Restless legs syndrome

Restless legs syndrome is a widely spread but little-known cause of sleep disorders.

In 1685, it was first described by Thomas Willis and in 1945, Karl Ekbom introduced the term restless legs syndrome in medical literature.

Incidence

Restless legs syndrome occurs in 1 to 15% of the population, depending on the study you rely on. Recent studies reveal that in Germany 2 – 3 % of the population suffer from restless legs syndrome that needs treatment. The incidence of restless legs syndrome increases with age. Men and women are afflicted equally often with the proportion of women prevailing if they were pregnant several times.

Symptoms

The patients complain of painful sensations, such as prickling, insect crawling, burning in the extremities, especially in the lower legs, more rarely in thighs and arms. Often there is a combination with aches and pains in the extremities. Typically, the complaints are less severe in the early hours and peak out at night between midnight and 4 a.m. Therefore sleep is partly disturbed enormously. Furthermore, the symptoms mainly occur during periods of inactivity, when lying down, sometimes when taking a rest during the day, e.g. sitting in front of the television, on the plane, in the cinema, as front-seat passenger in the car. In most cases, an immediate improvement can be achieved by movements and, if needed, by applying physical stimuli (rubbing, holding the effected area under cold water). In bed, the patients often stick out their legs from under the sheet since warmth may intensify the symptoms. Frequently, a combination with periodic limb movements is seen. Periodic limb movements occur in approx. 80% of the cases during sleep in combination with arousal reactions. The incidence of these limb movements connected with short arousal reactions of which the sleeper is oblivious may be a several hundred per night. The causes of primary restless legs syndrome are assumed to be balance disorders in the dopamine and/or iron metabolism in the central nervous system. Secondary restless legs syndromes occur in connection with other diseases. Approximately 20 % of uraemia patients suffer from restless legs syndromes. In chronic polyarthritis and other rheumatic diseases, RLS occurs in approx. 30 % of the cases and with iron deficiency in approx. 20 % of the cases. Often RLS can be detected temporarily during pregnancy in 10 – 15% of the cases. Polyneuropathies (diseases of the nervous systems) are other frequent causes of RLS symptoms.

Examination

Surprisingly seldom, the disorder is seen as the cause of the difficulty in falling and staying asleep. Therefore, physicians must often directly ask for it. With primary inheritable RLS, an increased presence of the disease among family members can be found. A detailed neurological and internal examination is absolutely necessary to rule out secondary RLS. An inpatient polysomnographic examination is required to rule out periodic limb movements with arousal reactions. It represents the only diagnostic method to detect limb movement.

Therapy

With symptomatic forms of restless legs syndrome, measures to eliminate the causes are given priority, such as e.g. prescribing iron supplements, treating renal insufficiency or polyneuropathies. With primary RLS, a symptomatic pharmaceutical treatment is preferred because the causes are still unclear. Pharmaceutical treatment is carried out with antiparkinson drugs, opioids, benzodiazepines and antieleptics. Dopamine agonists (antiparkinson drugs) are the first choice. For L-DOPA drugs a dose of 50 – 300, max. 400 mg is recommended. Opioids will be considered if dopamine agonists show no effect, if tolerances are developed or as exclusive therapy. Benzodiazepines as for example clonazepam improve the sleep structure, but they do not reduce nocturnal periodic limb movements. In individual cases, positive effects of antieleptics, such as for example valproate or carbamazepine are reported.