TSH Measurements Research Articles

Central Congenital Hypothyroidism Detected by Neonatal Screening in Sapporo, Japan (2000-2004): It's Prevalence and Clinical Characteristics.

In Sapporo, Japan, a neonatal screening program for congenital hypothyroidism (CH) has employed measurement of free thyroxine (T4) and TSH in the same filter-paper blood spot. This system has enabled us to identify primary CH and central CH during the neonatal period. The aim of this study was to clarify the prevalence and clinical characteristics of central CH. For this purpose, the screening program requested serum from infants with free T4 concentrations below the cut off value regardless of the TSH levels. Between January 2000 and December 2004, 83,232 newborns were screened and six central CH patients were detected as a result of follow-up of low free T4 and non-elevated TSH screening (1:13,872). This frequency is higher than in other studies. Four patients showed multiple pituitary hormone deficiency with pituitary malformations on magnetic resonance imaging. One patient was diagnosed as having Prader-Willie syndrome. The remaining patient was considered to have isolated central CH. Our study demonstrated that the frequency of central CH is 1:13,872. Free T4 measurement would also be advantageous in early recognition of multiple pituitary hormone deficiency.

Thyroid Dysfunction in Down's Syndrome and Screening for Hypothyroidism in Children and Adolescents Using Capillary TSH Measurement

Thyroid dysfunction is more common in individuals with Down's syndrome (DS) than in the general population, whose clinical features can mask the presenting signs and symptoms of hypothyroidism. Biochemical screening is necessary; however, venepuncture may be difficult. To assess the prevalence of thyroid dysfunction in children and adolescents with DS and the feasibility of screening for hypothyroidism using capillary dried blood spot thyroid stimulating hormone (TSH) from infancy. 394 children (217 boys, 177 girls) were clinically assessed for thyroid dysfunction and 305 children (aged 4 months to 18.9 years) were screened for hypothyroidism by capillary whole blood TSH sample. Thyroid dysfunction was detected in 4.6%, with 50% unscreened since neonatal screening. Parents reported minimal distress by fingerprick screening. DS is associated with an increased prevalence of thyroid dysfunction, particularly in preschool children. Biochemical screening is essential and capillary whole blood TSH sampling for hypothyroidism is feasible, less invasive and acceptable.

Maternal and Neonatal Iodine Nutrition In Cairo

Background Aims: A neonatal screening program for hypothyroidism began in Egypt in 2000. A high percentage of transient congenital hypothyroidism was detected in some Governorates[1] in addition to a high prevalence of iodine deficiency in some rural areas[2]. This study was conducted to assess iodine nutritional status of Egyptian pregnant women and their newborns in Abbassia district. Methods: Measurement of urinary iodine, serum fT3, fT4 and TSH and thyroid ultrasound were done to 113 Egyptian healthy pregnant mothers and their newborns on the 3rd day after delivery. Results: Iodine deficiency was detected in 29.2% of mothers and 19.46% of newborns. There were positive correlations (p 5mU/L was 8.85%. Forty six % of mothers consumed iodized salt with increase in severity of iodine deficiency with lack of salt iodization (p<0.05). Conclusion: Increasing dietary iodine intake during pregnancy is mandatory. The campaign of salt iodization in Egypt must be reinforced.

Effects of ghrelin administration on endocrine and metabolic parameters in obese women with polycystic ovary syndrome

