Serum thyroid stimulating hormone level for predicting utility of thyroid uptake and scan

BACKGROUND

Thyroid uptake and scan (TUS) is a clinical tool used for differentiation of thyrotoxicosis etiologies. Although guidelines recommend ordering a TUS for evaluation of low TSH levels, no specific value is defined. This study aimed to determine a TSH cutoff at which TUSs yield a greater likelihood of successful determination of etiology to avoid unnecessary testing.

METHODS

This was a retrospective study on 137 patients seen by an endocrinologist who underwent TUS for evaluation of low TSH (<0.4 μU/mL). A receiver operating curve analysis was performed to determine the TSH cutoff with maximal sensitivity and specificity for prediction of diagnostic utility.

RESULTS

Ninety percent of TUSs (n = 123) led to a diagnosis, while 10% (n = 14) were inconclusive or normal. Diagnoses included Graves' diseases (52%), toxic multinodular goiter (19%), thyroiditis (12%), and solitary toxic adenoma (7%). The median TSH value was 0.008 μU/mL (IQR 0.005, 0.011), and the median free T4 value was 1.7 μU/mL (IQR 1.3, 2.8). The ROC analysis produced an area under the curve of 0.86. The optimal TSH cutoff value was 0.02 μU/mL (sensitivity 80%, specificity 93%) for prediction of diagnostic yield.

CONCLUSION

This study demonstrates that TSH is a useful predictor of the utility of TUS in yielding an etiology of thyrotoxicosis. Our analysis showed that TUS had a greater likelihood of determining an etiology when TSH was ≤0.02 μU/mL. This information can help clinicians avoid unnecessary cost and patient time burden when TUS is unlikely to aid in determining the etiology of thyrotoxicosis.

Interplay Between Thyroid Hormone Status and Pulmonary Hypertension in Graves' Disease: Relevance of the Assessment in Thyrotoxic and Euthyroid Patients

BACKGROUND

Graves' disease (GD) is the most common cause of hyperthyroidism and can cause cardiac changes, such as pulmonary hypertension.

METHODS

This is a prospective study in which we obtained demographic, clinical, laboratory data and characteristics of the GD, in addition to investigating cardiorespiratory function, focusing on the detection of pulmonary hypertension. Patients were separated into two groups: thyrotoxicosis and euthyroidism. Ninety patients with GD of both sexes, over 18 years of age, were included. The cardiorespiratory assessment included an echocardiographic evaluation, a questionnaire of specific symptoms, spirometry and a six-minute walk test.

RESULTS

The hyperthyroid group included 42 patients (47.73%) and the euthyroid group 46 patients (52.27%); 78 were women (86.67%). The prevalence of pulmonary hypertension between the hyperthyroidism (48.57%) and the euthyroidism (29.41%) groups was not different. Free thyroxine levels (FT4) (OR 1.266), higher left atrium volume (OR 1.113) and right ventricle diameter were associated with pulmonary hypertension. A direct correlation between FT4 with forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1), as also an inverse correlation between initial oxygen saturation (SpO2) with diagnostic time and drop SpO2 with the ratio between the diastolic velocity E of the mitral flow and the diastolic velocity of the mitral ring (E/e') were observed in the euthyroid group. An inverse correlation between FT4 levels with walked distance as % of predicted value, and a direct correlation between E/e' ratio and walked distance as % of predicted value were observed in the hyperthyroid group.

CONCLUSION

We emphasize the importance of a cardiorespiratory reassessment in GD, even after a long-term control of the thyrotoxic state, as we demonstrate that about 30% of these patients remain with PH and are subject to specific treatment.

Randomised trial of block and replace vs dose titration thionamide in young people with thyrotoxicosis

OBJECTIVE

First-line treatment of thyrotoxicosis in young people is thionamide anti-thyroid drug (ATD) in a blocking dose with levothyroxine replacement (block and replace, BR) or in a smaller dose tailored to render the patient euthyroid (dose titration, DT). Our objective was to determine which regimen provides more stable biochemical control.

DESIGN

A multi-centre phase III, open-label randomised trial comparing BR with DT in patients aged 2-17 years with newly diagnosed thyrotoxicosis at 15 UK centres.

METHODS

Patients were randomised shortly after diagnosis and treated for 3 years. The primary outcome was the percentage of serum thyroid-stimulating hormone (TSH) levels in the reference range between 6 months and 3 years. Secondary outcomes included the proportion of Free thyroxine (FT4) levels in the reference range, adverse event frequency and 4 years outcome (remission/relapse).

