Restless legs symptoms in thyroid disorders

Sensitivity to thyroid hormones is associated with sleep duration in the euthyroid population with depression degree lower than moderate

We collected thyroid-related hormone index levels, sleep duration, and other basic characteristics of the population with depression from the NHANES 2009-2012 cycles and evaluated the association of Thyroid-Stimulating Hormone Index (TSHI) with sleep duration in the euthyroid population with depression via different analysis methods. We found that the association between TSHI and sleep duration was only found in patients with depression degree < Moderate (score: 1-14) rather than > Moderate group. Among the populations with degree < Moderate (N = 1918), only 4 indexes (parametric Thyroid Feedback Quantile Index, PTFQI, Thyrotroph Thyroxine Resistance Index, TT4RI, Thyroid-Stimulating Hormone TSH, and TSHI) reflecting the sensitivity to thyroid hormones were related to the sleep duration, with a significant non-linear relationship after adjusting for potential confounders (all P < 0.05). Trend analysis indicated that with the level increase of these 4 indexes, the sleep duration increased (all P for trend < 0.001). Further, we found that TSHI was relatively more important among the 4 indexes. Sum up, sensitivity to thyroid hormones is associated with sleep duration in the euthyroid population with depression degree lower than Moderate. Poor sensitivity referred to a longer sleep duration.

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.

Association between thyroid function and disease severity in restless legs syndrome

Background

Restless Legs Syndrome (RLS) is a common neurological disorder. Growing evidence shows that dopaminergic dysfunction and iron deficiency are associated with the pathogenesis of RLS. Additionally, the dopaminergic system is linked with the hypothalamic-pituitary-thyroid (HPT) axis. Thus, the current study aimed to compare thyroid function between RLS patients and healthy subjects and investigate the associations with clinical characteristics of RLS.

Methods

Serum levels of thyroid hormones were investigated in 102 first-episode drug-naïve RLS patients and 80 matched healthy controls (HCs). Baseline data and clinical characteristics were performed by professional personnel. In addition, multivariate regression was used to analyze the relationship between thyroid function and RLS.

Results

Compared with control group, RLS patients had significantly higher serum thyroid-stimulating hormone (TSH) levels (p < 0.001), and higher prevalence of subclinical hypothyroidism [Odds ratio (OR) 8.00; 95% confidence interval (CI) = 3.50–18.30; p < 0.001]. The Subclinical hypothyroidism rate (47.1 vs. 10%, p < 0.001) in RLS patients was higher than the HCs group. Regression analysis revealed that serum TSH (OR = 1.77; 95% CI = 1.41–2.23; p < 0.001) was independently associated with RLS. There was a statistically significant positive correlation between TSH and the Pittsburgh sleep quality index (PSQI) scores (r = 0.728, p < 0.001), and the International Restless Legs Scales (IRLS) points (r = 0.627, p < 0.001). Spearman correlation analysis showed that FT₃ was positive correlated with HAMA₁₄ score (r = 0.239, p = 0.015). In addition, compared with the good-sleeper group, poor-sleeper patients had significantly higher serum TSH levels (p < 0.001).

Conclusion

Serum levels of TSH and the prevalence of subclinical hypothyroidism were higher in RLS patients, indicating the imbalance between thyroid hormones (TH) and the dopaminergic system may contribute to the development of primary RLS. Additionally, the TH axis may influence the quality of sleep in RLS patients.

Thyroid Dysfunction and Sleep Disorders

Thyroid disorders and sleep disorders are common problems in the general population that can affect people of all ages, backgrounds, and sexes, but little is known about their clinical associations. We reviewed the literature assessing the associations between thyroid disease and sleep disorders and noted that hyperthyroidism and hypothyroidism have clinical overlap with sleep conditions such as insomnia, restless legs syndrome, and obstructive sleep apnea. These findings highlight the importance of identifying and managing thyroid dysfunction for patients with these common sleep disorders. Additional research is needed to further understand how thyroid dysfunction affects sleep physiology.

