Restless legs syndrome: an overview of the current understanding and management

Efficacy of Intravenous Iron Sucrose in Hemodialysis Patients with Restless Legs Syndrome (RLS): A Randomized, Placebo-Controlled Study

Background

Restless legs syndrome (RLS) is a common disorder in hemodialysis (HD) patients that causes sleep disturbances and diminished quality of life. Because iron deficiency has been implicated in the pathogenesis of RLS, we sought to investigate the effects of intravenous (IV) iron sucrose on symptoms of RLS in HD patients.

Material/Methods

The study was a randomized, placebo-controlled study of 1000 mg iron sucrose versus normal saline as placebo. Patients were evaluated at baseline and 2 weeks after the last injection. The severity of RLS was assessed using the International RLS Study Group rating scale (IRLS). Blood samples were taken to measure iron parameters reflecting the iron status, including serum ferritin (SF) concentration, percentage transferrin saturation (TSAT%) and hemoglobin (Hb), and other biochemical parameters as safety assessments, including creatinine (Cr), urea, intact parathyroid hormone (iPTH), and the index of urea clearance (Kt/V). Adverse events were monitored in all subjects during the period of infusion.

Results

After 2 weeks, IRLS scores decreased more in the IV-iron group (−7.38±2.03) than in the placebo group (−0.81±2.61) (P=0.000). Serum ferritin, TSAT, and hemoglobin increased more in the IV-iron group (227.63±77.64 μg/L; 26.06±7.77%; 13.98±3.62g/L, respectively) than in the placebo group (SF, p=0.000; TSAT, p=0.000; Hb, p=0.000, respectively). There were no significant differences between IV-iron and placebo groups in Cr, urea, iPTH, and Kt/V. No adverse effects were observed in the study.

Conclusions

IV iron sucrose is a safe and effective treatment for reducing RLS symptoms in HD patients over the short-term.

An evaluation of sleep quality and the prevalence of restless leg syndrome in vitamin D deficiency

Vitamin D is known to increase levels of dopamine and its metabolites in the brain and also protects dopaminergic neurons against dopaminergic toxins. The aims of the study were to assess the frequency and symptom severity of restless leg syndrome (RLS) and sleep quality in vitamin D deficiency. A total of 102 patients were enrolled in this cross-sectional study, comprising 57 vitamin D deficient patients as Group 1 and 45 patients with normal levels of vitamin D as Group 2. RLS was diagnosed according to the International RLS Study Group (IRLSSG) diagnostic criteria. Symptom severity was assessed using the IRLSSG rating scale and sleep quality was measured with the Pittsburgh sleep quality index (PSQI). RLS incidence was higher in Group 1 (p = 0.034). The PSQI scores were higher in Group 1 and the difference between the groups was determined as statistically significant (p < 0.05). No statistically significant difference was determined in respect of the clinical evaluation and the IRLSSG Symptom Severity Scale between the patients in Group 1 diagnosed with RLS and the patients in Group 2 diagnosed with RLS (p > 0.05). The findings of this study support the hypothesis that RLS is more frequent and more severe in vitamin D deficiency and indicate a negative effect of vitamin deficiency on sleep parameters.

A review of current treatment strategies for restless legs syndrome (Willis-Ekbom disease)

Restless legs syndrome (RLS), recently renamed Willis-Ekbom disease (WED), is a common movement disorder. It is characterised by the need to move mainly the legs due to uncomfortable, sometimes painful sensations in the legs, which have a diurnal variation and a release with movement. Management is complex. First, centres should establish the severity of RLS using a simple 10-item RLS severity rating scale (IRLS). They should also exclude secondary causes, in particular ensuring normal iron levels. Mild cases can be managed by lifestyle changes, but patients with a IRLS score above 15 usually require pharmacological treatment. Dopaminergic therapies remain the mainstay of medical therapies, with recent evidence suggesting opioids may be particularly effective. This article focuses on the different treatment strategies in RLS, their associated complications and ways to manage them.

