Authors: Muhammad B Yunus, professor of medicine, section of rheumatology, Jean C Aldag, associate professor of preventive medicine in medicine, Department of Medicine, University of Illinois College of Medicine at Peoria, Box 1649, Peoria, IL 61656, USA
Restless legs syndrome is characterized by an unpleasant, difficult-to-describe sensation in the legs that produces an invariable urge to move them frequently.(1,2,3) This symptom typically occurs at rest or before sleep and is alleviated by activity.(1,2,3) Restless legs syndrome may occur without or with an associated condition, such as rheumatoid arthritis.(1,3) We investigated the prevalence of restless legs syndrome and of leg cramps in patients with fibromyalgia syndrome, a common condition with widespread musculoskeletal aching and tender points,(2,4) and in controls.
Subjects, methods, and results
One hundred and thirty five consecutive new female patients referred with primary fibromyalgia, 54 women with rheumatoid arthritis without concomitant fibromyalgia, and 87 healthy, pain free women acting as controls were studied at our outpatient rheumatology clinic. All patients with fibromyalgia fulfilled the criteria of Yunus et al.(4) No subjects had peripheral neuritis.
White cell count; hemoglobin concentration; erythrocyte sedimentation rate; serum calcium, electrolyte, blood urea nitrogen, creatinine, and liver enzyme values; and thyroid function were normal in the patients with fibromyalgia.
Patients with rheumatoid arthritis had normal serum calcium, electrolyte, blood urea nitrogen, and creatinine values. Symptoms as well as tender points were evaluated by a questionnaire with ordinal grading (none, mild, moderate, severe). Global anxiety, depression, and mental stress were assessed by the following questions: “Do you think you are anxious or tense or have worries?,” “Do you feel depressed, low, and blue?,” and “Do you feel under mental stress?”
For statistical analysis symptoms were dichotomized (moderate or severe= yes; none or mild=no). When the sample was stratified by age (at the median), a Mantel-Haenszel 2 test was used to control for potential impact of age on leg symptoms. Analysis of variance was used for interval variables, followed by the Student-Neuman-Keuls test to examine differences between the groups.
Correlations between 12 preselected variables of interest were analyzed by Pearson’s correlation coefficient. A two tailed P value of Comment
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Our study shows an association between fibromyalgia syndrome and restless legs syndrome as well as leg cramps and confirms a previously reported association between rheumatoid arthritis and restless legs.(3) The basis of this association is not clear. Fibromyalgia is not a psychiatric condition,(2) and we found no association between restless legs syndrome and psychological state. It has been suggested that restless legs syndrome and periodic limb movement disorder, along with other dysfunctional syndromes such as irritable bowel syndrome, form a spectrum with overlapping features and a common biophysiological mechanism of neuroendocrine abnormality.(2) Such an abnormality may also be the underlying mechanism in restless legs syndrome,5 which is treatable with clonazepam, carbamazepine, and levodopa.(1,2,5)
In conclusion, restless legs syndrome and leg cramps are significantly more prevalent in patients with fibromyalgia syndrome and those with rheumatoid arthritis than in normal controls. An awareness of this association will help doctors manage the distressing leg symptoms among patients with fibromyalgia.
Funding: Department of Medicine, University of Illinois College of Medicine at Peoria.
1. Clough C. Restless legs syndrome. BMJ 1987;294:262-3. [Medline]
2. Yunus MB, Masi AT. Fibromyalgia, restless legs syndrome, periodic limb movement disorder and psychogenic pain. In: McCarty DJ, Koopman WJ, eds. Arthritis and allied conditions: a textbook of rheumatology. 12th ed. Philadelphia: Lea and Febiger, 1993:1383-1405.
3. Reynolds G, Blake DR, Hall HS, Williams A. Restless legs syndrome and rheumatoid arthritis. BMJ 1986;292:659-60. [Medline]
4. Yunus MB, Masi AT, Calabro JJ, Miller KA, Feigenbaum SL. Primary fibromyalgia (fibrositis): a clinical study of 50 patients with matched normal controls. Semin Arthritis Rheum 1981;11:151-71. [Medline]
5. Montplaisir J, Godbout R, Poirier G, Bedard MA. Restless legs syndrome and periodic movements in sleep: physio-pathology and treatment with L-dopa. Clin Neuropharmacol 1986;9:456-63. [Medline]
Source: BMJ 1996;312:1339