RESULTS

Eighty-two patients were randomised, with details on clinical course in 81 (62 Female); 40 were allocated to BR (41 DT). Three withdrew with one ineligible. The mean percentage of serum TSH within reference range was 60.2% in BR and 63.8% in DT patients; adjusted difference 4.3%, 95% CI (-7.8 to 16.4); P = 0.48. Proportions for FT4 were 79.2% in BR and 85.7% in DT patients; adjusted difference 6.8%, (-0.2 to 15.6); P = 0.13. Three patients developed neutropenia - all on BR. 6 BR and 10 DT patients were in remission at 4y.

CONCLUSION

This randomised trial has shown no evidence to suggest that BR, when managing the young patient with thyrotoxicosis, is associated with improved biochemical stability when compared to DT.

Identification of Resistance to Exogenous Thyroxine in Humans

Background: Thyroxine (T4) to triiodothyronine (T3) deiodination in the hypothalamus/pituitary is mediated by deiodinase type-2 (D2) activity. Dio2^(-/-) mice show central resistance to exogenous T4. Patients with resistance to exogenous thyroxine (RETH) have not been described. The aim of this study was to identify hypothyroid patients with thyrotropin (TSH) unresponsiveness to levothyroxine (LT4) and to characterize the clinical, hormonal, and genetic features of human RETH. Methods: We investigated hypothyroid patients with elevated TSH under LT4 treatment at doses leading to clinical and/or biochemical hyperthyroidism. TSH and free T4 (fT4) were determined by chemiluminescence, and total T4, T3, and reverse T3 (rT3) by radioimmunoassay. TSH/fT4 ratio at inclusion and T3/T4, rT3/T4, and T3/rT3 ratios at follow-up were compared with those from patients with resistance to thyroid hormone (RTH) due to thyroid hormone receptor-β (THRB) mutations. DIO2, including the Ala92-D2 polymorphism, selenocysteine binding protein 2 (SECISBP2), and THRB were fully sequenced. Results: Eighteen hypothyroid patients (nine of each sex, 3-59 years) treated with LT4 showed elevated TSH (15.5 ± 4.7 mU/L; reference range [RR]: 0.4-4.5), fT4 (20.8 ± 2.4 pM; RR: 9-20.6), and TSH/fT4 ratio (0.74 ± 0.25; RR: 0.03-0.13). Despite increasing LT4 doses from 1.7 ± 1.0 to 2.4 ± 1.7 μg/kg/day, TSH remained elevated (6.9 ± 2.7 mU/L). Due to hyperthyroid symptoms, LT4 doses were reduced, and TSH increased again to 7.9 ± 3.2 mU/L. In the euthyroid/hyperthyrotropinemic state, T3/T4 and T3/rT3 ratios were decreased (9.2 ± 2.4, RR: 11.3-15.3 and 2.5 ± 1.4, RR: 7.5-8.5, respectively) whereas rT3/T4 was increased (0.6 ± 0.2; RR: 0.43-0.49), suggesting reduced T4 to T3 and increased T4 to rT3 conversion. These ratios were serum T4-independent and were not observed in RTH patients. Genetic testing was normal. The Ala92-D2 polymorphism was present in 7 of 18 patients, but the allele dose did not correlate with RETH. Conclusions: Human RETH is characterized by iatrogenic thyrotoxicosis and elevated TSH/fT4 ratio. In the euthyroid/hyperthyrotropinemic state, it is confirmed by decreased T3/T4 and T3/rT3 ratios, and elevated rT3/T4 ratio. This phenotype may guide clinicians to consider combined T4+T3 therapy in a targeted fashion. The absence of germline DIO2 mutations suggests that aberrant post-translational D2 modifications in pituitary/hypothalamus or defects in other genes regulating the T4 to T3 conversion pathway could be involved in RETH.

Effect of high-dose intravenous glucocorticoid therapy on serum thyroid hormone concentrations in type 2 amiodarone-induced thyrotoxicosis: an exploratory study

PURPOSE

Type 2 amiodarone-induced thyrotoxicosis (AIT2) is a form of drug-induced destructive thyroiditis, usually treated with oral glucocorticoids (oGCs). Our objective was to investigate the short-term effects of intravenous glucocorticoids (ivGCs) on serum thyroid hormone concentrations in patients with AIT2.

