Search

Background: Severe pretibial myxedema (PTM) can be difficult to manage, highlighting the need to investigate newer therapies. Rituximab (RTX) and intravenous immunoglobulin (IVIg) have been tried in Graves' orbitopathy. Since PTM and orbitopathy share a similar underlying pathophysiology, this study aimed to explore these therapies for progressive PTM. Methods: The electronic database was screened for PTM patients evaluated at the Mayo Clinic, Rochester, from 2002 to 2016, and three patients who received IVIg and five who received RTX are reported. PTM pattern was classified as non-pitting edema, plaque and induration, nodular/nummular, and elephantiasis. PTM was confirmed by biopsy in six patients. Results: The patients' median age was 53.8 years, 75% were female, and all but one patient were either active or former smokers. All patients were euthyroid and had progressed despite various therapies prior to starting these agents. Six patients had a plaque and induration pattern, and two had a nodular pattern with elephantiasis. After therapy, six (75%) patients had PTM stability or improvement both subjectively and objectively (80% with RTX and 66% with IVIg). The three patients (one in the IVIg group and two in the RTX group) who had subjective improvement had a plaque pattern. One patient with elephantiasis had a transient response to IVIg and another had stability after RTX. Thyrotropin receptor antibody values and orbitopathy also improved in patients who demonstrated PTM improvement. No serious adverse events were reported, but one patient each had transient hypertension and injection-site thrombophlebitis after IVIg. Conclusions: Immunomodulation therapy was followed by PTM improvement or stability in most patients, with a slightly better response after RTX compared to IVIg. A validated response assessment instrument and larger series of patients are required to determine if the underlying disease process could be curtailed with these agents. [ABSTRACT FROM AUTHOR]

Background: Thyrotoxicosis has multiple etiologies, manifestations, and potential therapies. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions and patient preference. This document describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspecialty physicians and others providing care for patients with this condition. Methods: The American Thyroid Association (ATA) previously cosponsored guidelines for the management of thyrotoxicosis that were published in 2011. Considerable new literature has been published since then, and the ATA felt updated evidence-based guidelines were needed. The association assembled a task force of expert clinicians who authored this report. They examined relevant literature using a systematic PubMed search supplemented with additional published materials. An evidence-based medicine approach that incorporated the knowledge and experience of the panel was used to update the 2011 text and recommendations. The strength of the recommendations and the quality of evidence supporting them were rated according to the approach recommended by the Grading of Recommendations, Assessment, Development, and Evaluation Group. Results: Clinical topics addressed include the initial evaluation and management of thyrotoxicosis; management of Graves' hyperthyroidism using radioactive iodine, antithyroid drugs, or surgery; management of toxic multinodular goiter or toxic adenoma using radioactive iodine or surgery; Graves' disease in children, adolescents, or pregnant patients; subclinical hyperthyroidism; hyperthyroidism in patients with Graves' orbitopathy; and management of other miscellaneous causes of thyrotoxicosis. New paradigms since publication of the 2011 guidelines are presented for the evaluation of the etiology of thyrotoxicosis, the management of Graves' hyperthyroidism with antithyroid drugs, the management of pregnant hyperthyroid patients, and the preparation of patients for thyroid surgery. The sections on less common causes of thyrotoxicosis have been expanded. Conclusions: One hundred twenty-four evidence-based recommendations were developed to aid in the care of patients with thyrotoxicosis and to share what the task force believes is current, rational, and optimal medical practice. [ABSTRACT FROM AUTHOR]

Background: Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer. Methods: The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members. Results: The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research. Conclusions: We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders. [ABSTRACT FROM AUTHOR]

Background: Acute iodine excess in newborns can cause hypothyroidism, but there are limited data on the effects of iodine excess on thyroid function in older infants. The aim of this study was to measure the effects of chronic excess iodine intake on thyroid function in 6-24-month-old infants. Methods: In this cross-sectional study, infants ( n=696) in eastern Nepal were studied. Spot urine samples, venous blood samples, and household salt samples were collected, and urinary iodine concentration (UIC), serum free thyroxine (fT4), thyrotropin (TSH), thyroglobulin (Tg), and titrated household salt iodine concentration (SIC) were measured. Daily iodine intake was calculated from UIC based on estimates of urine volume at this age. Results: Median (25th-75th percentile) household SIC was 89 (70-149) ppm, while national legislation stipulates a fortification level of 50 ppm. Median UIC was 407 (312-491) μg/L; 76% of infants had a UIC >300 μg/L, suggesting iodine excess. Calculated mean iodine intake in 12-24-month-old infants was 220 μg/day, exceeding the recommended safe upper limit for iodine at this age (200 μg/day). Among the infants, 15.8% had an elevated Tg, 7.4% had subclinical hypothyroidism, but <1% had overt hypothyroidism. UIC was not a significant predictor of thyroid function, thyroid hormones, or Tg. Conclusion: In 6-24-month-old infants exposed to excessive iodine intake, ∼7% have subclinical hypothyroidism but <1% have overt hypothyroidism. These findings suggest the thyroid in late infancy is already able to adapt to high iodine intakes and, in most cases, maintain euthyroidism. [ABSTRACT FROM AUTHOR]

