My legs felt like they had soda bubbles fizzing inside them

RLS Symptoms

Current medical knowledge about RLS

Dr. Birgit HöglCommented by Prof. Birgit Högl
Department of Neurology & Sleep Disorders Clinic, Medical University of Innsbruck, Austria

Restless Legs Syndrome (RLS) can occur as a primary disorder or secondary to other conditions.

Primary or idiopathic RLS

It is still unclear what causes primary RLS, although there is a strong genetic predisposition, with about half of patients reporting a positive family history.1,2

Primary, or idiopathic, RLS is believed to result from a dysfunction of the dopaminergic system, an area in the brain, possibly occurring on the level of striatal and/or spinal dopamine receptors, and a neuron group localised in the hypothalamus as an integrated part of the system.1,2 The strongest evidence in support of this comes from pharmacological studies showing a significant improvement of symptoms with the administration of levodopa or dopamine agonists.1,3 It has also been suspected that decreased iron levels in the brain may be the underlying cause for this dysfunction of the dopaminergic system.3

Symptoms caused by primary RLS usually worsen over time, increase in frequency, and rarely improve without treatment.

Secondary RLS

Secondary RLS occurs as a result of other conditions, including iron deficiency anaemia, pregnancy and end–stage renal disease. Secondary RLS usually disappears when the contributing condition resolves.3


RLS genetics

RLS genetics diagram

Graph adapted from data included in: Winkelmann J et al. Clinical characteristics and frequency of the hereditary restless legs syndrome in a population of 300 patients. Sleep 2000; 23: 597-602.

A family history is likely in RLS, and familial RLS is prone to start at an early age, compared with nonfamilial RLS.

  • The findings displayed are from a German study of 300 RLS patients, among whom 232 had idiopathic (primary) RLS. The other 68 had secondary RLS ascribable to uremia. (End-stage renal disease is a known cause of RLS)
  • In the idiopathic RLS group, 42.3%, or almost half, had a definite family history, defined by a verified diagnosis in at least one first-degree relative. A further 12.6% had a possible family history, in which family members reported to have RLS could not be contacted for verification
  • In the uremic RLS group, 11.7% had a definite family history (additional to the identified non-hereditary basis for their RLS), and a further 5.8% had a possible family history
  • Patients with a definite family history were significantly younger at age of RLS onset than those with no previous family history, at 35.5 vs 47.2 years (P < 0.05). RLS symptoms, however, were similar in both groups.
 

Symptoms of RLS explained

Characteristic symptoms

RLS is characterised by an uncontrollable urge to move the legs, usually accompanied or caused by uncomfortable and often painful sensations in the legs.1,4 These symptoms are worse at rest and during the evening or night.5 RLS tends to be associated with involuntary semi-rhythmic leg movements during sleep, referred to as periodic limb movements of sleep (PLMS), which can often wake up the patient.1 This results in people with RLS finding it difficult to fall asleep and to stay asleep or to sit still or relax.6

Associated symptoms

People with RLS may also experience a range of associated symptoms, such as symptom–related sleep disruption which, in return, leads to daytime sleepiness compromising work⁄daytime performance.4,6 Not surprisingly, a majority of RLS patients complain about a lack of energy, a tendency to feel depressed or low and problems with concentration.6

References

  1. Silber MH et al. An algorithm for the management of Restless Legs Syndrome. Mayo Clin Proc 2004; 79(7): 916–922.
  2. Winkelmann J et al. Genome–wide association study of Restless Legs Syndrome identifies common variants in three genomic regions. Nature Genetics 2007; 39: 1000–1006.
  3. Allen RP et al. Restless Legs Syndrome: a review of clinical and pathophysiologic features. J Clin Neurophysiol 2001; 18(2): 128–147.
  4. Allen RP et al. Restless Legs Syndrome prevalence and impact REST general population study. Arch Int Medicine 2005; 165: 1286–1292.
  5. Allen RP et al. Restless Legs Syndrome: diagnostic criteria, special considerations, and epidemiology – A report from the Restless Legs Syndrome diagnosis and epidemiology workshop at the National Institutes of Health. Sleep Med 2003; 4(2): 101–119.
  6. Hening W et al. Impact, diagnosis and treatment of Restless Legs Syndrome in a primary care population: REST (RLS epidemiology, symptoms and treatment) primary care study. Sleep Med 2004; 5(3): 237–246.
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