Narcolepsy is caused due to various reasons. The most prominent reason is the low level of hypocretin in the cerebrospinal fluid. Hypocretin is produced by hypothalamus neurons and any condition that damages these neurons cause narcolepsy.

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What Is The Main Cause Of Narcolepsy?

Narcolepsy is a chronic neurological disorder, and like most of the other neurological problems, the exact cause of narcolepsy is not known. In most of the cases, narcolepsy is believed to occur due to the low level of a chemical present in the grain known as hypocretin. Hypocretin is also known as orexin. However, it is to be noted that the deficiency of this substance is not the only reason for developing narcolepsy.

Autoimmune Disorders: Autoimmune disorder is considered as the primary causative factor in the development of narcolepsy. Hypocretin regulates the sleep cycle and also amplifies and transmits nerve impulses. This chemical is produced by the neurons of the hypothalamus. The hypocretin-producing neurons are damaged probably due to autoimmune disorders1. Autoimmune disease occurs when the immune system of the body fails to identify its own cells and kills healthy tissues.

Swine Flu: Scientists have found an association of narcolepsy and exposure to swine flu1; although it remains unclear why swine flu causes narcolepsy. It is also to be noted that research carried in 2013 have concluded that narcolepsy may occur due to the swine flu vaccine, Pandemrix, although the risk of this occurrence was very small2.

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Brain injury: When the underlying condition is conclusively found to cause narcolepsy, such type of narcolepsy is known as secondary narcolepsy2. Secondary narcolepsy may be caused due to brain injury. Narcolepsy occurs when a particular part of the brain that regulates the sleep cycle and REM sleep gets damaged.

Family History: Although rare, but narcolepsy may also be caused due to family history as there are some genes involved in the development of narcolepsy. Research in 2009 indicates that during narcolepsy, there are some genetic changes occurred in T cell receptor gene3. These cells play an active role in the immune system. Variation in the T cell receptor gene increases the risk of developing narcolepsy. Although it may increase the risk of narcolepsy, it is to be complemented with other factors to develop this condition.

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Multiple Sclerosis: Patients with multiple sclerosis are at increased risk of developing narcolepsy. This is mainly because of two reasons. First, there is a common genetic link between Multiple sclerosis and narcolepsy. Second, multiple sclerosis is an autoimmune disease and may damage the hypothalamic neurons leading to deficiency of hypocretin3.

Encephalitis: Narcolepsy may also be caused due to Encephalitis2. This may be due to damage in that particular section of the brain that regulates the sleep cycle.

Who Is At Risk?

Various factors increase the risk of narcolepsy. Presence of these factors alone or in combination increases the risk of narcolepsy by many folds. Following are some of those factors:

Age: Although narcolepsy is found in the patients of all ages but children, young and adolescents are at higher risk of developing the condition as compared to other people. People at an age of 10 years to 30 years are at greatest risk1.

Family History: Family history increases the risk of narcolepsy by 20-40 times1. Certain genes are thought to be involved in the development of narcolepsy along with other factors.

Hormonal Changes: Hormonal changes occurring at the time of puberty may also have an effect on the development of narcolepsy2.

Infection: Patient exposed to swine flu or to some species of Streptococcus has increased risk of contracting narcolepsy2.

Sudden Change In Sleep Pattern: Sudden change in the sleep pattern results in the abnormality in the sleep-wake cycle and this may be the reason for narcolepsy2.

Conclusion

There are some conditions that cause narcolepsy while certain factors increase their risk. Conditions that are known to cause narcolepsy are an autoimmune disease, brain injury, encephalitis, and genetics.

References:  

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Pramod Kerkar

Written, Edited or Reviewed By:

, MD,FFARCSI

Pain Assist Inc.

Last Modified On: May 31, 2019

This article does not provide medical advice. See disclaimer

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