The novel peptide ghrelin displays multiple endocrine and non-endocrine actions. Its strong GH-releasing activity in humans has long been recognized. However, in obesity, ghrelin administration induces a blunted GH secretion, enhances glucose and reduces insulin levels. The effects of ghrelin administration have not been investigated in polycystic ovary syndrome (PCOS), which can be associated with obesity, hyperinsulinism, and GH hyposecretion. Leptin is a mediator for energy balance opposed to ghrelin; both of them are supposed to act as regulators of reproductive functions. Evaluate the endocrine and metabolic response to ghrelin administration in PCOS obese patients compared to body mass index (BMI)-matched and normal weight women. Nine obese PCOS patients (BMI: 35.4+/-1.2 kg/m(2)) (OB PCOS), 6 obese controls (BMI: 38.4+/-1.1 kg/m(2)) (Ob), and 6 normal-weight women (BMI: 23+/-0.6 kg/m(2)) (NW) were enrolled in the study. In all patients we performed: 1) basal hormonal evaluation including FSH, LH, estradiol, testosterone, androstenedione, DHEAS, SHBG, 17-hydroxyprogesterone (17OHP), IGF-I, free T3 (FT3), free T4 (FT4) and ghrelin levels; 2) metabolic evaluation as follows: concentration of non-esterified fatty acid (NEFA) and oral glucose tolerance test (OGTT) (75 g); homeostasis model assessment (HOMA); glucose and insulin response to ghrelin administration (1 microg/kg); 3) measurement of GH, PRL, TSH, and leptin levels after infusion of ghrelin. Administration of ghrelin increased glucose and reduced insulin levels in both Ob and OB PCOS. Moreover, ghrelin enhanced GH and PRL levels in all groups but it did not modify TSH and leptin levels. GH peak and area under the curve (AUC) in OB PCOS and Ob were lower than controls (p<0.05). Similar PRL peak and AUC values were observed in all groups. In both obese and PCOS obese patients, leptin levels are not influenced by ghrelin administration. Moreover, the GH response after ghrelin administration is blunted. However, ghrelin exerts glucose- enhancing and insulin-lowering effects, the latter absent in NW.

Hyperprolactinemia and immunohistochemical expression of intracellular prolactin and prolactin receptor in primary central nervous system tumors and their relationship with cellular replication

The role of prolactin (PRL) in the CNS remains uncertain. We evaluated the presence of hyperprolactinemia, intracellular prolactin (ICP), and prolactin receptor (PRL-R) in primary CNS tumors, and their relationship with cellular replication with a prospective cross-sectional study of 82 consecutive patients with primary CNS tumors admitted for neurosurgical resection between October 2003 and September 2005. Patients submitted to a questionnaire, and venous blood samples were obtained for measurement of serum PRL and TSH. Immunohistochemical analyses were performed to evaluate the presence of ICP, PRL-R, and Ki-67. Serum PRL levels ranged from 2 to 70 ng/ml, and hyperprolactinemia was detected in 25 cases (30.5%). ICP was detected in 18 patients (21.9%), in whom PRL ranged from 2 to 32 ng/ml. A positive correlation was found between PRL levels and the presence of ICP (Student's t test, P = 0.022). The PRL-R was observed immunohistochemically in 32 cases (39%). The frequencies of hyperprolactinemia, ICP, and PRL-R were similar across the several histological types of CNS tumors. Ki-67 index was similar in all groups. Hyperprolactinemia and intracellular presence of PRL and PRL-R were common findings in this population, suggesting a role for PRL in CNS tumor genesis.

Differential T4 Degradation Pathways in Young Patients with Preterminal and Terminal Renal Failure

The aim of this study is to analyze thyroid hormone parameters in large homogenous patient cohorts with preterminal (stage 4) and terminal (stage 5) renal failure in an area of low iodine intake. Thyroid parameters were measured in healthy controls (n=48), patients with preterminal renal failure (n=48) and patients with terminal renal failure undergoing hemodialysis (n=288). All patients were assessed by measurement of TSH, T4, T3, fT4, rT3, Tg and TPO-antibodies. There was a significant decrease of T4 and fT4 from healthy controls to patients with preterminal renal failure and to patients with terminal renal failure. T3 showed a decrease from healthy controls to patients with preterminal renal failure and to patients with terminal renal failure (1.54+/-0.06 microg/l VS. 1.05+/-0.05 microg/l VS. 1.09+/-0.23 microg/l, p<0.001 VS. controls). rT3 was significantly decreased in patients with terminal renal failure (0.24+/-0.01 microg/l VS. 0.25+/-0.02 microg/l VS. 0.16+/-0.01 microg/l, p<0.001). The rT3/T3 ratio was significantly elevated in patients with preterminal renal failure (p<0.01). TSH concentrations were in the normal range in all groups. Our data suggest different T4 degradation pathways in patients with preterminal and terminal renal failure.

