The restless legs syndrome.

The first description of the restless legs syndrome (RLS) is attributed to Thomas Willis in the 'London Practice of Physick' of 1685 (Ekbom, 1960). Here he wrote 'wherefore to some, when being a bed they betake themselves to sleep, presently in the arms and leggs, leapings and contractions of their tendons, and so great a restlessness and tossings of their members ensue, that the diseased are no more able to sleep than if they were in a place of the greatest torture'. In 1861 Whittmaack used the term anxietas tibiarum to describe nocturnal discomfort of the legs, which he considered was a common symptom of hysteria (Ekbom, 1945). The same phenomenon was called 'impatience musculaire' in the French literature (Ekbom, 1944; Bonduelle, 1952) and the leg jitters by Allison (1943). Ekbom's earliest descriptions of the RLS distinguished a common form which he called 'asthenia crurum paraesthetica' from a painful variant 'asthenia crurum dolorosa' (Ekbom, 1946). He identified the first of these in 34 cases. Paraesthesia with deep calf and shin discomfort started only when the legs were at rest and necessitated that they were moved to provide relief. He postulated that pregnancy was an aetiological factor and in some patients he diagnosed prostatitis, testosterone deficiency and the burning feet syndrome due to malnutrition. Ask-Upmark noted the disorder as a late effect of gastrectomy (Ask-Upmark & Meurling, 1955) and on the basis of anecdotal evidence of postural dependence of symptoms, suggested the cause was vascular congestion ofthe spinal cord (AskUpmark, 1959). Some authors doubted the existence ofa distinct syndrome; Purdon-Martin (1946) believed the symptoms were due to acroparaesthesia and Masland (1947) that they were a manifestation of myokymia. By 1960 Ekbom had studied 175 people whom he had identified with restlessness of the legs. He found that 5% of normal psychiatrically stable individuals were disturbed by restless sensations, but also believed it was symptomatic of anaemia, certain infectious diseases, diabetes, cold exposure or those taking phenothiazine drugs (Ekbom, 1945, 1950, 1960). A diabetic patient whose symptoms vanished on the side of a recent leg amputation was presented as evidence for a peripheral origin (Ekbom, 1961) and Bornstein (1961) speculated about abnormal connections with the reticular system. In recent years neuroleptic-induced akathisia has been compared with idiopathic RLS. Akathisia was originally described in its uncommon idiopathic form by Haskovec (1901) and later in relation to Parkinson syndromes (Sicard, 1923) and drugs such as promethazine (Sigwald et al., 1947) and the phenothiazines (Steck, 1954). It is characterized by a state of mental and motor restlessness which is accompanied by an irresistible compulsion to physically move about. Restlessness of the legs is common and similar to that occurring in idiopathic RLS, but inner restlessness of the mind and body is peculiar to akathisia. Confusion between these two conditions explains why promethazine and prochlorperazine have been considered both cause and ineffective remedy of RLS.