Narcolepsy

Narcolepsy is associated with episodes of sudden sleep attacks at inappropriate times, the sleep of the narcoleptic is characterized by its suddeness and the catalepsy which accompanies it, whereas people who have hypersomnia do not experience catalepsy, nor does their sleep occur suddenly, but rather manifests as a general all pervasive lethargy which continues throughout the day, with periods of sleeping. Sleep attacks may occur when the individual is fully engaged in an activity, as well as when engaged in monotonous activity.

Narcolepsy is considered to be an incurable neurological disorder characterized by : excessive daytime sleepiness, catalepsy, sleep paralysis, and hypnagogic hallucinations. It is not an uncommon disorder occurring in between 1 and 10 per 10,000 of populations in the US and Europe. It is far more prevalent in Japan, and rare in Israel.

The catalepsy experienced in narcolepsy is characterized by episodes of weakness or paralysis without loss of consciousness. The trigger for catalepsy usually involves the emotions, such as laughter, excitement or anger, the cataleptic attack may last from a few seconds to 30 minutes. The hypnagogic hallucinations involve the visual or auditory senses and present as simple or bizarre.

Sleep paralysis occurs on falling asleep or on awakening, during this period the person may be unable to move or speak, and may be incapable of taking a deep breath, the person remains fully aware of the condition. Hypnagogic hallucinations mostly occur with sleep onset REM periods, this does not occur in people who do not suffer from narcolepsy, unless they are sleep deprived, or are involved in shift work, for the latter group it is considerd to be normal.

The age of onset of narcolepsy occurs in the early teens, around 15, and up to 30 years of age, it has been known to occur earlier and much later, however these instances have been rare, both sexes are equally affected. Its cause is unknown and it has not been associated with any type of brain lesion.

Sudden sleep attacks have major economic, social, familial,and occupational consequences for the person with narcolepsy. Because the onset of the condition occurs in the early teen years it is often perceived to be a result of laziness , lack of drive and ambition, and for these reasons the condition may go undiagnosed with serious consequences for the development of the young teenager.

 Amphetamines and other stimulant drugs are prescribed to prevent the attacks, and imipramine, protriptyline, and chlorimipramine for catalepsy.

Read more: Hypocretin/Orexin levels in Narcolepsy

 References: Rowland, P Lewis MD Merritt's Textbook of Neurology 9th edition. Published Williams and Wilkins Baltimore. 1995.

Rolak, A Loren MD Neurology Secrets, 2nd edition Published Hanley and Belfus Inc. Philadelphia 1998.