What is restless legs syndrome?
Restless legs syndrome is a common condition affecting the nervous system, which causes an overwhelming, irresistable urge to move the legs.
It also causes an unpleasant feeling in the feet, calves and thighs, which is often felt as a crawling or creeping sensation.
The symptoms of RLS can vary from being mild to severe. In severe cases, the condition can be distressing and can disrupt daily activities.
Some people have symptoms now and again, while others have them every day. Read more about the symptoms of restless legs syndrome.
RLS is sometimes known as Ekbom syndrome.
Causes of RLS
In the majority of cases, there is no obvious cause of RLS. Doctors may refer to this as idiopathic RLS, or primary RLS. This type of RLS can run in families.
Some neurologists (experts in treating conditions that affect the nervous system) share the opinion that the symptoms may have something to do with low levels of a chemical called dopamine in the body. Dopamine plays a role in controlling muscle movement, and low levels of this chemical may cause the involuntary leg movements associated with RLS.
Some cases of RLS are caused by an underlying health condition, such as iron deficiency anaemia, or kidney failure. Doctors may refer to this as secondary RLS.
There is also a link between RLS and pregnancy and around one in five pregnant women will experience symptoms of RLS in the last three months (third trimester) of their pregnancy, although it is not clear exactly why.
Read more about the causes of restless legs syndrome.
Mild cases of RLS that are not linked to an underlying health condition may not require any treatment other than making a few lifestyle changes, such as:
- quitting smoking (if you smoke)
- avoiding alcohol and caffeine
- exercising regularly
If RLS is more troublesome, medication may be needed to regulate the levels of dopamine in the body.
If RLS is caused by iron deficiency anaemia, for example, then iron supplements may be all that is needed to treat the RLS symptoms.
Read more about the treatment of restless legs syndrome.
Who is affected?
As many as one in ten people are affected by RLS at some point in their life.
Women are twice as likely to develop RLS than men. The condition is also more common in middle age, but the symptoms can develop at any age, including childhood.
Often, addressing the underlying cause of RLS will cure the person of symptoms. If RLS is related to pregnancy, it will usually go away once a woman has given birth.
However, when the cause for RLS is unknown, the symptoms can get worse with time and severely affect the person's life. It is however not life-threatening, but it can severely disrupt sleep and trigger anxiety and depression.
Restless legs syndrome symptoms
Restless legs syndrome (RLS) typically causes an overwhelming urge to move your legs and an uncomfortable sensation in your legs and sometimes arms, chest and face.
A range of different sensations have been reported by people with RLS, including:
- tingling, burning, itching or throbbing
- a 'creepy-crawly' feeling
- feeling like fizzy water is inside the blood vessels in the legs
- cramping in the calf’s or legs
These unpleasant sensations can often be relieved by moving or rubbing your legs. They can range from mild to unbearable and are usually worse in the evening and during the night.
Some people experience symptoms now and again, while others have them every day. It may be difficult to sit for long periods of time, for example on a long train journey.
Just over half of people with RLS also experience episodes of lower back pain.
Periodic limb movements of sleep (PLMS)
About four out of five people with RLS also have a condition that is known as periodic limb movements of sleep (PLMS).
If you have PLMS, you will have jerky or twitchy leg movements at night, while you are asleep. The movements are involuntary (you have no control over them) and may occur every 10-60 seconds.
The leg movements of PLMS can be severe enough to wake up both you and your partner. They may also sometimes occur when you are awake and resting.
Restless legs syndrome causes
In many cases of restless legs syndrome (RLS) the exact cause is unknown.
There is conflicting evidence about the role of a brain chemical called dopamine with RLS.
Some people benefit from a type of medication called a dopamine agonist which raises the levels of dopamine in the brain. This had lead to some people arguing that the condition is related to low levels of dopamine.
The theory is that low levels of dopamine disrupt the nerve signals sent from the brain to the legs, causing the typical involuntary movements and unpleasant sensations. Dopamine levels naturally fall towards the end of the day, which may explain why the symptoms of RLS are often worse in the evening and during the night.
However a problem with the above theory is that in some people with RLS, dopamine agonists actually make their symptoms worse. So the link between dopamine and RLS is not as clear-cut as previously thought.
Another point is that dopamine levels often drop when people are feeling unhappy, so any drop in dopamine levels could be the result, not the cause, of the symptoms of RLS.
Further research is required on this matter.
Underlying health condition
Secondary RLS can occur as a complication of another health condition, or it can develop as a result of another health-related factor.
For example, you may develop secondary RLS if you:
- have iron-deficiency anaemia – low levels of iron in the blood can lead to a drop in dopamine, triggering RLS
- have a chronic (long-term) health condition – such as chronic kidney disease, diabetes, Parkinson’s disease, rheumatoid arthritis, an underactive thyroid gland or fibromyalgia
- are pregnant – particularly during the last trimester (week 27 to birth); in most cases, the symptoms of RLS disappear within four weeks of giving birth
There are a number of factors or triggers that do not cause RLS, but can make symptoms worse. These include a number of medications such as:
- antipsychotic medicine
- lithium (used in the treatment of bipolar disorder)
- calcium channel blockers (used in the treatment of high blood pressure)
- metoclopramide (used to relieve nausea)
Other reported triggers include:
- being overweight or obese
- lack of exercise
Restless legs syndrome diagnosis
No single test is currently available for diagnosing restless legs syndrome (RLS). The condition is usually diagnosed based on your symptoms and your previous medical and family history.