METHODS

Exploratory study of three naive AIT2 patients treated with iv methylprednisolone (two pulses of 400 mg with no interpulse oGCs), followed by oGCs, matched 1:3 with AIT2 patients treated with oGCs alone. Changes in serum thyroid hormone concentrations were evaluated in the short-term period (24 h and 7 days) and after a cumulative dosage of 400 and 800 mg equivalents of methylprednisolone; in addition, healing time and duration of exposure to GCs were calculated.

RESULTS

During the first 24 h of treatment, serum FT4 concentrations increased in ivGCs patients, and decreased in oGCs patients (+ 3.3% vs - 10.7%, respectively, p = 0.025). After 7 days, serum FT4 and FT3 concentrations decreased significantly in both groups, with no statistical difference between them (p = 0.439 for FT4 and p = 0.071 for FT3), even though the cumulative GCs dose was higher in ivGCs than in oGCs patients (800 mg vs 280 mg, p = 0.008). Furthermore, the iv administration of single 400 mg pulses of methylprednisolone resulted in a less significant decrease in serum thyroid hormone concentrations when compared to equivalent GCs doses fractionated in several consecutive days (p = 0.021 for FT4 and p = 0.052 for FT3). There were no significant differences in the healing time (p = 0.239) and duration of exposure to GCs (p = 0.099).

CONCLUSIONS

High-dose ivGCs therapy does not offer advantages over standard oGCs therapy in the rapid, short-term control of AIT2.

Postpartum Follow-Up of Patients with Subclinical Hypothyroidism During Pregnancy

Background: Subclinical hypothyroidism (SCH) in pregnancy is associated with adverse pregnancy and perinatal outcomes. However, few studies have investigated the evolution of postpartum thyroid function in these women. This study aimed to determine the postpartum outcomes of SCH during pregnancy and the clinical and biochemical factors related to the evolution of long-term hypothyroidism. Methods: A total of 393 women diagnosed with SCH during pregnancy (defined as thyrotropin [TSH] >4.0 μIU/mL with normal free thyroxine levels according to the 2017 American Thyroid Association guidelines) were prospectively followed up after delivery. Among them, 216 underwent long-term follow-up [median (interquartile range) follow-up time: 11 (7-19) months] postpartum. The clinical and biochemical characteristics of the women with long-term postpartum hypothyroidism and euthyroidism were compared. Linear mixed model (LMM) was used to explore the risk factors for longitudinal changes of TSH, and logistic regression analysis was employed to identify the independent predictors of long-term postpartum hypothyroidism. Results: The probability of long-term hypothyroidism after delivery in SCH during pregnancy was 38.9%. Among the subjects with normal thyroid function 6-week postpartum, 28.2% developed hypothyroidism during long-term follow-up. The LMM showed that gestational age at the time of SCH diagnosis (estimate: -0.018, p = 0.004) and thyroid peroxidase antibodies (TPOAb) (estimate: 0.001, p = 0.020) were significantly associated with longitudinal changes of TSH. The logistic regression model showed that TPOAb positive both during pregnancy and six-week postpartum was a risk factor for long-term hypothyroidism after delivery (odds ratio = 4.686 [95% confidence interval 1.242 to 17.680], p = 0.023). Conclusions: More than one-third of patients with SCH during pregnancy had persistent hypothyroidism after delivery. We recommend that patients with TPOAb positive both during pregnancy and six-week postpartum undergo close follow-up to detect persistent hypothyroidism, especially before the next pregnancy.

Hyperthyroxinemia with a non-suppressed TSH: how to confidently reach a diagnosis in this clinical conundrum

Disorders of thyroid function are among the commonest referrals to endocrinology. While interpretation of thyroid function testing is usually straightforward, accurate interpretation becomes significantly more challenging when the parameters do not behave as would be expected in normal negative feedback. In such cases, uncertainty regarding further investigation and management arises. An important abnormal pattern encountered in clinical practice is that of high normal or raised free thyroxine (fT4) with inappropriately non-suppressed or elevated thyroid-stimulating hormone (TSH). In this short review using two clinical vignettes, we examine the diagnostic approach in such cases. A diagnostic algorithm is proposed to ensure that a definitive diagnosis is reached in these challenging cases.

