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Objective: To evaluate the relation between systemic iron parameters (SIP) and substantia nigra (SN) iron deposits, as assessed by transcranial sonography (TCS) in restless legs syndrome (RLS)., Methods: We conducted a cross-sectional study in RLS patients, from whom blood samples with SIP were obtained, consisting of total iron-binding capacity (TIBC), serum ferritin, hemoglobin, transferrin saturation (TSAT), serum iron, and serum transferrin. TCS was performed over the SN, and the substantia nigra echogenicity index (SNEI) was determined according to established methods. Symptom severity was evaluated using the international restless legs scale (IRLS). A Spearman correlation was performed., Results: A total of 167 patients were studied. Correlations between SNEI and SIP were as follows: serum ferritin (R = 0.0422; n.s.), TSAT (R = 0.0883; n.s.), TIBC (R = -0.1091; n.s.), serum transferrin (R = -0.0420; n.s.), hemoglobin (R = 0.0185; n.s.), serum iron (R = 0.0389; n.s.). No correlation was found with age and IRLS (R = 0.1375; n.s. and R = 0.0880, n.s., respectively)., Conclusions: SIP are not correlated with SN iron content in RLS, quantified by means of TCS. TCS of the SN might be a more valid estimate and could be useful in the evaluation of RLS patients., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Restless legs syndrome (RLS) is one of the most common neurologic conditions, with an estimated prevalence in European and North American heritage populations of about 2% to 5%. Because RLS diagnosis is essentially clinical, a careful evaluation of the symptoms is mandatory. It is important to exclude RLS mimics and evaluate factors that could exacerbate RLS symptoms. It is mandatory to evaluate systemic iron parameters, because the initial treatment depends on this result. Other complementary tests could help support the diagnosis or exclude mimics. The decision about when and how to treat should be carefully tailored to each patient., Competing Interests: Disclosure C. Garcia-Malo reports grants from IRLSSG, outside the submitted work. The other authors have nothing to disclose., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: To evaluate the incidence of iron overload and anaphylaxis following intravenous (IV) iron treatment of restless legs syndrome (RLS)., Methods: A total of 58 consecutive RLS patients, meeting clinical requirements for IV iron treatment according to current IRLSSG guidelines were recruited. IV iron treatment consisted of two 500 mg infusions of ferric carboxymaltose (FCM) administered five days apart. During each of the three follow-up visits we obtained blood samples, substantia nigra echogenity index (SNEI) by means of transcranial sonography (TCS), and assessed the severity of RLS symptoms (IRLS scale). "Iron overload risk" was defined as transferrin saturation (TSAT) > 45% on two consecutive follow-up visits. In patients who had a reduction in systemic iron levels following treatment, an additional 500 mg of FCM was administered when feasible. In such cases an additional two follow-up visits were performed., Results: Among the total sample, only 2/58 participants met criteria for iron overload risk. They had no evidence of liver damage and did not require additional treatment. Among the 21 patients receiving an additional 500 mg infusion after, only one patient was diagnosed with iron overload risk. Among these three patients, only one was a hemochromatosis gene carrier. No anaphylaxis or other side-effects were reported., Conclusions: In real-life clinical conditions, the risk of iron overload is low when IV FCM is administered according to the safety limits defined in the current RLS treatment guidelines. However, a close clinical follow-up with periodic blood sampling for iron status, is needed., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Restless legs syndrome (RLS), also known as Willis-Ekbom disease (WED), is a common neurological disorder affecting up to 5% to 10% of the population, but it remains an underdiagnosed condition. RLS/WED is characterized by uncomfortable sensations, mainly in the legs, which appear during inactivity and worsen in the evening or at night. The prevalence of RLS/WED and periodic leg movements (PLMs) is increased in patients with sleep-disordered breathing, particularly in those with OSA, the most common sleep disorder encountered in sleep centers. New advances in the pathophysiology of RLS/WED have shown important implications for various genetic markers, neurotransmitter dysfunction, and iron deficiency. A practical approach to RLS/WED management includes an accurate diagnosis, the identification of reversible contributing factors, and the use of nonpharmacological therapies, including iron substitution (oral or IV) therapy. Many pharmacological agents are effective for the treatment of RLS/WED. Until recently, the first-line treatment of RLS/WED consisted of low-dose dopamine agonists (DA). However, given the fact that DAs cause high rates of augmentation of symptoms, international guidelines recommend that whenever possible the initial treatment of choice should be an α2δ ligand, and avoidance of dopaminergic agents unless absolutely necessary. If necessary, the lowest effective dose should be used for only the shortest possible time. The symptoms of RLS/WED can disrupt the quality of sleep as well as the quality of life. IV iron therapy may be considered in patients with refractory RLS. A better understanding of RLS/WED pathophysiology will allow patients to receive tailored therapy, resulting in an improved quality of life., (Copyright © 2020. Published by Elsevier Inc.)

