What is Restless Legs Syndrome (RLS), causes, Symptoms, Treatment

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There are a wide range of disorders which affect both quality and quantity of sleep, including insomnia, sleep apnoea, narcolepsy, depression and restless legs syndrome. While insomnia is quite a widespread complaint, other sleep-related problems, such as restless legs syndrome, are considerably less common.

Restless Legs Syndrome Symptoms

Restless legs syndrome (RLS) involves an intense urge to move the limbs, which is recognised to worsen during periods of inactivity. This link between inactivity and RLS is why the condition may seriously affect sleep. In Sleep Disorders, Wilson & Nutt (2008) highlight key symptoms associated with restless legs syndrome, to include the following:

  • desire to move limbs, usually linked to paraesthesia
  • tingly feelings
  • like insects crawling over skin
  • painful, burning, achy sensation
  • like water running over skin
  • worse in evening/at night
  • may cause onset insomnia
  • may lead to prolonged nighttime awakenings

What Causes Restless Legs Syndrome?

While it has been identified that restless legs syndrome affects between 4-6% of the population and worsens with age, the exact cause of RLS remains unknown. Risk factors associated with the condition, include pregnancy, kidney disease, family history of RLS and use of certain medications, such as antidepressants. According to Wilson & Nutt (2008), the current thinking on RLS suggests that there may be a link between the disorder and a dopamine receptor abnormality. Dopamine imbalance has already been proven to be a factor in other health problems, such as schizophrenia.

While RLS is often a primary disorder (and primary RLS probably has a genetic component) the condition may be secondary to or aggravated by the following:

  • Iron deficiency: Studies have shown abnormal iron and dopamine levels in the central nervous systems of individuals with RLS (iron is a cofactor in the conversion of the amino acid tyrosine to dopamine). Low serum iron stores, measured by serum ferritin, have been correlated with the severity of RLS symptoms.
  • Kidney failure: When kidney disease interferes with the normal production of erythropoietin, anemia and iron deficiency result. Up to 40% of patients with end-stage renal disease suffer from RLS.
  • Pregnancy: In general, women are more prone to RLS than men, and many women develop symptoms late in pregnancy. Studies have revealed a correlation between low hemoglobin levels (anemia) and symptoms of RLS in pregnant women.
  • Medications: Since RLS is a central nervous system disorder, medications that affect neurologic function can exacerbate symptoms (antihistamines, SSRI and tricyclic antidepressants, anti-emetics, lithium, etc).
  • Alcohol, caffeine, and tobacco: All of these substances have been implicated in worsening RLS symptoms.
  • Spinal cord injury.

Diagnosis

The diagnosis of RLS is based upon a patient’s history and physical examination. While laboratory analysis is not necessary to make the diagnosis, a battery of focused tests (metabolic panel and ferritin level) can help exclude secondary causes.

Criteria for diagnosing RLS include:

  • The urge to move one’s legs, usually accompanied by discomfort or unpleasant sensations (the arms or other body parts may be involved)
  • Symptoms that begin or worsen during periods of inactivity or rest
  • Symptoms that are partially or completely alleviated by movement
  • Symptoms that are worse in the evening or at night, or are only present at night (in severe cases, symptoms may occur during the day, but a careful history almost always reveals that complaints originally began in the evening or at night)

How to Treat Restless Legs Syndrome

There is clearly much research still required in this area in order to ascertain underlying causes of restless legs syndrome. Those responsible for treating the condition, including neurologists and sleep disorder specialists, mainly rely on the use of medication used to enhance the way in which the brain uses dopamine. As identified by Wilson & Nutt (2008), two pharmacological approaches to RLS treatment, involve the use of levo-DOPA and dopamine antagonists. It is also important to identify any medications which may be worsening RLS symptoms, such as antidepressants and antihistamines, then looking at alternatives.

A further approach to the treatment of restless legs syndrome is to help the patient improve sleep habits, by keeping a wake-sleep routine, avoiding food triggers, reducing caffeine and alcohol intake. Regular exercise may also help to manage the condition.