Pitfalls in the assessment of gestational transient thyrotoxicosis

Gestational transient thyrotoxicosis (GTT) is associated with direct stimulation of the maternal thyroid gland by human chorionic gonadotropin (hCG). It is characterized by slightly higher thyroid hormone and lower thyroid-stimulating hormone (TSH) levels in early pregnancy and mild or no symptoms. While GTT must be distinguished from Graves' disease (GD), which is associated with maternal and fetal complications, treated GD and new-onset GD in pregnancy are occasionally challenging to distinguish. Evaluating serum hCG levels and TSH receptor antibody (TRAb) titers can help, but the results are not irrefutable due to pregnancy-related immunosuppression. Moreover, GTT can follow unusual clinical courses in relation to some pregnancy complications. Excessive hCG production can cause severe GTT symptoms in patients with hyperemesis gravidarum, trophoblastic disease, or multiple pregnancies. Thyrotoxicosis can emerge beyond the second trimester in patients with gestational diabetes mellitus and mirror syndrome, because of delayed elevations in the hCG levels. Detailed knowledge about GTT is necessary for correct diagnoses and its appropriate management. This review focuses on the diagnosis of GTT, and, particularly, its differentiation from GD, and unusual clinical conditions associated with GTT that require comprehensive management.

Management of thyrotoxicosis during pregnancy

Thyrotoxicosis during pregnancy should be adequately managed and controlled to prevent maternal and fetal complications. The evaluation of thyroid function in pregnant women is challenged by the physiological adaptations associated with pregnancy, and the treatment with antithyroid drugs (ATD) raises concerns for the pregnant woman and the fetus. Thyrotoxicosis in pregnant women is mainly of autoimmune origin, and the measurement of thyroid stimulating hormone-receptor antibodies (TRAb) plays a key role. TRAb helps to distinguish the hyperthyroidism of Graves' disease from gestational hyperthyroidism in early pregnancy, and to evaluate the risk of fetal and neonatal hyperthyroidism in late pregnancy. Furthermore, the measurement of TRAb in early pregnancy is recommended to evaluate the need for ATD during the teratogenic period of pregnancy. Observational studies have raised concern about the risk of birth defects associated with the use of ATD in early pregnancy and challenged the clinical management and choice of treatment.

Influence of thyroid dysfunction on brain natriuretic peptide level in health examination participants

The tissue-specific circulating markers of thyroid hormone action on cardiac function have not been established. Although the relationship between thyroid function and plasma brain natriuretic peptide (BNP) levels has been evaluated in patients with thyroid disorders, the relationship between these parameters in the general population has not been yet studied. We conducted retrospective cohort study by health examination with concurrent measurements of TSH, free T4, body mass index, systolic blood pressure, hemoglobin, and estimated glomerular filtration rate from participants who visited the Department of Health Checkup, Enshu Hospital between July 2008 and March 2017. After participants with abnormal electrocardiogram and/or any history of cardiac disease were excluded, 2,807 individuals were subjected. Multivariate analyses demonstrated that, when compared to euthyroidism (n = 2,629), the increase in BNP levels was significant in overt thyrotoxicosis (n = 21) but not in subclinical thyrotoxicosis (n = 53) or subclinical hypothyroidism (n = 97). Interestingly, the standardized partial regression coefficient was the smallest for thyroid function category (overt thyrotoxicosis compared to euthyroidisim; β = 0.048, p = 0.006) among the independent variables including age, body mass index, systolic blood pressure, and hemoglobin. In longitudinal comparison, we identified 986 participants who had sequential data on the measurements and were stable as euthyroidism and subclinical hypothyroidism. Their annual percent change in BNP demonstrated no significant differences. In conclusion, a direct stimulatory effect of thyroid hormone on the secretion (or production) of BNP was confirmed even in a large number of health examination participants.

Diagnostic testing for Graves' or non-Graves' hyperthyroidism: A comparison of two thyrotropin receptor antibody immunoassays with thyroid scintigraphy and ultrasonography

OBJECTIVE

Graves' disease (GD) is the most common cause of hyperthyroidism. In many cases, when the aetiological diagnosis of GD is not evident based on the clinical evaluation and thyroid function testing, it may become challenging to distinguish Graves' hyperthyroidism from other forms of thyrotoxicosis. The current study was primarly carried out to compare the diagnostic effectiveness of two TSH receptor antibody immunoassays (IMAs), ultrasonography and thyroid scintigraphy in hyperthyroidism scenario.

METHODS

We retrospectively analysed consecutive patients with newly diagnosed and untreated thyrotoxicosis who underwent thyroid functional tests, both TRAb and TSI measurements, thyroid scintigraphy and ultrasonography. TRAb assessment was carried out by Kryptor^® compact PLUS, while TSI by Immulite^® . Echo pattern 3 corresponded to 'thyroid inferno', and the final diagnosis of GD vs non-Graves' hyperthyroidism was made according to the thyroid scan (qualitative scintigraphy). Receiver operating characteristic (ROC) curves were drawn using the final diagnosis as reference. Clinical sensitivity and specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated for all the tests.