Objective: To analyze changes in substantia nigra (SN) iron deposits, assessed by quantitative transcranial sonography (TCS), to obtain and compare substantia nigra echogenicity indices (SNEI) at baseline and after intravenous (IV) iron therapy in patients with restless legs syndrome (RLS)/Willis-Ekbom disease (WED)., Methods: A total of 30 consecutive subjects diagnosed with RLS/WED were recruited and underwent IV iron treatment. The SNEI, total daily dose of dopamine equivalents, and International Restless Legs Syndrome Rating Scale (IRLS) scores were obtained at baseline and following IV iron administration. Comparative statistics were performed by means of nonparametric testing., Results: The sample was stratified into two groups according to the median baseline SNEI and the grade of SN hypoechogenicity: severely hypoechogenic (HE) (n = 13) and moderately HE (n = 17). Following IV iron, the increase in SNEI among severely HE subjects was 19% (0.038 ± 0.046 cm 2 ; P < 0.01), whereas in moderately HE subjects it was 10% (0.021 ± 0.069 cm 2 ; P = 0.28). Among severely HE subjects, the average reduction in IRLS following IV iron was 10 ± 7.12 points (P < 0.01), in contrast to 1.85 ± 9.85 (not significant) among moderately HE subjects. Finally, we quantified the percentage of patients in each group who were able to reduce by ≥30% their total daily dopaminergic requirements (TDR) after IV iron, with a 57.14% reduction in the severely HE group vs 25% in the moderately HE group (P = 0.1). Three of 30 subjects (17%) were able to completely cease all dopaminergic treatment., Conclusion: Intravenous iron caused changes in SNEI in both groups of patients, reflecting an increase in brain iron stores. However, the increase in SNEI was greater in patients previously defined as severely HE. Furthermore, RLS/WED symptoms also improved more in severely HE subjects, and there was a greater reduction in TDR. This study highlights the role of TCS in quantifying brain iron deposits and in predicting which patients will likely benefit from IV iron., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Obstructive sleep apnoea (OSA) and restless legs syndrome (RLS) are two of the most prevalent sleep disorders and can coexist within the same patient. Nonetheless, the recognition of RLS among OSA patients has important clinical implications, since RLS can disrupt sleep despite adequate treatment of sleep disordered breathing and should be treated accordingly. Furthermore, the presence of OSA can also increase the severity of RLS. Therefore, it is important to be able to correctly identify both disorders and treat them effectively. The present article reviews our current knowledge on this comorbidity and discusses potential treatment options for RLS in the context of OSA., Competing Interests: Conflict of interest: S. Romero-Peralta has nothing to disclose. Conflict of interest: I. Cano-Pumarega has nothing to disclose. Conflict of interest: C. Garcia-Malo has nothing to disclose. Conflict of interest: L. Agudelo Ramos has nothing to disclose. Conflict of interest: D. Garcia-Borreguero reports personal fees from American Regent and grants from Merck, during the conduct of the study., (Copyright ©ERS 2019.)

