Restless legs syndrome--theoretical roles of inflammatory and immune mechanisms

Prevalence and clinical profile of patients with restless legs syndrome in Parkinson's disease: A meta-analysis

INTRODUCTION

Restless legs syndrome (RLS) is a sensorimotor disorder of sleep/wake regulation characterized by an urge to move the legs accompanied by a wide range of sensory symptoms, mainly affecting the lower limbs. An increased incidence of RLS has been demonstrated in Parkinson's disease (PD) and has been associated with severe motor and non-motor manifestations. We aimed to provide a reliable estimate of RLS prevalence and the clinical features associated with its occurrence in PD (PD-RLS).

METHODS

We performed a systematic literature search up to January 2024 using PubMed, Scopus, and PsycINFO databases. Articles were included if they provided data on PD patients with or without RLS, and these proportions were used to estimate the prevalence of PD-RLS. Clinical profile associated with PD-RLS was explored by comparing the clinical characteristics of PD patients with and without RLS.

RESULTS

Forty-six studies were included in the meta-analysis. Pooled RLS prevalence was 20 % of a total sample of 6990 PD patients and was associated with female sex, mixed motor phenotype, worse motor disturbances and functional disability, and a wide range of non-motor symptoms such as sleep disorders, cognitive and autonomic dysfunctions, and more severe neuropsychiatric manifestations. Sensitivity analyses indicated significant associations of PD-RLS with variables related to dopaminergic therapy. No association was found with serum ferritin, serum iron and hemoglobin levels.

CONCLUSIONS

The prevalence of PD-RLS exceeds that reported in the general population, suggesting the existence of a relationship between the two disorders. Dopaminergic treatment seems to play an ambivalent role relieving, worsening or "mimicking" RLS manifestations. However, the clinical profile of PD-RLS patients, characterized by a greater severity of non-motor symptoms, also suggests that neurotransmitter systems other than the dopaminergic one are involved in PD-RLS etiology.

Sleep disorders as both risk factors for, and a consequence of, stroke: A narrative review

BACKGROUND AND PURPOSE

Sleep disorders are increasingly implicated as risk factors for stroke, as well as a determinant of stroke outcome. They can also occur secondary to the stroke itself. In this review, we describe the variety of different sleep disorders associated with stroke and analyze their effect on stroke risk and outcome.

METHODS

A search term-based literature review ("sleep," "insomnia," "narcolepsy," "restless legs syndrome," "periodic limb movements during sleep," "excessive daytime sleepiness" AND "stroke" OR "cerebrovascular" in PubMed; "stroke" and "sleep" in ClinicalTrials.gov) was performed. English articles from 1990 to March 2023 were considered.

RESULTS

Increasing evidence suggests that sleep disorders are risk factors for stroke. In addition, sleep disturbance has been reported in half of all stroke sufferers; specifically, an increase is not only sleep-related breathing disorders but also periodic limb movements during sleep, narcolepsy, rapid eye movement (REM) sleep behavior disorder, insomnia, sleep duration, and circadian rhythm sleep-wake disorders. Poststroke sleep disturbance has been associated with worse outcome.

CONCLUSION

Sleep disorders are risk factors for stroke and associated with worse stroke outcome. They are also a common consequence of stroke. Recent guidelines suggest screening for sleep disorders after stroke. It is possible that treatment of sleep disorders could both reduce stroke risk and improve stroke outcome, although further data from clinical trials are required.

Proteomic insights into the pathophysiology of periodic limb movements and restless legs syndrome

OBJECTIVES

We used a high-throughput assay of 5000 plasma proteins to identify biomarkers associated with periodic limb movements (PLM) and restless legs syndrome (RLS) in adults.

METHODS

Participants (n = 1410) of the Stanford Technology Analytics and Genomics in Sleep (STAGES) study had blood collected, completed a sleep questionnaire, and underwent overnight polysomnography with the scoring of PLMs. An aptamer-based array (SomaScan) was used to quantify 5000 proteins in plasma. A second cohort (n = 697) that had serum assayed using a previous iteration of SomaScan (1300 proteins) was used for replication and in a combined analysis (n = 2107). A 5% false discovery rate was used to assess significance.

RESULTS

Multivariate analyses in STAGES identified 68 proteins associated with the PLM index after correction for multiple testing (ie, base model). Most significantly decreased proteins were iron-related and included Hepcidin (LEAP-1), Ferritin, and Ferritin light chain. Most significantly increased proteins included RANTES, Cathepsin A, and SULT 1A3. Of 68 proteins significant in the base model, 17 were present in the 1300 panel, and 15 of 17 were replicated. The most significant proteins in the combined model were Hepcidin (LEAP-1), Cathepsin A, Ferritin, and RANTES. Exploration of proteins in RLS versus non-RLS identified Cathepsin Z, Heme oxygenase 2 (HO-2), Interleukin-17A (upregulated in the combined cohort), and Megalin (upregulated in STAGES only) although results were less significant than for proteins associated with PLM index.

CONCLUSIONS

These results confirm the association of PLM with low iron status and suggest the involvement of catabolic enzymes in PLM/RLS.

Case report: A new treatment for restless leg syndrome: three cases

Restless legs syndrome is a movement disorder that seriously affects the quality of life of patients. It is characterized by marked discomfort mainly occurring in the deep tissues of the lower extremities, including deep muscle or bone chafing, as well as crawling sensations or pulling sensations. These sensations often cause patients to awaken after falling asleep and to feel the urge to walk around, which seriously affects their sleep quality. Patients with restless leg syndrome exhibit significantly enhanced sympathetic nerve activity and immune disorders, while stellate ganglion blockage can block sympathetic nerves and regulate immune cells and cytokines to maintain immune system homeostasis. We report three patients with restless legs syndrome complicated with severe nephrotic syndrome. After treatment with stellate ganglion block, the symptoms in the restless legs were relieved within 1 month, and the quality of sleep was significantly improved. Our findings suggest that stellate ganglion block has broad promise in the management of restless legs syndrome patients with severe comorbidities.

Review of the role of the endogenous opioid and melanocortin systems in the restless legs syndrome

Restless legs syndrome (RLS) is responsive to opioid, dopaminergic and iron-based treatments. Receptor blocker studies in RLS patients suggest that the therapeutic efficacy of opioids is specific to the opioid receptor and mediated indirectly through the dopaminergic system. An RLS autopsy study reveals decreases in endogenous opioids, β-endorphin and perhaps Met-enkephalin in the thalamus of RLS patients. A total opioid receptor knock-out (mu, delta and kappa) and a mu-opioid receptor knock-out mouse model of RLS show circadian motor changes akin to RLS and, although both models show sensory changes, the mu-opioid receptor knock mouse shows circadian sensory changes closest to those seen in idiopathic RLS. Both models show changes in striatal dopamine, anaemia and low serum iron. However, only in the total receptor knock-out mouse do we see the decreases in serum ferritin that are normally found in RLS. There are also decreases in serum iron when wild-type mice are administered a mu-opioid receptor blocker. In addition, the mu-opioid receptor knock-out mouse also shows increases in striatal zinc paralleling similar changes in RLS. Adrenocorticotropic hormone and α-melanocyte stimulating hormone are derived from pro-opiomelanocortin as is β-endorphin. However, they cause RLS-like symptoms and periodic limb movements when injected intraventricularly into rats. These results collectively suggest that an endogenous opioid deficiency is pathogenetic to RLS and that an altered melanocortin system may be causal to RLS as well.

Can restless legs be a sign of something else? A case report of spondyloarthritis presenting with restless legs syndrome and a review of the literature

Restless legs syndrome (RLS) is a chronic movement disorder characterized by an urge or need to move the limbs, usually associated with uncomfortable sensations in the legs and sleep disorders. In general, two clinical forms of RLS are described: primary and secondary. Although primary RLS has a familial component, the underlying mechanism is still not fully understood but seems to be related to abnormalities in the dopaminergic and glutamatergic pathways of the central nervous system. The secondary forms of the syndrome are associated with iron deficiency, renal failure, pregnancy, diabetes mellitus, peripheral neuropathy, and several rheumatologic disorders such as rheumatoid arthritis and Sjögren's syndrome. In a few clinical trials, an increased frequency of RLS has been reported in patients with spondyloarthritis. In this report, a case of coexistence of spondyloarthritis and RLS is presented, showing satisfactory improvement with conservative treatment and additionally adding naproxen. Anemia of chronic disease occurring in rheumatic diseases, and associated iron deficiency may contribute to the development of RLS.

Evaluation of the relationship between idiopathic restless legs syndrome and serum hepcidin levels

INTRODUCTION

The relationship between restless legs syndrome (RLS) and iron deficiency is a well-known topic. However, the etiology of the disease has not been determined. As the central iron deficiency is the most critical biological abnormality for RLS, we planned a study examining the relationship between RLS and hepcidin, which is the only regulatory hormone of iron metabolism known so far.

METHODS

International Restless Legs Syndrome Study Group diagnostic criteria (2014) were taken as a basis. A total of 40 RLS patients and 40 healthy controls were included in the study. To avoid the potential variables that might cause secondary RLS, all the participants were asked to provide hemogram, ferritin, iron, thyroid function tests, and sedimentation analysis. The hepcidin levels were measured with a Human Hepcidin (Hepc 25) ELISA kit (MyBioSource).