Hypothyroidism in restless legs syndrome

The diurnal nature of restless legs syndrome (RLS) and its response to dopamine hint that hormones are central in RLS pathophysiology. Hypothyroidism has been linked to RLS, but studies are limited. This study's objective is to determine whether RLS is more prevalent in persons with hypothyroidism and whether hypothyroidism is more prevalent in RLS sufferers. Persons with hypothyroidism and controls were recruited through an on-line registry of potential research participants. RLS was assessed using the Cambridge-Hopkins questionnaire. RLS persons and controls were recruited through RLS Foundation and on-line registry advertisements and assessed for hypothyroidism by self-report. The International RLS Study Group Severity Scale assessed RLS severity; 266 hypothyroid subjects and 321 controls were comparable in age (52.3 ± 13.4 versus 53.9 ± 11.7 years; p = .14) and gender (91.7% versus 91.3% women; p = .85), as were 354 RLS and 313 controls (59.1 ± 13.2 versus 58.2 ± 13.6 years; p = .41; 80.8% versus 78.3% women; p = .42). Hypothyroid participants versus controls had a significantly higher prevalence of RLS (14.3% versus 8.1%; p = .02). RLS participants versus controls had a significantly higher prevalence of hypothyroidism (22.3% versus. 13.8%; p = .005). RLS severity was similar in persons with and without hypothyroidism. Among 73 persons with RLS and hypothyroidism, 14 previously were hyperthyroid versus 0 of 37 persons with hypothyroidism alone (p = .004). RLS prevalence is increased in individuals with hypothyroidism; hypothyroidism prevalence is increased in individuals with RLS. Persons with hypothyroidism and RLS are significantly more likely than those with hypothyroidism alone to have had hyperthyroidism prior to hypothyroidism. Associations between RLS and thyroid disease may shed light on complex biological mechanisms underlying RLS.

Restless Legs Syndrome, and symptoms of Restless Syndrome in patients with Graves' disease: a cross-sectional survey

OBJECTIVES

Restless legs syndrome (RLS) is a frequent comorbid condition associated with distinct unrelated diseases. While the incidence of RLS has not been definitively confirmed, RLS-like symptoms have been reported in a section of Asian population who also had hyperthyroidism. The prevalence of RLS is generally low in Asian populations. Under these circumstances, we hypothesized that in a population where RLS is common, such as in Brazil, RLS could manifest as a comorbid ailment alongside Graves' disease, a common hyperthyroid condition.

METHODS

In a cross-sectional survey, 108 patients who presented with Graves' disease were analyzed for restless legs or associated symptoms.

RESULTS

Twelve patients (11.1%) displayed symptoms of RLS prior to the incidence of Graves' disease. These patients experienced worsening of the symptoms during their hyperthyroid state. Six patients (5.6%) developed RLS, consequent upon the incidence of Graves' disease as per the consensus of the panel of the experts. Fifteen patients (13.9%) also presented with RLS-like symptoms without any discernible circadian feature of the syndrome.

CONCLUSION

Our findings confirm that Graves' disease might trigger restless legs-like symptoms, while the condition of hyperthyroidism could also be complicated by definite RLS.

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.

Restless Legs Syndrome in NKX2-1-related chorea: An expansion of the disease spectrum

BACKGROUND

Molecular technologies are expanding our knowledge about genetic variability underlying early-onset non-progressive choreic syndromes. Focusing on NKX2-1-related chorea, the clinical phenotype and sleep related disorders have been only partially characterized.

METHODS

We propose a retrospective and longitudinal observational study in 7 patients with non-progressive chorea due to NKX2-1 mutations. In all subjects sleep and awake EEG, brain MRI with study of pituitary gland, chest X-rays, endocrinological investigations were performed. Movement disorders, pattern of sleep and related disorders were investigated using structured clinical evaluation and several validated questionnaires.

RESULTS

In patients carrying NKX2-1 mutations, chorea was mainly distributed in the upper limbs and tended to improve with age. All patients presented clinical or subclinical hypothyroidism and delayed motor milestones. Three subjects had symptoms consistent with Restless Legs Syndrome (RLS) that improved with Levodopa.

CONCLUSIONS

Patients with NKX2-1 gene mutations should be investigated for RLS, which, similarly to chorea, can sometimes be ameliorated by Levodopa.