RESULTS

A total of 124 untreated hyperthyroid patients were included in our study (GD, n = 86 vs non-Graves' hyperthyroidism, n = 38). ROC curves showed that the optimal cut-off values associated with the highest diagnostic sensitivity and specificity was 0.7 IU/L for TRAb Kryptor^® (93 [85.4-97.4] and 86.8 [71.9-95.5]) and 0.1 IU/L for TSI Immulite^® (94.2 [86.9-98.1] and 84.2 [68.7-93.9]), respectively. For the echo pattern 3, we found a good sensitivity (92.1%) and a high PPV (95.2%) but a quite low specificity value (69.8%) and a relative low NPV (57.5%). For thyroid scintigraphy, the TcTU cut-off value of 1.3% corresponded to the best limit for sensitivity and specificity in our patients (95.3 [88.5-98.7] and 96.4 [81.6-99.4]). The Passing-Bablok regression equation and the Bland-Altman test showed a great degree of correlation and agreement existed between TRAb Kryptor^® and Immulite^® TSI results.

CONCLUSIONS

Thyroid scintigraphy remains the most accurate method to differentiate causes of thyrotoxicosis. However, TRAb assays can be alternatively adopted in this setting, limiting the use of thyroid scintigraphy (TcTU evaluation) to TRAb-negative patients. Thyoid US is less accurate than both TRAb/TSI and thyroid scintigraphy, but the 'thyroid inferno' pattern provides a high PPV for GD.

Neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, and platelet-tolymphocyte ratio in different etiological causes of thyrotoxicosis

Background/aim

The most common causes of thyrotoxicosis include Graves’ disease (GD), toxic multinodular goiter (TMNG), toxic adenoma (TA), and subacute granulomatous thyroiditis (SAT). In our study, we aimed to see whether neutrophil‐to‐lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet‐to‐lymphocyte ratio (PLR), and mean platelet volume (MPV) may be helpful in the differential diagnosis of these diseases.

Materials and methods

We retrospectively analyzed the hospital records of the Endocrinology Clinic of our hospital between 2016 and 2019. We included data from 66 GD, 37 TA, and 35 SAT patients. We compared the data with those of 35 healthy subjects as controls.

Results

NLR, MLR, and PLR were found to be higher in the SAT group when compared to other groups. The post hoc analysis of comparison of NLR, MLR, and PLR in each group showed that NLR and PLR were significantly different in the SAT group when compared to the GD, TA, and controls groups (P < 0.001, P = 0.003, and P < 0.001 for NLR respectively and P < 0.001 for PLR in all groups). MPV levels were different between groups (P = 0.007). However, the intergroup analysis (Tukey’s test) failed to show a statistically significant difference for any of the groups. In patients with SAT, PLR and NLR were significantly higher than in the GD, TA, and control groups. MLR was also higher in SAT when compared to other groups, but the difference was not statistically significant.

Conclusion

High PLR and NLR may be helpful to differentiate SAT from GD and TA, the other common causes of thyrotoxicosis.

Serum iodine concentration in pregnant women and its association with urinary iodine concentration and thyroid function

OBJECTIVE

This study aims to evaluate the association of serum iodine concentration (SIC) with urinary iodine concentration (UIC) and thyroid function in pregnant women, as well as to provide the reference range of SIC of pregnant women in iodine-sufficiency area.

METHODS

Pregnant women were enrolled in the Department of Obstetrics, Tanggu Maternity Hospital, Tianjin from March 2016 to May 2017. Fasting venous blood and spot urine samples were collected. Serum free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), thyroglobulin (Tg), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), UIC and SIC were measured.

RESULTS

One thousand and ninety-nine participants were included in this study. The median UIC was 156 μg/L. The median SIC was 108 μg/L, and the 95% reference interval for SIC was 65.6-164.7 μg/L. SIC was positively correlated with UIC (r = 0.12, P < 0.001), FT3 (r = 0.23, P < 0.001), and FT4 (r = 0.50, P < 0.001) and was inversely correlated with TSH (r = -0.14, P < 0.001). Pregnant women with a SIC < 79.9 μg/L had a higher risk of hypothyroxinemia compared to those with higher SIC (OR = 2.44, 95% CI: 1.31-4.75). Those having SIC > 138.5 μg/L were more likely to have thyrotoxicosis than those with lower SIC values (OR = 13.52, 95% CI: 4.21-43.36).