Qu'est ce qu'un taux de TSH élevé ?

Measurement of TSH is the most sensitive test of thyroid function. The diagnostic of mild forms of dysthyroidism depends of the definition of the normal limits of serum TSH. The upper limit of TSH remains controversial. The conventional cut off of 4 to 4,5 mU/l is now under debate. Recent laboratories guidelines indicate that more than 95% of normal individuals have TSH levels below 2,5 mU/l. However this statistical value is not clinically receivable when summarizing the data available in several populations. The application of such an upper value of TSH would dramatically increase the diagnosis of subclinical hypothyroidism and might increase the use of thyroxin therapy in patients for whom there is no demonstrated therapeutic benefit. In conclusion, the conventional reference range of TSH from 0,4 to 4 mU/l remains applicable in a care practice setting.

Urine Iodine Measurements, Creatinine Adjustment, and Thyroid Deficiency in an Adult United States Population

The purpose of the study was to explore the relationships between urine iodine, creatinine, serum TSH, and total T(4) in a diverse population of U.S. adults with the aim of determining whether low urine iodine is associated with thyroid deficiency. Using the Health and Nutrition Surveys III data set, we examined median TSH and total T(4) values according to deciles of urine iodine (with and without creatinine correction). Stepwise regression analysis was used to further explore these relationships in the context of possible confounding variables. Exclusion criteria included age less than 21 yr, pregnancy, and the presence of thyroid antibodies. Among the 5963 men and 5722 women, median urine iodine concentrations do not vary with increasing age, whereas median creatinine levels decrease (P < 0.001). Urine iodine and creatinine concentrations are lower among women (P < 0.001). TSH increases with age (P < 0.001), whereas total T(4) decreases (P < 0.001). Neither TSH nor total T(4) median values are associated with urine iodine. If the urine iodine to creatinine ratio is used instead, an extensive redistribution of study subjects occurs that results in an apparent positive relationship between this ratio and TSH measurements. A multivariate regression analysis that accounts for age, body mass index, race, creatinine, iodine, estrogen use, smoking, and gender reveals only a weak association between levels of urine iodine and markers of thyroid function. Our analyses indicate that the U.S. nonpregnant adult population is iodine sufficient.

Thyroid Autoimmunity in Children and Adolescents with Type 1 Diabetes Mellitus: Prevalence and Risk Factors

Studies show great variation in prevalence of anti-thyroid antibodies in children with type 1 diabetes mellitus (DM1). There still is no consensus regarding screening of autoimmune thyroiditis in patients with DM1, especially in asymptomatic patients. To investigate the natural history and prevalence of autoimmune thyroiditis in pediatric patients with DM1 and relate it to potential risk factors. This study is a historical cohort, through research of the records of 474 patients with DM1 from 9 months to 25 years of age, between 1980 and 2005 - 222 boys (46.8%) and 252 girls (53.2%), with an average duration of DM1 of 9.3 +/- 5.8 years. The sample was selected by having at least one measurement of TSH and anti-thyroid autoantibodies (antithyroperoxidase or anti-microssomal and/or anti-thyroglobulin) at any time from diagnosis of DM1. A questionnaire was answered in order to study the variables of interest for the study. Thyroid function disorder was defined as altered levels of TSH, with or without altered free T4 levels. A total of 383 patients (9 months to 25 years of age) were studied, 199 girls (52%) and 184 boys (48%). Sixty-four (16.7%) had positive anti-thyroid antibodies, predominantly girls (p = 0.064). Average duration of DM1 was 9.3 +/- 5.8 years and those above this age had a higher incidence of thyroiditis (p = 0.01). The prevalence of thyroid function disorder in patients with DM1 was 7.3% (n = 28), mostly with thyroiditis (32.8% vs 2.2% with negative antibodies, p < 0.001). There was a positive association between thyroiditis, as well as thyroid function disorders, and other autoimmune disorders (p < 0.001 and p < 0.02, respectively). Prevalence of thyroiditis in the diabetic population is considerably higher than in the general population. Annual laboratory determinations of anti-TPO antibodies and dosage of TSH should be part of routine tests in the diabetic population, especially in girls, children with DM1 for > 9 years, patients above 12 years of age, and those in whom DM1 is associated with another autoimmune disease. Anti-thyroid antibody positivity may indicate the necessity for thyroid function testing at shorter intervals.