Background: The use of high-resolution ultrasound (US) imaging is a mainstay of the initial evaluation and long-term management of thyroid nodules and thyroid cancer. To fully capitalize on the diagnostic capabilities of a US examination in the context of thyroid disease, many clinicians consider it desirable to establish a universal format and standard of US reporting. The goals of this interdisciplinary consensus statement are twofold. First, to create a standardized set of US features to characterize thyroid nodules and cervical lymph nodes accurately, and second, to create a standardized system for tracking sequential changes in the US examination of thyroid nodules and cervical lymph nodes for the purpose of determining risk of malignancy. Summary: The Thyroid, Head and Neck Cancer (THANC) Foundation convened a panel of nine specialists from a variety of medical disciplines that are actively involved in the diagnosis and treatment of thyroid nodules and thyroid cancer. Consensus was achieved on the following topics: US evaluation of the thyroid gland, US evaluation of thyroid nodules, US evaluation of cervical lymph nodes, US-guided fine needle aspiration (FNA) of thyroid nodules, and US-guided FNA of cervical lymph nodes. Conclusion: We propose that this statement represents a consensus within a multidisciplinary team on the salient and essential elements of a comprehensive and clinically significant thyroid and neck US report with regards to content, terminology, and organization. This reporting protocol supplements previous US performance guidelines by not only capturing categories of findings that may have important clinical implications, but also delineating findings that are clinically relevant within those categories as specifically as possible. Additionally, we have included the specific features of diagnostic and therapeutic interventions that have not been previously addressed. [ABSTRACT FROM AUTHOR]

Background: Thyroglobulin, produced exclusively by the thyroid gland, has been proposed to be a more sensitive biomarker of iodine status than thyrotropin or the thyroid hormones triiodothyronine and thyroxine. However, evidence on the usefulness of thyroglobulin (Tg) to assess iodine status has not been extensively reviewed, particularly in pregnant women and adults. Summary: An electronic literature search was conducted using the Cochrane CENTRAL, Web of Science, PubMed, and Medline to locate relevant studies on Tg as a biomarker of iodine status. Since urinary iodine concentration (UIC) is the recommended method to assess iodine status in populations, only studies that clearly reported both Tg and UIC were included. For the purpose of this review, a median Tg <13 μg/L and a median UIC ≥100 μg/L (UIC ≥150 μg/L for pregnant women) were used to indicate adequate iodine status. We excluded studies conducted in subjects with either known thyroid disease or those with thyroglobulin antibodies. The search strategy and selection criteria yielded 34 articles of which nine were intervention studies. The majority of studies (six of eight) reported that iodine-deficient pregnant women had a median Tg ≥13 μg/L. However, large observational studies of pregnant women, including women with adequate and inadequate iodine status, as well as well-designed intervention trials that include both Tg and UIC, are needed. In adults, the results were equivocal because iodine-deficient adults were reported to have median Tg values of either <13 or ≥13 μg/L. Only studies in school-aged children showed that iodine-sufficient children typically had a median Tg <13 μg/L. Some of the inconsistent results may be partially explained by the use of different methodological assays and failure to assess assay accuracy using a certified reference material. Conclusions: These data suggest that Tg does hold promise as a biomarker of iodine deficiency. However, it is associated with limitations. A median Tg cutoff of 13 μg/L warrants further investigation, particularly in adults or pregnant women, as there is a lack of both observational and intervention studies in these groups. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to develop a novel open-window needle aspiration method and evaluate its efficacy in drainage and sclerotherapy of cystic thyroid nodules that cannot be aspirated with an 18-gauge needle. Methods: Two rectangular windows 5.0 mm in length and 1.0 mm wide were placed at the end of the percutaneous transhepatic cholangiography (PTCA) needle trocar to develop a new open-window intervention needle. The efficiency of the open-window intervention needle was compared either to a porous interventional needle or to an ordinary PTCA needle by assessing the aspiration efficiency. The efficacy of the modified open-window approach was tested by carrying out sclerotherapy and drainage on 21 thyroid cystic nodules that could not be aspirated with an 18-gauge needle and comparing it to aspiration with an 18-gauge PTCA needle of 50 cystic thyroid nodules. Results: The efficacy of aspirating coupling agents of various specifications using the new open-window intervention was superior to aspiration using the PTCA trocar needle or a porous needle ( p<0.05). Ethanol ablation efficacy in the treatment of 21 cystic thyroid nodules that could not be aspirated with an 18-gauge needle and the aspiration efficacy of 50 cystic thyroid nodules with an 18-gauge PTCA needle were not significantly different ( p>0.05). Conclusion: The new open-window intervention needle approach was highly effective in conducting ethanol ablation of cystic thyroid nodules that could not be aspirated using conventional methodologies. [ABSTRACT FROM AUTHOR]