RESULTS

The statistically significant results of our analysis show that the red blood cell count, the neutrophil count, the percentage of lymphocytes and neutrophils, and, more distinctively, hepcidin levels were higher in RLS patients in comparison with the control group.

CONCLUSION

In this study, no differences were found in iron and ferritin values. High levels of hepcidin, the main regulator of iron metabolism, in those with primary RLS support the possibility that hepcidin may play a role in the pathogenesis of RLS. We think that larger studies on this subject can give clearer ideas.

Vitamin D and Restless Legs Syndrome: A Review of Current Literature

This review presents a detailed summary of the current literature regarding RLS and vitamin D deficiency. To our knowledge it is the first review of its kind. We review the prevalence of vitamin D deficiency in RLS as well as the evidence for the use of vitamin D supplementation in RLS management. We further examine the literature for proteomic and genetic evidence of a role for vitamin D in the pathogenesis of RLS. An alteration in vitamin D binding protein in RLS is one of the most consistent findings in the proteomic studies. Furthermore, we examine the interaction of vitamin D with calcium, phosphorus, and parathyroid hormone and the possible role of these connections in RLS. We also explore the possible nexus between RLS and vitamin D in renal disease, cardiovascular and cerebrovascular disease as well as inflammation. In addition, we review the potential interaction between vitamin D and RLS with iron, dopamine and other neurotransmitter systems including the endogenous opiate, serotoninergic, glutamatergic and adenosinergic systems. We also explore the role of vitamin D in RLS Augmentation (i.e., the paradoxical worsening of RLS symptoms when dopaminergic agents are used as a therapy for RLS). Although the literature is not entirely consistent in affirming vitamin D deficiency in RLS or the amelioration of RLS symptoms with vitamin D therapy, the collective studies overall indicate that vitamin D deficiency is common enough in RLS patients to suggest that RLS patients should have their vitamin D levels checked and any deficiency corrected as a standard of care.

Highlights 

Patients with Restless Legs Syndrome (RLS) may be deficient in vitamin D and therapy with vitamin D may ameliorate RLS. We present the first review dedicated solely to evaluating the relationship between RLS and vitamin D and present a case for the role of vitamin D in RLS pathogenesis.

European Working Group on SARS-CoV-2: Current Understanding, Unknowns, and Recommendations on the Neurological Complications of COVID-19

The emergence of COVID-19 was rapidly followed by infection and the deaths of millions of people across the globe. With much of the research and scientific advancement rightly focused on reducing the burden of severe and critical acute COVID-19 infection, the long-term effects endured by those who survived the acute infection has been previously overlooked. Now, an appreciation for the post-COVID-19 condition, including its neurological manifestations, is growing, although there remain many unknowns regarding the aetiology and risk factors of the condition, as well as how to effectively diagnose and treat it. Here, drawing upon the experiences and expertise of the clinicians and academics of the European working group on COVID-19, we have reviewed the current literature to provide a comprehensive overview of the neurological sequalae of the post-COVID-19 condition. In this review, we provide a summary of the neurological symptoms associated with the post-COVID-19 condition, before discussing the possible mechanisms which may underly and manifest these symptoms. Following this, we explore the risk factors for developing neurological symptoms as a result of COVID-19 and the post-COVID-19 condition, as well as how COVID-19 infection may itself be a risk factor for the development of neurological disease in the future. Lastly, we evaluate how the post-COVID condition could be accurately diagnosed and effectively treated, including examples of the current guidelines, clinical outcomes and tools that have been developed to aid in this process, as well as addressing the protection provided by COVID-19 vaccines against post-COVID-19 condition. Overall, this review provides a comprehensive overview of the neurological sequalae of the post-COVID-19 condition.

A Narrative Review of the Lesser Known Medications for Treatment of Restless Legs Syndrome and Pathogenetic Implications for Their Use

Background

There are several well-known treatments for Restless Legs Syndrome (RLS), including dopamine agonists (pramipexole, ropinirole, rotigotine), anticonvulsants (gabapentin and its analogs, pregabalin), oral or intravenous iron, opioids and benzodiazepines. However, in clinical practice, treatment is sometimes limited due to incomplete response or side effects and it is necessary to be aware of other treatment options for RLS, which is the purpose of this review.

Methods

We performed a narrative review detailing all of the lesser known pharmacological treatment literature on RLS. The review purposefully excludes well-established, well-known treatments for RLS which are widely accepted as treatments for RLS in evidence-based reviews. We also have emphasized the pathogenetic implications for RLS of the successful use of these lesser known agents.

Results

Alternative pharmacological agents include clonidine which reduces adrenergic transmission, adenosinergic agents such as dipyridamole, glutamate AMPA receptor blocking agents such as perampanel, glutamate NMDA receptor blocking agents such as amantadine and ketamine, various anticonvulsants (carbamazepine/oxcarbazepine, lamotrigine, topiramate, valproic acid, levetiracetam), anti-inflammatory agents such as steroids, as well as cannabis. Bupropion is also a good choice for the treatment of co-existent depression in RLS because of its pro-dopaminergic properties.

Discussion

Clinicians should first follow evidence-based review recommendations for the treatment of RLS but when the clinical response is either incomplete or side effects are intolerable other options can be considered. We neither recommend nor discourage the use of these options, but leave it up to the clinician to make their own choices based upon the benefit and side effect profiles of each medication.

Summary

Clinicians should first follow evidence-based reviews for RLS but when response is incomplete and side effects intolerable, other medications can be considered. We do not make a recommendation on these options but leave it up to the clinician to make their own choice based upon the benefit and side effect profiles of each medication.

Putative Animal Models of Restless Legs Syndrome: A Systematic Review and Evaluation of Their Face and Construct Validity

Restless legs syndrome (RLS) is a sensorimotor disorder that severely affects sleep. It is characterized by an urge to move the legs, which is often accompanied by periodic limb movements during sleep. RLS has a high prevalence in the population and is usually a life-long condition. While its origins remain unclear, RLS is initially highly responsive to treatment with dopaminergic agonists that target D2-like receptors, in particular D2 and D3, but the long-term response is often unsatisfactory. Over the years, several putative animal models for RLS have been developed, mainly based on the epidemiological and neurochemical link with iron deficiency, treatment efficacy of D2-like dopaminergic agonists, or genome-wide association studies that identified risk factors in the patient population. Here, we present the first systematic review of putative animal models of RLS, provide information about their face and construct validity, and report their role in deciphering the underlying pathophysiological mechanisms that may cause or contribute to RLS. We propose that identifying the causal links between genetic risk factors, altered organ functions, and changes to molecular pathways in neural circuitry will eventually lead to more effective new treatment options that bypass the side effects of the currently used therapeutics in RLS, especially for long-term therapy.

Association between clinical outcomes and restless legs syndrome in Japanese patients with ulcerative colitis

Restless legs syndrome (RLS) is a common sleep disorder in the Western population. The prevalence of restless legs syndrome in the Japanese population is 4.6%. Inflammatory and/or immune alteration might be associated with the development of restless legs syndrome. Ulcerative colitis is a chronic inflammatory bowel disease. Evidence regarding the association between ulcerative colitis and the prevalence of restless legs syndrome is limited. Herein, we investigated the association between clinical outcomes and the prevalence of restless legs syndrome in Japanese patients with ulcerative colitis. This was a cross-sectional study using baseline data from a prospective cohort study. Subjects in this study were 273 patients with ulcerative colitis. The definition of restless legs syndrome was achieved using a self-administered questionnaire based on the diagnostic criteria for restless legs syndrome in an epidemiological study approved by the Executive Committee of the International Restless Leg Syndrome Study Group in 2002. Clinical outcomes were clinical remission and mucosal healing. The association between clinical remission and mucosal healing and the prevalence of restless legs syndrome was assessed by multivariate logistic regression analyses. The percentage of clinical remission and mucosal healing was 58.4% and 63.1%, respectively. The prevalence of restless legs syndrome in this cohort was 4.7%. Clinical remission (adjusted odds ratio 0.23, 95% confidence interval 0.05-0.93) and mucosal healing (adjusted odds ratio 0.23, 95% confidence interval 0.05-0.90) were independently inversely associated with restless legs syndrome. No association between serum haemoglobin and restless legs syndrome was found. In conclusion, clinical remission and mucosal healing were independently and inversely associated with the prevalence of restless legs syndrome in Japanese patients with ulcerative colitis.

The relationship between the frequency and severity of restless legs syndrome and anaemia in patients with ankylosing spondylitis

Background Background The study aims to determine the frequency of restless legs syndrome (RLS) in patients with ankylosing spondylitis (AS) and the relationship between the International Restless Legs Syndrome Study Group Rating Scale (IRLSSG-RS) score and anemia. Material and Methods It was a case-control study that included 106 patients with AS and 106 age- and sex-matched healthy controls in the rheumatology clinic of a training and research hospital. The patients were divided into two groups according to their hemoglobin levels. A hemoglobin level lower than 12 g/dL in women and less than 13 g/dL in men was the criterion for anemia. Results Although the frequency of RLS was higher in AS patients than in control groups, there was no significant difference in the IRLSSG-RS score between AS patients and control groups. 23 (57.5%) of the AS patients with anemia had RLS, and the IRLSSG-RS score was 21.3±5.7. Of the AS patients without anemia, 11 (16.7%) had RLS, and the IRLSSG-RS score was 15±6. Statistically significant differences between AS patients with and without anemia regarding RLS frequency and IRLSSG-RS score were found. The IRLSSG-RS scores of AS patients were negatively correlated with serum iron and hemoglobin level. Conclusions Patients with AS had a higher RLS frequency than the control group; AS patients with anemia had a higher RLS and IRLSSG-RS score than AS patients without anemia. Also, a negative and significant correlation was found between the IRLSS-RS score and serum iron and hemoglobin levels in AS patients.