Restless legs syndrome and its variants in acute ischemic stroke

BACKGROUND

The clinical-radiological correlation between restless legs syndrome (RLS) or its variants and acute ischemic stroke remains unclear.

METHODS

This study prospectively included 104 consecutive patients with acute ischemic stroke, confirmed by diffusion-weighted imaging. The frequency and clinical characteristics of RLS or RLS variants were evaluated according to the International RLS Study Group criteria, as was the topography of the associated lesions.

RESULTS

Among 104 patients with acute ischemic stroke, 6 (5.8%) and 2 patients (1.9%) had RLS and RLS variants, respectively, for a total of 8 patients (7.7%). Three (3.3%) had poststroke RLS/RLS variants: 2 (66.7%) had bilateral symptoms and 1 (33.3%) had unilateral symptoms contralateral to the lesion. RLS symptoms developed within 2 days after the onset of stroke. Forty percent of prestroke RLS/RLS variant patients experienced exacerbation of their symptoms after stroke onset, and two-thirds of poststroke RLS/RLS variant patients required treatment for their RLS/RLS variants. Patients positive for RLS/RLS variants tended to have difficulty falling asleep, but there was no difference in daytime sleepiness, sleep quality, depressive symptoms, stroke subtypes, comorbid diseases, laboratory data, or modified Rankin Scale scores at admission or discharge between patients with and without RLS/RLS variants. RLS/RLS variants were most frequently observed to accompany lesions in the medulla (25%), followed by the pons (15.4%), the corona radiata (14.8%), the basal ganglia (3.8%), and the cortex (3.8%).

CONCLUSION

RLS/RLS variants were found in 8% of acute ischemic stroke patients. Adequate screening and management are needed to improve patients' quality of life.

Risk factors of primary and secondary restless legs syndrome among a middle-aged population in Saudi Arabia: A community-based study

INTRODUCTION:

Restless legs syndrome (RLS) is etiologically divided into primary and secondary syndromes. However, a comparative description of both types is lacking in the literature. We compared primary and secondary RLS with respect to demographic determinants, associated risk factors, and comorbidities.

METHODS:

Following a cross-sectional survey on the prevalence of RLS in a Saudi population, RLS cases were identified using the International RLS Study Group (IRLSSG) criteria. Cases were assessed with an interview-based questionnaire regarding baseline characteristics, risk factors, and comorbidities and with lower limb examinations and laboratory measurements. RLS severity was assessed using the IRLSSG Severity Rating Scale.

RESULTS:

In total, 78 patients with RLS, including 50 (64.1%) primary and 28 (35.9%) secondary cases, were examined. Of the primary cases, 35 (70%) were male; of the secondary cases, 25 (89.3%) were female (P < 0.001). Multivariate regression confirmed the association of male gender with primary RLS (odds ratio = 14.53, 95% confidence interval [2.9–75], P = 0.001). There were more dark- and black-skinned participants in the primary RLS group (38, 72%) than in the secondary group (15, 28%) (P = 0.042). Iron deficiency was observed in most (26, 92%) of the secondary cases. More severe symptoms were reported in secondary than in primary RLS cases (P < 0.05).

CONCLUSIONS:

Primary RLS is more common but less severe than secondary RLS. Male gender and ethnicity play significant roles in primary RLS, whereas female gender and iron deficiency may be the main risk factors associated with secondary RLS.

Prevalence, severity, and impact on quality of life of restless leg syndrome in patients with liver cirrhosis in India

BACKGROUND AND AIM

Restless leg syndrome (RLS) has recently been shown to be increased in patients with liver cirrhosis (LC). We prospectively studied the prevalence and severity of RLS, and the effect of its presence on the quality of life (QoL) in Indian patients with LC.

METHODS

Adult patients with stable LC (n = 121; 98 male; median age 47 [range 18-68] years; Child-Pugh class A/B/C 59/39/23), were prospectively enrolled along with a group of healthy, adult controls (n = 121; 84 male; median age 42 [19-70] years). Patients with recent (<4 weeks) worsening were excluded. The subjects underwent an initial screening for RLS, followed by a re-evaluation to confirm the diagnosis, using the International RLS Diagnostic Criteria, and assessment of its severity. All participants underwent QoL assessment.