Background: Pituitary and thyroid autoimmunity can be triggered by pregnancy. We report the first association of combined growth hormone (GH) and prolactin secretion deficiency due to autoimmune damage to GH- and prolactin-secreting cells in a patient with postdelivery lactation failure, presenting subsequently with primary autoimmune hypothyroidism. Patient Findings: A 34-year-old woman presented with lactation failure following the delivery of her first child. She had a family history of hypothyroidism without a history of pituitary dysfunction. Physical examination did not show any abnormal findings. Laboratory investigations showed normal gonadotropin levels after the restoration of normal menstrual cycles following pregnancy, normal basal and stimulated cortisol levels, but an impaired GH response to insulin-induced hypoglycemia, and low basal prolactin and insulin-like growth factor-1 concentrations. Thyroid function was normal when initially investigated three months after delivery, but five months later, marked primary hypothyroidism (thyrotropin levels >100 mIU/L) occurred. Immunological investigation revealed the presence of antipituitary antibodies, identified by double immunofluorescence and targeting GH- and prolactin-secreting cells. Antithyroid antibodies, in the normal range three months postpartum, became significantly elevated when the hypothyroidism appeared. Autoimmune hypophysitis is responsible for selective or multiple pituitary-hormone deficiencies, sometimes involving thyrotropin secretion and causing secondary hypothyroidism, but usually associated with hyperprolactinemia. To our knowledge, this is the first observation of autoimmune hypopituitarism involving deficient growth hormone and prolactin secretion in a patient with lactation failure after delivery, subsequently followed by severe primary autoimmune hypothyroidism, thus falling into an unusual constellation of autoimmune polyendocrine syndrome type 3. Conclusions: Considering the well-known relationship between pregnancy and autoimmunity, an early postdelivery immunological and functional investigation in women presenting with disorders of lactation may be useful to detect potential pituitary and thyroid dysfunction even at a subclinical stage. [ABSTRACT FROM AUTHOR]

Background: Surgical management of symptomatic benign thyroid nodules in patients with previous lobectomy poses a dilemma for physicians. Radiofrequency (RF) ablation may provide a treatment option that avoids surgery and preserves thyroid function. We evaluated whether RF ablation of benign thyroid nodules affects thyroid function in patients with previous lobectomy. Methods: A total of 11 patients with 14 thyroid nodules were enrolled using the following criteria: (i) having a predominantly solid nodule; (ii) reporting pressure symptoms or cosmetic problems; (iii) cytological confirmation of benignancy; (iv) no malignant features detected using ultrasound; (v) serum thyroid hormone and thyrotropin (TSH) levels within normal limits; and (vi) refusal of or ineligibility for surgery. Thyroid function, nodule volumes, and clinical concerns were evaluated before RF ablation and during follow-up after RF ablation. Results: The mean follow-up duration after RF ablation was 43.7±30.7 months (range=7-92 months). The mean nodule volume was 9.7 mL (0.9-57.6 mL) before the procedure, and was significantly decreased at the last follow-up ( p<0.001) with a mean volume reduction rate of 87.2%. The mean symptom score ( p=0.003) and cosmetic score ( p=0.003) were both significantly decreased at the last follow-up. Levels of TSH, free thyroxine, and triiodothyronine were not significantly different prior to treatment and at the last follow-up ( p>0.05), and remained normal in all patients. Conclusions: In patients with previous lobectomy, RF ablation should be considered as a first-line treatment for symptomatic benign thyroid nodules to preserve thyroid function. [ABSTRACT FROM AUTHOR]

