Prevalence and characteristics of restless legs syndrome (RLS) in the elderly and the relation of serum ferritin levels with disease severity: hospital-based study from Istanbul, Turkey

Exploring the causes of augmentation in restless legs syndrome

Long-term drug treatment for Restless Legs Syndrome (RLS) patients can frequently result in augmentation, which is the deterioration of symptoms with an increased drug dose. The cause of augmentation, especially derived from dopamine therapy, remains elusive. Here, we review recent research and clinical progress on the possible mechanism underlying RLS augmentation. Dysfunction of the dopamine system highly possibly plays a role in the development of RLS augmentation, as dopamine agonists improve desensitization of dopamine receptors, disturb receptor interactions within or outside the dopamine receptor family, and interfere with the natural regulation of dopamine synthesis and release in the neural system. Iron deficiency is also indicated to contribute to RLS augmentation, as low iron levels can affect the function of the dopamine system. Furthermore, genetic risk factors, such as variations in the BTBD9 and MEIS1 genes, have been linked to an increased risk of RLS initiation and augmentation. Additionally, circadian rhythm, which controls the sleep-wake cycle, may also contribute to the worsening of RLS symptoms and the development of augmentation. Recently, Vitamin D deficiency has been suggested to be involved in RLS augmentation. Based on these findings, we propose that the progressive reduction of selective receptors, influenced by various pathological factors, reverses the overcompensation of the dopamine intensity promoted by short-term, low-dose dopaminergic therapy in the development of augmentation. More research is needed to uncover a deeper understanding of the mechanisms underlying the RLS symptom and to develop effective RLS augmentation treatments.

Protein tyrosine phosphatase receptor type delta (PTPRD) gene in an animal model of restless legs syndrome

The pathophysiology of the restless legs syndrome (RLS) is related to dopaminergic dysfunction, reduced iron and variations in gene expression, such as the protein tyrosine phosphatase receptor type delta gene (PTPRD). Animal models could be key to achieving a mechanistic understanding of RLS and to facilitate efficient platforms for evaluating new therapeutics. Thus, the aim of this study was to evaluate the expression of PTPRD, of genes and proteins associated with RLS, the sleep patterns and the cardiovascular parameters in an animal model of RLS (spontaneously hypertensive rat [SHR]). Rats were divided into two groups: (i) Wistar-Kyoto and (ii) SHR. Cardiovascular parameters were assessed by tail plethysmography. Polysomnography was used to analyse the sleep pattern (24 h). For the PTPRD analyses, quantitative polymerase chain reaction (qPCR) and indirect enzyme-linked immunosorbent assay (ELISA) techniques were used. To evaluate the tyrosine hydroxylase enzyme, dopamine transporter (DAT) and type 2 dopaminergic receptor, qPCR and Western Blotting techniques were used. For the quantification of iron, ferritin and transferrin, the ELISA method was used. SHRs had higher blood pressure, alterations in sleep pattern, lower expression of protein content of PTPRD, lower expression of DAT, and lower serum concentrations of ferritin. These data suggest that the behavioural, physiological, and molecular changes observed in SHRs provide a useful animal model of RLS, reinforcing the importance of this strain as an animal model of this sleep disorder.

Are serum ferritin and transferrin saturation risk markers for restless legs syndrome in young adults? Longitudinal and cross-sectional data from the Western Australian Pregnancy Cohort (Raine) Study

Restless legs syndrome has been associated with serum iron deficiency in clinical studies. However, studies investigating this relationship have had inconsistent results and there are no studies in young adults. Therefore, we investigated the relationship between serum measures of iron stores and restless legs syndrome in young adults in the community. Participants in the Western Australian Pregnancy Cohort (Raine) Study answered questions on restless legs syndrome (n = 1,100, 54% female) at age 22 years, and provided serum measures of iron stores (ferritin and transferrin saturation) at ages 17 and 22 years. Restless legs syndrome was diagnosed when four International RLS Study Group criteria were met (urge to move, dysaesthesia, relief by movement, worsening during evening/night) and these symptoms occurred ≥5 times per month. Logistic regression was used to assess associations between serum iron stores and restless legs syndrome, adjusting for potential confounders. The prevalence of restless legs syndrome at age 22 years was 3.0% (n = 33, 70% female). Among those who provided restless legs syndrome and iron data at age 22 years (n = 865), the median (interquartile range) ferritin was not different between the restless legs syndrome (55 [29.5-103.5] µg L^-1 ) and the non-restless legs syndrome group (65.0 [35.0-103.3] µg L^-1 , p = 0.2), nor were there differences in iron deficiency prevalence (p = 0.36). There was no association between restless legs syndrome (22 years) and iron stores (17, 22 years) before or after adjustment for potential confounders. There was no association between restless legs syndrome at 22 years and iron stores at 17 or 22 years in this cohort. Serum iron stores may not be a useful indicator of restless legs syndrome risk in young adults in the community.

