Narcolepsy is one of the causes of excessive daytime sleepiness (EDS).It is characterised by overwhelming daytime drowsiness and sleep attacks, causing the patient to fall asleep at the most inopportune moments, for example, while eating or during a meeting. It affects both genders equally and onset is usually in the puberty years. The exact causes of narcolepsy are unknown, but many patients with narcolepsy have increased destruction of the neurons that produce a wakefulness-promoting hormone called hypocretin. Research has also shown an association with genetics and exposure to certain influenza viruses.
Excessive daytime sleepiness (EDS) is the most important and usually the first symptom. It presents as frequent drowsiness and inability to stay awake during the day, even after getting enough sleep at night. The condition is troublesome and occasionally results in embarrassing situations.
Cataplexy is a loss of muscle control triggered by strenuous exercise or intense emotions such as laughter, anger and joy. It is less common than EDS, and can cause a range of physical changes from slurred speech to total physical collapse, lasting from a few seconds to a few minutes.
Sleep paralysis refers to episodes when the patient is unable to talk or move for brief periods upon falling asleep or waking up.
Hypnagogic hallucinations are very vivid, scary dreams and sounds, which the patient experiences when semi-awake and beginning to dream. The patient experiences these dreams as reality, and these may be particularly vivid and frightening.
Automatic behaviour occurs when familiar routines or boring tasks are performed with no recollection or memory of them later.
Sleep paralysis and hypnagogic hallucinations can occur in people without narcolepsy.
To diagnose narcolepsy, the patient first undergoes a medical history and physical examination. This is followed by a polysomnogram (PSG) and a multiple sleep latency test (MSLT).
A polysomnogram measures the various body functions during sleep, including:
The multiple sleep latency test is performed in the day to assess how easily the patient falls asleep, and also the type of sleep pattern produced. It records the brain waves, heart rate, muscle activity and eye movements.
No blood test is involved in the diagnosis of narcolepsy.
There is no cure for narcolepsy, but the symptoms can be managed with medication and lifestyle modifications. The aim is to maintain alertness and control some of the lesser-occurring symptoms if they occur.
Stimulants to help the patient stay awake or alert, and antidepressants which help alleviate the symptoms of cataplexy, hypnagogic hallucinations and sleep paralysis may be used on its own or in combination to manage the symptoms.
Drug treatment is only one component of treating narcolepsy. It is equally important to ensure that good sleep hygiene practices are followed, including ensuring that adequate sleep is obtained at night, maintaining regular sleep and wake times every day including weekends, taking short naps in the day, getting regular exercise and avoiding nicotine and alcohol at night.
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