Establishment of an animal model for thyroid associated ophthalmopathy by treatment of mice with human thyrotropin receptors-activated splenocytes

To establish an animal model for thyroid-associated ophthalmopathy (TAO) by treatment of homoimmune BALB/c mice with human thyrotropin receptors ( hTSHR )-activated splenocytes. METHODS Twenty three BALB/c mice were randomly divided into group A and B, which were immune with recombinant plasmid pcDNA3. 1/hTSHR or blank plasmid pcDNA3. 1 for 3 times at 3-week intervals, respectively. Mice in these two groups were sacrificed 18 weeks after immunization and the splenocytes were isolated. Other 26 homoimmune BALB/c mice were divided randomly into group C and group D which received splenocytes from group A and group B, respectively. Four weeks later the orbital tissues were harvested for pathological examination and serum was collected for TT4, TSH and TRAb measurements. RESULTS After immunization with recombinant plasmid pcDNA3. l/hTSHR, orbital tissues displayed edema and mucinous degeneration in 25% of mice but no proliferation of adipose tissue and fibrous tissue (group A). After immunization with hTSHR-activated splenocytes, orbital tissues displayed proliferation of adipose tissues and fibrous tissues, degeneration and disruption of muscular fibers microscopically in 50% of mice (group C). Under electronic microscope, expansion of smooth endoplasmic reticulum and disorder of myofibrils were found in these mice. In all mice from group B and group D, orbital tissues were normal histologically. After immunization with splenocytes, serum total T4 levels were significantly elevated ( P = 0. 036) in group C (7. 130+/-1.017) [microg /dl when compared with group D (6. 431+/-0. 573) microg /dl. Serum TSH levels were significantly reduced (P = 0. 020) in group C (0. 070+/-0. 032) microIU/ml when compared with group D (0. 098+/-0. 020) microIU/ml. Serum TRAb levels were slightly increased in group C(0. 202 +/-0. 067) as compared to group D(0. 151+/-0. 055) , however, this difference was statistically non-significant (P = 0. 055 ). TAO animal model established by immunizing homoimmune BALB/c mice with hTSHR-activated splenocytes is similar to human TAO in histological characteristics and is a feasible and reliable experimental method. Our study also proves that the thyrotropin receptor and T cell aiming directly at this auto-antigen play important roles in the autoimmune process of TAO.

Unmasking of central hypothyroidism following growth hormone replacement in adult hypopituitary patients

The effect of GH replacement on thyroid function in hypopituitary patients has hitherto been studied in small groups of children and adults with conflicting results. We aimed to define the effect and clinical significance of adult GH replacement on thyroid status in a large cohort of GH-deficient patients. We studied 243 patients with severe GH deficiency due to various hypothalamo-pituitary disorders. Before GH treatment, 159 patients had treated central hypothyroidism (treated group) while 84 patients were considered euthyroid (untreated group). GH dose was titrated over 3 months to achieve serum IGF-1 concentration in the upper half of the age-adjusted normal range. Serial measurements of serum T4, T3, TSH and quality of life were made at baseline and at 3 and 6 months after commencing GH replacement. In the untreated group, we observed a significant reduction in serum T4 concentration without a significant increase in serum T3 or TSH concentration; 30/84 patients (36%) became hypothyroid and needed initiation of T4 therapy. Similar but lesser changes were seen in the treated group, 25 of whom (16%) required an increase in T4 dose. Patients who became hypothyroid after GH replacement had lower baseline serum T4 concentration, were more likely to have multiple pituitary hormone deficiencies and showed less improvement in quality of life compared with patients who remained euthyroid. GH deficiency masks central hypothyroidism in a significant proportion of hypopituitary patients and this is exposed after GH replacement. We recommend that hypopituitary patients with GH deficiency and low normal serum T4 concentration should be considered for T4 replacement prior to commencement of GH in order to provide a robust baseline from which to judge the clinical effects of GH replacement.

