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Cause

Orexin is a natural hormone produced in our brain that helps us to stay awake (2-4). In most people with narcolepsy, the small region of their brain where orexin is produced is not working properly. Certain cells in this area are irreversibly damaged by an autoimmune process – that is, the patient's own immune system has attacked the cells in this brain region. The probability of this type of autoimmune reaction is partly inherited. Among people who have a genetic disposition towards this autoimmune condition, the risk of developing the disease may be increased by infections or by the vaccination against swine flu (5).

Changed sleep cycles

Healthy people sleep in cycles of about 90 minutes each. A normal sleep cycle includes phases with stable and deep sleep, followed by a phase with rapid eye movement (REM). In the REM phase, the person’s eyes move around quickly while their eyelids are closed, and this is the phase in which we have most of our dreams (6).

In people with narcolepsy, the sleep cycles are disturbed. Instead of spending time in the “non-REM" phases of stable and deep sleep, patients go into REM phase shortly after falling asleep (7).

Symptoms

The classic symptoms of narcolepsy include abnormal sleepiness during the day, disturbed sleep at night, hallucinations, sleep paralysis and cataplexy. The intensity of the symptoms can be very different from one patient to another, and some symptoms (e.g. cataplexy) may be completely absent (8).

Excessive sleepiness during daytime

The sleepiness during daytime is the central symptom of narcolepsy. Patients often describe it as irresistible and uncontrollable. They feel tired and lethargic during the day and may fall asleep suddenly. These naps are often very short, and the patients feel refreshed and more alert afterwards (7,9).

One consequence of daytime sleepiness may be ‘automatic behaviours’ in which patients continue activities being half-asleep - these actions may be executed with errors or purposeless (7).

Disturbed sleep at night

A less well-known but common symptom of narcolepsy is disturbed sleep at night, in which patients wake up frequently (9).

Sleep-related hallucinations

Narcolepsy patients often suffer from intense hallucinations while falling asleep or waking up. These can include seeing, hearing or touching things that don’t exist in reality but are often experienced as highly realistic. The hallucinations are mainly perceived as threatening or unpleasant (7).

Sleep paralysis

In healthy people sleep paralysis, which is the total inability to move, is normal during sleep and prevents them moving around while dreaming. Patients with narcolepsy, in contrast, often suffer from sleep paralysis at the beginning or end of sleep and they may consciously experience being paralysed. This could last from a few seconds to some minutes and can be a very frightening experience (7).

Cataplexy

Cataplexy is the term for a brief temporary loss of muscles tonus. It ranges from mild cases, in which for example the facial muscles go limp, to severe forms, where a patient loses the strength to stay upright and drops. Episodes of cataplexy can be triggered by emotions such as laughing, anger or surprise and usually last only a few seconds (10).

 

  1. Longstreth WT, Koepsell TD, Ton TG, Hendrickson AF, van Belle G. The epidemiology of narcolepsy. Sleep. 2007; 30 (1): 13-2
  2. Nishino S, Ripley B, Overeem S, Lammers GJ, Mignot E. Hypocretin (orexin) deficiency in human narcolepsy. Lancet. 2000; 355 (9197): 39-40
  3. Thannickal TC, Nienhuis R, Siegel JM. Localized loss of hypocretin (orexin) cells in narcolepsy without cataplexy. Sleep. 2009; 32 (8): 993-8
  4. Thannickal TC, Moore RY, Nienhuis R, Ramanathan L, Gulyani S, Aldrich M, et al. Reduced number of hypocretin neurons in human narcolepsy. Neuron. 2000; 27 (3): 469-74
  5. Bonvalet M, Ollila HM, Ambati A, Mignot E. Autoimmunity in narcolepsy. Curr Opin Pulm Med. 2017; 23 (6): 522-9
  6. Rechtschaffen A, Kales A. Los Angeles: University of California, Brain Information Service/Brain Research Institute. 1968
  7. Dauvilliers Y, Billiard M, Montplaisir J. Clinical aspects and pathophysiology of narcolepsy. Clin Neurophysiol. 2003; 114 (11): 2000-17
  8. Deutsche Gesellschaft für Neurologie - Leitlinien Narkolepsie. 2012:https://www.dgn.org/images/red_leitlinien/LL_2012/pdf/030-056l_S1_Narkolepsie__verlaengert.pdf
  9. Roth T, Dauvilliers Y, Mignot E, Montplaisir J, Paul J, Swick T, et al. Disrupted nighttime sleep in narcolepsy. J Clin Sleep Med. 2013;9 (9): 955-65.
  10. Dauvilliers Y, Arnulf I, Mignot E. Narcolepsy with cataplexy. Lancet. 2007; 369 (9560): 499-511.

