Narcolepsy

Narcolepsy is a sleep disorder that makes people very drowsy during the day. People with narcolepsy find it hard to stay awake for long periods of time. They fall asleep suddenly. This can cause serious problems in their daily routine.

Sometimes narcolepsy also causes a sudden loss of muscle tone, known as cataplexy (KAT-uh-plek-see). This can be triggered by strong emotion, especially laughter. Narcolepsy is divided into two types. Most people with type 1 narcolepsy have cataplexy. Most people who don't have cataplexy have type 2 narcolepsy.

Narcolepsy is a life-long condition for which there's no cure. However, medicines and lifestyle changes can help manage the symptoms. Support from others — family, friends, employers and teachers — can help people cope with the disorder.

Narcolepsy Type 1

NT1 is associated with the symptom of cataplexy, which is the sudden loss of muscle tone. NT1 was formerly known as “narcolepsy with cataplexy.”

Not all patients who are diagnosed with NT1 experience episodes of cataplexy. NT1 can also be diagnosed when a person has low levels of hypocretin-1, a chemical in the body that helps control wakefulness.

Even when not present at diagnosis, cataplexy eventually occurs  Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source in a significant number of people with low levels of hypocretin-1.

Narcolepsy Type 2

NT2 was formerly known as “narcolepsy without cataplexy.” People with NT2 have many similar symptoms as people with NT1, but they do not have cataplexy or low levels of hypocretin-1.

If a person with NT2 later develops cataplexy or low hypocretin-1 levels, their diagnosis can be reclassified as NT1. This change in diagnosis is estimated to occur in about 10% of cases.

Symptoms

The symptoms of narcolepsy may get worse during the first few years of the disorder. Then they continue for life. They include:

• Excessive daytime sleepiness. People with narcolepsy fall asleep without warning. It can happen anywhere and at any time. It may happen when you're bored or during a task. For example, you may be working or talking with friends and suddenly fall asleep. It can be especially dangerous if you fall asleep while driving. You might fall asleep for only a few minutes or up to a half-hour. After waking, you'll often feel refreshed but you'll get sleepy again.

You also may experience a decrease in how alert and focused you feel during the day. Daytime sleepiness often is the first symptom to appear. Feeling sleepy makes it hard to focus and function.

Some people with narcolepsy continue doing a task when they fall asleep briefly. For example, you may fall asleep while writing, typing or driving. You might continue to perform that task while asleep. When you awaken, you can't remember what you did, and you probably didn't do it well.

• Sudden loss of muscle tone. This condition is called cataplexy. It can cause slurred speech or complete weakness of most muscles. Symptoms may last up to a few minutes.

Cataplexy can't be controlled. It's triggered by intense emotions. Often the emotions that cause cataplexy are positive. Laughter or excitement may cause the symptoms. But sometimes fear, surprise or anger can cause the loss of muscle tone. For example, when you laugh, your head may drop without your control. Or your knees may suddenly lose strength, causing you to fall.

Some people with narcolepsy experience only one or two episodes of cataplexy a year. Others have several episodes a day. Not everyone with narcolepsy has these symptoms.

• Sleep paralysis. People with narcolepsy often experience sleep paralysis. During sleep paralysis, you can't move or speak while falling asleep or upon waking. It's usually brief — lasting a few seconds or minutes. But it can be scary. You may be aware of it happening and can recall it afterward.

Not everyone with sleep paralysis has narcolepsy.

• Hallucinations. Sometimes people see things that aren't there during sleep paralysis. Hallucinations also may happen in bed without sleep paralysis. These are called hypnagogic hallucinations if they happen as you fall asleep. They're called hypnopompic hallucinations if they happen upon waking. For example, you might feel as if there is a stranger in your bedroom. These hallucinations may be vivid and frightening because you may not be fully asleep when you begin dreaming.
• Changes in rapid eye movement (REM) sleep. REM sleep is when most dreaming happens. Typically, people enter REM sleep 60 to 90 minutes after falling asleep. But people with narcolepsy often move more quickly to REM sleep. They tend to enter REM sleep within 15 minutes of falling asleep. REM sleep also can happen at any time of the day.

Diagnosis Criteria

A). recurrent period of an irrepressible need to sleep, lapsing in to sleep, or napping occurring within the same day. These must have been occurring at least three times per week over the past 3 months.

B). the presence of at least one of the following:

1. Episodes of cataplexy, defined as either (a) or (b), occurring at least a few times per month:

1. In individual with long-standing disease, brief (second to minutes) episodes of sudden bilateral loss of muscle tone with maintained consciousness that is precipitated by laughter or joking.
2. In children or in individuals within 6 months of onset, spontaneous grimaces or jaw-opening episodes with tongue thrusting or a global hypertonia, without any obvious emotional triggers.

   2).   Hypocretin deficiency, as measured using cerebrospinal fluid (CSF) hypocertin-1 immunoreactivity values (less than or equal to one-third of values obtained in healthy subjects tested using the same assay, or less than or equal to 110pg/ml). low CSF levels of hypocretin-1 must not be observed in the context of acute brain injury, inflammation, or infection.

3). Nocturnal sleep polysomnography  showing rapid eye movement (REM) sleep latency less than or equal to 15 minutes, or a multiple sleep latency test showing a mean sleep latency less than or equal to 8 minutes and two or more sleep-onset REM periods.

Treatments

There is no cure for narcolepsy type 1 or type 2. The goals of treatment for narcolepsy are improving patient safety, reducing symptoms, and enhancing quality of life.

For many people with narcolepsy, the disease remains generally stable over time. In some cases, certain symptoms may improve as the patient ages, and rarely, remission of symptoms may happen spontaneously. So far, experts do not know why the disease unfolds differently in different people.

Treatments for NT1 and NT2 are similar except that NT2 does not involve potentially taking any medications for cataplexy.

A combination of medical and behavioral approaches can significantly decrease but not eliminate symptoms. Some level of EDS normally persists despite treatment. All therapies should be carried out under the guidance of a doctor who can best tailor a treatment plan to the patient’s specific situation.

Behavioral Approaches to Treatment

Behavioral approaches are non-medical forms of therapy, and there are multiple ways that they can be incorporated into the daily habits of people with narcolepsy.

• Planning short naps: Because brief naps are refreshing for people with narcolepsy, budgeting time for naps during the day can reduce EDS. Accommodations at school or work may be necessary to make time for naps.
• Having healthy sleep hygiene: To combat poor sleep at night, people with narcolepsy can benefit from good sleep habits. Good sleep hygiene includes a consistent sleep schedule (for bedtime and waking up), a sleep environment with minimal distractions and disruptions, and limited use of electronic devices before bed.
• Avoiding alcohol and other sedatives: Any substance that contributes to sleepiness may worsen daytime narcolepsy symptoms.
• Driving with caution: People with narcolepsy should talk with the doctor about safe driving. Napping before driving and avoiding long or monotonous drives are examples of measures to improve safety.
• Eating a balanced diet: People with narcolepsy have a higher risk of obesity, which makes eating well an important part of their overall health.
• Exercising: Being active can help prevent obesity and may contribute to improved sleep at night.
• Seeking support: Support groups and mental health professionals can promote emotional health and counteract the risks of social withdrawal, depression, and anxiety in people with narcolepsy.

Reference:-

• https://www.sleepfoundation.org/narcolepsy
• https://www.mayoclinic.org/diseases-conditions/narcolepsy/symptoms-causes/syc
•  DSM-5
• picture from net