Restless Legs Syndrome (RLS)

Restless legs syndrome (RLS) is a disorder of the part of the nervous system that affects movements of the legs. Because it usually interferes with sleep, it also is considered a sleep disorder.

• People with RLS have strange sensations in their legs (and sometimes arms) and an irresistible urge to move their legs to relieve the sensations.
• The sensations can be difficult to describe: they are usually not painful, but an uncomfortable, "itchy," "pins and needles," or "creepy crawly" feeling deep in the legs.
• The sensations are usually worse at rest, especially when lying in bed.
• The sensations lead to walking discomfort, sleep deprivation, and stress.

RLS affects about 8% to 10% of the US population. Men and women are affected equally. It may begin at any age, even in infants and young children. Most people who are affected severely are middle-aged or older.

The severity of RLS symptoms ranges from mild to intolerable. Symptoms get gradually worse over time in about two thirds of people with the condition and may be severe enough to be disabling. The symptoms are generally worse in the evening and night and less severe in the morning. While the symptoms are usually quite mild in young adults, by age 50 the symptoms cause severe nightly sleep disruption that leads to decreased alertness in the daytime.

RLS is often unrecognized or misdiagnosed. In many people the condition is not diagnosed until 10-20 years after symptoms begin. Once correctly diagnosed, RLS can often be treated successfully.

The cause of restless legs syndrome (RLS) is not known.

• RLS was once thought to be due to disease in the blood vessels of the legs or in the nerves in the legs that control leg movement and sensation. Both of those suggestions have been rejected by further scientific research.
• RLS may be related to abnormalities in brain chemicals (neurotransmitters) that help regulate muscle movements, or to abnormalities in the part of the central nervous system that controls automatic movements. Research is still being done in these areas.

RLS can be primary or secondary:

• Secondary RLS is caused by an underlying medical condition.
• Primary (idiopathic) RLS has no known underlying cause. Primary RLS is far more common than secondary RLS.

Many different medical conditions can cause secondary RLS.

• The two most common conditions are iron-deficiency anemia and peripheral neuropathy.
  • Iron-deficiency anemia ("low blood") means low levels of red blood cells as a result of inadequate iron in the body.
  • Peripheral neuropathy is damage to the nerves of the arms and legs. Peripheral neuropathy has many causes. Diabetes is a common cause of peripheral neuropathy. Peripheral neuropathy causes numbness or lack of sensation, tingling, and pain in the affected areas.
• As many as 40% of pregnant women experience RLS symptoms. The symptoms usually fade within a few weeks after delivery.
• Certain medications or substances can cause RLS. Alcohol, caffeine, anticonvulsant drugs (for example, methsuximide [Celontin], phenytoin [Dilantin]), antidepressant drugs (for example, amitriptyline [Endep, Elavil], paroxetine [Paxil, Paxil CR, Pexeva]), beta-blockers, H2 blockers, lithium (Eskalith, Lithobid), and neuroleptics (antipsychotics) may cause RLS.
• Withdrawal from vasodilator drugs, sedatives, or imipramine (Tofranil, Tofranil-PM) can cause RLS symptoms.
• Cigarette smoking is linked to RLS.
• Other secondary causes include magnesium deficiency, vitamin B-12 deficiency, severe kidney disease (especially if dialysis is required), amyloidosis, Lyme disease, damage to the spinal nerves, rheumatoid arthritis, Sjögren's syndrome, and uremia (kidney failure causing build-up of toxins within the body).

While causes of primary RLS are unknown, some of the risk factors are known:

• In 25% to 75% of cases, primary RLS seems to run in families. Such hereditary cases of RLS tend to start earlier in life and get worse more slowly than other cases.
• Psychiatric factors, stress, and fatigue can worsen the symptoms of RLS.

Other conditions linked to RLS include:

• Parkinson's disease
• Stomach surgery
• Chronic obstructive pulmonary disease (COPD)
• Some tumors
• Chronic venous insufficiency or varicose veins
• Myelopathy or myelitis (damage or inflammation of the spinal cord)
• Hypothyroidism or hyperthyroidism
• Acute intermittent porphyria, a rare metabolic disease leading to accumulation of toxins
• Fibromyalgia
• Peripheral cholesterol microemboli (fragments of cholesterol in the blood vessels)

The International Restless Legs Syndrome Study Group described the following symptoms of restless legs syndrome (RLS):

• Strange itching, tingling, or "crawling" sensations occurring deep within the legs. These sensations sometimes occur in the arms and typically occur during the night.
• A compelling urge to move the limbs to relieve these sensations
• Restlessness: Floor pacing, tossing and turning in bed, rubbing the legs
• Symptoms may occur only with lying or sitting. Sometimes persistent symptoms occur that are worse with lying or sitting and better with activity.
• In very severe cases, the symptoms may not improve with activity.

Other symptoms of RLS include the following:

• Sleep disturbances and daytime sleepiness are very common.
• Involuntary, repetitive, periodic, jerking limb movements occur either in sleep or while awake and at rest. These movements are called periodic leg movements of sleep or periodic limb movement disorder. About 80% of people with RLS also have this condition.

In some people with RLS, the symptoms do not occur every night, but they come and go. These people may go weeks or months without symptoms (remission) before the symptoms return again.

If a person has any of the symptoms already described or have problems sleeping and don't know why, should talk to a health-care professional.