Thyroid Abnormalities Associated with Protracted Childhood Exposure to131I from Atmospheric Emissions from the Mayak Weapons Facility in Russia

Between 1948 and 1960, the Mayak nuclear weapons facility in Ozyorsk, Russia discharged relatively high levels of radionuclides, primarily (131)I, into the atmosphere, resulting in appreciable exposure to the residents of Ozyorsk. To evaluate the association between thyroid diseases and childhood exposure to radioiodines, we screened 894 Ozyorsk residents born between 1952 and 1953. The study population was comprised of 581 exposed individuals living in Ozyorsk during the years of heaviest exposure and 313 nonexposed individuals who moved to Ozyorsk when radiation exposure from Mayak largely had ended. The screening protocol included a patient interview, palpation of the thyroid, cervical lymph nodes and salivary glands, an ultrasound examination, and measurement of fT4, TSH and TPOAb. Twenty-eight percent of the study group was diagnosed with a thyroid abnormality. The prevalence of nodular disease was significantly higher in the exposed group (20.7%) compared with the nonexposed (14.4%) group (relative risk = 1.4, 95% CI = 1.1; 1.9). Risks were larger for solitary nodules and for nodules > or = 10 mm in diameter. Expansion of the study to increase the number of persons screened as well as detailed dose estimation would offer an unique opportunity to evaluate thyroid disease in relation to chronic exposure to radioiodines during childhood.

Single-Dose Rexinoid Rapidly and Specifically Suppresses Serum Thyrotropin in Normal Subjects

Retinoid X receptor agonists (rexinoids) have demonstrated benefit in patients with certain malignancies but appear to cause central hypothyroidism in some patients with advanced cancer. The influence of rexinoids on thyroid function in healthy subjects is not clear. The objective of this study was to determine the effect of a single dose of bexarotene on levels of TSH, T4, and T3 in healthy subjects. This study was a randomized, double-blind, placebo-controlled, crossover trial. This study was conducted at the General Clinical Research Center (University of Colorado Health Sciences Center, Aurora, CO). Six healthy adults (>18 yr old) were studied. Single-dose rexinoid (bexarotene, 400 mg/m2) or placebo, with TSH measurements at 0, 1, 2, 4, 8, 12, 24, and 48 h, were used. The main outcome was the serum TSH level at 24 h. Single-dose bexarotene suppressed serum TSH (P < 0.001) over time. Compared with placebo, levels of TSH were significantly lower by 12 h (P = 0.043); the nadir of 0.32 +/- 0.02 mU/liter (P < 0.001) was seen at 24 h. Free T4 index and free T3 index were also significantly lower than placebo over time (48 h) (P = 0.029; P = 0.004, respectively). Serum prolactin, cortisol, and triglycerides were not affected (P > 0.05 for all). There was no significant effect of single-dose bexarotene on rT3 or T3/rT3 ratio at 24 h. A single dose of a rexinoid can rapidly and specifically suppress serum TSH levels in healthy subjects. These data provide insight into the mechanisms by which rexinoids cause central hypothyroidism and potential ways this effect can be used for treatment of disorders such as thyroid hormone resistance and TSH-secreting pituitary tumors.