Background: Percutaneous ethanol injection (PEI) is used to treat cystic or mixed benign thyroid nodules. This treatment can result in rare complications, and three cases of Graves' disease (GD) without Graves' ophthalmopathy (GO) have been reported after PEI treatment of toxic thyroid adenomas. Here we present a 55-year-old male patient who developed GD and severe GO after PEI treatment of a mixed cystic-solid, nontoxic thyroid nodule. Patient Findings: Six months after PEI, the nodule volume had decreased from 8.9 to 3.0 mL, but we observed severe hyperthyroidism with elevated serum free triiodothyronine, free thyroxine, and thyrotropin receptor antibody levels. We also observed ophthalmopathy with symmetrical orbit and soft tissue involvement (grade b/c) and a clinical activity score of 4/7. The diagnosis of GO was confirmed by bilateral corneal damage, increased intraocular pressure on upgaze, and inconstant diplopia. A computed tomography scan showed that the inferior, medial, and superior extraocular muscles were bilaterally enlarged, the perineural space at the orbital cone was slightly reduced and the ophthalmic vein was congested. Summary: A cause-effect relationship between PEI and GD/GO was likely in this patient because of the temporal sequence. Although the mechanism was unknown, we speculated that the thyroid tissue damage caused by PEI released a large amount of antigenic materials from follicular thyroid cells, including thyrotropin receptor protein, which triggered the autoimmune inflammatory response against the thyroid itself and the orbital soft tissues. The patient did not have any risk factors for either GD or GO. Conclusions: This observation raises the concern, therefore, that unpredictable and severe complications, such as GD and GO, may occur in a few patients treated with PEI. [ABSTRACT FROM AUTHOR]

Background: Thyrotoxicosis has multiple etiologies, manifestations, and potential therapies. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions and patient preference. This article describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspeciality physicians and others providing care for patients with this condition. Methods: The development of these guidelines was commissioned by the American Thyroid Association in association with the American Association of Clinical Endocrinologists. The American Thyroid Association and American Association of Clinical Endocrinologists assembled a task force of expert clinicians who authored this report. The task force examined relevant literature using a systematic PubMed search supplemented with additional published materials. An evidence-based medicine approach that incorporated the knowledge and experience of the panel was used to develop the text and a series of specific recommendations. The strength of the recommendations and the quality of evidence supporting each was rated according to the approach recommended by the Grading of Recommendations, Assessment, Development, and Evaluation Group. Results: Clinical topics addressed include the initial evaluation and management of thyrotoxicosis; management of Graves' hyperthyroidism using radioactive iodine, antithyroid drugs, or surgery; management of toxic multinodular goiter or toxic adenoma using radioactive iodine or surgery; Graves' disease in children, adolescents, or pregnant patients; subclinical hyperthyroidism; hyperthyroidism in patients with Graves' ophthalmopathy; and management of other miscellaneous causes of thyrotoxicosis. Conclusions: One hundred evidence-based recommendations were developed to aid in the care of patients with thyrotoxicosis and to share what the task force believes is current, rational, and optimal medical practice. [ABSTRACT FROM AUTHOR]

Background:Thyroid hormone is prerequisite for proper fetal and postnatal neurodevelopment, growth, and metabolism. Although much progress has been made in the characterization of genes implicated in thyroid development and function, the majority of genes involved in this process are still unknown. We have previously applied serial analysis of gene expression (SAGE) to identify novel genes preferentially expressed in the thyroid, and this has resulted in the characterization of DUOX2and IYD(also known as DEHAL1), two genes encoding essential enzymes in the production of thyroid hormone. In the current study we characterize the gene C16orf89, which is linked to another thyroid-specific SAGE tag CCAGCTGCCT.Methods:We establish tissue-specific expression of C16orf89using novel tissue-specific SAGE libraries and quantitative polymerase chain reaction. In addition, we characterize the C16orf89gene and protein, and analyze its mRNA expression in response to thyrotropin and during mouse development.Results:C16orf89is predominantly expressed in human thyroid tissue with a specificity intermediate between thyroid transcription factors and proteins involved in thyroid hormone synthesis. C16orf89shows the same expression pattern as Nkx2-1(thyroid transcription factor 1) from embryonic day (E) 17.5 onward in the developing mouse thyroid and lung. The developmental timing of C16orf89mRNA expression is similar to that of the iodide transporter Slc5a5(also known as Nis). Both transcripts are detected from E17.5 in the developing thyroid. This is clearly later than the onset of TgmRNA expression (from E14.5), while Nkx2-1and IydmRNA can already be detected in the E12.5 thyroid. In in vitrocell culture C16orf89expression is stimulated by thyrotropin. The major splice variant encodes a 361 amino acid protein that is well conserved between mammals, contains an N-terminal signal peptide, is secreted in a glycosylated form, and does not contain any known functional domain.Conclusions:We present a novel gene highly expressed in thyroid that encodes a currently enigmatic protein. [ABSTRACT FROM AUTHOR]