Restless Legs Syndrome: From Pathophysiology to Clinical Diagnosis and Management

Restless legs syndrome (RLS), a common neurological sensorimotor disorder in western countries, has gained more and more attention in Asian countries. The prevalence of RLS is higher in older people and females. RLS is most commonly related to iron deficiency, pregnancy and uremia. The RLS symptoms show a significant circadian rhythm and a close relationship to periodic limb movements (PLMs) in clinical observations, while the pathophysiological pathways are still unknown. The diagnostic criteria have been revised in 2012 to improve the validity of RLS diagnosis. Recent studies have suggested an important role of iron decrease of brain in RLS pathophysiology. Dopaminergic (DA) system dysfunction in A11 cell groups has been recognized long ago from clinical treatment and autopsy. Nowadays, it is believed that iron dysfunction can affect DA system from different pathways and opioids have a protective effect on DA system. Several susceptible single nucleotide polymorphisms such as BTBD9 and MEIS1, which are thought to be involved in embryonic neuronal development, have been reported to be associated with RLS. Several pharmacological and non-pharmacological treatment are discussed in this review. First-line treatments of RLS include DA agents and α2δ agonists. Augmentation is very common in long-term treatment of RLS which makes prevention and management of augmentation very important for RLS patients. A combination of different types of medication is effective in preventing and treating augmentation. The knowledge on RLS is still limited, the pathophysiology and better management of RLS remain to be discovered.

[Geriatric inpatients with iron deficiency-associated Restless Legs Syndrome. A retrospective analysis]

OBJECTIVE

The Restless Legs Syndrome (RLS) is a clinically relevant condition in geriatric patients. An association between iron deficiency and RLS is largely acknowledged. The clinical and therapeutic management of iron deficiency-associated RLS has been, however, poorly evaluated in geriatric patients.

METHODS

Data from all RLS inpatients admitted to a geriatric unit between 2009 and 2011 were retrospectively collected on demographics and clinical characteristics, iron status, drug treatment including iron substitution, as well as comprehensive geriatric assessment (CGA) scores.

RESULTS

RLS was diagnosed in 56 of the 4,063 admitted patients during the two years. Of the RLS cases, 20 (36%) showed iron deficiency. Thirteen of these were treated with iron substitution according to the existing guidelines. Both RLS patients with and without iron deficiency showed a significant clinical improvement between admission to discharge according to the CGA scores.

CONCLUSION

Iron substituted geriatric patients with iron deficiency-associated RLS substantially benefited from the treatment, similarly to RLS patients without iron deficiency. A multidimensional assessment, careful iron metabolism examination and adequate treatment choice should be equally importantly considered in geriatric patients with RLS.

Insomnia and Restless Leg Syndrome in Patients Undergoing Chronic Hemodialysis in Rafsanjan Ali Ibn Abitaleb Hospital

Background:

Sleep is one of the most fundamental human needs; without any doubt sleep is even more essential for sick patients, especially for patients with chronic illnesses. Sleep disturbance may lead to anxiety and reduced quality of life. Restless leg syndrome (RLS) is a sensory-motor disorder accompanied by a strong desire to move the legs or other parts of the body, which can cause sleep disturbance. Its etiology is unknown, but increased urea and creatinine levels before dialysis, iron deficiency due to kidney failure and end-stage renal disease (ESRD) are mentioned as causes.

Objectives:

This study is designed to examine the prevalence of insomnia and restless leg syndrome in patients undergoing chronic hemodialysis in Rafsanjan Ali Ibn Abitaleb Hospital.

Patients and Methods:

In this study we used two questionnaires to evaluate the presence of RLS and insomnia in ESRD patients who were undergoing hemodialysis treatment as kidney replacement therapy.

Results:

According to our results, 54.5% of patients were diagnosed with RLS, and of those 65.2% and 42.9% were women and men, respectively. RLS is seen more often among patients with blood group type A, but this result was not statistically significant. There was a statistically significant correlation between RLS and a positive family history of RLS, between RLS and the number of hemodialysis treatments per week and also between RLS and the Insomnia Severity Index. Unlike previous studies, in this study we did not find any statistically significant correlation between RLS and biochemical factors such as serum iron, TIBC, BUN, creatinine, potassium, calcium and phosphorous levels.

Conclusions:

The frequency of RLS among our patients was remarkable and we conclude that all patients who are undergoing hemodialysis should be screened for RLS, which can assist in providing proper attention and treatment.