Uncovering the mechanism of Radix Paeoniae Alba in the treatment of restless legs syndrome based on network pharmacology and molecular docking

Restless legs syndrome (RLS) is a neurological motor disorder with a high prevalence. The treatment efficacy of RLS is unsatisfactory. Radix Paeoniae Alba (RPA) can effectively treat RLS symptoms such as the discomfort of the legs. RPA has great potential for the development of new medications for RLS. Hence, we explored the mechanism of RPA in the treatment of RLS using network pharmacology and molecular docking. The active components and targets of RPA were obtained from the Traditional Chinese Medicine System Pharmacology database and analysis platform and PharmMapper platform. The RLS-related targets were found in GeneCards, OMIM, DrugBank, and DisGeNET databases. The overlapping targets of RPA and RLS were then collected. The "active components-overlapping targets" network was built, and network topology analysis was performed. Furthermore, Cytoscape 3.9.1 software was used to screen the key components of RPA in the treatment of RLS. Protein-protein interaction was performed using the Search Tool for the Retrieval of Interacting Genes. The gene ontology functions and Kyoto Encyclopedia of Genes and Genomes signaling pathways were analyzed using ClusterProfiler, PathView, and other R packages to reveal the main mechanism of RPA in treating RLS. Component and protein structures were downloaded from the Traditional Chinese Medicine System Pharmacology and Protein Data Bank databases, respectively. The AutoDock 4.2.6 software was used for molecular docking. A total of 12 active components and 109 targets of RPA, as well as 2387 RLS-related targets, were collected. Following that, 47 overlapping targets were obtained. Furthermore, 5 key components and 12 core targets were screened. The results of gene ontology functions were as follows: 2368 biological processes, 264 molecular functions, and 164 cellular components. A total of 207 Kyoto Encyclopedia of Genes and Genomes signaling pathways were obtained, including the lipid and atherosclerosis pathway, the endocrine resistance pathway, the prolactin signaling pathway, and the IL-17 signaling pathway. The components and the core targets completed molecular docking stably. RPA has multi-component, multi-target, and multi-pathway characteristics in treating RLS, which could provide a basis for future research and improve clinical efficacy.

Increased risk of sleep-related movement disorder in patients with Helicobacter pylori infection: A nationwide population-based study

Background and purpose

Evidence increasingly suggests that Helicobacter pylori infection (HPI) is associated with movement disorders such as Parkinson's disease (PD). However, the relationship between HPI and sleep-related movement disorders (SRMD) remains unknown. This nationwide population-based study tried to demonstrate whether patients with HPI have a higher risk of developing SRMD in a general adult population.

Methods

The study cohort enrolled 9,393 patients who were initially diagnosed with HPI between 2000 and 2013. Notably, 37,572 age- and sex-matched controls without prior HPI were selected as the reference. A Cox proportional hazard regression analysis was performed for multivariate adjustment.

Results

Patients with HPI had a higher risk of developing SRMD (adjusted hazard ratio [HR] = 2.18, 95% confidence interval [CI] = 1.26–3.82, p < 0.01). Patients with HPI aged ≥65 years exhibited the highest risk (HR = 3.01, 95% CI = 1.90–5.30, p < 0.001), followed by patients aged 45–64 years (HR = 1.69, 95% CI = 1.26–2.90, p <0.01) and <45 years (HR = 1.49, 95% CI = 1.12–2.49, p < 0.01). Patients were most likely to develop SRMD 5 years or more after diagnosis of HPI (HR = 3.33, 95% CI = 1.97–5.89, p < 0.001). The increased risk of SRMD in male patients with HPI (HR = 2.73, 95% CI = 1.53–4.79, p < 0.001) was greater than in female patients (HR = 1.14, 95% CI = 1.04–1.65, p < 0.05).

Conclusion

Patients with HPI were associated with an increased risk for SRMD, with a higher risk in men, aged ≥65 years, and diagnosed for more than 5 years.

Is Restless Legs Syndrome De Facto Thyroid Disease?

While a primary role in the pathogenesis of restless legs syndrome (RLS) has been attributed to dysfunction of the dopaminergic system and impaired iron metabolism (particularly in the central nervous system), it has been hypothesized that an imbalance between thyroid hormones and dopaminergic activity may be the starting point for all aspects of RLS. Although this hypothesis was proposed more than a decade ago, it has not yet been verified beyond doubt. The main aim of this study is to compare the prevalence of RLS in a population of patients with the most common thyroid gland diseases with a population of individuals with a healthy thyroid gland. The study included 237 participants divided into smaller groups according to the thyroid disease concerning them. Each participant had a laboratory diagnosis, an ultrasound scan and an assessment of the fulfilment of RLS criteria according to the International Restless Legs Syndrome Study Group (IRLSSG) criteria. The results obtained were subjected to statistical analysis. RLS is significantly more common in patients with known thyroid disease; Hashimoto’s disease, among others, manifests a 2.56× higher risk of a positive diagnosis for RLS than the general population. The association of RLS with thyroid disease is notable, although it is difficult to conclude unequivocally that there is a cause-and-effect relationship between the two. Further investigation into a potentially autoimmune cause of restless legs syndrome should be considered.

Exploring the role of the endogenous opiate system in the pathogenesis of anemia in an opiate receptor knock-out model of Restless Legs Syndrome

Restless Legs Syndrome (RLS) is characterized by bothersome leg discomfort accompanied by an urge to move to obtain relief and symptoms are worse at night and on lying down. There is at least partial and temporary relief with activity. It is also an opioid responsive disorder, often accompanied by iron deficiency with or without anemia, and inflammation may be a precipitating factor in some cases. We created two in-vivo opiate receptor knock out mouse models of RLS - a triple opiate receptor knock-out mouse and a mu opiate receptor knock-out mouse. Both sets of animals were restless during the sleep period as is also true of RLS. Both of our knockout models showed statistically significantly decreased Hemoglobin and Hematocrit indicating anemia and both models showed statistically significant decreases in serum iron suggestive of either iron deficiency anemia or inflammatory anemia. The rest of the hematologic studies were not consistent enough to determine which of these two types of anemia was present in either model. An additional experiment in normal wild type mice showed a statistically significant decrease in serum iron when an opiate receptor blocker was used. To our knowledge this is the first demonstration that deficiency of endogenous opioids might play a role in the production of anemia. Our hypothesis is that an intact endogenous opiate system is necessary for red cell homeostasis. The presence of opioid receptors both on red blood cells and on various immunologically based white blood cells suggest mechanisms by which deficiency in the endogenous opiate system could cause anemia of either the iron deficiency or inflammatory types. The administration of opioid agonists or antagonists to iron deficient cultures of red blood cell precursors is a next step in determining the role of the endogenous opiate system in the maintenance of red cell homeostasis and in the possible prevention of iron deficiency or inflammatory anemia where iron dysregulation is key.

Microglia Are Necessary to Regulate Sleep after an Immune Challenge

Microglia play a critical role in the neuroimmune response, but little is known about the role of microglia in sleep following an inflammatory trigger. Nevertheless, decades of research have been predicated on the assumption that an inflammatory trigger increases sleep through microglial activation. We hypothesized that mice (n = 30) with depleted microglia using PLX5622 (PLX) would sleep less following the administration of lipopolysaccharide (LPS) to induce inflammation. Brains were collected and microglial morphology was assessed using quantitative skeletal analyses and physiological parameters were recorded using non-invasive piezoelectric cages. Mice fed PLX diet had a transient increase in sleep that dissipated by week 2. Subsequently, following a first LPS injection (0.4 mg/kg), mice with depleted microglia slept more than mice on the control diet. All mice were returned to normal rodent chow to repopulate microglia in the PLX group (10 days). Nominal differences in sleep existed during the microglia repopulation period. However, following a second LPS injection, mice with repopulated microglia slept similarly to control mice during the dark period but with longer bouts during the light period. Comparing sleep after the first LPS injection to sleep after the second LPS injection, controls exhibited temporal changes in sleep patterns but no change in cumulative minutes slept, whereas cumulative sleep in mice with repopulated microglia decreased during the dark period across all days. Repopulated microglia had a reactive morphology. We conclude that microglia are necessary to regulate sleep after an immune challenge.

Restless Leg Syndrome in Hemodialysis Patients: A Narrative Review

BACKGROUND

Restless legs syndrome (RLS) is a clinical entity characterized by sensory-motor manifestations commonly observed in end-stage renal illness. Evidence suggests that RLS is a multifactorial phenomenon that can be influenced by many critical factors, including genetic predisposition, dietary patterns, and deficiency in some vitamins. Iron metabolism disorders and metabolic derangements have been generally accepted as predisposing elements in RLS. Furthermore, both pharmacological and neuroimaging studies demonstrated dopamine deficiency and dopamine receptors decrease in basal ganglia during RLS.

REVIEW SUMMARY

A literature search was done in three databases (PubMed, Google Scholar, and Cochrane) to identify the pertinent articles discussing the epidemiology, pathogenesis, and management of RLS in hemodialysis patients. RLS can affect the morbidity and mortality of patients treated with dialysis. It also has significant impacts on the quality of life since it can lead to insomnia, increased fatigue, mental health troubles, and other movement problems. Appropriate measures should be considered in this particular population so to prevent and treat RLS. Many drugs and other nonpharmacological methods have been investigated to attenuate the disease's severity. No treatment, however, could offer long-term effects.