RESULTS

RLS was commoner in LC patients (8/121; 6.6 %) than in controls (1/121; p < 0.05; odds ratio = 8.5 [1.1-69.0]). Presence of RLS showed no association with specific gender (male 7/98, female 1/23), Child-Pugh class (A 5/59, B 1/39 and C 2/23) or cause of liver disease (alcohol 3/32, hepatitis B 1/18, hepatitis C 3/28, and cryptogenic 1/25). RLS severity was moderate (5), severe (2), or very severe (1). Though QoL scores were lower in patients with LC than in controls, those in patients with and without RLS were similar.

CONCLUSION

RLS was commoner in patients with LC than in controls, but did not correlate with liver disease severity and did not adversely influence QoL in LC.

Prevalence and sleep related disorders of restless leg syndrome in hemodialysis patients

Background:

Despite being frequently described, Restless Leg Syndrome (RLS) in patients, who are on hemodialysis, is a common disease which, has not been well documented in Iran.

Objectives:

The current study aimed to investigate the prevalence of RLS and its sleep disorders in Iranian patients on hemodialysis.

Patients and Methods:

In this multicenter cross sectional study, 397 consecutive patients on hemodialysis were evaluated by face-to-face interviews. RLS was diagnosed using the International RLS Study Group (IRLSS) criteria. In addition, three validated sleep disorder questionnaires (Insomnia Severity Index, Epworth sleepiness scale and Pittsburgh sleep quality index) were completed by the patients.

Results:

One hundred-twenty-six patients with RLS (31.7%; mean age 57.6 ± 15.4 years) participated in the current study. RLS mostly occurs in females (P < 0.001). RLS cases showed poorer quality of sleep (Pittsburgh Sleep Quality Index > 5, P = 0.001), higher scores of Epworth Sleepiness Scale (P < 0.001) and insomnia severity index (P = 0.001). Except thyroid gland dysfunction (P < 0.03, OR ≈ 2.50) and anti-hypertensive medications (P < 0.01, OR ≈ 1.7), there were no significant differences between age, duration of dialysis, etiology of renal insufficiency, intake of nicotine, alcohol or caffeine, and other associated comorbidities between the patients with and without RLS.

Conclusions:

In the current study, prevalence of RLS was near the weighted-mean prevalence of other studies (mean 30%, range 8%t-52%). This is not just racial variability and may attribute to narrow or wide definition of the disease, plus variations of the prevalence recording time, and sometimes not using the standard criteria or standard interview.

Impact of experimental hypothyroidism on monoamines level in discrete brain regions and other peripheral tissues of young and adult male rats

The levels of dopamine (DA), norepinephrine (NE) and serotonin (5-HT) in different brain regions as well as in blood plasma, cardiac muscle and adrenal gland of young and adult male albino rats were measured following experimentally induced hypothyroidism. Hypothyroidism induced by daily oral administration of propylthiouracil (PTU, 5mg/kg body wt) caused a significant reduction in DA levels in most of the tissues examined of both young and adult rats after 21 and 28 days, in NE levels after all the time intervals studied in young rats, and after 21 and 28 days in adult rats. 5-HT exhibited a significant reduction in the selected brain regions and blood plasma after 21 and 28 days and in cardiac muscle after all the time intervals in the two age groups of animals. It may be suggested that the changes in monoamine levels induced by hypothyroidism may be due to disturbance in the synthesis and release of these amines through the neurons impairment or may be due to an alteration pattern of their synthesizing and/or degradative enzymes.