CONCLUSIONS

Serum iodine level is associated with UIC and thyroid function in pregnant women. Low SIC was associated with increased risk for iodine deficiency and hypothyroxinemia, while high SIC was related to excess and thyrotoxicosis.

Increased Risk of Antithyroid Drug Agranulocytosis Associated with Amiodarone-Induced Thyrotoxicosis: A Population-Based Cohort Study

BACKGROUND

Agranulocytosis occurs in 0.2-0.5% of patients treated with the antithyroid drugs (ATDs) methimazole and propylthiouracil. The objectives of this study were to evaluate the risk of ATD-related agranulocytosis in patients with amiodarone-induced thyrotoxicosis (AIT), and to compare it with the agranulocytosis risk in patients with thyrotoxicosis due to other etiologies treated with ATDs.

METHODS

This was a retrospective cohort study. Participants were 14,781 adult patients with thyrotoxicosis, newly treated with an ATD between January 1, 2002, and December 31, 2015. Among them were 593 patients treated by ATDs due to AIT. The main outcome measures were incidence rates and crude and adjusted hazard ratios using univariate and multivariable Cox regression models for ATD-related agranulocytosis within one year of treatment initiation, in association with AIT.

RESULTS

Agranulocytosis occurred in 28 (0.19%) of patients newly treated with methimazole or propylthiouracil during the first year of follow-up. Of these 28 patients, 8/593 (1.35%) were AIT patients and 20/14,188 (0.14%) were thyrotoxic patients that was not AIT related (p < 0.001). Incidence rates were 22 (9.47-43.36) cases/1000 person-years of follow-up in AIT, and 1.79 (1.09-2.76)/1000 person-years of follow-up in non-AIT thyrotoxicosis (p < 0.0001). In univariate Cox regression analysis, risk for ATD agranulocytosis associated with AIT was 9.71 (4.28-22.05) compared to the risk in non-AIT thyrotoxicosis. In a multivariable model, adjusting for age, sex, body mass index, smoking history, year of cohort entry, diabetes mellitus, hypertension, renal failure, beta blockers, calcium channel blockers, anti-aggregants, and dose of ATDs, the risk associated with AIT was 5.70 (2.14-15.21). In a model adjusted for a propensity score to receive amiodarone, risk for ATD agranulocytosis associated with AIT was 6.32 (1.22-32.70).

CONCLUSIONS

ATD use is associated with a higher risk for agranulocytosis in patients with AIT.

Bilateral, Asymmetric Keratoconus Induced by Thyrotoxicosis With Long-term Stability After Corneal Cross-linking

PURPOSE

To present a case of bilateral, asymmetric keratoconus presenting unilaterally after partial thyroidectomy with delayed presentation in the second eye after thyrotoxicosis, with disease stabilization following corneal cross-linking (CXL).

METHODS

Case report and literature review.

RESULTS

A 17-year-old girl with a history of Graves' disease underwent partial thyroidectomy without thyroid hormone replacement therapy with normal baseline ophthalmic examination of corrected distance visual acuity (CDVA) of 20/20 and no manifest astigmatism in either eye. At age 29 years, keratoconus manifested in the right eye and standard protocol CXL was performed. At age 40 years, the right eye remained stable after CXL, but keratoconus manifested in the left eye and epithelium-off accelerated CXL was performed with subsequent disease stabilization.

CONCLUSIONS

This case demonstrates the association between thyrotoxicosis and keratoconus and the bilateral nature of keratoconus, and highlights the potentially asymmetric presentation of thyroid-induced keratoconus. CXL had a long-term stabilizing effect over 10 years despite the ongoing effects of thyroid gland dysfunction. [J Refract Surg. 2018;34(5):354-356.].

[Apparent thyrotoxicosis in a patient with multiple sclerosis: biochemical assay interference due to high dose biotin use]

BACKGROUND

Supraphysiological doses of biotin are being tested in patients with multiple sclerosis. Biotin can cause interference with laboratory assessment of thyroid function, and therefore give a false suggestion of thyrotoxicosis.

CASE DESCRIPTION

A 64-year-old patient was referred for assessment of thyrotoxicosis, due to Graves' disease. Antithyroid medication was started, but there was no effect on laboratory results. In addition, he developed symptoms which subsequently could be attributed to iatrogenic hypothyroidism. Biotin interference, when assaying TSH and thyroxin, was suspected. Upon further investigation, the patient revealed to use high doses of biotin. After discontinuation of the biotin treatment, the thyroid function test normalized.