As highlighted above, restless legs syndrome can have a significant affect on sleep, resulting in fatigue, low energy levels and insomnia. RLS treatment primarily involves the use of medications, while alternative approaches to improving sleep patterns, such as relaxation techniques, dietary modification and abstaining from alcohol may help. The use of problematic medication, including antidepressants for treatment of major depression, may need to be reviewed.

Vitamins, Minerals and Herbs Can Relieve Agony of RLS

Restless legs syndrome is a fairly common ailment that affects 1-10% of the population. Even children can suffer from RLS. Other people often have difficulty understanding how annoying the constant need to move one’s legs can be.

The culprit can be low levels of some neurotransmitters and sometimes circulation is to blame. There are many useful drug therapies, but some supplements have also been proven effective.

Dopamine and RLS

One of the best known causes of RLS is deficiency of the neurotransmitter dopamine. The most common drug therapy is Parkinson’s disease medications that increase the levels of dopamine in the brain, such as levodopa (L-dopa) and ropinirole (Requip).

Dopamine levels can also be increased with the amino acid L-tyrosine. Tyrosine is a normal constituent of food, but it is also available as an over-the-counter supplement.

Another option is an amino acid called DL-phenylalanine. Not only does it increase brain levels of dopamine, but also those of endogenous opioids such as beta endorphin. Studies have found low levels of beta endorphin in certain areas of brain in RLS sufferers and opioids have been used as a treatment, though usually only for refractory RLS.

GABA and RLS

Gamma-aminobutyric acid is the main inhibitory neurotransmitter. A deficiency of GABA or receptors not responding to it properly has been suggested as a possible cause of RLS and benzodiazepines, a class of sedative drugs affecting the GABA receptors, are sometimes used as a treatment for refractory cases.

Several over-the-counter supplements can increase brain levels of GABA, such as the herb valerian and the amino acid taurine. GABA itself is also available as a supplement, but in many people it may not cross the blood-brain barrier effectively.

Vitamins and Minerals

Supplementation of folic acid (folate), one of the B complex vitamins, has been used to bring relief from restless legs and there is some evidence of its efficacy, at least in cases of deficiency. Because folic acid is very safe, there is no reason why everyone with RLS shouldn’t try it.

Iron deficiency anemia has been implicated as a possible cause of RLS. One should have one’s hemoglobin and preferably ferritin levels checked before considering iron supplementation, as excess iron is harmful. In studies many of those with low or low normal ferritin levels have benefited from iron supplements.

Magnesium is used in the treatment of muscle cramps and some sleep disorders, but for some reason it has been studied very little in restless legs syndrome. One very small study found it effective for reducing symptoms of RLS and a related condition known as periodic limb movements disorder (PLMD). It may be especially useful in RLS in pregnancy.

Other possibly helpful vitamins and minerals include inositol (often counted among the B complex vitamins), niacin (vitamin B3), pyridoxine (vitamin B6), vitamin B12, calcium and potassium, but they have not been studied in this use.

RLS and Circulation

In some small studies hydroxyethylrutosides, derivatives of rutin (a natural flavonoid found in many foods) have brought relief for RLS caused by chronic venous insufficiency (CVI), a condition reducing blood circulation to the legs. They may be difficult to source, but rutin is commonly available as a supplement.

Hawthorn (crataegus), vitamin E and pycnogenol might also be helpful for RLS caused by chronic venous insufficiency, but not likely to help in the absence of circulatory problems.

References

Wilson, S & Nutt, D. (2008) Sleep Disorders Oxford University Press

Walters AS, Ondo WG, Zhu W, Le W. Does the endogenous opiate system play a role in the Restless Legs Syndrome? A pilot post-mortem study. J Neurol Sci. 2009 Apr 15;279(1-2):62-5.

Hornyak M, Voderholzer U, Hohagen F, et al. Magnesium therapy for periodic leg movements-related insomnia and restless legs syndrome: an open pilot study. Sleep. 1998 Aug 1;21(5):501-5.

Patrick LR. Restless legs syndrome: pathophysiology and the role of iron and folate. Altern Med Rev. 2007 Jun;12(2):101-12.

MacLennan WJ, Wilson J, Rattenhuber V, et al. Hydroxyethylrutosides in elderly patients with chronic venous insufficiency: its efficacy and tolerability. Gerontology. 1994;40(1):45-52.