Transient Willis-Ekbom's disease (restless legs syndrome) during pregnancy may be caused by estradiol-mediated dopamine overmodulation

Willis-Ekbom's disease (WED), formerly called restless legs syndrome, is more common in pregnant than in non-pregnant women, implying that the physiological and biochemical changes during pregnancy influence its development. During pregnancy, many hormone levels undergo significant changes, and some hormones significantly increase in activity and can interfere with other hormones. For example, the steroid hormone estradiol interferes with the neuroendocrine hormone dopamine. During pregnancy, the activity of the thyroid axis is enhanced to meet the increased demand for thyroid hormones during this state. Dopamine is a neuroendocrine hormone that diminishes the levels of thyrotropin and consequently of thyroxine, and one of the roles of the dopaminergic system is to counteract the activity of thyroid hormones. When the activity of dopamine is not sufficient to modulate thyroid hormones, WED may occur. Robust evidence in the medical literature suggests that an imbalance between thyroid hormones and the dopaminergic system underpins WED pathophysiology. In this article, we present evidence that this imbalance may also mediate transient WED during pregnancy. It is possible that the main hormonal alteration responsible for transient WED of pregnancy is the excessive modulation of dopamine release in the pituitary stalk by estradiol. The reduced quantities of dopamine then cause decreased modulation of thyrotropin, leading to enhanced thyroid axis activity and subsequent WED symptoms. Iron deficiency may also be a predisposing factor for WED during pregnancy, as it can both diminish dopamine and increase thyroid hormone.

Are we aware of restless legs syndrome in COPD patients who are in an exacerbation period? Frequency and probable factors related to underlying mechanism

A few previous studies have reported that the patients with chronic obstructive pulmonary disease (COPD) have a 29.1% to 36.8% frequency of restless legs syndrome (RLS). In this study, we observed RLS symptoms in patients experiencing COPD exacerbation to better understand the relationship between the many clinical parameters of COPD and the presence of RLS and to attract the attention of specialists on the association between the two conditions. Twenty-two male patients in COPD exacerbation; 17 healthy individuals were evaluated in this study. The patients were evaluated using the 2003 RLS symptom criteria outlined by the International Restless Legs Syndrome Study Groups (IRLSSG). The Pittsburgh Sleep Quality Index and Epworth daytime sleepiness scale were used to assess the sleep quality of patients. The RLS symptoms were correlated with blood levels of laboratory and clinical parameters. Statistical analyses were performed using SPSS 17.0 statistical software packet. The Pittsburgh Sleep Quality Index and Epworth daytime sleepiness scale scores were increased in COPD patients and correlated significantly with RLS symptoms. It was found that 54.5% of COPD patients with acute exacerbations were observed to have RLS symptoms. The Pittsburgh Sleep Quality Index was significantly higher in COPD patients with RLS symptoms compared to COPD patients without RLS symptoms (p < 0.05). We did not observe any significant difference in the previously reported metabolic and clinical parameters associated with RLS in COPD patients with and without RLS. RLS symptoms increase during COPD exacerbation and lead to decreased sleep quality.

Linking restless legs syndrome with Parkinson's disease: clinical, imaging and genetic evidence

Restless legs syndrome (RLS) and Parkinson's disease (PD) are both common neurological disorders. There has been much debate over whether an etiological link between these two diseases exists and whether they share a common pathophysiology. Evidence pointing towards a link includes response to dopaminergic agents in PD and RLS, suggestive of underlying dopamine dysfunction in both conditions. The extrastriatal dopaminergic system, in particular altered spinal dopaminergic modulation, may be variably involved in PD patients with RLS symptoms. In addition, there is now evidence that the nigrostriatal system, primarily involved in PD, is also affected in RLS. Furthermore, an association of RLS with the parkin mutation has been suggested. The prevalence of RLS has also been reported to be increased in other disorders of dopamine regulation. However, clinical association studies and functional imaging have produced mixed findings. Conflicting accounts of emergence of RLS and improvement in RLS symptoms after deep brain stimulation (DBS) also contribute to the uncertainty surrounding the issue. Among the strongest arguments against a common pathophysiology is the role of iron in RLS and PD. While elevated iron levels in the substantia nigra contribute to oxidative stress in PD, RLS is a disorder of relative iron deficiency, with symptoms responding to replacement therapy. Recent ultrasonography studies have suggested that, despite overlapping clinical features, the mechanisms underlying idiopathic RLS and RLS associated with PD may differ. In this review, we provide a concise summary of the clinical, imaging and genetic evidence exploring the link between RLS and PD.

