What Is the Main Cause of Restless Leg Syndrome?

Medically Reviewed on 12/21/2022
restless legs syndrome
The main causes of restless leg syndrome (RLS) include brain dopamine concentrations, genetic history, and brain iron concentrations.

Restless leg syndrome (RLS), also known as Willis Ekbom disease, is a disorder characterized by unpleasant sensations in the legs (such as twitching, prickling, or pulling) that cause a strong and uncontrollable desire to move the legs or walk around to relieve the sensations. These symptoms are also seen in the hands and other parts of the body.

The exact cause of RLS is unknown; however, there has been a significant amount of study regarding the cause of RLS during the last 20 years.

According to research, three components appear to contribute to the disease:

  1. Brain dopamine concentrations: Because RLS is associated with movements of the muscles, researchers believe that it may be caused by an imbalance in the brain chemical dopamine, which is responsible for transmitting impulses and controlling movements of the muscles.
  2. Genes: There is a possibility that RLS runs in the family because almost half the people with the condition have a close relative who also has the disorder. More research needs to be done to confirm this aspect.
  3. Brain iron concentrations: Research suggests that iron deficiency may be the single most consistent finding and the strongest environmental risk factor linked with RLS. Treatment of iron deficiency typically significantly alleviates RLS symptoms. Several studies support the hypothesis that decreased brain iron levels are associated with RLS. Despite having normal blood iron and ferritin levels, lumbar puncture-derived cerebrospinal fluid revealed that iron storage protein ferritin is low in people with RLS.

16 Medical conditions associated with RLS

It has been noted that certain medical conditions, such as the following, may cause RLS syndrome:

  1. Late-stage kidney disease
  2. Dialysis
  3. Uremia
  4. Iron deficiency anemia
  5. Rheumatoid arthritis
  6. Osteoarthritis
  7. Peripheral neuropathy
  8. Multiple sclerosis
  9. Parkinson’s disease
  10. Attention deficit hyperactivity disorder
  11. Anxiety disorders
  12. Depression
  13. Diabetes mellitus
  14. Fibromyalgia
  15. Hypothyroidism
  16. Pregnancy (seen mostly in the third trimester and resolves after delivery)

Symptoms of RLS are triggered and worsened by the following:

What are the treatment options for restless leg syndrome?

Treatment of restless leg syndrome (RLS) mainly involves treating the underlying condition and managing symptoms.

Treatment depends on the intensity of symptoms and other medical conditions that are associated with RLS.

Mild RLS

A person with mild RLS does not require any active treatment, and conservative treatment is recommended to alleviate the symptoms.

  • Adopt a good sleep schedule
  • Get adequate sleep
  • Avoid activities that interfere with sleep before bedtime:
    • Watching television
    • Using smartphones or computers
    • Performing vigorous exercise
  • Increase exercise or physical activity in the morning
  • Apply heat pads or massage legs to provide relief
  • Take hot water baths or soak the legs in warm water
  • Reduce stress
  • Quit alcohol and smoking
  • Avoid or limit the intake of caffeinated products such as:
    • Coffee
    • Tea
    • Colas
    • Chocolates

Severe RLS

People with severe RLS are given prescription medications to treat the underlying cause and alleviate symptoms.

  • Iron supplements: Iron supplementation may alleviate symptoms in people with RLS who are iron deficient. It should only be used after other dietary treatments have failed. Iron supplements do not appear to be beneficial for people with RLS who have iron levels that are normal or above normal.
  • Dopamine agonists: Dopamine agonists suppress the impulse to move, alleviate sensory complaints in the legs and diminish involuntary leg jerks during sleep. The U.S. Food and Drug Administration–approved dopamine agonists for RLS include ropinirole, pramipexole, and rotigotine patch.
  • Other medications:
    • Anticonvulsant or antiseizure drugs such as carbamazepine or gabapentin are prescribed to provide sedation or narcotic effect that relieves pain and aids in sleeping.
    • Other medications are given to manage the underlying cause such as diabetes, thyroid issues, arthritis, and others.

All drugs have the potential for negative effects and should only be taken under the supervision of a physician who is specialized in the treatment of RLS.

The same medicine may not be successful for all people, and a specific medication may be effective at first but become less effective with time.


Why do we sleep? See Answer

What are the symptoms of restless leg syndrome?

The primary symptom of restless leg syndrome (RLS) is an uncontrollable need to move the legs. This sensation is described by some as a sense of discomfort and fatigue in the lower leg. Rest aggravates the feelings, whereas activity relieves them.