CONCLUSION

Further efforts are still required to improve the understanding of RLS pathogenic trends to find more specific and efficient therapies. A wide range of treatment options is available. However, it can be individualized according to the patients' several factors.

The prevalence and potential aetiological factors associated with restless legs syndrome in patients with chronic kidney disease: a cross-sectional study

BACKGROUND

There is limited understanding of aetiological factors of and treatment options for restless leg syndrome (RLS) in patients with chronic kidney disease (CKD). This study aimed to estimate the prevalence of RLS in CKD patients and identify factors that may contribute to RLS.

METHODS

A questionnaire-based cross-sectional study of patients with CKD stage 4 (CKD 4), pre-dialysis stage 5 (CKD-5ND) and haemodialysis-dependent stage 5 (CKD-5D) was conducted. Eligible patients were enrolled from the local dialysis units and renal clinics. The International RLS Study Group rating scale was used to establish the diagnosis of RLS and quantify its severity.

RESULTS

212 patients with CKD 4 (n = 92), CKD-5ND (n = 14) and CKD-5D (n = 106) were included. The overall prevalence of RLS was 32.1%. Women had a significantly higher odds of having RLS despite adjustment for age, diabetes, cardiovascular disease and whether patients were on dialysis (odds ratio 2.8 [95% confidence intervals 1.5-5.2]). In pre-dialysis groups, patients with RLS had significantly higher serum ferritin (323.9 [SD 338.1] vs 177.5 [SD 178.5] µg/L, p = 0.020) compared to non-RLS patients. In dialysis patients (CKD-5D), those with RLS had significantly higher total white cell (8.0 [SD 3.5] vs 6.8 [SD 1.9] × 10⁹/L, p = 0.026) and neutrophil (6.4 [SD 3.9] vs 4.6 [SD1.7] × 10⁹/L, p = 0.002) counts compared to patients without RLS.

CONCLUSION

RLS remains a significant problem in patients with CKD and may be related to underlying inflammation. Targeting this pathway may be useful. Prevalence of RLS, diagnosed using validated measures, is higher than previous reports.

TRIAL REGISTRATION

N/A (the current study is not a trial).

Chronic inflammation markers and cytokine-specific autoantibodies in Danish blood donors with restless legs syndrome

Restless Legs Syndrome (RLS) is a neurological sensorimotor disorder negatively impacting sufferers’ quality of sleep and health-related quality of life. The pathophysiology of RLS is poorly understood and research focusing on the link between RLS and inflammation has been limited. Our study aimed to investigate whether chronic inflammation markers C-reactive protein (CRP) and soluble urokinase-type plasminogen activator receptor (suPAR), as well plasma levels of five different cytokine-specific autoantibodies (c-aAb), i.e. modulators of inflammation, associate with RLS in otherwise healthy individuals. CRP, suPAR and c-aAb were measured in plasma samples of participants from the Danish Blood Donor Study in 2010. Returning donors between 2015 and 2018 completed the validated Cambridge-Hopkins RLS-questionnaire for RLS assessment, resulting in datasets with RLS assessment and values for CRP (N = 3564), suPAR (N = 2546) and c-aAb (N = 1478). We performed logistic regression models using the CRP, suPAR or c-aAb as the independent variable and RLS status as the dependent variable, adjusted for appropriate covariates. Our study indicates that a high concentration of CRP is associated with RLS, while an increased probability of experiencing frequent RLS symptoms in those with an elevated plasma suPAR level appears to be mediated through lifestyle factors. We additionally report that a high titer of autoantibodies specific against the cytokine interferon-alpha was associated with RLS. Our results support the existence of links between systemic inflammation and RLS, though further RLS studies on CRP, suPAR and c-aAb in larger cohorts are warranted to confirm our findings and further reveal the hitherto underexplored links between RLS and inflammation.

Restless legs syndrome is associated with long-COVID in women

STUDY OBJECTIVES

Sleep disturbance is common in long-COVID (LC). Restless legs syndrome (RLS) is characterized by sleep disturbance and has been reported after viral infections. Therefore, we evaluated RLS symptoms cross-sectionally in individuals with LC at both current and pre-coronavirus disease 2019 (pre-COVID-19) time points.

METHODS

Adults on LC-focused Facebook pages were recruited for an online assessment of symptoms before COVID-19 infection and during their present LC state in a cross-sectional manner. The LC group documented baseline symptoms retrospectively. Questions were included about the presence/severity of RLS symptoms and assessments of fatigue, quality of life, and sleep apnea. A control group was recruited and included individuals ≥ 18 years of age who never had overt symptoms of COVID-19. Pregnancy was an exclusion criterion for both groups.

RESULTS

There were 136 participants with LC (89.7% females, age 46.9 ± 12.9 years) and 136 controls (65.4% females, age 49.2 ± 15.5). RLS prevalence in females with LC was 5.7% pre-COVID-19 and 14.8% post-COVID-19 (P < .01) vs 6.7% in control females. Severity of RLS was moderate in both groups. Logistic regression predicting post-COVID-19 RLS among females with LC failed to find significant effects of hospitalization, sleep apnea, neuropathic pain severity, or use of antihistamines and antidepressants.

CONCLUSIONS

The baseline prevalence of RLS in females with LC was similar to the general population group as well as to patients in epidemiological studies. The prevalence significantly increased in the LC state. Postinfectious immunological mechanisms may be at play in the production for RLS symptoms.

CITATION

Weinstock LB, Brook JB, Walters AS, Goris A, Afrin LB, Molderings GJ. Restless legs syndrome is associated with long-COVID in women. J Clin Sleep Med. 2022;18(5):1413-1418.

Investigating the inflammation marker neutrophil-to-lymphocyte ratio in Danish blood donors with restless legs syndrome

Background

Restless Legs Syndrome (RLS) is a neurological sensorimotor disorder that occurs in the evening and night, thereby impacting quality of sleep in sufferers. The pathophysiology of RLS is poorly understood but inflammation has been proposed as possibly being involved. The neutrophil-to-lymphocyte ratio (NLR) can be used as an inflammation marker but results from small studies have been inconclusive in determining whether NLR is associated with RLS. We aimed to assess whether an association between NLR and RLS exists in a large cohort of healthy individuals.

Methods

Neutrophils and lymphocytes were measured in blood samples of 13,055 individuals from the Danish Blood Donor Study, all of whom completed the validated Cambridge-Hopkins RLS-questionnaire for RLS assessment.

Results

In the sample, 661 individuals were determined as current RLS cases (5.1%). A higher proportion of individuals with RLS were females (62.5% vs 47.5%; P<0.001) and RLS cases were older than controls (P<0.001), but no differences in body mass index (BMI), smoking or alcohol consumption were found between the two groups. An increased NLR was observed in RLS cases compared to controls (median NLR: 1.80 vs 1.72; P = 0.033). In an unadjusted logistic regression model, increased NLR was associated with RLS (OR = 1.10 per NLR unit increase [95%CI:1.01–1.20]; P = 0.032); however, the association was not significant in multivariate models adjusting for sex and age (P = 0.094) or sex, age, alcohol consumption, smoking status and BMI (P = 0.107).

Conclusion

We found no association between RLS and NLR among Danish blood donors after adjusting for sex, age, alcohol consumption, smoking status and BMI. Further studies are needed to determine whether inflammation is a risk factor for RLS.

No association between plasma hepcidin levels and restless legs syndrome - results from the Danish Blood Donor Study

BACKGROUND

Restless Legs Syndrome (RLS) is a neurological sensorimotor disorder that occurs in the evening and night, thereby often impacting quality of sleep in sufferers. The aetiology of RLS is not completely understood although iron dysregulation has been suggested as a likely pathway. The relationship between RLS and the iron regulatory protein hepcidin has not been studied in large cohorts. We aimed to assess whether an association between plasma hepcidin variation and RLS exists in a large cohort of healthy individuals.

METHODS

Plasma hepcidin levels were measured in 9708 Danish blood donors from the Danish Blood Donor Study all of whom correctly completed the validated Cambridge-Hopkins RLS-questionnaire for RLS assessment.

RESULTS

A total of 466 blood donors were determined as current RLS cases in the sample (4.8%). RLS cases had a significantly higher proportion of females (56.7% vs 46.7%; P < 0.001) and were older (median age [IQR] 40.6 years vs 38.0 years; P = 0.010) than controls. RLS cases were also more frequent smokers (P = 0.004). No significant differences were found in body mass index (BMI), alcohol consumption, time of donation and donation history between cases and controls. No difference in plasma hepcidin levels was observed between RLS cases and controls (median concentration [IQR]: 10.5 ng/ml [6.3-16.4] in RLS cases vs 10.5 ng/ml [6.0-16.5] in controls). Using a logistic regression model, we found that hepcidin levels were not associated with RLS after adjusting for age, sex, alcohol consumption, smoking status, donation time and donation history (OR = 1.00 [0.99-1.02] per 1 ng/ml increase of hepcidin; P = 0.429).

CONCLUSION

Our study in Danish blood donors did not find an association between RLS and plasma hepcidin levels. Our findings suggest that plasma hepcidin's role as a potential diagnostic biomarker of RLS is inadequate.