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

Theories for restless legs syndrome (RLS) pathogenesis include iron deficiency, dopamine dysregulation and peripheral neuropathy. Increased prevalence of small intestinal bacterial overgrowth (SIBO) in controlled studies in RLS and case reports of post-infectious RLS suggest potential roles for inflammation and immunological alterations. A literature search for all conditions associated with RLS was performed. These included secondary RLS disorders and factors that may exacerbate RLS. All of these conditions were reviewed with respect to potential pathogenesis including reports of iron deficiency, neuropathy, SIBO, inflammation and immune changes. A condition was defined as highly-associated if there was a prevalence study that utilized an appropriate control group. Small case reports were recorded but not included as definite RLS-associated conditions. Fifty four diseases, syndromes and conditions have been reported to cause and/or exacerbate RLS. Of these, 38 have been reported to have a higher prevalence than age-matched controls, 9 have adequate sized reports and have general acceptance as RLS-associated conditions and 7 have been reported in case report form. Overall, 42 of the 47 RLS-associated conditions (89%) have also been associated with inflammatory and/or immune changes. In addition, 43% have been associated with peripheral iron deficiency, 40% with peripheral neuropathy and 32% with SIBO. Most of the remaining conditions have yet to be studied for these factors. The fact that 95% of the 38 highly-associated RLS conditions are also associated with inflammatory/immune changes suggests the possibility that RLS may be mediated or affected through these mechanisms. Inflammation can be responsible for iron deficiency and hypothetically could cause central nervous system iron deficiency-induced RLS. Alternatively, an immune reaction to gastrointestinal bacteria or other antigens may hypothetically cause RLS by a direct immunological attack on the central or peripheral nervous system.

Imbalance between thyroid hormones and the dopaminergic system might be central to the pathophysiology of restless legs syndrome: a hypothesis

Data collected from medical literature indicate that dopaminergic agonists alleviate Restless Legs Syndrome symptoms while dopaminergic agonists antagonists aggravate them. Dopaminergic agonists is a physiological regulator of thyroid-stimulating hormone. Dopaminergic agonists infusion diminishes the levels of thyroid hormones, which have the ability to provoke restlessness, hyperkinetic states, tremors, and insomnia. Conditions associated with higher levels of thyroid hormones, such as pregnancy or hyperthyroidism, have a higher prevalence of Restless Legs Syndrome symptoms. Low iron levels can cause secondary Restless Legs Syndrome or aggravate symptoms of primary disease as well as diminish enzymatic activities that are involved in dopaminergic agonists production and the degradation of thyroid hormones. Moreover, as a result of low iron levels, dopaminergic agonists diminishes and thyroid hormones increase. Iron therapy improves Restless Legs Syndrome symptoms in iron deprived patients. Medical hypothesis. To discuss the theory that thyroid hormones, when not counterbalanced by dopaminergic agonists, may precipitate the signs and symptoms underpinning Restless Legs Syndrome. The main cause of Restless Legs Syndrome might be an imbalance between the dopaminergic agonists system and thyroid hormones.

Prevalence of idiopathic and secondary restless legs syndrome in Korean Women

OBJECTIVE

The aim of this study was to identify the prevalence of idiopathic and secondary restless legs syndrome (RLS) and to compare them among Korean women.

METHODS

A total of 1000 women aged 40-69 years from the general population were included in the study. The questionnaire used to gather data included modified International Restless Legs Syndrome Study Group (IRLSSG) criteria, and questions related to RLS.

RESULTS

Of the entire cohort, 65 subjects were diagnosed as having RLS according to IRLSSG criteria. The overall prevalence of RLS was thus 6.5%. Of those subjects with symptoms of RLS, 81.5% complained of insomnia. The age at the onset of RLS was 38.9 +/- 8.6 years. RLS symptoms were experienced every day by 18.5% of affected subjects. None of the RLS subjects revealed in this study had previously been diagnosed or treated for their RLS problems.

CONCLUSION

The prevalence of RLS reported herein is low compared with that reported for Western countries. Our study provides further evidence for low prevalence of RLS in Asian populations and supports the view that RLS is poorly recognized by both physicians and the general population, resulting in suboptimal management of the disorder.

Restless legs syndrome and Parkinson's disease: is there an etiologic link?