Background:Generalized vitiligo is an autoimmune disease of skin pigmentation that is associated with increased prevalence of other autoimmune diseases, particularly autoimmune thyroid disease (AITD; principally Hashimoto's disease and Graves' disease), both in vitiligo patients and their close relatives, suggesting a heritable predisposition involving, in part, shared susceptibility genes.Summary:This review summarizes current knowledge of vitiligo epidemiology and genetics, highlighting recent findings from genome-wide approaches to disease gene identification, emphasizing susceptibility loci shared with other autoimmune diseases, particularly AITD, as well as some important differences.Conclusions:Inherited susceptibility to generalized vitiligo involves a number of specific genes, many of which are shared with other autoimmune diseases that are epidemiologically associated with vitiligo, including AITD, confirming a longstanding hypothesis about the genetic basis of these disorders. These genes provide potential therapeutic targets for novel approaches to treatment as well as for approaches to presymptomatic diagnosis and disease prevention in individuals with inherited susceptibility to this group of autoimmune diseases. [ABSTRACT FROM AUTHOR]

Introduction:Over the years, several drugs used in the treatment of nonthyroidal conditions have been shown to affect thyroid function. As novel drugs are introduced, novel interactions are described. The aim of this review is to summarize clinically relevant thyroidal side effects of drugs used for nonthyroidal conditions. Special focus is given to recent developments and to drugs with the largest clinical relevance.Summary:Thyrosine kinase inhibitors are novel drugs used in the treatment of several neoplasias, including thyroid cancer. Thyroidal side effects are being increasingly detected with these drugs. Some drugs in this category affect thyroid hormone metabolism and therefore only affect patients on thyroid replacement. Others affect the thyroid directly profoundly, causing primary hypothyroidism. Immune modulators used in infectious, inflammatory, and neoplastic conditions also cause hyper- and hypothyroidism, through poorly understood immune or nonimmune mechanisms. The effects of amiodarone on the thyroid have been long recognized. However, given the complexity of these effects, several areas in this field remain problematic, such as the identification of subtypes of hyperthyroidism and the best treatment strategies. Lithium also has important antithyroid effects and it is a commonly prescribed medication. Its antithyroid effects may have clinical utility in selected clinical situations. Other drugs known to affect thyroid hormone absorption, metabolism, and transport are also briefly reviewed.Conclusions:Several drugs are known to alter thyroid function as a side effect of their primary pharmacological action. Some of these effects have been recognized for decades, but novel thyroid–drug interactions are being recognized as new drugs are developed. It is important for the clinician to be familiar with thyroid–drug interactions, as enhanced surveillance may be necessary in patients undergoing therapies known to affect thyroid function. [ABSTRACT FROM AUTHOR]

Context:When the liver function tests are aggravated after starting antithyroid drugs (ATDs) in Graves'' hyperthyroidism, discontinuation of ATDs is generally considered. However, a question arises whether such aggravation constitutes an adverse effect of the drugs or not.Objective:The aim of this study was to clarify the influence of thyrotoxicosis on liver function tests, comparing the results with those in thyrotoxicosis induced by painless thyroiditis.Design:We prospectively studied liver biochemical tests in 30 patients with Graves'' disease and in 27 patients with painless thyroiditis.Main outcomes:Twenty-three (76.7) untreated Graves'' disease patients and 14 (51.9) untreated painless thyroiditis patients were found to have at least one liver function test abnormality. One month after starting ATD therapy in patients with Graves'' disease, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) elevations from initial values were observed in 16 (53.3). Similar elevations of AST and ALT from initial values at 1 month were observed in 10 (37.0) and 7 (25.9) patients with painless thyroiditis, respectively. Alkaline phosphatase (ALP) increased gradually after starting ATD therapy and maintained an elevated value for 35 months in Graves'' disease. In painless thyroiditis, ALP also increased gradually, similarly to that in Graves'' disease, but changes were mild. Elevation of ALT after 1 month of ATD therapy in Graves'' disease was significantly higher in patients whose estimated disease duration was 6 months or more compared to those with duration of less than 6 months. Elevated AST and ALT at 1 month after ATD therapy decreased to normal ranges, even though patients were receiving the same ATDs in Graves'' disease.Conclusion:Similar serial changes in liver function tests in both Graves'' disease and painless thyroiditis strongly suggest that increases of AST and ALT after starting ATD therapy may not be due to ATD side effects but may be induced by changes in thyroid function. [ABSTRACT FROM AUTHOR]

