Monthly Archives: January 2017

What Have Fairy Tales Got to Do With Sleep Medicine?

Sleeping Beauty.jpg

“Fairy tales? That’s the best you could think of to drag people in?”

“What’s wrong with it? It’s accurate…”

“I dunno man, you used to be all about the science. Now this feels all click-bait territory *shudders*”

“…”

By fairy tales, I am of course referring to sleeping beauty. Not a champion of feminist thought, this story tells the tale of a young woman who awaits the kiss of a prince to awaken her from an eternal slumber. Although there is no disorder which makes you sleep indefinitely there is a close contender with something called Kleine-Levin syndrome (KLS) – also known as ‘sleeping beauty’ syndrome.

What is Kleine-Levin syndrome?

Kleine-Levin syndrome is an episodic and extremely rare sleep disorder whereby the individual goes through periods of excessive sleepiness (hypersomnia). We all go through periods of feeling exhausted and may find ourselves sleeping for that bit longer. Maybe in extreme cases we’ve found that we’ve spent the whole day in bed fast asleep (thanks new year’s). However, imagine spending up to 20 hours a day asleep for weeks, or even months with no indication when you’ll ‘wake up’ and go back to normal. You miss school, friends, hobbies, and significant portions of your life as your teenage years drifts steadily away. Your dreams seem more real than reality and you lose interest in everything around you. This is a taste of what those with KLS experience and have to deal with.

Other than spending most of the day asleep, sufferers also experience memory, speech, and comprehension problems. In addition, hallucinations, derealisation (feeling as if in a dream), hypersexuality and megaphagia (increased eating behaviour) and paranoia also co-occur with the sleep and cognitive symptoms. It usually tends to emerge around adolescence and usually runs its course over about 8 years (with individual variability). Unsurprisingly, KLS causes significant disruption to academic performance, social lives, and sometimes memory of affected individuals.

What is its prevalence?

It is such a rare disorder that it has been difficult to get an accurate representation of its prevalence. We do know is that it is more prevalent in males but it seems to persist for longer in females for yet unknown reason. Some studies claim the prevalence is as low as 1 in a million but there is little research to support this number. Due to its rarity, most of our available knowledge on this study has been gained through case studies.

What causes this disorder?

This is uncertain although there is research attempting to shed light on this enigmatic illness. A systematic review carried out just over a decade ago found that in over 40% of reported cases, the first episode of KL-syndrome was preceded by an infection or fever. However, in 39% of cases there was no obvious precipitating trigger and the same lack of trigger is found in 84% of subsequent episodes of KL-syndrome. Although onset tends to occur during the latter months of the year, there is no strong argument for why this might be the case. Moreover, the disease may appear to disappear with little understanding why the symptoms disappear.

The link between infections and KLS has led some to argue that it may have an immune-system cause. However, there is little evidence for a link between dysfunctional immune functioning and KLS. Researchers have found some support for a link between certain types of hypersomnia and autoimmunity disorders but it is still unclear whether this extends to KLS.

A study by Dr. Jing Wang and colleagues at the Binzhou Medical University Hospital examined a large group of individuals with KLS (N=44) to identify potential markers of KLS. They found that a large subset of these individuals (N=34) were found to have reductions in a chemical called orexin in their cerebrospinal fluid (CSF) during a relapse compared to a period of remission. Orexin is a neurochemical which is important for wakefulness and is reduced in another disorder characterised by hypersomnia – narcolepsy. However, levels of orexin were not as low as those seen in narcolepsy. Interestingly, this cohort also showed a similar pattern of viral infection preceding the initial episode of hypersomnia / KLS.

Treatment

Again, it should come with little surprise that there are limited treatment options for those with KLS. One route is to reduce the fatigue through stimulants. However, this approach is not effective for other symptoms of the disorder. A different approach is to treat KLS using a mood stabiliser, lithium, which has shown some promise in reducing the length and frequency of episodes, and in reducing the behavioural symptoms. However, evidence for the efficacy of this treatment is limited and it forms one of many possible pharmacological treatments which require wider study.

Difficulties in Diagnosis

This is an extremely rare disorder and not many will have had experience with this diagnosis. However, it is treated with scepticism from some physicians and the general public. Some see it as laziness or not unusual for adolescents and students to sleep for most of the day. It is also not unusual for an individual with KLS to be given a diagnosis of depression in light of similar symptoms to an unknowing physician. A diagnosis of KLS can be laborious to reach as it will be given after identifying whether the individual’s symptoms are not better explained by a whole host of other diagnoses or causes. We have known about this disorder for more than a century and yet we have no convincing theory for why it occurs or how to treat it.

Although there is a lot we don’t know about KLS there is still active research determined to better understand and treat this disorder. If you’re interested in learning more about what it’s like to live with this illness this documentary is a good start.

Inquisitive Tortoise

References:

Arnulf, I., Zeitzer, J. M., File, J., Farber, N., & Mignot, E. (2005). Kleine–Levin syndrome: a systematic review of 186 cases in the literature. Brain,128(12), 2763-2776.

Barateau, L., Lopez, R., Arnulf, I., Lecendreux, M., Franco, P., Drouot, X., … & Dauvilliers, Y. (2017). Comorbidity between central disorders of hypersomnolence and immune-based disorders. Neurology, 88(1), 93-100.

Kornum, B. R., Rico, T., Lin, L., Huang, Y. S., Arnulf, I., Jennum, P., & Mignot, E. (2015). Serum cytokine levels in Kleine–Levin syndrome. Sleep medicine, 16(8), 961-965.

Leu-Semenescu, S., Le Corvec, T., Groos, E., Lavault, S., Golmard, J. L., & Arnulf, I. (2015). Lithium therapy in Kleine-Levin syndrome An open-label, controlled study in 130 patients. Neurology, 85(19), 1655-1662.

Poppe, M., Friebel, D., Reuner, U., Todt, H., Koch, R., & Heubner, G. (2003). The Kleine-Levin Syndrome. Neuropediatrics, 34(03), 113-119.

Wang, J. Y., Han, F., Dong, S. X., Li, J., An, P., Zhang, X. Z., … & Yan, H. (2016). Cerebrospinal Fluid Orexin A Levels and Autonomic Function in Kleine-Levin Syndrome. Sleep, 39(4), 855.

Image Credits:

Sleeping Beauty (Header)

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