The International Restless Legs Syndrome Study Group has identified some basic criteria for diagnosing RLS. These are:
- an overwhelming urge to move your legs, usually with an uncomfortable sensation such as itching or tingling
- symptoms occur or worsen when you are resting or inactive
- symptoms are relieved by moving your legs or rubbing them
- symptoms are worse during the evening or at night
A confident diagnosis can be made if you have all the above symptoms.
If your doctor suspects that you have RLS, they may refer you for a number of blood tests to confirm or rule out a number of possible secondary underlying causes. For example, you may have blood tests to rule out health conditions such as anaemia, diabetes and problems with your kidney function.
Assessing your symptoms
Your doctor will also want to ask you about the pattern of your symptoms, to assess whether you have mild, moderate, severe or very severe RLS.
They may ask:
- how often your symptoms occur
- how unpleasant you find your symptoms
- if your symptoms cause significant distress
- if your sleep is being disrupted, making you tired during the day
Mild RLS can usually just be treated by making lifestyle changes. Moderate to very severe RLS usually requires medication to bring symptoms under control. Read more about the treatment of restless leg syndrome.
If you have RLS and are experiencing severe disruption to your sleep, sleep tests such as polysomnography may be recommended.
Polysomnography is a test that measures your breathing rate, brain waves, and heartbeat throughout the course of a night. This type of test will confirm whether you have periodic limb movements of sleep.
Restless legs syndrome treatment
If your restless leg syndrome (RLS) is known to be linked to an underlying cause, then treating that cause can often lead to a complete cure.
For example, iron deficiency can be treated by taking iron supplements, and RLS associated with pregnancy usually goes away on its own within four weeks of the birth.
If RLS has no obvious cause, then treatment falls into one of two categories:
- lifestyle changes
A number of lifestyle changes may be enough to ease the symptoms of RLS. These include:
- avoiding stimulants, such as caffeine, tobacco and alcohol
- not smoking
- taking regular, daily exercise – but avoid exercising near bedtime
- establishing a regular sleeping pattern – for example, going to bed and getting up at the same time every day; not napping during the day; taking time to relax before going to bed; avoiding caffeine close to bedtime
- avoiding medicines that trigger the symptoms of RLS or make them worse – if you think your medication is causing your symptoms, continue taking it and make an appointment to see your doctor.
During an attack of RLS, you may find the following measures helpful in relieving symptoms:
- massaging your legs
- taking a hot bath in the evening
- applying a hot or cold compress to your leg muscles
- doing activities that distract your mind, such as reading or watching television
- relaxation exercises such as yoga or tai chi
- walking and stretching
On this last point a small medical trial carried out in 2011 found that a type of osteopathic exercise technique called positional release manipulation (PRM) could be of benefit to people with RLS.
PRM involves holding different parts of the body in position that has been found to reduce feelings of discomfort and pain.
Though larger studies will be required before it is clear that PRM is an effective treatment for most cases of RLS.
(Osteopathy is a complementary or alternative medicine that claims to be a way of detecting, treating and preventing health problems by moving, stretching and massaging a person’s muscles and joints.)
Levodopa may be recommended if you only have symptoms now and again. This is because if you took levodopa every day, there is a high risk that it would actually make your symptoms worse.
Levodopa is available in tablet or liquid form and you should take it once you feel the symptoms of RLS coming on.
The medication will make you feel very sleepy, often very suddenly, so you should never drive or use tools or machinery after taking levodopa.
Levodopa can cause nausea, so it is usually combined other medications to reduce the nausea.
Dopamine agonists are usually recommended if you are having more frequent symptoms. They include:
These medications can make you feel very sleepy so you should never drive or use tools after taking them.
Other side effects of these medications include:
Another dopamine agonist called cabergoline has proved to be effective in the treatment of RLS but tends only to be used if the medications mentioned above prove ineffective. This is because it can cause a range of serious side effects, which your doctor will discuss with you.
You may need to be prescribed a mild opiate-based painkiller such as codeine or tramadol to relieve any pain associated with RLS.
Side effects of these types of painkillers include:
- feeling sick
- dry mouth
Another medication that can be used to both relieve pain and relieve symptoms of RLS is gabapentin. Side effects of gabapentin include dizziness and feeling tired and sleepy.
If you are having a particularly severe flare-up of symptoms that is disrupting your sleep, it may be recommended that you take a short-term course of medication to help you sleep.
These types of medications are known as hypnotics and include temazepam and loprazolam.
Hypnotics are usually only recommended to be used on short-term basis (typically no longer than week).
You may find you still feel sleepy or 'hungover' the next morning after taking your medication.