- What is narcolepsy?
- What are the signs and symptoms of narcolepsy?
- What causes narcolepsy?
- What are the types of narcolepsy?
- What is cataplexy?
- What is hypocretin?
- How is narcolepsy diagnosed?
- How is narcolepsy treated?
- How does narcolepsy affect day-to-day life?
- Which specialist treats narcolepsy?
Narcolepsy is a neurological condition which affects your brain’s control over when you sleep. It’s a condition characterised by 'sleep attacks' during the day, where you suddenly fall asleep without control.
Narcolepsy is relatively rare, affecting just one in 2000 people, and affecting men and women equally. The cause is not clear, but it’s thought that narcolepsy can be triggered by puberty, menopause, an infection, or major psychological stress. Most people who are diagnosed with narcolepsy are between 20 and 40 years old.
As already mentioned, the most well-known symptom of narcolepsy is sleep attacks during the day. Other symptoms include:
- Excessive daytime sleepiness
- Disturbed night-time sleep
- Cataplexy – a sudden loss of strength and control in some muscles, resulting in slurred speech, a dropping head, and sometimes falls
- Sleep paralysis – a sudden inability to move when falling asleep or waking up which generally lasts for a few minutes
- Hallucinations when going to sleep or waking up
- Automatic behaviour – doing an activity without having any memory of doing it afterwards
There are various causes of narcolepsy. The most common cause of narcolepsy is the lack of hypocretin, the brain chemical that modulates the body's wakefulness. However, it's not always the case and sometimes causes are unclear. Possible narcolepsy triggers can be:
- Hormonal changes, either during puberty or the menopause.
- Psychological stress
- Infections, such as the swine flu or the flu vaccination medication against it, Pandemrix.
- A sudden change in sleep patterns.
- An inherited genetic fault.
Another cause could relate to immune system problems. It's been found that some people with narcolepsy produce antibodies, which are released by the body to destroy diseases and toxins, against the trib 2 protein. This protein is produced in the same area of the brain that creates hypocretin, resulting in a lack of hypocretin. This means the brain isn't as able to regulate sleep cycles.
The two main types of narcolepsy are Type 1 narcolepsy and Type 2 narcolepsy.
Type 1 narcolepsy, which was previously known as narcolepsy with cataplexy, is where a patient either has low levels of hypocretin.
Also called narcolepsy without cataplexy, Type 2 narcolepsy usually has less severe symptoms than Type 1 narcolepsy. Excessive daytime sleepiness is experienced but usually doesn't have muscle weakness triggered by emotions.
Cataplexy is a symptom of narcolepsy. It refers to the muscular weakness that is suddenly triggered by strong emotions. Examples of these emotions can be:
Facial muscles, weakness at the knees and total collapse can occur in a cataplexy attack. Furthermore, people can have slurred speech and impaired eyesight such as double vision and inability to focus. Length of attacks can range from up to a few seconds, less than two minutes, and up to 30 minutes.
Hypocretin, also called orexins, are excitatory neuropeptide hormones. The levels of hypocretin are found to be low in many people who have narcolepsy, and it's been found that the body's ability to maintain a state of wakefulness is regulated by hypocretin.
Diagnosis is carried out by a GP and involves ruling out other conditions which can cause similar symptoms, such as sleep apnoea, restless leg syndrome, epilepsy, or an underactive thyroid gland.
To make a diagnosis, the GP will look at your sleeping patterns and medical history, and conduct some tests. The most common narcolepsy tests include:
- Polysomnographic (PSG) testing – this measures the electrical activity of your brain as you fall asleep, and during sleep.
- Multiple sleep latency test (MSLT) – this measures your 'sleep latency', which is how fast you fall asleep.
- Lumbar puncture – this is used to remove a sample of your cerebrospinal fluid. People with narcolepsy often have a deficiency of the chemical hypocretin in their brain, so an examination of your cerebrospinal fluid can determine whether this is the case.
There is a lot you can do to improve narcolepsy symptoms through good sleep routines and changes to your diet. These include avoiding caffeine, avoiding eating just before bed, keeping your bedroom at a comfortable temperature, and taking frequent naps through the day.
In addition, a doctor might prescribe medication. Options include:
- A stimulant, such as modafinil or dexampthetamine – these help to keep you awake through the day
- Sodium oxybate – this can help you to sleep at night and therefore tackle daytime sleepiness, and can also improve cataplexy
- Antidepressants – these are sometimes offered as an option to treat sleep paralysis and hallucinations.
Narcolepsy is a long-term condition so it can have an impact on many areas of life.
With good management of your symptoms, most occupations are open to people with narcolepsy. Your employer has a legal obligation under disability discrimination law to make allowances that enable you to work, such as allowing you to take naps or offering flexitime.
Narcolepsy UK have some useful advice on managing work and narcolepsy.
Similarly, as long as you are able to keep your symptoms under control, you will be able to drive a car, motorcycle or moped, and can get insurance. In the UK you must inform the DVLA that you have narcolepsy. They will issue you a fixed-term driving license and check every few years that you are controlling your symptoms.
The type of medical specialists that treat narcolepsy are neurologists.