Cause of Restless Leg Syndrome

Restless leg syndrome is a disorder that affects as many as 7 to 10% of the population at any given time.

Yet the disorder itself is hard to understand. It has several qualities that make it both difficult to diagnose and difficult to treat:

• It's a spectrum disorder, which means that some people experience worse restless leg symptoms than others.
• It is a subjective disorder, so while some may feel their symptoms to be intense, others may find it more manageable.
• It is its own distinct neurological disorder, but it can have several different causes that affect both how it's treated and how it's diagnosed.

In many ways, what causes restless legs is not entirely known. But what follows is a breakdown of what those in the medical community believe are the causes of restless leg syndrome.

What Causes RLS?

It should be noted that in some cases there may be no cause of restless leg syndrome. Some people simply experience some degree of RLS during their life without any clear reason.

Still, the medical community agrees on the following potential causes of RLS. It should be noted, however, that your RLS may be caused by one, some, all, or none of the following issues.

Heredity

Many researchers believe that restless leg syndrome is largely hereditary.

Estimates range from 25% to 75%, but most researchers agree that a large number of those that suffer from restless leg syndrome are genetically predisposed to the issue.

This appears to be even more likely if the individual suffering from restless leg appears to develop the disorder at a young age, where environmental and age-related factors become less likely.

Although heredity is considered a cause of restless leg syndrome, the specific issue may still differ. For example, some may be predisposed to anemia, which can cause RLS, while others may be prone to the RLS itself.

Doctors have potentially linked several genes to restless leg syndrome, including MEIS1, BTBD9, and MAP2K5, and many chromosomes including 14q, 12q, 20p, and 9p. It's unclear which ones are responsible for the disorder, and it's possible that it may differ between races, family histories, and ethnic backgrounds.

Dopamine Issues

Most researchers believe that restless leg syndrome is linked to some type of dopamine balance issue.

That's because the symptoms of RLS tend to change depending on the natural dopamine cycle. Dopamine is at its lowest in the evenings, which is also when RLS tends to be exhibited.

Dopamine agonists also appear to help treat RLS, although the body has a tendency to adapt to these drugs and simply cause the restless leg syndrome to come earlier.

In addition, the dopamine issue doesn’t appear to be related to any serious brain disorder. While Parkinson's medications are used as treatments for restless leg, those with RLS do not appear to be more prone to Parkinson's disease.

Once again, it's unclear if there is some type of underlying issue that leads to a dopamine imbalance, or there is simply a dopamine imbalance in the brain or both. Still, it does appear that somehow dopamine plays a role in the development of restless leg syndrome.

Vitamin Deficiencies

Vitamin deficiencies are the most identifiable potential cause of restless leg syndrome. Many studies have found that those with RLS are low in various vitamins, and often with simple lifestyle changes or vitamin supplementation, the restless leg syndrome appears to go away.

In most cases, although not all, restless leg syndrome is associated with anemia. Doctors have found, however, that not all patients with RLS are anemic. One of the theories is that those with RLS may simply require more of various vitamins than the general population. Commonly linked vitamins include:

Many vitamin deficiencies are linked to anemia. However, scientists are still unclear whether anemia is a cause or a secondary issue related to vitamin deficiencies. A high percentage of those living with RLS are anemic (20%) indicating that there is some connection between the two.

Regardless, vitamin deficiency appears to be one of the leading causes of restless leg syndrome.

Pregnancy

RLS appears to affect as many as 17% of pregnant women.

Because no one knows what causes RLS, it's unclear what changes within a pregnant woman's body to lead to restless leg symptoms. It's likely that some combination of hormonal changes and nutritional intake is the cause.

RLS does not appear to have any effect on the fetus, and generally, when pregnancy causes restless leg, the symptoms go away after childbirth. Talk to your doctor before you begin any treatment. They may recommend that you wait.

Underlying Disorders

In the vast majority of cases, what causes restless leg syndrome is unknown and usually not life-threatening or indicative of any major health problem. Dietary deficiencies can be dangerous, but most can be fixed with supplementation or a change in diet.

In some cases, however, restless leg syndrome may be a symptom of an underlying disorder. When disease causes RLS, treatment for RLS involves first combatting the disease.

The following are known causes of restless leg syndrome:

• Varicose Veins
• Diabetes
• Thyroid Disease
• Auto-immune Diseases
• Fibromyalgia
• Sleep Apnea
• Parkinson's Disease

Celiac disease is an example of an auto-immune disease that may cause restless leg syndrome. In the case of celiac, however, the cause is still likely to be related to iron deficiency, as those with celiac may have a shortage of iron in their bloodstream.

Those that believe they have restless leg shouldn't be too concerned that it is a sign of another underlying disorder. Generally, restless legs will be one of many symptoms when some other disorder is present, with RLS potentially being the lesser of your concerns.

RLS is also more likely to be related to vitamin deficiencies and/or no cause at all.

Still, because of these underlying diseases that could cause restless leg syndrome, it's generally recommended that you see a doctor first to rule them out. RLS treatments often change dramatically when there is a primary disease.

Medication-Induced RLS

In some cases, it's also possible for restless leg syndrome to be caused by medications you're taking. Few medications have been linked directly to RLS, but various types of medications have been known to cause restless leg in some patients. These include:

• Antidepressants
• Antihistamines
• Antipsychotics
• Anticonvulsants
• Antiemetics

Drug withdrawal may also be what causes RLS. Benzodiazepine and opioid withdrawal are both known to contribute to a restless leg-like experience.

In many of these cases, the drug itself may not be causing the RLS but may make already present restless leg symptoms worse.

If the disorder is caused by a medication, stopping the medication should eventually stop the disorder. Still, always talk to your doctor before stopping any type of medication.

Examining the Cause of Restless Leg Syndrome

Despite advancements in recent years, it's still difficult for doctors and scientists to pinpoint the exact cause of RLS.

In fact, there is controversy in the medical community about whether it should be considered more than one different type of disease, or whether they should all fit within the RLS category. For example, many believe that if the RLS is caused by diabetes, then it should be considered a symptom only and not a separate problem.

Others disagree because the mechanism is generally the same and treatments often still work to combat the RLS directly.

Regardless, while it may still not be 100% clear what causes restless leg syndrome in general, there are ways to figure out what may be causing your specific RLS and how best to go about treating it.