Restless Legs Syndrome – Causes, Signs and Symptoms

restless legs syndrome

Also called: RLS

Summary

Restless legs syndrome (RLS) is characterized by an unpleasant discomfort that is perceived in the legs (and occasionally the arms) and felt to decrease when patients move their limbs. This relief is, however, usually temporary, as patients feel the need to continually move their limbs. RLS disrupts sleep as a result, causing fatigue that may affect many aspects of a patient’s life.

As many as 12 million Americans are estimated to have RLS, according to the National Institutes of Health. Many experts believe that this disorder is underdiagnosed and that the prevalence may be higher.

Patients often report leg discomfort that is described as creeping, crawling, pulling, itching, tingling, burning, aching or painful sensations. Others perceive it as arising deep within their legs. There are two major types of RLS:

  • Primary restless legs syndrome. This results from unknown factors. In most cases, primary RLS is a lifelong condition that can progress over time.

  • Secondary restless legs syndrome. This form results from an underlying condition, such as pregnancy, fibromyalgia or diabetes, or is a side effect from certain medications. Symptoms typically subside if the source of the disorder is resolved.

More than 80 percent of people with RLS also have an associated condition known as periodic limb movement disorder, in which a person’s leg involuntarily twitches or jerks excessively for anywhere from 10 seconds to a full minute.

Women are at greater risk of developing RLS than men. The incidence increases as people age, with many diagnosed sometime during middle age.

At present, no test can definitively detect RLS. Diagnosis is typically based on the patient’s symptoms after other possible causes are ruled out.

Patients with RLS can often find relief by making certain lifestyle changes. More severe cases may require medication. The U.S. Food and Drug Administration has approved two anticonvulsant drugs to treat RLS.

About restless legs syndrome

Restless legs syndrome (RLS) is a condition in which patients feel compelled to move their legs during rest in response to feelings of discomfort in the legs. Most people with RLS describe a tingling, burning or crawling sensation that is relieved only by moving the legs. However, the relief is usually temporary, requiring patients to move their legs again and again. In some cases, RLS also affects a patient’s arms.

It is not precisely known how many people have RLS. According to the National Institutes of Health (NIH), as many as 12 million Americans may have the condition. Other experts believe that the disorder is underdiagnosed and that the number of people affected is likely to be much higher.

Though RLS does not pose any great danger to a person’s health, patients often find it very uncomfortable. In an attempt to prevent their symptoms, patients often pace the floor, constantly move their legs while sitting (e.g., jiggling or stretching them) or toss and turn in bed. Because symptoms are especially likely to occur at night, many patients report difficulty falling asleep or remaining asleep. Fatigue during the day is commonly associated with RLS because of sleep disturbance.

There are two major types of RLS:

  • Primary restless legs syndrome. Also known as idiopathic RLS, it is the result of unknown factors. In most cases, primary RLS is a lifelong condition that can get worse over time. This is especially true when symptoms begin in childhood or early adulthood. Some patients have symptoms that fluctuate, whereas others experience symptoms that are more persistent. This is the more common form of RLS.

  • Secondary restless legs syndrome. This form of RLS is the result of an underlying illness or a side effect of certain medications (e.g., antiseizure medications). It can also occur during pregnancy. Symptoms typically disappear once the patient’s illness subsides, medical condition returns to normal, or after the patient stops taking the inciting medication.  

More than 80 percent of people with RLS also have an associated condition known as periodic limb movement disorder, according to the NIH. In this condition, a person’s legs involuntarily twitch or jerk excessively for about 10 to 60 seconds. As with RLS, symptoms tend to strike at night and may occasionally involve the arms. The cause of this disorder is also unknown.

Risk factors and causes of restless legs syndrome

Experts speculate that restless legs syndrome (RLS) may result from an imbalance of the brain chemical dopamine. This chemical transmits signals in parts of the brain that control muscle movement. Stress may also play a role in RLS, because symptoms often worsen during periods of stress.

When a cause for RLS is unknown (idiopathic), as it is in a majority of cases, a physician will diagnose the patient with primary RLS. This form of RLS tends to run in families, and people whose parents have the condition have a higher risk of developing RLS.

In a smaller number of cases, RLS can be traced to an underlying condition. This form of the disorder is diagnosed as secondary RLS. Pregnancy is one of the chief causes of secondary RLS, which is most likely to occur during the third trimester. Other conditions that may cause secondary RLS include:

  • Diabetic neuropathy
  • Other forms of nerve damage in the limbs (peripheral neuropathy)
  • Iron deficiency and anemia
  • Other mineral or vitamin deficiencies
  • Fibromyalgia
  • Kidney failure with resulting uremia (formation of urea and other wastes in the blood)
  • Parkinson’s disease
  • Rheumatoid arthritis

The use of certain medications can also trigger RLS. These include certain anti-seizure (anticonvulsant) and anti-nausea drugs, antidepressants, antipsychotics and some cold and allergy medications, notably antihistamines. Finally, lifestyle choices such as use of tobacco or excessive consumption of alcohol or caffeine may worsen symptoms of RLS.

Women appear to be affected more than men. In particular, women who are pregnant have increased rates of RLS. The disorder is diagnosed across all racial and ethnic groups but appears to be more common in people of northern European descent.

About two of every five cases of this disorder are diagnosed in people under the age of 20. Nonetheless, the incidence of RLS increases as people become older, with many diagnosed in middle age. When RLS first appears later in life, symptoms are usually more frequent and severe. In these cases, RLS is likely to be the result of a medical condition.

Signs and symptoms of restless legs syndrome

Patients with restless legs syndrome (RLS) feel the need to move their legs (and sometimes arms) when they sit or lay down. This is done in an effort to relieve discomfort in the limbs, which has been described as a deep creeping, crawling, pulling, itching, tingling, burning, aching or painful sensations.