Thyroid Hormone Synthesis and Secretion in Humans after 80 Milligrams of Iodine for 15 Days and Subsequent Withdrawal

In animals, acute iodine administration results in acute intrathyroidal inhibition of iodinations followed by escape of the inhibition if the excessive iodine intake continues. In humans, the intrathyroidal nonhormonal and hormonal iodine concentration after exposure to large doses of iodine for a relatively long period of time is not known. To determine whether, in human thyroid, administration of large doses of iodine for a relatively long time results in alterations of intrathyroidal hormonal (HI) T4 and T3 and total iodine (TI) content, as well as whether changes in serum concentration of thyroid hormones and TSH would occur after iodine administration or discontinuation. In 33 euthyroid patients with single thyroid nodule or hyperparathyroidism, Lugol solution (80 mg iodine) was administered for 15 d before operation. Groups of six to eight patients underwent operation 0, 5, 10, and 15 d after iodine withdrawal. TI, HI in a sample of thyroid tissue, and serum concentration of T4, T3, and TSH were measured. In 21 normal euthyroid subjects who did not undergo operation, a similar protocol was used and serial blood measurements were taken. Intrathyroidal TI, HI, and serum thyroid hormone and TSH measurements were the main outcome measure. Intrathyroidal HI content and serum T4 and T3 were unchanged during and after iodine discontinuation. TI was increased during iodine administration and returned to control values 5 d after discontinuation of iodine. The ratio of HI/TI was decreased and returned to control values 15 d after the iodine was discontinued. Serum TSH was increased during iodine administration and returned to control values 10 d after iodine withdrawal. In humans, administration of iodine for a relatively long period of time was accompanied by increased intrathyroidal TI, but no changes in HI or demonstrable increases of serum T4 and T3 were observed. It is hypothesized that the maintenance of normal intrathyroidal HI is the result of the combined inhibitory effect of iodine on thyroid hormone synthesis and on the release of T4 and T3 from the thyroid.

Initially Elevated TSH and Congenital Central Hypothyroidism Due to a Homozygous Mutation of the TSH Beta Subunit Gene: Case Report and Review of the Literature

Congenital central hypothyroidism (CCH) is a rare disease which can be caused by mutations in the gene for the thyrotropin (TSH) beta subunit ( TSHB). The diagnosis is usually delayed because the TSH serum levels in these patients are not elevated leading to a negative result in the neonatal TSH screening. Herein, we report a 2-year-old girl with CCH due to a mutation in the TSHB gene, in whom the unusual finding of an initially elevated TSH level complicated the diagnostic workup. The proposita, who had a supposedly normal TSH screening result, is a German girl of non-consanguineous parents. At 5 weeks of age, her thyroid function tests showed peripheral hypothyroidism with a moderately increased TSH (23.8 microIU/ml) so that thyroid hormone substitution was initiated. At the age of 2 years, the administration of TRH failed to increase the TSH serum concentrations, which prompted TSH measurements with two different assay systems. Variable TSH levels ranging from not detectable low to elevated were found so that central hypothyroidism due to a mutation in the TSHB gene was suspected. This was confirmed by molecular analysis of the TSHB gene, which identified a homozygous deletion (delta 313 T) in the coding sequence. This mutation has been found in the German population before and may be a founder mutation. We conclude that depending on the assay system variable TSH serum levels in individuals with mutations in the TSHB gene may complicate the diagnostic workup.

