Narcolepsy

Narcolepsy is a neurological disorder that causes people to be excessively drowsy during the day or to fall asleep unexpectedly, putting the person and others at risk of accidental injury when driving or operating machinery. Narcolepsy tends to remain a life-long condition but symptoms can be managed through medications and self-help treatment.

In New Zealand it is estimated that narcolepsy affects up to 3000 people. Men and women are equally affected. Narcolepsy symptoms most commonly start appearing between 15 to 25 years of age and only rarely begins after the age of 40.

It is thought that narcolepsy occurs because of a problem in the part of the brain which controls the transition between sleep and wakening. Many cases (but not all) are thought to relate to a lack of brain chemical hypocretin. Genetic and autoimmune factors may play a role in the development of the condition. Lifestyle and environmental factors such as shift work may aggravate the condition.

Symptoms

Narcolepsy causes people to fall asleep suddenly - anytime, anywhere (sometimes referred to as "sleep attacks"). The narcoleptic may sleep for only a few seconds or for more than an hour. They wake refreshed but become sleepy again within an hour or so. These sleep episodes occur on average two to six times per day, especially after meals. Occasionally people may continue to perform tasks during these episodes of sleep but have no recollection of this when they awake.

The other main symptoms of the condition include:

• Extreme daytime sleepiness

• Hallucinations – where vivid, intense dreams are experienced. Approximately 40% of people with narcolepsy experience intense dream-like imagery. Most hallucinations are visual and incorporate elements of the actual environment. They usually occur just before falling asleep.

• Cataplexy – where there is a sudden loss of voluntary muscle tone and muscle weakness when awake. Cataplexy is usually triggered by strong emotions such as laughter, anger, surprise or fear. In severe cases the person may collapse. In less severe cases, the person may experience weakening of the knees and drooping of the jaw and facial muscles. Speech and movement become difficult or impossible, although there is no loss of consciousness. Cataplexy can last a few seconds or minutes. It affects up to 75% of people with narcolepsy

• Sleep paralysis – where the person is unable to move just as they are falling asleep or waking up. Approximately 30% to 50% of people with narcolepsy experience sleep paralysis and it can be frightening to experience. Sleep paralysis can last for several seconds to a few minutes and finish spontaneously.

• Disturbed night-time sleep. The usual night-time sleeping pattern is disrupted in the narcoleptic and they may suffer from an increased number of awakenings.

Narcolepsy symptoms usually develop slowly and initially may be subtle. Generally symptoms develop one at a time and do not appear in any specific order. The severity of symptoms can vary widely, and often the condition is not suspected until symptoms become severe.

Diagnosis

As narcolepsy is a complex disorder, it may take several years to correctly diagnose. Your doctor will obtain a detailed history of your sleeping patterns. You may be asked to keep a sleep-wake diary over a period of time. The diary will specify time and quality of sleep. Your doctor will also look for any underlying causes for your symptoms (such as underactive thyroid) or aim to rule out other conditions that may cause daytime sleepiness, such as obstructive sleep apnoea.

You may be referred to a neurologist or sleep physician for specialist assessment. Tests which monitor the brain, muscle activity and breathing throughout all the stages of sleep (eg: polysomnography (PSG), or multiple sleep latency testing) may be undertaken. If there are symptoms of depression, anxiety or mental health disorder, you may be referred to a psychiatrist.

Treatment

There is no known cure for narcolepsy; however, symptoms can be controlled by medications. Stimulants may be used to treat sleep attacks and certain anti-depressants can help control cataplexy, sleep paralysis and hypnogogic hallucinations.

Regular sleep hours, scheduled day time naps and regular exercise are important. Avoiding meals high in carbohydrates can also be helpful. The doctor may also recommend referral to a Sleep Clinic or Sleep Management Centre.

Self-help

The following can help with the management of the condition:

• Go to bed at the same time every night, whenever possible, and get an adequate amount of sleep at night

• Eliminate anything that is likely to interrupt sleep

• Scheduled naps during the day may help to control daytime sleepiness

• Eat light meals during the day and avoid carbohydrate heavy meals

• Avoid caffeinated beverages, such as coffee, tea or cola for several hours before bed time

• Avoid driving unless you have been certified fit to drive by your doctor in accordance with Land Transport Safety Authority (LTSA) guidelines.

Driving

The New Zealand Transport Agency says individuals should not drive if they are suspected of having narcolepsy that may impair their ability to drive safely. A person should not drive once a diagnosis of narcolepsy has been made until:

• There is a satisfactory response to treatment, and clearance is given by an appropriate specialist, or

• It is established that the individual does not suffer from the full range of symptoms, in particular unpredictable episodes of cataplexy, and, therefore, is unlikely to be a significant road safety risk.

The NZTA may impose licence conditions for regular medical assessment.

Support groups

The Narcolepsy Support Group of New Zealand can provide support and information for people suffering from narcolepsy.

E-mail: [email protected]

Website: www.narcolepsy.org.nz

The Sleep Apnoea Association of NZ Inc. (SAANZ) promotes awareness and provides up to date information of sleep apnoea and sleep disorders.

Email: [email protected]

Website: www.sleepapnoeanz.org.nz

References

NHS Choices (2016). Narcolepsy. https://www.nhs.uk/conditions/narcolepsy/ [accessed 31-5-2018]
Anderson, K.N., Anderson, L.E. & Glanze, W.D. (eds.) (2006) Mosby’s Medical, Nursing, & Allied Health Dictionary (6th ed.) St. Louis: Mosby-Year Book, Inc.
Brandt, M. L. and Odle, T. G (2006) Narcolepsy. The Gale Encyclopedia of Medicine. Third Edition. Jacqueline L. Longe, Editor. Farmington Hills, MI. Thompson Gale.
National Institutes of Health (2010) What Are the Signs and Symptoms of Narcolepsy? National Heart, Lung and Blood Institute. Bethesda. http://www.nhlbi.nih.gov/health/health-topics/topics/nar/signs.html
NZTA (2014). Medical aspects of fitness to drive. https://www.nzta.govt.nz/resources/medical-aspects/10/#101 [accessed 31-5-2018]

Last Reviewed – May 2018

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