CONCLUSION

It is expected that in the future, patients with multiple sclerosis will use biotin more often. Therefore, it is important for healthcare professionals to be aware that biotin can interfere with immunoassays for thyroid hormones, to avoid misdiagnosis and unnecessary treatment for hyperthyroidism.

Hyperthyroidism in patients with ischaemic heart disease after iodine load induced by coronary angiography: Long-term follow-up and influence of baseline thyroid functional status

OBJECTIVE

To study the effect of a iodine load on thyroid function of patients with ischaemic heart disease (IHD) and the long-term influence of unknown subclinical hyperthyroidism.

CONTEXT

Subclinical hyperthyroidism is considered an independent risk factors for cardiovascular morbidity of patients with IHD. They routinely undergo coronary angiography with iodine contrast media (ICM) which may induce or even worsen hyperthyroidism.

DESIGN

A cross-sectional study followed by a longitudinal study on patients with subclinical hyperthyroidism.

PATIENTS

810 consecutive IHD outpatients without known thyroid diseases or treatment with drugs influencing thyroid activity undergoing elective coronary angiography.

MEASUREMENTS

We evaluated thyroid function either before and 1 month after ICM; patients with thyrotoxicosis at baseline or after ICM were then followed up for 1 year.

RESULTS

58 patients had hyperthyroidism at baseline (HB, 7.2%), independently associated to FT4 levels, thyroid nodules and family history of thyroid diseases. After ICM, the prevalence of hyperthyroidism was 81 (10%). Hyperthyroidism after ICM was positively predicted by baseline fT4 levels, thyroid nodules, age over 60, male gender, family history of thyroid diseases. Three months after ICM, 34 patients (4.2%) still showed hyperthyroidism (22 from HB, 13 treated with methimazole). One year after ICM, hyperthyroidism was still present in 20 patients (2.5%, all from HB, 13 treated).

CONCLUSIONS

The prevalence of spontaneous subclinical hyperthyroidism in IHD is surprisingly elevated and is further increased by iodine load, particularly in patients with thyroid nodules and familial history of thyroid diseases, persisting in a not negligible number of them even after one year.

RELATIONSHIP BETWEEN THE EFFECTIVENESS OF INORGANIC IODINE AND THE SEVERITY OF GRAVES THYROTOXICOSIS: A RETROSPECTIVE STUDY

OBJECTIVE

Inorganic iodine is often used to treat patients with Graves thyrotoxicosis who do not tolerate thionamides due to adverse effects. However, predictors of continued inorganic iodine efficacy have not been fully elucidated. This study aimed to investigate the factors affecting the continued efficacy of potassium iodide (KI) in patients with Graves thyrotoxicosis.

METHODS

In this study, among 1,197 patients with Graves disease who were initially treated with thionamides, we retrospectively studied 24 consecutive Japanese patients whose treatment was changed to KI alone due to the adverse effects of thionamides. We divided these patients into 2 groups: patients who had maintained euthyroid function for at least 180 days (nonrecurrence group, n = 11), and patients who had not maintained euthyroid function for 180 days (recurrence group, n = 13).

RESULTS

Free triiodothyronine (FT3) and free thyroxine (FT4) levels on the day of changing from thionamides to KI were statistically higher in the recurrence group than in the nonrecurrence group (FT3, 9.3 [range, 5.2-11.6] vs. 3.7 [3.3-4.8] pg/mL, P = .02 and FT4, 3.6 [1.8-4.5] vs. 1.4 [1.2-1.9] ng/dL, P = .02). FT4 levels on the day of drug change were significantly higher in the recurrence group, even after adjusting for thionamide or KI dose. In the recurrence group, the duration of KI effect was inversed correlated with FT3 and FT4 levels on the day of drug change.

CONCLUSION

Continued efficacy of KI after thionamides might be inversely correlated with thyrotoxicosis severity on the day of drug change.

ABBREVIATIONS

ANOVA = analysis of variance eTV = estimated thyroid volume FT3 = free triiodothyronine FT4 = free thyroxine IQR = interquartile range KI = potassium iodide MMI = thiamazole PTU = propylthiouracil RAIT = radioactive iodine therapy TRAb = TSH receptor antibody TSH = thyroid stimulating hormone.

