter rapid eye movement (REM) sleep far quicker than the general population.
Taking the time to study thoroughly before taking these exams is essential if you want to get reliable results from them. A sleep record or actigraphy may be required to prove that you have been able to maintain a regular sleep routine for at least seven days prior to the test. Stopping the use of any drugs or treatments that can affect sleep is also recommended before testing begins.
In the lead-up to your sleep study, your doctor or a sleep lab technician can give you detailed instructions and explain what to expect.
Hypocretin and HLA Testing
Cerebrospinal fluid (CSF) is drawn from the lower spine via a lumbar puncture, and its hypocretin content is analyzed in a lab. Hypocretin, also known as orexin, is a neurotransmitter that regulates sleep and wakefulness. If your hypocretin levels are low, it may be a sign that you have narcolepsy type 1, which is caused by the death of neurons in the brain that make the chemical.
Almost everyone with NT1 also carries a mutation in a gene called HLA-DQB1*06:02, which is associated with reduced hypocretin levels. This polymorphism can be sought up with human leukocyte antigen (HLA) testing, but as it is present in many persons who do not have narcolepsy, it cannot be used as a diagnostic tool on its own.
Other Medical Tests
If your doctor suspects and wants to rule out another ailment as the source of your symptoms, they may order further, non-routine tests, such as blood work or imaging.
What Are the Criteria for Diagnosing Narcolepsy?
The doctor will be able to tell if your case of narcolepsy fits the established criteria by considering your symptoms, the findings of the physical exam, and the outcomes of any sleep studies or other testing that have been performed.
The diagnostic criteria for narcolepsy types 1 and 2 are different. The presence or absence of cataplexy, the rapid and transient decrease of muscular tone associated with happy emotions, is a key differentiator between the two illnesses. Cataplexy is a condition unique to NT1.
The following table provides a comparison of the diagnostic criteria:
Narcolepsy Type 1
Two conditions must be met by the patient:
- A prolonged case of EDS (lasting three months or more)
- PSG/MSLT findings of rapid eye movement (REM) sleep phase (Sleep) awakening and symptom onset in cataplexy
- CSF hypocretin levels are low.
Narcolepsy Type 2
All five of the following conditions must be present in the patient:
- A prolonged case of EDS (lasting three months or more)
- PSG/MSLT findings indicating rapid eye movement (REM) sleep beginning and waking up before midday
- The absence of cataplexy symptoms
- Findings of hypocretin in the cerebrospinal fluid (CSF) are either normal or are not known.
- There is no other illness that can explain the patient’s symptoms and lab results.
A person’s diagnosis may shift when more information becomes available. As many as 10% of those who are first diagnosed with NT2 will go on to develop cataplexy and be reclassified as NT1.
What Disorders Can Mimic Narcolepsy?
Diagnosing narcolepsy can be challenging because its symptoms are shared by different disorders.
About a third of Americans don’t get enough sleep, which can lead to drowsiness during the day. Multiple neurological and behavioral health issues, including insomnia and sleep apnea, can potentially contribute to EDS.
Cataplexy is quite NT1-specific, yet it might still be misunderstood as a seizure or a stroke. Some of the symptoms of narcolepsy, such as sleep paralysis and hallucinations, can also arise on their own or as a symptom of another disorder.
Although NT1 can be diagnosed with a test for hypocretin levels in the cerebrospinal fluid (CSF), NT2 has no such reliable biomarker. Doctors often have to exercise discretion when making a diagnosis of narcolepsy due to symptom overlap with other conditions such as idiopathic hypersomnia and insufficient sleep syndrome.
Is Narcolepsy Diagnosed the Same Way in Children, Teens, and Adults?
Young children, adolescents, and adults all employ the same diagnostic criteria and procedures for narcolepsy. However, additional factors may be taken into account when assessing pediatric patients:
- Narcolepsy in children may be misinterpreted as attention-deficit/hyperactivity disorder (ADHD) or another behavior problem due to the irritability or hyperactivity that may accompany EDS.
- In children, the first signs of cataplexy may manifest as smaller motions, often confined to the face. These may go unnoticed or be mistaken for tics of the face.
- It is sometimes crucial to have parental involvement in the diagnosis procedure, especially for younger children who may have difficulty recalling their sleep habits or verbalizing symptoms like sleep paralysis or hallucinations.
- Some adolescents with narcolepsy may initially test normal on the MLST because it has not been explicitly validated for use in this age group.
What Questions Can You Ask Your Doctor About Narcolepsy?
Being well-prepared for a doctor’s appointment about narcolepsy is a big benefit. You should be prepared to give a detailed account of your symptoms and their duration. It could be helpful if you came prepared with a list of questions to ask. Here are some possible questions:
- I’m wondering if my signs and symptoms point to narcolepsy.
- Is there anything else that might explain my symptoms?
- What diagnostic procedures would you suggest for me to find out what’s causing my symptoms?
- Do you have any advice on how I might best prepare for the examinations you suggest?
- When can we expect to hear about how the tests went?
- Is there anything I can do in the interim to alleviate my symptoms?
- Is it advisable to see a doctor, perhaps a sleep doctor?
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