Restless legs syndrome in pediatric onset multiple sclerosis

BACKGROUND

Restless legs syndrome/Willis-Ekbom disease (RLS/WED) was shown to have a high prevalence among adults with multiple sclerosis (MS).

OBJECTIVE

We aimed to investigate the prevalence of RLS/WED and to define the disease characteristics in young patients with pediatric onset multiple sclerosis (POMS) METHOD: 50 patients with POMS were questioned for the presence of RLS/WED. The demographic, clinical and laboratory data were compared between POMS patients with and without RLS/WED, including the total number of clinical and/or radiological MS attacks, interval between first two attacks, EDSS, number of the hyperintense and/or contrast-enhancing lesions, localization of demyelinating lesions, IgG index in cerebrospinal fluid, oligoclonal band, serum ferritin, C-reactive protein, ratio of neutrophil to lymphocyte count, and 25‑hydroxy vitaminD.

RESULTS

Eleven patients (22%) had RLS/WED - mostly of moderate in severity (54.5%). Mean EDSS score was significantly higher in POMS patients with RLS/WED than those without (p = 0.003). The Ig G index was almost two times higher in POMS patients with RLS/WED, but it failed to reach to the statistically significant level (p = 0.073).

CONCLUSION

Our study demonstrated high prevalence of RLS/WED in young patients with POMS. Higher EDSS scores in patients with POMS and RLS/WED indicates disease-related factors in the emergence of RLS/WED.

Sleep in children and young adults with cystic fibrosis

Large gains have been made in the management of respiratory diseases associated with cystic fibrosis (CF). Initial studies evaluating sleep issues in CF focused on respiratory problems of nocturnal hypoxia, alveolar hypoventilation and risk of airway obstruction from nasal polyps with treatment evaluations including long term oxygen therapy or noninvasive ventilation in case of nocturnal hypercapnia. More recent studies include patients whose lung function is better preserved, and have permitted more focus on sleep patterns and sleep quality. This literature identified that reduced sleep duration and poor sleep quality are common and may be explained by chronic pain and cough, frequent stools, gastro-oesophageal reflux, nasal obstruction or sinusitis, and drugs such as corticosteroids or beta-agonists. In the teenage years, poor sleep hygiene, sleep debt and poor sleep quality are associated with depression, poor academic performance, less physical activity, and a decrease in quality of life. Restless leg syndrome also seems to be common in adult patients with CF. These sleep problems seem more important in patients with a low lung function but may also be observed in patients with preserved lung function. The consequences of poor sleep may potentially exaggerate the multi-organ morbidity of CF, such as pain, inflammation, susceptibility to infection, and glucose intolerance, but these aspects are largely under-evaluated. Sleep should be evaluated on a routine basis in CF and prospective studies assessing the benefits of interventions aiming at improving sleep duration and sleep quality urgently needed.

Restless Legs Syndrome Shows Increased Silent Postmortem Cerebral Microvascular Disease With Gliosis

Background

Patients with restless legs syndrome (RLS) have increased silent microvascular disease by magnetic resonance imaging. However, there has been no previous autopsy confirmation of these magnetic resonance imaging findings. RLS is also frequently associated with inflammatory and immunologically mediated medical disorders. The postmortem cortex in patients with RLS was therefore evaluated for evidence of microvascular and immunological changes.

Methods and Results

Ten microvascular injury samples of precentral gyrus in 5 patients with RLS (3 men, 2 women; mean age, 81 years) and 9 controls (2 men, 7 women; mean age, 90 years) were studied by hematoxylin and eosin stains in a blinded fashion. None of the subjects had a history of stroke or neurologic insults. In a similar manner, the following immunohistochemistry stains were performed: (1) glial fibrillary acidic protein (representing gliosis, reactive change of glial cells in response to damage); (2) CD3 (a T‐cell marker); (3) CD19 (a B‐cell marker); (4) CD68 (a macrophage marker); and (5) CD117 (a mast cell marker). Patients with RLS had significantly greater silent microvascular disease (P=0.015) and gliosis (P=0.003). T cells were increased in RLS compared with controls (P=0.009) and tended to colocalize with microvascular disease (P=0.003). Other markers did not differ. There was no correlation between microvascular lesion load and RLS severity or duration.

Conclusions

Patients with RLS had statistically significantly more silent cerebral microvascular disease and gliosis than controls compatible with previous magnetic resonance imaging studies and with studies showing a link between RLS and hypertension, clinical stroke, and cardiovascular disease. T‐cell invasion may be a secondary phenomenon.

Restless legs syndrome is increased in postural orthostatic tachycardia syndrome

STUDY OBJECTIVES

Postural orthostatic tachycardia syndrome (POTS) and restless legs syndrome (RLS) are both characterized by sleep disturbance along with autoimmune/inflammatory features and autonomic dysfunction. However, to our knowledge, there has been no direct study looking at the prevalence of RLS in patients with POTS patients compared with healthy participants (controls).

METHODS

Ninety-six physician-diagnosed patients with POTS (89 female and 7 male) and 130 controls (99 female and 31 male) were administered the Cambridge Hopkins questionnaire. Participants who were diagnosed with probable or definite RLS on the Cambridge Hopkins questionnaire were then contacted to determine the severity of RLS with the International Restless Legs Scale.

RESULTS

More patients with POTS (15 of 96; 15.6%) than controls (6 of 130; 4.6%) were diagnosed with probable or definite RLS on the Cambridge Hopkins questionnaire (P = .0048). A sensitivity analysis with only female respondents yielded similar results. RLS severity was in the moderate range (12.23 ± 9.22).

CONCLUSIONS

There is a higher prevalence of RLS in patients with POTS patients compared with controls. This association may have to do with shared increased inflammatory/autoimmune load and autonomic dysfunction.

Sleep Disorders and Cognitive Dysfunctions in Parkinson's Disease: A Meta-Analytic Study

A relationship between sleep disorders and cognitive dysfunctions was reported in Parkinson's Disease (PD), however, some studies did not confirm the link. A meta-analytic study was performed to investigate the relationship between sleep disorders and cognitive dysfunctions, and to clarify the evolution of cognitive status in PD patients with sleep disorders.The systematic literature search was performed up to November 2020 using PubMed, Scopus, and PsycINFO databases. We included studies published in peer-reviewed journals in English providing results about neuropsychological comparison between patients with or without sleep disorders. Meta-analysis on cross-sectional data included 54 studies for REM Sleep Behavior Disorder (RBD), 22 for Excessive Daytime Sleepiness (EDS), 7 for Obstructive Sleep Apnea (OSA), 13 for Restless Legs Syndrome (RLS), and 5 for insomnia, the meta-analysis on longitudinal data included 7 studies.RBD was related to deficits of global cognitive functioning, memory, executive functions, attention/working memory, language, and visuospatial abilities. EDS was associated with deficits of global cognitive functioning and attention and working memory abilities, whereas RLS and OSA were related to global cognitive dysfunction. Moreover, we revealed that PD patients with RBD and those with EDS performed worse than PD patients without sleep disorders at follow-up rather than baseline evaluation. Our results suggest that sleep disorders are associated with cognitive deficits supporting indirectly that these, especially the REM Sleep Behavior Disorder, reflect abnormalities of frontal networks and posterior cortical areas. Sleep disorders in patients with PD seem to also increase the risk for long-term cognitive decline.

Changes in Hepcidin Serum Levels Correlate with Clinical Improvement in Idiopathic Restless Legs Syndrome Patients

BACKGROUND

Restless legs syndrome (RLS) is a common sensory motor neurological disorder that is related to iron-dopamine dysregulation and immune system alteration. We aimed to assess the effects of serum hepcidin, an iron-regulating hormone, in drug-naive RLS patients compared to healthy controls and to evaluate its role in helping to predict clinical improvement after treatment with dopamine agonist.

METHODS

Nonanemic and drug-naive RLS patients (n = 18) and healthy controls (n = 15) were enrolled. The serum hepcidin and iron-related values in the serum were measured upon the first visit in both groups and 12 weeks later after dopaminergic treatment in 12 patients. Information about sociodemographic characteristics, sleep-related profiles, mood and anxiety was obtained upon the first visit in all participants as well as after treatment in RLS patients.

RESULTS

Serum hepcidin levels exhibited no significant differences between patients with drug-naïve RLS and healthy controls at diagnosis (7.1 ± 2.4 vs. 7.0 ± 3.2 ng/mL, p = 0.357). Decreased hepcidin levels were significantly associated with decreased RLS severity (β = 0.002, 95% CI = 0.00-0.00, p = 0.005) and improved quality of life (β = 0.002, 95% CI = 0.00-7.01, p = 0.044) in a dose-dependent manner after 12 weeks of treatment with a dopamine agonist. This association was independent of age, sex, inflammatory markers, sleep quality, insomnia, daytime sleepiness, depression and anxiety.

CONCLUSIONS

This study demonstrates the role of hepcidin in evaluating the positive therapeutic response in RLS.

Bidirectional association between irritable bowel syndrome and restless legs syndrome: a systematic review and meta-analysis

BACKGROUND

Several observational studies have shown that patients with irritable bowel syndrome (IBS) may have a high risk of restless legs syndrome (RLS). This systematic review and meta-analysis aimed to comprehensively investigate the bidirectional association between IBS and RLS.