Narcolepsy during Pregnancy and Lactation

As the symptoms of narcolepsy frequently start in early adulthood, it is quite important to know how to deal with narcolepsy during pregnancy. Just a handful of studies have addressed the impact of narcolepsy on pregnancy.

Medication during pregnancy and lactation

Narcolepsy patients who desire children or those who know they are pregnant should most definitely contact their physician. With regard to medication, the doctor and the patient should jointly assess the risk-benefit ratio in order to decide what medications should be continued as usual, reduced in terms of dose, or discontinued altogether.

The large majority of doctors advise women who desire children, are pregnant or breastfeeding, to discontinue the drugs they take for treating the symptoms of narcolepsy (1).

One of the properties of drugs given for the treatment of narcolepsy is that they permeate the placenta. In other words, the unborn child also undergoes the treatment, so to speak. Likewise, the active substance of commonly used drugs for narcolepsy is passed on to the newborn infant through breast milk. (1)

Potential complications during pregnancy

In rare cases, a narcolepsy patient may experience cataplexy during labour (2) and this can influence the process of delivery.

The data of a recently published study show that gestational diabetes occurs more frequently in patients with narcolepsy and cataplexy than in healthy women; the birthweight of the newborn also appears to be higher. Induction of labour is more frequently needed in patients with narcolepsy.

Care of the Newborn

Many narcolepsy patients report that the disease affects their care of newborn infants. In the majority of patients, the care of newborns is rendered difficult by daytime sleepiness or falling asleep involuntarily while breastfeeding or feeding the infant (2).

1. Thorpy M, Zhao CG, Dauvilliers Y. Management of narcolepsy during pregnancy. Sleep Med. 2013;14(4):367-76.
2. Maurovich-Horvat E, Kemlink D, Högl B, Frauscher B, Ehrmann L, Geisler P, et al. Narcolepsy and pregnancy: a retrospective European evaluation of 249 pregnancies. J Sleep Res. 2013;22(5):496-512.
3. Maurovich-Horvat E, Tormášiová M, Slonková J, Kemlink D, Maurovich-Horvat L, Nevšímalová S, et al. Assessment of pregnancy outcomes in Czech and Slovak women with narcolepsy. Med Sci Monit. 2010;16(12):SR35-40.
4. Calvo-Ferrandiz E, Peraita-Adrados R. Narcolepsy with cataplexy and pregnancy: a case-control study. J Sleep Res. 2018;27(2):268-72.

Narcolepsy in Children

Narcolepsy symptoms can begin at any age.

About 20 % of all patients are 10 years old or younger when they first experience the disease (1).

When children have narcolepsy, their symptoms are often interpreted wrongly, which can make the condition even more distressing for the child.

If daytime sleepiness is the main symptom, it may be difficult to reach a diagnosis, because it is hard to tell this apart from a child’s normal need for sleep (2). Also, children tend to compensate for their sleepiness though hyperactivity, so that hyperactivity disorders are often diagnosed when the real problem is narcolepsy (1, 3).

Narcolepsy in children can also be mistaken for laziness, defiant behavior, epilepsy, other neurological or medical conditions or intellectual disability (2, 3). Falls caused by cataplexic events may be interpreted as clumsiness (2).

The symptoms of narcolepsy can trigger anxiety, feelings of shame and helplessness and depression in children. Especially if the child experiences a lack of understanding and judgmental attitudes from people around them, they are likely to withdraw from social interaction (2).

Excessive daytime sleepiness can also negatively affect concentration, memory and other cognitive functions, resulting in poor performance at school (2).

Behavioral problems and depression may also result, leading to impaired quality of life (3).

To prevent long-term negative psychological effects, timely diagnosis is essential.

1. Mayer G, Kotterba S. 2001. p. 249-54.
2. Stores G. The protean manifestations of childhood narcolepsy and their misinterpretation. Dev Med Child Neurol. 2006;48(4):307-10.
3. Stores G, Montgomery P, Wiggs L. The psycho-social problems of children with narcolepsy and those with excessive daytime sleepiness of uncertain origin. Pediatrics. 2006;118(4): e1116-23.