Objectives: To determine whether long-term treatment with dopaminergic agents (DAs) might dampen the response to a non-dopaminergic agent, such as gabapentin enacarbil., Methods: We performed a two-week randomized, double-blind, crossover, and placebo-controlled study in a single, referral center in dopamine treatment-naive patients and non-augmented patients continuously treated with dopaminergics for the last five consecutive years. Following washout from any previous CNS-active drugs, patients were randomized into one of two groups for two consecutive two-week treatment periods with gabapentin enacarbil (GBPen) and placebo. Treatment was administered at 7 PM at a fixed dose of 600 mg/day. RLS severity was measured weekly using the International RLS Scale (IRLS) and Clinical Global Improvement (CGI). An M-SIT was also performed between 6 pm and midnight at the end of each treatment condition., Results: There were no significant differences between groups in age, sex, duration of disease, ferritin levels, RLS severity at baseline, or existing concomitant conditions. Both groups improved more during treatment with GBPen than during placebo on the IRLS scale, CGI and mSIT. However, improvements were greater in the DA-naïve group than in long-term treatment with DAs group on the IRLS (p < 0.05), CGI (p < 0.01), and mSIT (p < 0.01)., Conclusions: Previous long-term treatment with DAs reduces future response to GBPen in RLS patients. Potential pathiophysiological explanations are discussed. Our finding has strong implications for the initial choice of treatment in RLS and supports the notion that initial treatment should not be started with DAs., Classification of Evidence: The study provides class II evidence supporting reduced effects of gabapentin enacarbil in RLS patients previously exposed to long-term treatment with dopamine agonists., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Two types of drugs have been extensively investigated for the treatment of restless legs syndrome (RLS)/Willis-Ekbom disease (WED): dopamine agonists and α2δ ligands to the α2δ subunit of calcium channels. Comparative studies show that both classes of drugs are similarly effective in treating RLS symptoms over the short- and long-term. While dopamine agonists are more effective in treating periodic limb movements (PLMs), α2δ ligands are more effective in consolidating sleep. However, given the fact that dopamine agonists cause high rates of augmentation of symptoms, recent international guidelines recommend that whenever possible the initial treatment of choice should be an α2δ ligand. In fact, the most effective preventive strategy involves not using dopaminergic agents unless absolutely necessary. Indeed, should dopaminergic treatment be needed to handle the symptoms effectively, then it is recommended that the dopaminergic load be reduced by using the lowest effective dose for the shortest possible period of time. However, it must be taken into account that the only α2δ ligand approved for RLS/WED is gabapentin enacarbil, which is not yet available in Europe. Furthermore, recent studies have also reported on the efficacy of opioids as a second-line treatment of RLS/WED, following treatment failure with dopamine agonists. Recent guidelines have taken these new data into account and highlight that a low dose of an opioid (prolonged-release oxycodone or methadone) may be considered in patients with very severe augmentation of symptoms. Alternative non-dopaminergic treatment concepts based on glutamatergic and adenosinergic mechanisms are currently in development, and are likely to provide encouraging therapeutic alternatives., (© 2019 Elsevier Inc. All rights reserved.)