METHODS

All conservational studies on IBS and RLS were searched in MEDLINE (assessed by PubMed), Embase, Web of Science, CINAHL, the Cochrane Library database and Google Scholar from inception to June 14, 2020. The Newcastle-Ottawa Scale and Agency for Healthcare Research and Quality were used to assess the methodological quality of the cohort and cross-sectional studies, respectively. The pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using Reviewer Manager 5.3.

RESULT

A total of five cross-sectional studies of moderate methodological quality and one cohort study of high methodological quality were included in our review. Four cross-sectional studies and one cohort study involving 86 438 individuals met the criteria of IBS predicating the onset of RLS. Patients with IBS had a nearly three-fold increased odds of RLS compared with controls (OR = 2.60, 95%CI: 2.17-3.12, P < 0.00001; I² = 48%, P = 0.11). Three sensitivity analyses confirmed the robustness of the pooled result. Two cross-sectional studies involving 3581 individuals met the criteria of RLS predicating the onset of IBS. RLS patients had a nearly four-fold increased odds of IBS compared with controls without RLS (OR = 3.87, 95%CI: 1.73-8.66, P = 0.0010; I² = 77%, P = 0.04).

CONCLUSION

In this systematic review and meta-analysis, we found a substantial bidirectional association between IBS and RLS. More prospective, high-quality, population-based studies are warranted in the future.

Deficiency of Meis1, a transcriptional regulator, in mice and worms: Neurochemical and behavioral characterizations with implications in the restless legs syndrome

Restless legs syndrome is a sleep-related sensorimotor neurological disease affecting up to 10% of the population. Genetic analyses have identified Myeloid Ecotropic viral Integration Site 1 (MEIS1), a transcriptional regulator, to be associated with not only the restless legs syndrome but also self-reported symptoms of insomnia and sleep. This study is to determine if Meis1 deficiency in mice can lead to restless legs syndrome-like phenotypes, and if it is the case, what the underlying mechanisms are. We used two genetic model systems, Caenorhabditis elegans and mice. Egg retention assay and fluorescent reporters were used with C. elegans. For mice, we performed behavioral tests, serum and brain iron detection, qRT-PCR, western blot, immunohistochemistry, and in vitro brain-slice recording. Our results showed that with C. elegans, the function of dop-3, an orthologue of DRD2, was diminished after the knockdown of unc-62, an ortholog of MEIS1. Additionally, unc-62 knockdown led to enhanced transcription of the orthologue of tyrosine hydroxylase, cat-2. Meis1 knockout mice were hyperactive and had a rest-phase-specific increased probability of waking. Moreover, Meis1 knockout mice had increased serum ferritin and altered striatal dopaminergic and cholinergic systems. Specifically, Meis1 knockout mice showed an increased mRNA level but decreased protein level of tyrosine hydroxylase in the striatum. Furthermore, Meis1 knockout mice had increased striatal dopamine turnover and decreased spontaneous firing regularity of striatal cholinergic interneurons. Our data suggest that Meis1 knockout mice have restless legs syndrome-like motor restlessness and changes in serum ferritin levels. The symptoms may be related to dysfunctional dopaminergic and cholinergic systems.

COVID-19-associated sleep disorders: A case report

PURPOSE

We reported one patient infected with acute respiratory syndrome coronavirus-2 (SARS-CoV-2) presented with sleep disorders; insomnia and restless leg syndrome.

METHODS

Patient data were obtained from medical records from Al-Raghy Isolation Hospital in Assuit University.

RESULTS

A 49-year-old female patient presented with insomnia and restless leg syndrome associated with anosmia, ageusia. Three days before, she had developed a cough, malaise and athenia, headache, arthralgia, myalgia affecting mainly upper limbs, diarrhea and a fever followed by tachypnea. The naso-oropharyngeal swab test for coronavirus disease 2019 (COVID-19) by qualitative real-time reverse-transcriptase-polymerase-chain-reaction assay was positive. The patient was treated with Oseltamivir 75mg and clarithromycin 500 mg (12 hourly for each respectively) for 10 days with paracetamol. Two weeks later, the patient made a complete neurological and respiratory recovery.

CONCLUSION

Our case highlighted the rare occurrence of restless leg syndrome and insomnia during the COVID-19 pandemic. The era of sleep disorders spectrum in patients with COVID-19 remains to be characterized suggesting a frightening scientific association between COVID-19 and neuropsychiatric illness.

Effects of Acupressure and Acupuncture-Like Transcutaneous Electrical Nerve Stimulation on Sleep Quality Among Pregnant Women

BACKGROUND

Despite the adverse consequences of poor sleep during pregnancy, relatively few safe interventions exist for improving sleep among pregnant women. Nonpharmacological interventions are increasingly gaining acceptance. However, the effects of acupressure and acupuncture-like transcutaneous electrical nerve stimulation (ACUTENS) have not been widely reported.

OBJECTIVES

The purpose of this study is to investigate the effects of low-frequency transcutaneous electrical nerve stimulation, otherwise known as ACUTENS, and acupressure on sleep quality among pregnant women.

METHODS

Purposive sampling of 42 pregnant women with sleep disorders was conducted, and the participants were randomized into 3 groups, i.e., acupressure, ACUTENS, and usual care. interventions, which were carried out twice weekly for six weeks. The Pittsburgh Sleep Quality index was used to determine the overall sleep quality.

RESULTS

The preintervention scores of sleep quality were 12.5 (3.75), 12.5 (4.0), and 13.0 (3.5) in the ACUTENS, acupressure, and usual care groups, respectively. The Kruskal-Wallis test did not show any significant difference in the preintervention sleep quality scores (H = 0.379, p = 0.827). Participants in the usual care group recorded the least improvement, with a score of 5.0 (2.25), the ACUTENS group recorded a score of 4.5 (3.0), and the greatest improvement was recorded in the acupressure group, with a score of 4.0 (2.2) after 6 weeks of intervention. The Kruskal-Wallis test did not show any significant difference in the postintervention sleep quality scores among the 3 groups (H = 0.666, p = 0.717).

CONCLUSION

This study showed that ACUTENS and acupressure as an adjunct to usual care are not more effective than usual care alone in improving sleep quality among pregnant women.

Circulating levels of cytokines are increased in restless legs syndrome

BACKGROUND

Restless legs syndrome [RLS] is known as a disease of iron and dopaminergic dysregulation but inflammatory processes might also have a role in the pathogenesis. In this study, we compared the circulating levels of hsCRP, IL-1β, IL-6, and TNF-α in patients with primary restless legs syndrome [RLS] and healthy control subjects.

METHODS

We prospectively included 29 patients with primary RLS and 65 healthy controls [HC], all age-sex matched. The diagnosis of RLS was established using international guidelines. IRLSSG Severity Scale was used to evaluate the severity of RLS. Plasma levels of hsCRP, IL-1β, IL-6, and TNF-α were measured in all participants.

RESULTS

The mean age of patients was 37.8 ± 11.3 and 52% of RLS group were women. Serum IL-1β, IL-6, and TNF-α levels of the patient group were statistically significantly higher compared to HC [p < 0.001 for all variables]. Plasma levels of hsCRP did not differ between groups. There were 8 patients with mild RLS [28%], 13 patients with moderate RLS [45%], and 8 patients with severe RLS [28%]. Only IL-6 values were significantly different between the groups. In the severe group, the value of IL-6 was significantly higher than in the other groups [p: 0.03].

CONCLUSION

These results showing higher circulating levels of inflammatory cytokines in patients with RLS support the notion that inflammation may be involved in the pathogenesis of primary RLS. However, it is necessary to perform further studies to determine if this finding is a cause or an effect.

Relation of serum hepcidin levels and restless legs syndrome in chronic hemodialysis patients

BACKGROUND

Iron deficiency anemia, pregnancy, and end-stage renal disease (ESRD) are common causes of secondary restless legs syndrome (RLS). Serum ferritin is considered the most specific test associated with the total amount of body iron stores. However, due to the increase of serum ferritin secondary to inflammation in chronic hemodialysis (HD) patients, serum ferritin test results do not fully reflect decreased iron stores in these patients. The present study evaluates the serum hepcidin levels, as the main regulator of iron metabolism, and its relationship with RLS in chronic HD patients.

METHODS

The present cross-sectional study involved 72 patients (36 with and 36 without RLS) who received chronic HD treatment between April 2014 and April 2015. Demographic and biochemical data were evaluated in all patients, and statistical analyses were performed.

RESULTS

The mean age and mean dialysis vintage of all patients (56% women) included in the study were 65.3 ± 11.6 years and 41.5 ± 36.5 months, respectively. Serum hepcidin, hemoglobin A1C (HbA1C), and ferritin levels were significantly higher in patients with RLS (p = 0.001, p = 0.032, p = 0.042, respectively). In addition, a positive correlation was found between International Restless Legs Syndrome Study Group severity scale score and serum hepcidin levels, HbA1C, and ferritin (r = 0.387, p = 0.001; r = 0.426, p = 0.034; r = 0.240, p = 0.046, respectively). A multivariate linear regression analysis revealed hepcidin and HbA1C to be independently associated with the presence of RLS.

CONCLUSION

A significant relationship was detected between RLS and increased serum hepcidin levels in chronic HD patients, and uncontrolled diabetes was noted to contribute to this association.

Bioinformatic analysis of proteomic data for iron, inflammation, and hypoxic pathways in restless legs syndrome

OBJECTIVE/BACKGROUND

We performed bioinformatic analysis of proteomic data to identify the biomarkers of restless legs syndrome (RLS) and provide insights into the putative pathomechanisms, including iron deficiency, inflammation, and hypoxic pathways.