Management of Restless Legs Syndrome/Willis-Ekbom Disease in Hospitalized and Perioperative Patients

Restless legs syndrome (RLS) is a sensorimotor disorder that can cause significant discomfort, impaired quality of life, poor mood, and disturbed sleep. Because the disorder is chronic and associated with multiple comorbidities, RLS can be seen in an inpatient or perioperative setting. Certain characteristics of the hospitalized or surgical context can exacerbate or unmask RLS. Importantly, RLS and the associated discomfort and insomnia can prolong hospital stay and negatively impact outcomes. RLS medications should be continued during the hospital admission when possible. Avoidance of excessive phlebotomy and medications known to trigger RLS is helpful. Patients should increase activity when acceptable.

Quality measures for the care of adult patients with restless legs syndrome

ABSTRACT

The American Academy of Sleep Medicine (AASM) commissioned several Workgroups to develop quality measures for the care of patients with common sleep disorders, including adults with restless legs syndrome (RLS). Using the AASM process for quality measure development, the RLS Work-group developed three target outcomes for RLS management, including improving the accuracy of diagnosis, reducing symptom severity, and minimizing treatment complications. Seven processes were developed to support these outcomes. To achieve the outcome of improving accuracy of diagnosis, the use of accepted diagnostic criteria and assessment of iron stores are recommended. To realize the outcome of decreasing symptom severity, routine assessment of severity and provision of evidence-based treatment are recommended. To support the outcome of minimizing treatment complications, counseling about potential side effects and assessing for augmentation and impulse control disorders, when indicated, are recommended. Further research is needed to validate optimal practice processes to achieve best outcomes in adult patients with RLS.

Sleep disorders: A review of the interface between restless legs syndrome and iron metabolism

Restless legs syndrome (RLS) is characterized by unpleasant sensations mainly in the legs. 43% of RLS-associated conditions have also been associated with systemic iron deficiency. The objective of this study was to review in the literature the relationship between iron metabolism and RLS. With an initial search using the keywords combination “Iron Metabolism OR Iron Deficiency AND Restless Legs Syndrome,” 145 articles were screened, and 20 articles were selected. Few studies were found for this review in the period of 2001–2014, however, the correlation between RLS and iron was evident.

Sleep in older adults: normative changes, sleep disorders, and treatment options

Approximately 5% of older adults meet criteria for clinically significant insomnia disorders and 20% for sleep apnea syndromes. It is important to distinguish age-appropriate changes in sleep from clinically significant insomnia, with the latter having associated daytime impairments. Non-pharmacologic therapies, such as cognitive-behavioral therapy for insomnia, can be highly effective with sustained benefit. Pharmacologic therapies are also available, but may be associated with psychomotor effects. A high index of suspicion is crucial for effective diagnosis of sleep apnea because symptoms commonly noted in younger patients, such as obesity or loud snoring, may not be present in older patients.

Iron in Restless Legs Syndrome

A link between restless legs syndrome (RLS) and iron has been recognized for several decades. Yet, the precise role that iron or other components of iron metabolism play in bringing about RLS is still a matter of debate. During the last few years, many new pieces of evidence from genetics, pathology, imaging, and clinical studies have surfaced. However, the way this evidence fits into the larger picture of RLS as a disease is not always easily understood. To provide a better understanding of the complex interplay between iron metabolism and RLS and highlight areas that need further elucidation, we systematically and critically review the current literature on the role of iron in RLS pathophysiology and treatment with a special emphasis on genetics, neuropathology, cell and animal models, imaging studies, and therapy.

Dilution of candidates: the case of iron-related genes in restless legs syndrome

Restless legs syndrome (RLS) is a common multifactorial disease. Some genetic risk factors have been identified. RLS susceptibility also has been related to iron. We therefore asked whether known iron-related genes are candidates for association with RLS and, vice versa, whether known RLS-associated loci influence iron parameters in serum. RLS/control samples (n = 954/1814 in the discovery step, 735/736 in replication 1, and 736/735 in replication 2) were tested for association with SNPs located within 4 Mb intervals surrounding each gene from a list of 111 iron-related genes using a discovery threshold of P = 5 × 10(-4). Two population cohorts (KORA F3 and F4 with together n = 3447) were tested for association of six known RLS loci with iron, ferritin, transferrin, transferrin-saturation, and soluble transferrin receptor. Results were negative. None of the candidate SNPs at the iron-related gene loci was confirmed significantly. An intronic SNP, rs2576036, of KATNAL2 at 18q21.1 was significant in the first (P = 0.00085) but not in the second replication step (joint nominal P-value = 0.044). Especially, rs1800652 (C282Y) in the HFE gene did not associate with RLS. Moreover, SNPs at the known RLS loci did not significantly affect serum iron parameters in the KORA cohorts. In conclusion, the correlation between RLS and iron parameters in serum may be weaker than assumed. Moreover, in a general power analysis, we show that genetic effects are diluted if they are transmitted via an intermediate trait to an end-phenotype. Sample size formulas are provided for small effect sizes.