Few reports have addressed normal serum thyroglobulin (Tg) values in newborns and infants. In the present study, serum Tg was measured in 228 normal children (110 females and 118 males) aged from 3 to 180 days of life, all presenting normal age-related serum thyrotropin (thyroid-stimulating hormone TSH) values and negative anti-Tg and antithyroperoxidase antibodies. Serum Tg was measured by Radioimmunoassay (RIA) (two methods) and Immunometricassay (IMA) (three methods). Mean Tg values measured by the five methods exhibited among-method biases, although a significant positive correlation was observed. Serum Tg levels measured by the five methods showed a correlation with age, but not with TSH or gender. During the first days of life, relatively high mean Tg levels were observed, which progressively decreased until they reached a plateau. Therefore, with the aim of establishing reference values, the population was separated into two age groups: from 3 to 15 days of life (group A) and from 16 to 180 days of life (group B). Mean Tg concentration in group A was statistically higher than in group B. Tg centile distributions were calculated with the aim of establishing the normal levels of serum Tg for each method. We conclude that for a correct interpretation of serum Tg levels, the age and the methods used should be considered. [ABSTRACT FROM AUTHOR]

Perchlorate is a competitive inhibitor of the sodium/iodine symporter, decreasing the active transport of iodine into the thyroid. It was used as an antithyroid drug in the treatment of hyperthyroidism in the 1950s and 1960s but was discontinued because of the occasional occurrence of aplastic anemia. More recently, lower doses of perchlorate have been used successfully in the treatment of iodine-induced hyperthyroidism. There has been concern that naturally occurring perchlorate and industrial contamination of water supplies with perchlorate might pose a health hazard by inducing or aggravating underlying thyroid dysfunction. In a series of studies in normal volunteers, administration of perchlorate from 2 weeks to 6 months and in perchlorate production workers exposed intermittently to high levels of perchlorate for years, no abnormalities of circulating thyroid hormones, thyroid-stimulating hormone, thyroglobulin, or ultrasound evaluation of thyroid structure were observed even though the thyroid 123I uptake was decreased in some studies. Further studies of the effects of perchlorate on thyroid function in normal volunteers will now be difficult to carry out due to the adverse publicity that perchlorate and the studies on its effect have received. [ABSTRACT FROM AUTHOR]

Objective: Many hypothyroid subjects receiving L-thyroxine (L-T4) complain of psychological symptoms or cognitive dysfunction. However, there is limited validated information on these self-reports. Design: Cross-sectional comparison of 20 euthyroid and 34 treated hypothyroid subjects, aged 20–45 years, with normal thyroid-stimulating hormone (TSH) levels. Subjects underwent the following validated measures: Short Form 36 (SF-36); Symptom Checklist 90–Revised (SCL-90-R); Profile of Mood States (POMS); and tests of declarative memory (Paragraph Recall, Complex Figure), working memory (N-Back, Subject Ordered Pointing, Digit Span Backwards), and motor learning (Pursuit Rotor). Main outcomes: L-T4-treated subjects had higher mean TSH and free T4 levels, but free triiodothyronine (T3) levels were comparable to controls. L-T4-treated subjects had decrements on SF-36 and SCL-90-R summary scales and subscales. These subjects performed slightly worse on N-Back and Pursuit Rotor tests. Neither TSH nor thyroid hormone levels were associated with performance on psychological or cognitive measures. Conclusions: This group of L-T4-treated subjects had decrements in health status, psychological function, working memory, and motor learning compared to euthyroid controls. Higher mean TSH levels suggest this may be related to suboptimal treatment, although there were no correlations between TSH levels and outcomes. These findings are limited by potential selection bias, and randomized studies targeting different TSH levels and memory subdomains would clarify these issues. [ABSTRACT FROM AUTHOR]