Diagnosis and Neurological Sleep Laboratories in Austria

In their respective guidelines, the Austrian, German and Swiss Societies of Neurology have established standards for the diagnosis of narcolepsy (1).

A targeted medical history of the core symptoms - excessive daytime sleepiness and cataplexy - is recommended as the first step. As narcolepsy is known to run in families, the patient’s family medical history should also be obtained. (1)

By means of various sleep questionnaires and sleep diaries, the patient should record his sleeping behaviour (1). The Epworth Sleepiness Score (ESS), for instance, registers daytime sleepiness and is believed to reflect the chances of falling asleep under specific conditions of daily life (such as watching TV) (2).

Furthermore, a polysomnography – which monitors various bodily functions during sleep – and a so-called Multiple Sleep Latency Test (MSLT) should be performed. One should specifically look for phases of shorter times to fall asleep and early onset REM sleep. Besides, a typical finding in narcolepsy patients is interrupted sleep and shorter times to fall asleep during the day. (1)

In some cases in may be necessary to perform further investigations such as the determination of orexin levels in cerebrospinal fluid or imaging procedures. (1)

As narcolepsy is a neurological sleep disorder, the diagnosis should be established in a neurological sleep laboratory, for example in following facilities in Austria:

The complete, updated list of the neurological sleep laboratories in Austria may be found here:

 http://www.schlafmedizin.at/schlaflabore.html

Everyday life

Narcolepsy can have very negative effects on quality of life. Patients regularly experience social exclusion – due to the symptoms and their own efforts to manage them, and also to a lack of understanding of their condition by the people around them.

Narcolepsy can have very negative effects on quality of life. Patients regularly experience social exclusion – due to the symptoms and their own efforts to manage them, and also to a lack of understanding of their condition by the people around them.

Narcolepsy in society

The symptoms of narcolepsy – such as daytime sleepiness and cataplexy – are unsettling for other people who observe them and are often mistakenly interpreted as signs of laziness, lack of interest, or even alcoholism or drug dependence. People with narcolepsy suffer a lot under this stigmatization. They often withdraw from social interactions, partly to avoid emotional situations that could trigger episodes of cataplexy, and partly due to embarrassment about the symptoms.

Narcolepsy in partnership and the family

Narcolepsy can also cause problems with partners and family. If sufferers try to avoid emotional situations, they may appear reserved and distant. Talking openly about the disease can improve people’s understanding of the situation and restore patients’ self-confidence. This is a key to maintaining as active a life as possible.

Since daytime sleepiness also causes a higher risk of accidents, narcolepsy also influences the kind of work patients can do. Some jobs are incompatible with the disease, for example driving motor vehicles, operating hazardous machinery, or working at height (for example as a roofer). Monotonous activities can increase the risk of falling asleep, and irregular working hours can make the disease worse overall.

Narcolepsy at school and at work

Narcolepsy can manifest in school age. Falling asleep in class is often interpreted wrongly, and this can be very distressing for the pupil. Undiagnosed narcolepsy can negatively affect school performance and may result in poor grades that do not accurately reflect the pupil’s true abilities.

Since daytime sleepiness also causes a higher risk of accidents, narcolepsy also influences the kind of work patients can do. Some jobs are incompatible with the disease, for example driving motor vehicles, operating hazardous machinery, or working at height (for example as a roofer). Monotonous activities can increase the risk of falling asleep, and irregular working hours can make the disease worse overall.

Narcolepsy and travel

People with narcolepsy can take several precautions that make travelling easier. Travelling with a trusted companion is a great help. If this is not possible, many airports and railway stations offer help in the form of support staff or wheelchairs. These can help to avoid agitation and physical exertion that could trigger cataplexy. To enable quick and correct treatment in emergencies, it is recommended to carry an emergency medical information card with you. It is also important to note that many medications prescribed for narcolepsy fall under controlled substances laws, and formalities have to be observed when travelling with them. For trips of up to 30 days in duration within the Schengen area, a note from the prescribing doctor, certified by the district medical officer, must be carried (1). For travel outside the Schengen area, the patient must check the legal situation in the country or countries they are travelling to and must take appropriate measures to comply with the rules.

BMGF Reiseinformationen: Mitnahme von Medikamenten ins Ausland 

Epworth Sleepiness Scale (ESS)

Detailed information about ESS and its interpretation can be found via official site https://epworthsleepinessscale.com/

Below you may find a download link to the daytime sleepiness questionnaire.
 

Questionnaire on Daytime Sleepiness Epworth Sleepiness Scale