Prospective study of obesity, hypertension, high cholesterol, and risk of restless legs syndrome

Because previous cross-sectional studies suggest an association between metabolic disorders and restless legs syndrome (RLS), we prospectively evaluated whether obesity, hypercholesterolemia, and hypertension were associated with increased risk of RLS. Our study consisted of 42,728 female participants from the Nurses' Health Study II and 12,812 male participants from the Health Professionals Follow-up Study, free of RLS at baseline (2002 for men and 2005 for women), and free of diabetes and arthritis through follow-up (2002-2008 for men and 2005-2009 for women). RLS symptoms were assessed using the International RLS Study Group's standardized questionnaire. We considered RLS symptoms a "case" if the symptoms occurred ≥5 times/month and met International RLS Study Group criteria. We found that obesity was associated with an increased risk RLS among both men and women (P difference for sex >0.5). The pooled multivariate-adjusted odds ratio (OR) for RLS was 1.57 (95% confidence interval [CI]: 1.33-1.85; P trend <0.0001) for body mass index >30 versus ≤23 kg/m(2) and 1.56 (95% CI: 1.29-1.89; P trend = 0.0001) comparing two extreme waist circumference quintiles, adjusting for age, ethnicity, smoking, physical activity, use of antidepressant, and other covariates. A similar significant association was found for high cholesterol; the pooled adjusted OR for total serum cholesterol >240 versus <159 mg/dL was 1.33 (95% CI: 1.11-1.60; P trend = 0.002). There was no significant association between hypertension and RLS risk (adjusted OR: 0.90; 95% CI: 0.79-1.02). In this large, prospective study, we found that obesity and high cholesterol, but not high blood pressure, were significantly associated with an increased risk of developing RLS. © 2014 International Parkinson and Movement Disorder Society.

Ascertainment of iron deficiency and depletion in blood donors through screening questions for pica and restless legs syndrome

BACKGROUND

Pica and restless legs syndrome (RLS) are associated with iron depletion and deficiency. The presence of pica and RLS was prospectively assessed in blood donors.

STUDY DESIGN AND METHODS

During a 39-month period, 1236 donors deferred for fingerstick hemoglobin (Hb) level of less than 12.5 g/dL and 400 nondeferred "control" donors underwent health screening and laboratory testing (complete blood count, ferritin, iron, transferrin). Pica and RLS were assessed by direct questioning. Deferred donors and iron-deficient control donors were given 325 mg of ferrous sulfate daily for 60 days. Reassessments were performed and additional iron tablets dispensed at subsequent visits.

RESULTS

Pica was reported in 11% of donors with iron depletion or deficiency, compared with 4% of iron-replete donors (p < 0.0001). Pagophagia (ice pica) was most common and often of extraordinary intensity. Female sex, younger age, and lower mean cell volume and transferrin saturation values were strongly associated with pica. Donors with pica given iron reported a marked reduction in the desire to consume the nonnutritive substance by Days 5 to 8 of therapy, with disappearance of symptoms by Days 10 to 14. RLS was reported in 16% of subjects with iron depletion or deficiency compared with 11% of iron-replete donors (p = 0.012). Iron replacement generally resulted in improvement of RLS symptoms; however, at least 4 to 6 weeks of iron therapy was necessary.

CONCLUSION

The presence of pica is associated with a high probability of iron depletion or deficiency in blood donors; however, RLS lacks a strong correlation in this population. Screening questions for pagophagia may be useful in the ascertainment of iron deficiency in donors and may identify those who would benefit from oral iron.

High incidence of iron depletion and restless leg syndrome (RLS) in regular blood donors: intravenous iron sucrose substitution more effective than oral iron

BACKGROUND AND OBJECTIVES

Iron depletion is common in regular blood donors. The objective of the study was to investigate the frequency and severity of iron depletion in regular blood donors and whether IV iron is more effective than oral to avoid iron depletion and symptoms thereof, especially restless legs syndrome (RLS).

METHOD

One hundred and twenty blood donors with at least five previous whole blood donations were randomized to receive either IV iron sucrose (Venofer(®), RenaPharma/Vifor, Uppsala, Sweden), 200 mg, or to 20×100 mg of oral iron sulphate (Duroferon(®), GlaxoSmithKline, Stockholm, Sweden), after each blood donation during 1 year. Iron status and RLS incidence and severity were investigated.

RESULTS

Iron status was generally poor among regular blood donors, especially in women, with a high incidence of iron depletion (>20%) and RLS (18%). The IV iron group increased storage iron to a greater extent than the oral iron group after 12 months (P=0·0043). Female donors were more responsive to IV iron sucrose compared to oral iron sulphate, particularly female donors below 50 years of age. RLS severity scores were significantly lower in the IV iron group. The two treatments were safe.

CONCLUSION

Iron status is poor in regular blood donors, restless legs syndrome is common, and the routine iron supplementation is insufficient. IV iron sucrose substitutes iron loss in blood donors more efficiently compared with oral iron sulphate, especially in women. Iron substitution to blood donors should be individualized and based on P-ferritin monitoring.