Dopaminergic drugs have been widely used over the last decades for the treatment of restless legs syndrome (RLS)/Willis-Ekbom disease (WED). While the majority of studies show an initial improvement in symptoms, longer studies and clinical experience show that either treatment efficacy decreases with time, and/or augmentation develops: dopaminergic augmentation has been reported to be the main reason for treatment discontinuation and treatment failure in RLS/WED. The current review discusses the main reasons for treatment failure in RLS/WED and outlines the most recent expert-based strategies to prevent and manage it. The main strategy for preventing augmentation is to consider non-dopaminergic medications such as α2δ ligands for initial RLS/WED treatment; these effective drugs have been shown to have little risk of augmentation. Alternatively, should dopaminergic drugs be elected as initial treatment, then the daily dose should be kept low and not exceed maximum recommended doses, however, it should be kept in mind that even low dose dopaminergics can cause augmentation. Patients with low iron stores should be given appropriate iron supplementation. Daily treatment should start only when symptoms significantly impact quality of life in terms of frequency and severity; while intermittent treatment might be considered in intermediate cases. Treatment of existing augmentation should be initiated, where possible, with the elimination/correction of extrinsic exacerbating factors (iron levels, antidepressants, antihistamines, etc.). In cases of mild augmentation, dopamine agonist therapy can continue by dividing or advancing the dose, or increasing the dose if there are breakthrough nighttime symptoms. Alternatively, the patient can be switched to an α2δ ligand or rotigotine. For severe augmentation, the patient can be switched to an α2δ ligand or rotigotine, noting that rotigotine may produce augmentation at higher doses with long-term use. In more severe cases of augmentation an opioid may be considered, bypassing α2δ ligands and rotigotine., (Copyright © 2018. Published by Elsevier Ltd.)

Objectives: Recent animal models of restless legs syndrome (RLS) suggest that brain iron deficiency is associated with a hypoadenosinergic state, with downregulation of adenosine A 1 receptors (A1R) in the striatum and cortex. We hypothesized that an increase in extracellular adenosine induced by inhibitors of adenosine transporters, such as the non-selective ENT1/ENT2 inhibitor dipyridamole, would result in an improvement in RLS symptoms., Methods: In a prospective two-month open-label, non-placebo controlled clinical trial, 15 untreated idiopathic RLS patients began treatment with 100 mg dipyridamole (with uptitration to 400 mg if necessary). Multiple Suggested Immobilization Tests and polysomnography were performed at baseline and at eight weeks. Severity was assessed at four and eight weeks using the IRLS, and the CGI scales. The primary endpoint was therapeutic response (50% improvement in IRLS total score)., Results: Thirteen patients completed the study. IRLS score improved from a mean (±S.D.) of 23.4 ± 4.6 at baseline to 10.7 ± 4.5 at eight weeks. Six out of 13 patients were full responders and four were partial responders. The mean (±S.D.) effective dose of dipyridamole at eight weeks was 281.8 ± 57.5 mg/day. Sleep variables also improved, and the mean (±S.D.) periodic leg movement index decreased from 26.7 ± 7.2 to 4.3 ± 1.9. Dipyridamole was generally well tolerated. Main side effects were abdominal cramps, diarrhea, dizziness, and flushing., Conclusions: These preliminary results suggest that dipyridamole has significant therapeutic effects on both sensory and motor symptoms, as well as sleep. In addition, it provides evidence that hypoadenosinergic mechanisms play a central role in RLS., Classification of Evidence: The study provides class III evidence supporting the therapeutic effects of dipyridamole in RLS., (Copyright © 2018. Published by Elsevier B.V.)

Restless legs syndrome (RLS), also known as Willis-Ekbom disease (WED) is a neurological condition with an overall prevalence in adults of 5-10% in Europe and North America. It is characterised by strong feelings of restlessness and distressing paraesthesia-like sensations in the lower legs, particularly when at rest. The symptoms vary considerably in severity and frequency. RLS/WED has a variable clinical expression influenced by genetic, environmental, and medical factors. Research into the pathophysiology of RLS/WED has found that various genetic markers and existing dysfunctions in dopaminergic mechanisms and iron mechanisms play a central role. Until recently, the first line treatment of RLS/WED was with low dose dopamine agonists, with three drugs having been approved by the US Food and Drug Administration and the European Medicines Agency. However, the occurrence of dopaminergic augmentation and an overall increase in severity of symptoms during long term treatment with dopamine agonists is leading to a shift towards non-dopaminergic alternatives as initial treatments, and particularly to α 2 δ ligands. Recent international guidelines recommend, whenever possible, to start treatment with these drugs (α 2 δ ligands) to avoid augmentation from the start. Other (eg, glutamatergic or adenosine) neurotransmitters might also play an important role in causing RLS/WED and might thus lead to new treatments., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)