Disfunción tiroidea en mujeres con sospecha de fibromialgia

Due to its prevalence, morbidity, and frequency rate, fibromyalgia (FM) represents a health problem and produces high healthcare resource utilization. Serum thyrotropin (TSH) measurement is recommended as a first-line laboratory test to exclude hypothyroidism as a cause of FM syndrome. The aim of this study was to analyze the prevalence of thyroid dysfunction (TD), the frequency of TSH measurement, the effect of levothyroxine treatment, and whether screening for TD is justified in women with suspected FM. A cross-sectional descriptive study was performed in 400 consecutive female outpatients with suspected FM and in 384 controls from January 2001 to October 2004. TSH measurement was used as the first line test to detect TD. The prevalence of TD in patients with suspected FM (40/400; 10%; 95% CI: 7-13%) and controls was similar (46/384; 12%; 95% CI: 9-15%). No differences were found in the types and grades of TD. The prevalence of TD was higher in patients with suspected FM and connective tissue diseases (12%) than in those without these diseases (5%). The most frequent TD was subclinical hypothyroidism (5.5% in suspected FM and 6.7% in controls), and in 93% of these cases TSH concentrations were <10 mIU/L. FM persisted in all women with hypothyroidism even after euthyroidism was achieved with levothyroxine. A total of 870 TSH determinations were performed in 360 euthyroid patients with suspected FM. The prevalence of TD in women with suspected FM does not differ from that in the general population. Screening for TD does not appear to be justified in women without diseases that increase their risk. In many cases the request for thyroid function tests is excessive. Treatment for hypothyroidism does not affect FM.

Lack of association between serum TSH or free T4 and body mass index in euthyroid subjects

There is ongoing debate regarding the influence of minor changes in thyroid status within the normal range and body mass index (BMI). Overt thyroid dysfunction is well recognized to affect weight, but the influence of minor perturbations of thyroid function remains unclear. To examine in euthyroid subjects the association of serum concentrations of TSH and free T4 within the normal range and BMI. To compare serum TSH and free T4 concentrations in nonobese and obese subjects. A cohort of 401 euthyroid subjects with normal serum TSH (361 females, 40 males, mean age 48.2 years) who had been referred to a Thyroid Clinic due to the presence of a thyroid nodule or goitre. Measurements of serum TSH and free T4 were recorded, together with BMI (calculated from weight and height). Associations between measures of TSH, free T4 and BMI were investigated. There was no association between either serum TSH or free T4 concentration when considered as a continuous variable and BMI, and no difference in BMI when subjects were categorized according to serum TSH or free T4. There was also no difference in serum TSH or free T4 between lean and obese euthyroid subjects. Evidence of thyroid autoimmunity indicated by the presence of antibodies to thyroid peroxidase was likewise not associated with a difference in BMI. This study provides no evidence for an association between thyroid status within the normal range and BMI.

American Association of Clinical Endocrinologists and Associazione Medici Endocrinologi Medical Guidelines for Clinical Practice for the Diagnosis and Management of Thyroid Nodules

Thyroid nodules are common and are frequently benign. Current data suggest that the prevalence of palpable thyroid nodules is 3% to 7% in North America; the prevalence is as high as 50% based on ultrasonography (US) or autopsy data. The introduction of sensitive thyrotropin (thyroid-stimulating hormone or TSH) assays, the widespread application of fine-needle aspiration (FNA) biopsy, and the availability of high-resolution US have substantially improved the management of thyroid nodules. This document was prepared as a collaborative effort between the American Association of Clinical Endocrinologists (AACE) and the Associazione Medici Endocrinologi (AME). Most Task Force members are members of AACE. We have used the AACE protocol for clinical practice guidelines, with rating of available evidence, linking the guidelines to the strength of recommendations. Key observations include the following. Although most patients with thyroid nodules are asymptomatic, occasionally patients complain of dysphagia, dysphonia, pressure, pain, or symptoms of hyperthyroidism or hypothyroidism. Absence of symptoms does not rule out a malignant lesion; thus, it is important to review risk factors for malignant disease. Thyroid US should not be performed as a screening test. All patients with a palpable thyroid nodule, however, should undergo US examination. US-guided FNA (US-FNA) is recommended for nodules > or = 10 mm; US-FNA is suggested for nodules < 10 mm only if clinical information or US features are suspicious. Thyroid FNA is reliable and safe, and smears should be interpreted by an experienced pathologist. Patients with benign thyroid nodules should undergo follow-up, and malignant or suspicious nodules should be treated surgically. A radioisotope scan of the thyroid is useful if the TSH level is low or suppressed. Measurement of serum TSH is the best initial laboratory test of thyroid function and should be followed by measurement of free thyroxine if the TSH value is low and of thyroid peroxidase antibody if the TSH value is high. Percutaneous ethanol injection is useful in the treatment of cystic thyroid lesions; large,symptomatic goiters may be treated surgically or with radioiodine. Routine measurement of serum calcitonin is not recommended. Suggestions for thyroid nodule management during pregnancy are presented. We believe that these guidelines will be useful to clinical endocrinologists, endocrine surgeons, pediatricians, and internists whose practices include management of patients with thyroid disorders. These guidelines are thorough and practical, and they offer reasoned and balanced recommendations based on the best available evidence.