Restless legs syndrome risk factors, behaviors, and diagnoses in persons with early to moderate dementia and sleep disturbance

In this study, restless legs syndrome (RLS) risk factors, RLS-associated behaviors, and the ability to understand and answer an RLS diagnostic interview were investigated. In 23 older adults with early to moderate dementia and nighttime sleep disturbance, the most common risk factors for RLS were a periodic leg movement sleep index > 15 (54.55%), based on polysomnography, and use of selective serotonin reuptake inhibitors (SSRIs) (34.78%). The most common RLS-associated behaviors were repetitious mannerisms (56.52%) and general restlessness (34.78%), according to direct observation from research assistants. Finally, older adults with early to moderate dementia were unable to understand and reliably answer the RLS diagnostic interview. Older persons with mild to moderate dementia and sleep disturbance may require objective diagnostics to identify RLS.

Compulsive habits in restless legs syndrome patients under dopaminergic treatment

Since the introduction of levodopa therapy and dopaminergic replacement therapy to abate symptoms of idiopathic Parkinson's disease, repetitive compulsive behaviors have been reported and are now considered to be drug-related response complications. As dopamine (DA) agonists are the licensed treatment in Restless Legs Syndrome (RLS), a survey was conducted to determine the extent to which patients with RLS present compulsive behaviors. The aim of this study was to investigate the relationship between DA agonists and the occurrence of motor or behavioral compulsions, stress, depression, and sleep disturbance in RLS patients. A questionnaire was mailed three times, at four-month intervals over a period of 8 months to all patients of the Quebec Memory and Motor Skills Disorders Clinic diagnosed with RLS. In addition to recording all medication information for RLS treatment, patients were assessed on the International Restless Legs Syndrome Study Group Rating Scale (IRLS), the Beck Depression Inventory-II (BDI-II), the Sleep Scale from the Medical Outcomes Study (MOS) and on a visual analog scale for current level of stress. A section pertaining to hobby, mania, and compulsion was also included. Analyses are based on 97 out of 151 patients (64.2%) with RLS who returned the three questionnaires. Twelve patients (12.4%) on stable DA agonist therapy (average dose 0.52+/-0.59 mg Pramipexole equivalent) developed a new compulsive behavioral repertoire. Eating (3 women, 1 man), buying food or clothes (2 women, 1 man), trichotillomania (1 woman, 1 man), and gambling (1man) were among the compulsions developed under DA treatment. In addition, two women presented new tic-like phenomena. In contrast to the RLS patients without compulsive behaviors (53 treated with DA agonist; 32 untreated), those with compulsive habits reported experiencing more stress, depression and sleep problems. Patients with RLS with mood and stress states may be at greater risk of developing compulsive behaviors while receiving standard dosage DA agonist treatment. These behaviors are clearly linked to short-term satisfaction and underline the role of dopaminergic mesolimbic stimulation in the reinforcement process of rewarding behavioral sequences.

A randomized, double-blind, placebo controlled, multi-center study of intravenous iron sucrose and placebo in the treatment of restless legs syndrome

Iron deficiency may exacerbate symptoms in the Restless Legs Syndrome (RLS). We investigated the effect of intravenous iron sucrose or placebo on symptoms in patients with RLS and mild to moderate iron deficit. Sixty patients with primary RLS (seven males, age 46 (9) years, S-ferritin < or =45 microg/L) recruited from a cohort of 231 patients were randomly assigned in a 12-months double-blind, multi-centre study of iron sucrose 1000 mg (n = 29) or saline (n = 31). The primary efficacy variable was the RLS severity scale (IRLS) score at week 11. Median IRLS score decreased from 24 to 7 (week 11) after iron sucrose and from 26 to 17 after placebo (P = 0.123, N.S. for between treatment comparison). The corresponding scores at week 7 were 12 and 20 in the two groups (P = 0.017). Drop out rate because of lack of efficacy at 12 months was 19/31 after placebo and 5/29 patients after iron sucrose (Kaplan-Meier estimate, log rank test P = 0.0006) suggesting an iron induced superior long term RLS symptom control. Iron sucrose was well tolerated. This study showed a lack of superiority of iron sucrose at 11 weeks but found evidence that iron sucrose reduced RLS symptoms both in the acute phase (7 weeks) and during long-term follow up in patients with variable degree of iron deficiency. Further studies on target patient groups, dosing and dosing intervals are warranted before iron sucrose could be considered for treatment of iron deficient patients with RLS.