RLS has the following characteristics:

  • Uncomfortable sensations beneath the skin mostly in the calf area, which to get relief, the person may move their legs uncontrollably. These sensations include:
    • Pulling
    • Burning
    • Drawing
    • Tingling
    • Bubbling
    • Crawling
  • People with RLS also experience itching, discomfort, and aching pain.
  • Although these feelings are most common in the lower legs, they can occur in the thighs, feet, and even the arms. In some cases, these may be the earliest symptoms of RLS.
  • Symptoms frequently appear at night when people are at their most relaxed, with their legs at rest and lying down. People have uncomfortable feelings and a strong need to move their legs. When you resist the temptation to move your legs, tension builds up until the legs shake involuntarily. This causes difficulty sleeping.
  • Symptoms can occur during the day when sitting, and the person may find it difficult to sit on flights, vehicle rides, classes, or meetings. Movement helps people alleviate their discomfort. As a result of insufficient or bad sleep, people may feel extremely fatigued during the day.
  • RLS episodes are most common between 10 p.m. and 4 a.m. Symptoms usually worsen just after midnight and subside by the next morning. If the condition worsens, people may have symptoms throughout the day. However, the problem is always worst at night.
  • Most people with RLS have semi-rhythmic movements during sleep. These movements are termed periodic limb movement disorder (PLMD), also known as nocturnal myoclonus.

Characteristics of periodic limb movement disorder (PLMD) include:

  • Just as with RLS, episodes of PLMD are seen at nighttime that often peaks around midnight.
  • During sleep, the leg muscles contract and jerk every 20 to 40 seconds. These motions might last as little as a second or as long as 10 seconds.
  • Movements caused by PLMD do not disturb or wake up the person with PLMD, but anyone sleeping on the same bed as the person with PLMD can recognize the shaking.
  • Four out of five people (80 percent) with RLS may have PLMD, but only 33 percent of people with PLMD have RLS.

What is restless leg syndrome?

Restless leg syndrome (RLS) is classified as a sleep disorder by doctors because it frequently occurs or worsens while you are sleeping.

  • You may experience difficulty sitting for a longer period, and usually, symptoms occur in the evening, making it difficult to sleep.
  • If RLS is not treated, it may worsen and lead to sleepless nights, which can lead to trouble at work or home over time.

RLS is seen among all age groups and gender with almost 10 percent of the United States population affected by the condition. Women in their 40s and 50s are more likely to have severe symptoms.

This disease may go unnoticed or be misdiagnosed for years, especially if symptoms are minor or don't occur frequently. However, once detected, therapy may help relieve the symptoms.

2 Forms (Types) of RLS

Restless leg syndrome (RLS) can be classified into two forms:

  1. Early-onset RLS: People with early-onset RLS have symptoms beginning before the age of 45 years old.
    • These people are more likely to have a family history of the disorder.
    • They frequently suffer from RLS without any associated discomfort.
    • Women tend to develop RLS at a younger age than men.
  2. Late-onset RLS: Late-onset RLS may be caused by neurological disorders and may be present with pain in the legs.
    • People with late-onset RLS may not have a family history of RLS.

How is restless leg syndrome diagnosed?

There is no definitive diagnostic method for restless leg syndrome (RLS); however, a diagnosis is typically done through the following:

Medical history

RLS is frequently diagnosed based mostly on the person's description of symptoms. Usually, the first step in a diagnosis is to collect information about a person's sleep and personal history.

The doctor may ask questions regarding the following aspects:

  • Sleeping habits and sleep disorders
  • Feelings of sensations in the legs and when they occur
  • Habits such as drinking and smoking
  • Other eating habits
  • Other health disorders and a list of medications
  • Lifestyle and stressors in life
  • Sleep apnea (breathing issues while sleeping)
  • Physical activity and working hours
  • Family history of the disease

Blood workup

  • Iron profile:
    • Blood is tested in the laboratory to check for possible iron deficiency anemia, which doctors count the levels of
  • Other tests:
    • The blood collected from the person may be subjected to various tests to determine the presence of disorders that may lead to RLS, which include

Radiological tests

  • Magnetic resonance imaging of the brain: Detects possible stroke or myelopathy
  • Electromyography: Records electrical activity of the muscles and helps assess any damage to the nerves controlling the muscles.

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Medically Reviewed on 12/21/2022
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Restless Legs Syndrome (RLS): https://www.sleepfoundation.org/restless-legs-syndrome

Causes of Restless Legs Syndrome: https://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/restless-legs-syndrome/what-is-rls/causes.html

Restless Legs Syndrome: https://familydoctor.org/condition/restless-legs-syndrome/