PATIENTS/METHODS

Patients with drug-naïve idiopathic RLS were recruited at a university hospital from June 2017 to February 2018. Serum samples from patients with RLS (n = 7) and healthy sex- and age-matched controls (n = 6) were evaluated by proteomic analysis. For differentially expressed proteins (DEPs) in patients with RLS, compared to those in controls, the expression profiles and protein-protein interaction (PPI) network were characterized between dysregulated proteins and extracted proteins involved in iron deficiency, hypoxia, and inflammation responses using the String database (http://string-DB.org). The PPI network was visualized by Cytoscape ver. 3. 7. 1. Statistical analyses of the validation Western blot assays were performed using a Student's t-test.

RESULTS

Interactome network analysis revealed a relationship among the eight proteins, their associated genes, and 150, 47, and 11 proteins related to iron deficiency, inflammation, and hypoxic pathways, respectively. All DEPs were well associated with inflammation, and complement 3, complement C4A, alpha-2 HS glycoprotein, and alpha-2 macroglobulin precursor were found to be in hub positions of networks involved in PPIs including iron deficiency, hypoxia pathway, and inflammation. C3 and C4A were verified using western blotting.

CONCLUSIONS

We identified key molecules that represent the selected cellular pathways as protein biomarkers by PPI network analysis. Changes in inflammation can mediate or affect the pathomechanism of RLS and can thus act as systemic biomarkers.

(Neuro)Inflammatory Component May Be a Common Factor in Chronic Widespread Pain and Restless Legs Syndrome

Purpose of Review

Recent studies have linked fibromyalgia (nociplastic pain) and depression to neuroinflammation. Restless legs syndrome (RLS) is highly prevalent in CWP (chronic widespread pain) and FMS (fibromyalgia syndrome) as well as in depression. This review focuses on evidence in the relationship between CWP and RLS and possible common pathophysiological mechanisms.

Recent Findings

CWP is chronic pain spread over various locations of the body and is a cardinal sign of fibromyalgia. Poor sleep quality is a common symptom in fibromyalgia as well as high levels of fatigue, poor cognition, and other associated features which include depression, headache, and abdominal pain. Evidence for a bilateral relationship between pain and sleep deficit is robust. The latest research focus is not only on insomnia symptoms in chronic pain but also on other types of sleep disorders such as RLS which is characterized by complaints of an “urge to move” frequently associated with dysesthesias. These sensations can also have painful characteristics. Thus, there is a possible overlap between these two entities. The high prevalence of RLS (33–54%) in CWP has been shown in several studies. The pathophysiological mechanisms behind CWP and RLS are still not completely known, but there is a rising amount of evidence on proinflammatory and neuroinflammatory processes in CWP. In RLS, there are links to dopaminergic dysfunction and more generally to monoaminergic dysfunctional circuits, BID (brain iron deficiency), altered glutamatergic neurotransmission, and genetic traits. Depression is a common comorbidity as well in CWP as RLS, and proinflammatory mechanisms have also been demonstrated in this condition.

Summary

The association between CWP and RLS is shown to be high and the pathogenesis of both conditions is still not completely understood. Recent research is focusing on proinflammatory and neuroinflammatory processes, not uniquely emerging in fibromyalgia/CWP, but inflammatory features have been found in depression as well as in sleep deficit. Proinflammatory/neuroinflammatory processes may be an underlying, common factor in both CWP and RLS that future research should investigate further.

Mu opioid receptor knockout mouse: Phenotypes with implications on restless legs syndrome

Restless legs syndrome (RLS) is characterized by an irresistible need to move the legs while sitting or lying at night with insomnia as a frequent consequence. Human RLS has been associated with abnormalities in the endogenous opioid system, the dopaminergic system, the iron regulatory system, anemia, and inflammatory and auto-immune disorders. Our previous work indicates that mice lacking all three subtypes of opioid receptors have a phenotype similar to that of human RLS. To study the roles of each opioid receptor subtype in RLS, we first used mu opioid receptor knockout (MOR KO) mice based on our earlier studies using postmortem brain and cell culture. The KO mice showed decreased hemoglobin, hematocrit, and red blood cells (RBCs), with an appearance of microcytic RBCs indicating anemia. Together with decreased serum iron and transferrin, but increased ferritin levels, the anemia is similar to that seen with chronic inflammation in humans. A decreased serum iron level was also observed in the wildtype mice treated with an MOR antagonist. Iron was increased in the liver and spleen of the KO mice. Normal circadian variations in the dopaminergic and serotoninergic systems were absent in the KO mice. The KO mice showed hyperactivity and increased thermal sensitivity in wakefulness primarily during what would normally be the sleep phase similar to that seen in human RLS. Deficits in endogenous opioid system transmission could predispose to anemia of inflammation and loss of circadian variations in dopaminergic or serotonergic systems, thereby contributing to an RLS-like phenotype.

Sleep apnea-hypopnea syndrome caused by ankylosing spondylitis: A case report

INTRODUCTION

Sleep apnea-hypopnea syndrome (SAHS) is a multifactorial disease characterized by recurrent hypopnea or respiratory interruption during sleep, which causes intermittent hypoxemia, hypercapnia, and sleep structure disturbances. An association between ankylosing spondylitis (AS) and the type of SAHS has rarely been reported in the literature. Here, we present a case of SAHS in a patient with AS and discuss the possible mechanism underlying the type of SAHS.

PATIENT CONCERNS

A 46-year-old man presented with a 15-year history of AS. He had been receiving sulfasalazine for symptomatic relief and had never been on immunosuppressive therapy.

DIAGNOSIS

The patient was diagnosed with SAHS in addition to AS.

INTERVENTIONS

We instituted treatment with methylprednisolone (5 mg, oral, daily), leflumomide (20 mg, oral, daily), bicyclol tablets (25 mg, oral, 3 times a day), and ursodeoxycholic acid tablets (10 mg/kg, oral, daily). The patient received etanercept (50 mg, sc, once a week) as his condition deteriorated. In addition, for management of SAHS symptoms, the patient received nasal continuous positive airway pressure (CPAP) during sleep.

OUTCOMES

Six months after commencement of the treatment, the clinical manifestations of SAHS and AS had significantly improved.

CONCLUSIONS

We hypothesize that patients with AS are prone to sleep apnea due to airway compression, central depression of respiration, abnormal inflammatory responses. Hence, careful assessment toward potential SAHS symptoms should be considered especially in patients with AS.

Evaluation of upper endoscopic findings in patients with restless legs syndrome and gastric complaints

BACKGROUND

The effect of gastrointestinal system disorders on Restless Legs Syndrome/Willis-Ekbom disease (RLS/WED) has been previously demonstrated by using serological tests. However, this association has not been supported by histopathological studies so far.

OBJECTIVE

To investigate the relationship between RLS/WED, upper endoscopic imaging and histopathological results in patients diagnosed with RLS who underwent endoscopy because of gastrointestinal system (GIS) complaints.

METHODS

Case-control study, including 100 patients diagnosed with RLS who presented dyspeptic complaints and underwent upper GIS endoscopy and 106 age- and sex-matched controls. RLS diagnosis was evaluated according to the four main diagnostic criteria determined by the International RLS Study Group. All patients underwent upper GIS endoscopic intervention and at least one gastric and/or antral biopsy.

RESULTS

There was no significant difference between patients and controls in relation to endoscopically seen gastric ulcer, duodenal ulcer, gastroesophageal reflux disease (GERD) findings and Helicobacter pylori (HP) positivity (p>0.05). Intestinal metaplasia and mucosal atrophy were more common in RLS/WED patients compared to controls (p=0.026 and p=0.017, respectively). Additionally, ferritin levels were found to be lower than the reference value.

CONCLUSIONS

The detection of increased severity of intestinal metaplasia, mucosal atrophy, and gastric inflammation in RLS/WED patients with dyspeptic complaints may entail the close gastrointestinal system evaluation of these patients. However, larger randomized and controlled trials are required on this subject where patients are evaluated by upper GIS endoscopic biopsy.

Does restless legs syndrome impact cognitive function via sleep quality in adults with Parkinson's disease?

Purpose: Restless legs syndrome (RLS) is a sleep disorder that results in sleep dysfunction. Sleep disruption can have profound negative consequences in adults with Parkinson's disease (PD), potentially including cognitive dysfunction. This study examined the relationships among RLS, cognition, and sleep quality in persons with PD.Materials and methods: Participants (N = 79) with idiopathic PD completed six questionnaires evaluating RLS, sleep quality, daytime sleepiness, global cognitive function, sleep apnea risk, and depression. Participants were further examined for body mass index composition and motor symptom severity (MDS-UPDRS Part III).Results: Persons with RLS (n = 25) had significantly worse cognitive function (p = 0.035, d = -0.56) and sleep quality (p < 0.0001, d = -1.19), and more daytime sleepiness (p = 0.009, d = 0.67) than those without RLS (n = 54). Cognitive function was not significantly correlated with sleep quality (rs = 0.113) or daytime sleepiness (rs = -0.001). The association between RLS and cognition was not attenuated by controlling for sleep quality or daytime sleepiness.Conclusions: This study is unique as it is the first to consider the possibility that RLS in PD may be associated with cognitive deficits through a pathway involving sleep quality. Persons with RLS and PD have greater deficits in both sleep quality and cognitive function than individuals without RLS; however, cognitive dysfunction among those with PD and RLS in this sample is not accounted for by sleep quality.