Some patients find it difficult to describe these sensations, but others have compared it to feeling like insects are crawling around inside their legs. Symptoms of RLS do not usually resemble common discomfort of the limbs, such as muscle cramps or numbness.

The unpleasant sensations that provoke RLS typically affect the calf but can occur at any point between the thigh and ankle. They also can affect any part of the arm. Patients often find relief by moving their legs or arms, but this reprieve is only brief.

Symptoms are most likely to occur at night, particularly as patients are trying to get to sleep or during the early stages of sleep. Because of this delay in sleep onset, patient can have different sleep disorders, including trouble falling asleep or have problems remaining asleep. These problems can result in daytime fatigue and difficulty with concentration. Patients may be less productive at work and may struggle to carry out day-to-day tasks. This lack of sleep also can lead to mood swings and depression.

RLS symptoms can range from mild to severe. Patients with mild RLS may not notice any symptoms until they are required to sit or lay still for long periods of time (e.g., during airplane travel, long car trips, while sitting in a movie theater). Patients with moderate RLS may experience symptoms once or twice a week. Severe cases can produce symptoms that occur more than twice a week. RLS symptoms often can worsen during periods of stress.

Patients diagnosed with secondary RLS generally experience symptoms at the same time as the illness, medication or medical condition causing their RLS. Symptoms usually disappear after the precipitating cause goes away. Pregnant women many not experience symptoms of RLS until their third trimester. These symptoms often disappear within a few weeks of delivering the infant, although they can reappear later in life.

Many people with RLS also experience wild, involuntary jerking or twitching of their legs (or arms) for up to a minute. This usually occurs at night, when patients are resting or laying down. This type of involuntary movement is a sign of a condition known as periodic limb movement disorder.

Diagnosis methods for restless legs syndrome

In diagnosing restless legs syndrome (RLS), a physician will typically first review the patient’s medical history and perform a physical examination. The physician will pay particular attention to the health of the nerves in the spinal cord and legs and arms, as well as blood flow to the legs and arms.

The physician will likely ask patients about the history of their symptoms, including when they first occurred and the exact nature of the restlessness. Patients may be asked about their sleeping habits and how rested they feel during the day. The physician may ask about medications and consumption levels of caffeine, tobacco, alcohol and other substances. Sleeping partners may also be questioned.

At present, there is no test available to definitively diagnose RLS. Usually a physician will try to rule out other causes before diagnosing RLS. Blood tests and urine tests may be performed to rule out medical conditions that may be responsible for a patient’s symptoms. These lab tests also may be used to help reveal the presence of certain illnesses known to cause RLS, including diabetes, kidney disease and vitamin or mineral deficiencies.

Electromyography and nerve conduction studies may be ordered to measure electrical activity in muscles and nerves. A Doppler sonography (an ultrasound that also measures blood flow) may also be used to evaluate muscle activity in the legs.  A polysomnographic recording may be ordered to document periodic movement during sleep.

Typically, RLS is diagnosed when all other conditions are ruled out and certain criteria are met. Patients with RLS usually feel the urge to move their legs or hands because of unpleasant sensations in their limbs. Symptoms worsen during periods of rest or inactivity and are at least temporarily relieved by movement, including walking or stretching. The urge to move the limbs is worse in the evening or at night, as patients are trying to get to sleep or during the early stages of sleep.

Treatment and prevention of restless legs syndrome

Lifestyle modification is the first step in treating mild cases of restless legs syndrome (RLS). Avoiding alcohol, tobacco and caffeine can help reduce symptoms, as can avoiding medications that tend to trigger symptoms.

Many patients benefit from making modifications to their sleep routine. For example, patients are urged to make their bedroom as conducive to sleep as possible. This includes shutting out all unnecessary light and keeping the room cool and quiet. The bedroom should be used only for sleeping and intimacy, and patients are urged to go to bed and to arise at the same time every night and day. Many patients also find that going to bed later and waking later helps them feel more rested.

Regular, moderate levels of exercise may also help relieve symptoms. Walking and stretching or using heat (thermotherapy) and ice packs (cryotherapy) on the limbs also has been shown to relieve symptoms in some patients. Hot or cold baths may provide relief for some.

More severe cases of RLS may require medication. The U.S. Food and Drug Administration has approved two anticonvulsants (anti-seizure drugs) for the treatment of moderate to severe primary RLS: ropinirole (Requip) and pramipexole (Mirapex). These medications, known as dopamine agonists, are typically used to treat Parkinson’s disease.

Other medications that may be helpful for some patients include sedatives, opioids or other pain relievers, and supplements of iron or other minerals or vitamins.

Patients may find that some medications are more effective for them than others. Some drugs may work for a period of time before they need to be replaced by other drugs because they stop working or even begin to worsen symptoms, a condition known as augmentation. In addition, medications that bring relief to some patients may worsen symptoms in other individuals.

Questions for your doctor regarding RLS

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about restless legs syndrome (RLS):

  1. My legs occasionally feel restless. Is this RLS?

  2. Can my sleep partner look for signs when I sleep that might help determine if I have RLS?

  3. What tests will you do to determine whether I have RLS? How should I prepare for these tests?

  4. Do I have primary or secondary RLS?

  5. Is an underlying illness, medical condition or medications I am taking responsible for my symptoms?

  6. Do you suspect I also have periodic limb movement disorder?

  7. What are my treatment options?

  8. What are the risks of these treatments?

  9. How effective are treatments in eliminating symptoms?

  10. What are my options if the medication I’m using doesn’t work?

  11. What lifestyle changes can I make to help relieve my symptoms?
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