Obesity and restless legs syndrome in men and women

BACKGROUND

Obesity and restless legs syndrome (RLS) are both associated with hypofunction of dopamine in the CNS. We therefore examined whether individuals who are obese have an increased risk of RLS in two ongoing US cohorts, the Nurses' Health Study II and the Health Professional Follow-up Study.

METHODS

We included 65,554 women and 23,119 men free of diabetes, arthritis, and pregnancy in the current analyses. Information on RLS was assessed using a set of standardized questions. Participants were considered to have RLS if they met four RLS diagnostic criteria recommended by the International RLS Study Group and had restless legs > or =5 times/month. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed using logistic regression models adjusting for age, smoking, use of antidepressant, phobic anxiety score, and other covariates. Log ORs from the two cohorts were pooled by a fixed-effects model.

RESULTS

There were 6.4% of women and 4.1% of men who were considered to have RLS. Multivariate adjusted ORs for RLS were 1.42 (95% CI: 1.3, 1.6; p trend <0.0001) for participants with body mass index (BMI) >30 vs <23 kg/m(2) and 1.60 (95% CI: 1.5, 1.8; p trend <0.0001) for highest vs lowest waist circumference quintiles. Greater BMI in early adulthood (age 18-21 years) and weight gain were also associated with a higher prevalence of RLS (p trend <0.01 for both).

CONCLUSIONS

Both overall and abdominal adiposity are associated with increased likelihoods of having restless legs syndrome (RLS). Further prospective studies are warranted to clarify causative association between obesity and risk of developing RLS.

Evolution of non-treated restless legs syndrome

PURPOSE: The primary concern of this study is to evaluate the clinical course of restless legs syndrome (RLS) in a group of patients who refused treatment. METHOD: This study compares the outcome of a group of RLS patients after one year without any specific treatment. The International Restless Legs Syndrome Scale (IRLS) was applied at baseline (irls_1) and after one year (irls_2). The patients answered a simple questionnaire for the evaluation of possible environmental or life habit changes after one-year evolution. Serum ferritin was determined at baseline. An improvement index (%improvement) was established through the formula: irls_1- irls_2/irls_1 ' 100. Results were compared and a correlation analysis performed. RESULTS: A negative significant correlation was found between the patientsí age and irls_2 (r= -0.9 p=0.0018) and between %improvement and irls_2 (r= -0.88 p=0.0039). A positive and significant correlation was determined between %improvement and age. There was only a marginally significant correlation between serum ferritin and ilrs_2 (r= -0.7 p=0.052). No significant changes were found in the other elements analyzed. CONCLUSION: A favorable outcome was found in this group of RLS patients after one year evolution without treatment. The outcome was positively influenced by the patientsí age.

Clinical studies with ropinirole in Parkinson's disease and RLS

Ropinirole is a modern dopamine agonist with a half-life of medium extent that is highly selective for D(2)-receptors. Ropinirole is an indole derivative and thus does not belong to the group of ergoline dopamine receptor agonists. Its effect has been proved in a number of controlled studies in both monotherapy and combination treatments of Parkinson's disease. We can meanwhile refer to the long-term data of studies that have been run for more than 10 years. The substance has also been approved for the management of restless legs syndrome. A long-acting formula of the substance will be available soon.

Augmentation as a treatment complication of restless legs syndrome: Concept and management

Augmentation constitutes the main complication of long-term dopaminergic treatment in restless legs syndrome (RLS). Although this condition was first described in 1996, and is characterized by an overall increase in severity of RLS symptoms (including earlier onset of symptoms during the day, faster onset of symptoms when at rest, expansion to the upper limbs and trunk, and shorter duration of the treatment effect), precise diagnostic criteria were not established until 2003. These criteria have recently been updated to form a new definition of augmentation based on multicentric studies. The present article reviews our current knowledge on clinical diagnosis, evaluation, pathophysiology, and treatment recommendations for this condition.

Clinical presentation, diagnosis, and quality of life issues in restless legs syndrome

Restless legs syndrome (RLS) is a generally underdiagnosed and undertreated condition. It is a common cause of sleep disturbance that can severely disrupt normal life functioning. However, because of the failure to recognize RLS as a distinct disorder, clinicians have minimized the significance of the morbidity experienced by some patients. A positive family history is present in >50% of patients with RLS. Indeed, a person with RLS is 3 to 6 times more likely to have a positive family history of RLS than is an individual who does not have the disease. The differential diagnosis of RLS includes both movement and sleep disorders. Establishing an accurate diagnosis is crucial because effective treatment is available. In 2002, RLS experts revised diagnostic criteria and established 4 essential criteria for the diagnosis. Assessing the most bothersome symptoms and quantifying the severity of RLS are important because not all patients require medical therapy. Moreover, therapy may vary according to which symptom represents the major problem.