The prevalence of insomnia and restless legs syndrome among Japanese outpatients with rheumatic disease: A cross-sectional study

The prevalence of symptomatic insomnia and the prevalence of restless legs syndrome (RLS) are known to be higher among patients with rheumatic diseases compared to the general population. The prevalences of insomnia and RLS reported in a questionnaire by Japanese patients with rheumatic diseases at an outpatient clinic were analyzed herein. The association between the patients' disease activity and their sleep quality was analyzed. Of 121 rheumatic disease patients, 70 were enrolled. The median (interquartile range) age at enrollment was 62.0 (47.8-68.0) years. There were 58 women (82.9%) and 12 men (17.1%), and 43 patients (61.4%) with rheumatoid arthritis (RA), nine (12.9%) with systemic lupus erythematosus (SLE), and 18 (25.7%) with other rheumatic diseases. Twenty patients (28.6%) had one or more moderate-to-severe insomnia symptoms, and 10 (14.3%) were diagnosed with RLS. Among the patients with RA, the swollen joint count based on a 28-joint assessment (SJC28) was significantly higher in the insomnia group (n = 13) compared to the non-insomnia group (n = 30) (p = 0.006). A classification and regression tree (CART) analysis showed that the cut-off points of ≥3 mg/day prednisolone (PSL) treatment and <16.54% as the transferrin saturation (TSAT) value would best predict RLS in rheumatic disease. Patients with rheumatic disease had a high prevalence of symptomatic insomnia and RLS. A higher dose of PSL and lower TSAT were associated with the occurrence of RLS.

Restless legs syndrome is associated with mast cell activation syndrome

STUDY OBJECTIVES

Mast cell activation syndrome (MCAS) is an inflammatory and allergic disorder. We determined the prevalence of restless legs syndrome (RLS) in MCAS because each common syndrome may be inflammatory in nature and associated with dysautonomia.

METHODS

Individuals with MCAS were evaluated for RLS by two standard questionnaires. Prevalence comparisons included spouse control patients and two prevalence publications. MCAS diagnosis required mast cell (MC) symptoms in ≥ 2 organs plus ≥ 1 elevated MC mediators, improvement with MC therapy, and/or increased intestinal MC density. Clinical variables were studied.

RESULTS

There were 174 patients with MCAS (146 female, 28 male, mean age 44.8 years) and 85 spouse control patients (12 female, 73 male, mean age 50.9 years). Patients with MCAS as a whole had a higher prevalence of RLS (40.8%) than spouse control (12.9%) (P < .0001) Male patients with MCAS had a higher prevalence of RLS (32.1%) than male controls (12.3%, odds ratio [OR] 3.4, confidence interval [CI] 1.2-9.7, P = .025), American men (8.4%, OR 5.2, CI 2.2-12.0, P < .001), and French men (5.8%, OR 7.7, CI 3.4-17.1, P < .001). Female patients with MCAS also had a higher prevalence of RLS (42.5%) than female controls (16.7%) but this did not reach statistical significance perhaps because of the sample size of the female controls. However, female patients with MCAS had a statistically higher prevalence of RLS than American women (10.0%, OR 6.7, CI 4.5-9.7, P < .0001) and French women (10.8%, OR 6.1, CI 4.4-8.6, P < .0001).

CONCLUSIONS

RLS appears to be associated with MCAS. Effects of mast cell mediators, inflammation, immune mechanisms, dysautonomia, or hypoxia may theoretically activate RLS in MCAS.

Restless Legs Syndrome in Chronic Kidney Disease: Is Iron or Inflammatory Status To Blame?

STUDY OBJECTIVES

Restless legs syndrome (RLS) is increased in pediatric chronic kidney disease (CKD). In adults without CKD, central nervous system iron deficiency is involved in RLS pathogenesis and a low serum ferritin levels is consequently an indication for initiation of iron therapy. However, children with CKD are at risk for iron deficiency and inflammation, which raises serum ferritin. We examined the role of iron deficiency and inflammation in RLS in pediatric CKD.

METHODS

This cross-sectional study examined RLS prevalence in three groups of pediatric patients with CKD: nontransplant, nondialysis CKD (estimated GFR < 60 mL/min/1.73 m²) (n = 27); renal transplant recipients (n = 65); and dialysis (n = 32). RLS was diagnosed using a validated questionnaire. Serum ferritin < 100 ng/mL or transferrin saturation < 20% defined iron deficiency. Serum high sensitivity C-reactive protein ≥ 1 mg/L defined inflammation.

RESULTS

Among 124 patients, RLS prevalence was 15.3%; this did not differ across groups. There was no significant difference in RLS prevalence between those with and without iron deficiency, defined by either reduced ferritin or transferrin. Median ferritin levels in patients with RLS tended to be higher than in those without RLS (51.2 versus 40.1 ng/mL; P = .08). Inflammation (elevated CRP) also did not differ significantly by RLS status (57.9% [with RLS] versus 41.2% [without RLS], P = .18).

CONCLUSIONS

Neither ferritin nor inflammation differentiated pediatric patients with CKD with and without RLS. This study suggests that the factors mediating the pathogenesis and, potentially, treatment, of RLS in pediatric CKD may be different from non-CKD populations.

Blood pressure profile and endothelial function in restless legs syndrome

Restless legs syndrome (RLS) is frequently comorbid with hypertension and cardiovascular diseases; however this relationship and underlying mechanisms remain controversial. After clinical evaluation, 84 drug-free patients with primary RLS (53 women; mean age 55.1 ± 12.3 years) and 76 controls (47 women; mean age 52.2 ± 15.3 years) underwent 24-hour ambulatory blood pressure (BP) and polysomnographic monitoring, and peripheral arterial tonometry to assess endothelial function for 61 patients and 69 controls. Hypertension was diagnosed in 11.9% of patients with RLS based on office measurement, and in 46.4% on the 24 h recording, with nighttime hypertension, two times more frequent than daytime hypertension. Periodic limb movement during sleep (PLMS), markers of sleep fragmentation, and systolic and mean BP non-dipping profile were more frequent among patients. BP non-dipping status was associated with older age, later RLS onset and diagnosis, RLS severity and higher sleep fragmentation. The mean 24-hour, daytime and nighttime BP values, the frequency of hypertension and the endothelial function were comparable between groups. However, both systolic and diastolic BP trajectories over a 24-hour period differed between groups. In conclusion, patients with RLS exhibit a 24-hour BP deregulation with increased frequency of systolic non-dipping profiles that could worsen the risk for CVD morbidity and mortality.

Use of antidepressants and risks of restless legs syndrome in patients with irritable bowel syndrome: A population-based cohort study

Previous research has suggested an association between antidepressants use and clinical restless legs syndrome (RLS) in patients, but there has never been a single study investigating the risk of RLS in irritable bowel syndrome (IBS) patients treated with antidepressants. Hence, we aimed to explore the association between IBS and RLS and to examine the risk of RLS in IBS patients treated with antidepressants. With the use of the National Health Insurance Research Database of Taiwan, 27,437 adults aged ≥ 20 years with newly diagnosed IBS (ICD-9-CM Code 564.1) and gender- and age-matched 54,874 controls without IBS were enrolled between 2000 and 2012. All patients were followed-up until RLS diagnosis, withdrawal from the National Health Insurance program, or end of 2013. We used the Cox proportional hazards model to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) of RLS. RLS was more prevalent in IBS patients than in the non-IBS group (7.57 versus 3.36 per 10,000 person-years), with an increased risk of RLS (adjusted HR [aHR], 1.91; 95% CI, 1.52-2.40). Multivariate Cox proportional hazards analysis identified older age (age, 51-65 years; aHR, 1.67; 95% CI, 1.09-2.56; and age > 65; aHR, 1.59; 95% CI, 1.02-2.48), hypothyroidism (aHR, 4.24; 95% CI, 1.92-9.37), CAD (aHR, 1.70; 95% CI, 1.17-2.48), and depression (aHR, 3.15; 95% CI, 2.14-4.64) as independent RLS risk factors in IBS patients. In addition, the male SSRIs users were associated with significantly higher risk of RLS (aHR, 3.05 95% CI, 1.34-6.92). Our study showed that the IBS group has higher risk of RLS. Moreover, SSRIs use may increase the risk of RLS in male IBS patients.

Post-polio Syndrome: More Than Just a Lower Motor Neuron Disease

Post-polio syndrome (PPS) is a neurological condition that affects polio survivors decades after their initial infection. Despite its high prevalence, the etiology of PPS remains elusive, mechanisms of progression are poorly understood, and the condition is notoriously under-researched. While motor dysfunction is a hallmark feature of the condition, generalized fatigue, sleep disturbance, decreased endurance, neuropsychological deficits, sensory symptoms, and chronic pain are also often reported and have considerable quality of life implications in PPS. The non-motor aspects of PPS are particularly challenging to evaluate, quantify, and treat. Generalized fatigue is one of the most distressing symptoms of PPS and is likely to be multifactorial due to weight-gain, respiratory compromise, poor sleep, and polypharmacy. No validated diagnostic, monitoring, or prognostic markers have been developed in PPS to date and the mainstay of therapy centers on symptomatic relief and individualized rehabilitation strategies such as energy conservation and muscle strengthening exercise regimes. Despite a number of large clinical trials in PPS, no effective disease-modifying pharmacological treatments are currently available.