Original articleRestless legs syndrome in 218 patients: associated disorders
Introduction
Restless legs syndrome (RLS), a very common disorder, is characterized by discomfort in the legs described as creeping, crawling, tingling, or painful [1]. The unpleasant sensations are precipitated by rest and relieved by activity. These symptoms are worse at bedtime and thus RLS patients complain of sleep disturbance, especially insomnia. Most RLS patients have periodic limb movements in sleep (PLMS) documented by polysomnography (PSG). These findings are diagnostic of periodic limb movement disorder (PLMD) [2]. It may be that RLS is simply a manifestation or a presentation of PLMD, and that the separation into distinct diagnostic entities may not be appropriate. It is likely that RLS may be present in 10–15% of the population [3]. The physiological mechanisms causing RLS are unknown. The disorder, idiopathic in most cases, has been associated with iron deficiency [4], polyneuropathy [5], rheumatoid arthritis [6], and hemodialysis [7], [8]. Patients may become symptomatic at any age and have been reported to wait a mean of 2 years after first seeking medical attention before a diagnosis is made [9]. In an attempt to shed light on the reason for delayed diagnosis, and to confirm that RLS was more common in groups of patients with certain diseases, we compared the diagnoses patients had received in the 5 years prior to sleep laboratory evaluation to a matched control group from the general population.
Section snippets
Selection of patient and control subjects
We selected all patients diagnosed as having RLS/PLMS at the St. Boniface General Hospital Sleep Disorders Center from 1990 to 1998. We excluded those with a sleep breathing disorder (apnea/hypopnea index >5). All patients met the diagnostic criteria of International Classification of Sleep Disorders for RLS [10]. They had most often been referred for assessment of a sleep complaint of insomnia (sleep onset and/or sleep maintenance) or daytime sleepiness, or suspected sleep apnea. These
Results
The age distribution of the RLS patients is shown in Table 1. The 103 male patients had a mean age of 49.2±14.8 (standard deviation, SD) years, the 118 female patients had a mean age of 48.5±15.3 years.
Discussion
For several years before the RLS diagnosis was established, our patients were diagnosed as having various disorders more frequently than controls. Our data suggests the possibility that development of RLS is associated with many etiologic factors. All the RLS patients we reported had been referred to the sleep disorders center because of chronic sleep-related complaints. Although insomnia was by far the most common presenting complaint, some patients presented with features that suggested a
Conclusions
We conclude that RLS is associated with many disorders. It seems reasonable that a clinician should include a sleep history in evaluation of patients with these disorders, since these patients may require treatment of the distressing RLS symptoms.
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