The etiologic link between restless legs syndrome (RLS) and Parkinson's disease (PD) has been debated. Since dopaminergic dysfunction and response to dopaminergic agents are consistent features in RLS and PD, some authors have suggested that these two diseases may share common pathophysiology. However, presently there is not enough evidence to suggest that the actual pathophysiologic mechanism in both diseases is identical. The nigrostriatal dopaminergic system is primarily involved in PD and it is possible that the extrastriatal dopaminergic system may be variably involved in those PD patients with RLS symptoms. Further clinical, imaging, pharmacologic, and genetic studies will be needed to address the many unanswered questions related to the link between RLS and PD.

Restless legs syndrome in lung transplant recipients

BACKGROUND

Given the increased incidence of steroid-induced diabetes and drug-induced anemia, renal dysfunction and neuropathy, we believed that lung transplant recipients would be at an increased risk of developing restless legs syndrome (RLS). We performed a cross-sectional, observational study to determine the prevalence and characteristics of RLS in this population.

METHODS

Patients filled out two questionnaires during a routine visit: (1) a diagnostic tool for RLS, based on the core clinical features; and (2) a 10-question rating scale used to assess severity. Data were obtained by medical record review with regard to demographics, lung transplant characteristics and known risk factors for RLS.

RESULTS

Forty-two lung transplant recipients (age 46.6 +/- 15.4 years [mean +/- SD]; 24 women, 18 men) without a family history of RLS were recruited. RLS was found in 47.6% (20 of 42) of the patients and 80% had moderate or severe RLS. Seventy-five percent of those with RLS were women (p = 0.03). RLS patients had a serum calcium level that was higher than those without RLS (p = 0.05) and were more likely to be recipient (p = 0.02) or donor positive (p = 0.07) for cytomegalovirus (CMV). All 4 hypothyroid patients on replacement therapy were in the RLS group. The prevalence of diabetes mellitus and chronic renal failure were not significantly different between the RLS and non-RLS groups.

CONCLUSIONS

There was a very high prevalence of RLS in our lung transplant population and most patients had moderate or severe symptoms. RLS patients were more likely to be women, donor or recipient positive for CMV, hypothyroid, and to have an elevated serum calcium level.

Predisposing factors of restless legs syndrome in pregnancy

The occurrence of restless legs syndrome in pregnancy is well known. However, the mechanism of this association is unclear. In this study, we aimed to identify the factors that predispose women to have restless legs syndrome during pregnancy. A total of 146 pregnant women were included in the study. Patients were asked questions regarding demographic characteristics, complications of pregnancy, medical therapy (vitamin and iron intake), sleep disorders, muscle cramps, and excessive daytime sleepiness. Electroneurography, routine blood biochemistry tests, complete blood count, and thyroid function tests were performed and vitamin B12, folic acid, serum iron, iron-binding capacity, ferritin, iron saturation, prolactin, estradiol, and progesterone were measured. Of the participants, 38 were diagnosed as having restless legs syndrome. In women with restless legs syndrome, additional medical problems, night cramps, and excessive daytime sleepiness were more frequent. In women without restless legs syndrome, serum hemoglobin levels were significantly higher and the use of supplemental iron or vitamins was greater. Among the women with restless legs syndrome, progesterone levels were slightly higher but this difference was not statistically significant. In summary, in this study, lower hemoglobin levels and supplementation deficits of iron and vitamins were found be the risk factors for restless legs syndrome in pregnancy.

Restless legs syndrome: a review

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

An urge to move with L-thyroxine: clinical, biochemical, and polysomnographic correlation

We report on the cause and effect relationship of restless legs syndrome (RLS) with L-thyroxine treatment in a hypothyroid patient with low serum ferritin. Upon challenge and withdrawal of L-thyroxine, there was a significant change in the International Restless Legs Syndrome Study Group severity score (26/40 to 6/40), the periodic limb movements (PMLS) index (20/hour to 10/hour), the number of arousals due to PLMS (59 to 22), sleep efficiency (74 to 85%), and biochemical parameters. RLS symptoms can complicate thyroxine replacement in at-risk hypothyroid patients with low serum ferritin. Early diagnosis and iron replacement could significantly reduce patient morbidity.