For most people with restless legs syndrome (RLS), poor sleep and daytime sleepiness are the most bothersome symptoms. Many people do not link their sleep problem with the strange sensations in their legs. If a person has these sensations, be sure to mention it to a health-care professional. This provides a very important clue to what is causing the person to sleep poorly.

Sleep disturbances have many different causes. A health-care professional may ask the patient many detailed questions. These questions concern current medical problems, prior medical problems, family medical problems, medications, work history, travel history, personal habits, and lifestyle. The health-care professional will look for signs of an underlying cause for the patient's sleep problem.

There is no lab test or imaging study that can prove that a person has RLS. However, certain tests can identify underlying medical causes such as anemia, other deficiencies, and metabolic disorders that could cause RLS.

• The patient may have blood drawn to check iron levels, blood cell counts and hemoglobin, basic organ functions, chemistry, and thyroid hormone levels. The patient may also may be checked for certain infections that could cause secondary RLS.
• Needle electromyography and nerve conduction studies may be done if the health-care professional sees signs of neuropathy.
• Polysomnography (sleep testing) may be necessary to diagnose the sleep disturbances and determine if the patient has periodic limb movements. This is especially important in people who continue to have significant sleep disturbances despite relief of RLS symptoms with treatment.

There is no cure for primary restless legs syndrome, although various treatments often can relieve symptoms. Treatment should be tailored for the individual's symptoms. Treatment for secondary restless legs syndrome involves treating the underlying cause.

In many cases, personal habits can make a sleeping disorder worse. Sometimes they are the main cause of the problem. Here are some things a person with RLS can do that may relieve symptoms.

• Avoid or limit alcohol, caffeine, and nicotine for several hours before bedtime.
• Take medications (prescription and nonprescription) only as directed.
• Get some exercise every day.
• Avoid eating a heavy meal close to bedtime.
• Maintain a regular sleep schedule.
• Avoid daytime naps.
• Use the bed only for sleeping or sex.
• Try not to use bedtime as worry time.

The first principle of therapy to treat restless legs syndrome (RLS) is to avoid substances or foods that may be causing or worsening the problem. Avoiding alcohol, caffeine, and nicotine may partly relieve symptoms. The health-care professional should review the patient's medications and determine whether any drug he or she is taking could be causing the problem.

Any underlying medical conditions, such as anemia, diabetes, nutritional deficiencies, kidney disease, thyroid disease, varicose veins, or Parkinson's disease, should be treated. Dietary supplements to correct vitamin or mineral deficiency may be recommended. In some cases, these treatments relieve RLS symptoms.

Affected individuals may benefit from physical therapy, such as stretching, hot or cold baths, whirlpool baths, hot or cold packs, limb massage, or vibratory or electrical stimulation of the feet and toes before bedtime. Exercise and relaxation techniques also may be helpful.

Daily drug treatment is recommended only for people who have restless legs syndrome (RLS) symptoms at least three nights a week, or as determined by your doctor. Drugs used to treat primary RLS do not cure the condition, but only relieve symptoms. People whose RLS symptoms occur sporadically may be prescribed medication to take when they have symptoms.

The following drugs are most widely prescribed to treat RLS. They may be given alone or, in certain cases, in combinations.

• Dopaminergic agents: These agents increase the level of the neurotransmitter dopamine in the brain. They may improve the leg sensations in RLS. Examples include the drug combination of levodopa (Larodopa) and carbidopa (Sinemet).
• Dopamine agonists: These agents also increase dopamine levels in the brain but are less likely than levodopa to cause certain side effects. These drugs have their own side effects. These side effects may be especially difficult for older people. Examples are pergolide mesylate (Permax), bromocriptine mesylate (Parlodel), pramipexole (Mirapex), and ropinirole hydrochloride (Requip).
• Benzodiazepines: These agents are sedatives and also help you sleep through the symptoms. Examples are temazepam (Restoril), alprazolam (Xanax), and clonazepam (Klonopin)
• Opiates: These drugs are most often used to treat pain, but they can relieve RLS symptoms. Because opiates are very addictive, they are usually used only when other drugs don't work - and usually for a very short period of time. Low-potency opiates, which are used in people with mild or intermittent symptoms, include codeine and propoxyphene (Darvon, Dolene); higher potency agents, such as oxycodone hydrochloride (Roxicodone), methadone hydrochloride (Dolophine), and levorphanol tartrate (Levo-Dromoran), are used in more severe cases.
• Anticonvulsants: These agents are used to treat severe muscle spasms. In RLS, they are used mainly for people who have pain, neuropathy, or daytime symptoms. The most widely used examples are gabapentin (Neurontin) and pregabalin (Lyrica).
• Alpha2 agonists: These agents stimulate alpha2 receptors in the brain stem. This activates nerve cells (neurons) that "turn down" the part of the nervous system that controls muscle movements and sensations. An example is clonidine hydrochloride (Catapres). This drug may help in cases of primary RLS but has no effect on periodic limb movements during sleep (PLMS).

The health care professional will probably ask the patient to return for one or more follow-up visits after trying his or her recommendations.

Sleep disorders often can be at least partly prevented by developing healthy sleep habits. See a health-care professional regularly for proper care of any medical or mental problems.

Strange sensations in the legs, persistent insomnia, and daytime sleepiness are not part of normal aging. In most cases, the symptoms of restless legs syndrome are treatable or improve with treatment of the underlying condition.