Lithium treatment and thyroid abnormalities

BackgroundAlthough the interactions between lithium treatment and thyroid function have long been recognised, their clinical relevance is still controversial. This paper sets out a review of the literature to date, considering that lithium still represents the gold standard among prophylactic treatments of manic-depression several decades after its introduction.MethodPubMed database was used to search for English-language articles relating to lithium treatment and thyroid function. As the amount of relevant papers totalled several hundreds, this review refers to previous reviews, especially with regard to older literature. Moreover, the authors particularly refer to a series of studies of thyroid function performed in a cohort of patients at different stages of lithium treatment, who were followed up by their group from 1989 onwards.ResultsThe main findings from this review included: a) lithium definitely affects thyroid function as repeatedly shown by studies on cell cultures, experimental animals, volunteers, and patients; b) inhibition of thyroid hormone release is the critical mechanism in the development of hypothyroidism, goitre, and, perhaps, changes in the texture of the gland which are detected by ultrasonic scanning; c) compensatory mechanisms operate and prevent the development of hypothyroidism in the majority of patients; d) when additional risk factors are present, either environmental (such as iodine deficiency) or intrinsic (immunogenetic background), compensatory potential may be reduced and clinically relevant consequences may derive; e) hypothyroidism may develop in particular during the first years of lithium treatment, in middle-aged women, and in the presence of thyroid autoimmunity; f) thyroid autoimmunity is found in excess among patients suffering from affective disorders, irrespective of lithium exposure; g) in patients who have been on lithium for several years, the outcome of hypothyroidism, goitre, and thyroid autoimmunity do not much differ from those observed in the general population; h) hyperthyroidism and thyroid cancer are observed rarely during lithium treatment.RecommendationsThyroid function tests (TSH, free thyroid hormones, specific antibodies, and ultrasonic scanning) should be performed prior to starting lithium prophylaxis. A similar panel should be repeated at one year. Thereafter, annual measurements of TSH may be sufficient to prevent overt hypothyroidism. In the presence of raised TSH or thyroid autoimmunity, shorter intervals between assessments are advisable (4–6 months). Measurement of antibodies and ultrasonic scanning may be repeated at 2-to-3-year intervals. The patient must be referred to the endocrinologist if TSH concentrations are repeatedly abnormal, and/or goitre or nodules are detected. Thyroid function abnormalities should not constitute an outright contraindication to lithium treatment, and lithium should not be stopped if a patient develops thyroid abnormalities. Decisions should be made taking into account the evidence that lithium treatment is perhaps the only efficient means of reducing the excessive mortality which is otherwise associated with affective disorders.

Standardisation des immunodosages de la TSH : production de nouveaux calibrateurs et harmonisation des tests

Discordances among TSH measurements have been long documented over the past two decades but are still poorly understood at the molecular level. This review presents an overview of TSH structural polymorphism in the pituitary stock compared to various recombinant preparations and the circulating hormone. Comparative immunochemical analysis of pituitary TSH and a recombinant hormone produced in mammalian cells demonstrate that several epitopes are differentially expressed as a result of alteration in glycosylation. Consequently, variable antibody recognition may be generated between blood samples and internal calibrators among assays. There is thus a need for designing new calibrators which best mimick circulating TSH for developing harmonization of TSH tests.