Cotter and O’Keefe The sensation is deep seated, often described as being in the shin bones, and most commonly felt between the knee and ankle. It may be described as a creepy, crawly, shock- like, tense, electric, buzzing, itchy, or even numb sensation. Bizarre analogies may be draw such as ‘worms under the skin’ or ‘cola in the veins’. There is a variable response to temperature, with some finding heat an aggravating factor and removing the bedclothes, whilst others find that wearing socks or taking a hot bath improves symptoms. RLS patients not only feel an urge to move but, while this may be resisted for a time, they must at some stage actually yield to the urge and move the legs. This movement should lead to immediate, even if sometimes only partial, relief that persists while moving. Mild cases can get relief from rubbing the legs or stretching them in the bed, but people with more severe symptoms need to get out of bed and walk, or stretch, or march on the spot. There is always a strong circadian pattern to symptoms in RLS. The peak is usually during the earlier part of the night, but the precise timing will vary depending on the sleep habits and the trough of circadian rhythm for the individual. The rest-induced and circadian patterns of RLS can be distinguished. Thus, symptoms during rest at night are worse than symptoms at rest during the day. There are a number of conditions that may be confused with RLS. Akathisia is a closely related condition that shares the sense of restlessness, the inability to sit still and, less prominently, the sleep disturbances (Walters et al 1991). However, the restlessness is generalized and internal rather than localized to the limbs and associated with paresthesias. The history of exposure to neuroleptic medications and associated extrapyramidal features also differentiate akathisia from RLS. Nocturnal leg cramps are characterized by episodes of pain, usually lasting up to a few minutes, caused by sudden, intense involuntary contractions of muscles or muscle groups. Residual discomfort and tenderness may persist for hours afterwards. They should be readily distinguishable from RLS by history alone. Polyneuropathy may lead to symptoms of burning in the legs and feet at night. However, there is no restlessness and no improvement with movement. Also, physical examination in these cases will reveal a sensory and occasionally motor deficit. Peripheral vascular disease can result in rest pain at night, which should be readily identifiable; clinical examination may demonstrate ischaemic features in the leg. Painful legs and moving toes is an uncommon condition associated with involuntary toe movements and with pain in the legs that has a similar distribution to that seen in RLS (Dressler et al, 1994). The major difference is that the pain in the former is not relieved by movement. Why is RLS neglected? RLS is often unrecognized or misdiagnosed. In a study published in 1996 of patients who belonged to the ‘Night Walkers’ support group, patients delayed seeking attention for many years, but even after they sought medical help, accurate diagnosis frequently took a decade or more (Walters et al 1996). The expansion in knowledge and the increased publicity about the condition in recent years seems to have Table 1 Features of restless legs syndrome (RLS). Modified from Allen RP, Picchietti D, Hening WA, et al. 2003. 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 Mar, 4:101-19. A. Essential criteria:These features must be present for a diagnosis of RLS. 1. An urge to move the legs, usually accompanied or caused by uncomfortable or unpleasant sensations in the legs. (Sometimes the urge to move is present without the uncomfortable sensations and sometimes the arms or other body parts are involved in addition to the legs.) 2. The urge to move or unpleasant sensations begin or worsen during periods of rest or inactivity such as lying or sitting. 3. The urge to move or unpleasant sensations are partially or totally relieved by movement, such as walking or stretching, at least as long as the activity continues. 4. The urge to move or unpleasant sensations are worse in the evening or night than during the day or only occur in the evening or night. (When the symptoms are very severe, the worsening at night may not be noticeable, but must have been previously present.) B. Supportive clinical features of RLS: Presence of these features may help resolve any diagnostic uncertainty. 1. Periodic limb movements (during wakefulness or sleep). 2. Family history of RLS in a first degree relative. 3. Response to dopaminergic therapy. C. Associated clinical features:These features may provide additional information about the patient’s diagnosis. 1. Clinical course following certain identifiable patterns. 2. Sleep disturbance. 3. Normal medical evaluation/ physical examination. 466 Therapeutics and Clinical Risk Management 2006:2(4)