Restless legs syndrome: a review

Restless legs syndrome (RLS) is a sensorimotor disorder characterized by an irresistible urge to move the limbs accompanied by uncomfortable sensations, leading to sleep disturbances. It is associated with psychiatric comorbidities and a decreased quality of life. RLS is common and most severe among females and the elderly. It may be primary or secondary to other conditions and may be familial. Linkage to several chromosomal loci have been demonstrated. The pathogenesis of RLS involves dopaminergic dysfunction, iron metabolism, and abnormalities in supraspinal inhibition. The mainstay of RLS therapy are dopamine agonists or levodopa. This article reviews the clinical characteristics, epidemiology, diagnosis, pathogenesis, and treatment of RLS.

Ropinirole, a non-ergoline dopamine agonist

Dopamine agonists have become indispensable in the treatment of Parkinson's disease. In every-day practice, however, the decision to select the best compound for an individual patient is rendered difficult because of the large number of substances available on the market. This review article provides a closer look at the experimental and clinical studies with ropinirole published so far. Ropinirole is a non-ergoline dopamine agonist which has been proven to be effective in both, monotherapy and combination therapy of idiopathic Parkinson's disease. In addition to ameliorating bradykinesia, rigor, and tremor, ropinirole facilitates the daily life and improves depressive moods of patients with Parkinson's disease. The long-term complications of levodopa are avoided, and problems commonly associated with levodopa treatment are reduced. Ropinirole appears to have a neuroprotective effect. In addition to Parkinson's disease, ropinirole has also been used successfully in the treatment of restless legs syndrome.

Validation of the “L-DOPA test” for diagnosis of restless legs syndrome

We developed and validated a standardized test procedure to evaluate the accuracy of the supportive diagnostic criterion "response to dopaminergic treatment" in restless legs syndrome (RLS). Forty-eight patients who fulfilled at least three of the four essential criteria for RLS, thus including uncertain clinical cases for a nonexpert, were recruited. Patients received a preliminary diagnosis of RLS or non-RLS. All patients underwent a polysomnography (PSG) and were then asked to perform the diagnostic L-DOPA test at home, which consisted in the application of one single dose of 100/25 mg L-DOPA/benserazide and a subsequent observational period of 2 hours. Before, and in 15-minute intervals after, drug intake, the patients rated the severity of the "symptoms in the legs" and the "urge to move the legs" using a 100-mm visual analogue scale. Considering a 50% improvement as a positive test result, we found a sensitivity of 88% ("symptoms in the legs") and 80% ("urge to move the legs") with a specificity of 100% for both test items. A rate of 90% or 83% of all patients could be correctly diagnosed by the L-DOPA test. Both scales were able to predict the response to dopaminergic agents in the subsequent course of the treatment by 100%. The periodic leg movements arousal index as assessed by polysomnography was less appropriate for the prediction of the correct diagnosis. We recommend the L-DOPA test for diagnostic decision making in all patients with an unclear RLS diagnosis according to the essential diagnostic criteria of the International RLS Study Group.

Genetics of restless legs syndrome

Restless legs syndrome (RLS) is a common disorder, although under-diagnosed, with a prevalence of up to 15% depending on the population sampled. Familial aggregation has been widely shown since Ekbom formerly described the condition in 1960; twin studies support a genetic contribution in the development of this disorder. Molecular genetic approaches have identified three genomic regions in RLS susceptibility, however no specific mutations have yet been identified. Herein, we review the current status of genetics in RLS, providing some methodological guidelines to help future research.

Periodic limb movements and other movement disorders in sleep: neuropsychiatric dimensions

Movement disorders such as Parkinson's disease and Tourette's syndrome, primarily manifest during wakefulness, intrude into sleep. There are some disorders, however, such as periodic limb movements in sleep, restless legs syndrome, paroxysmal nocturnal dystonia, bruxism, and somnambulism, which occur primarily during sleep. The diagnosis and management of these disorders pose a challenge to neuropsychiatric practice, not only because they may be difficult to distinguish from other neuropsychiatric disorders, but also because psychiatric disorders are often co-morbid with them. Study of these disorders is necessary for an understanding of the interaction of sleep and movement, and how disturbance in one may affect the other.