No Effect of Levothyroxine and Levothyroxine-Induced Subclinical Thyrotoxicosis on the Pharmacokinetics of Sorafenib in Healthy Male Subjects

BACKGROUND

Patients receiving the multikinase inhibitor sorafenib for locally recurrent or metastatic, progressive, differentiated thyroid carcinoma (DTC) refractory to radioactive iodine often receive concomitant levothyroxine for thyrotropin (TSH) suppression. In the Phase 3 DTC trial (DECISION), sorafenib exposure was approximately twofold higher than that observed in other cancers. This study assessed sorafenib pharmacokinetics without and with concomitant levothyroxine to examine whether a levothyroxine interaction or levothyroxine-induced subclinical thyrotoxicosis results in increased sorafenib exposure in patients with DTC.

METHODS

This was an open-label, two-period sequential treatment study in healthy male subjects. In period 1, day 1, subjects received a single oral dose of sorafenib 400 mg, followed by a minimal 10-day washout. In period 2, day 1, levothyroxine 300 μg was administered orally once daily (q.d.) for 14 days. After 10 days, a single oral concomitant dose of sorafenib 400 mg was given. Blood samples for sorafenib pharmacokinetic analyses were obtained pre-dose and at time points up to 96 hours after sorafenib dosing. Samples for thyroid tests were collected before and after levothyroxine dosing.

RESULTS

Twenty-five subjects completed the study and were evaluable for pharmacokinetic analysis. Levothyroxine 300 μg q.d. was well tolerated and induced subclinical thyrotoxicosis, producing full suppression of TSH (M ± SD = 0.032 ± 0.027 mIU/L) and increased free thyroxine (from 0.94 ± 0.09 to 1.77 ± 0.33 ng/dL) and free triiodothyronine (from 2.87 ± 0.28 to 4.24 ± 0.66 pg/mL) levels by day 11 of period 2. The geometric mean (%CV) sorafenib maximum concentration (C_max) without and with levothyroxine was 2.09 (68.1) and 1.78 (63.9) mg/L, respectively, with a corresponding geometric mean area under the curve of 68.1 (68.2) and 64.3 (66.3) mg·h/L. Median (range) time to C_max was 4.00 (2.98-16.0) and 4.02 (1.98-36.0) hours, respectively. Mean (%CV) half-life was 24.0 (25.3) and 25.7 (21.0) hours. All study drug-related adverse events were mild and included headache and fatigue for sorafenib, and headache, increased alanine aminotransferase and glutamate dehydrogenase, fatigue, and nervousness for levothyroxine.

CONCLUSIONS

Levothyroxine 300 μg q.d. for 14 days was well tolerated, induced subclinical thyrotoxicosis, and did not affect sorafenib pharmacokinetics. The findings suggest that concomitant use of levothyroxine with sorafenib is not likely responsible for the previously reported increase in sorafenib exposure in patients with DTC. However, the possible effects of long-term levothyroxine dosing were not assessed.

Clinical Features of Nivolumab-Induced Thyroiditis: A Case Series Study

BACKGROUND

The programmed cell death-1 (PD-1) pathway is a novel therapeutic target in immune checkpoint therapy for cancer. It consists of the PD-1 receptor and its two ligands, programmed death-ligand 1 (PD-L1) and programmed death-ligand 2 (PD-L2). Nivolumab is an anti-PD-1 monoclonal antibody approved for malignant melanoma, advanced non-small cell lung cancer, and advanced renal cell carcinoma in Japan. Thyrotoxicosis and hypothyroidism have both been reported in international Phase 3 studies and national post-marketing surveillance of nivolumab in Japan.

METHODS

This study analyzed five consecutive cases with thyroid dysfunction associated with nivolumab therapy. Second, it examined the mRNA and protein expressions of PD-L1 and PD-L2 by reverse transcription polymerase chain reaction and Western blotting.

RESULTS

All patients were diagnosed with painless thyroiditis. Thyrotoxicosis developed within four weeks from the first administration of nivolumab and normalized within four weeks of onset in three of the five patients. Hypothyroidism after transient thyrotoxicosis developed in two patients, and preexisting hypothyroidism persisted in one patient. The other two patients were treated with glucocorticoids and discontinued nivolumab therapy for comorbid adverse events. One did not develop hypothyroidism, and the other developed mild, transient hypothyroidism. In addition, it was verified that normal thyroid tissue expresses PD-L1 and PD-L2 mRNA and those proteins.

CONCLUSIONS

In the present cases, nivolumab-induced thyrotoxicosis seemed to be associated with painless thyroiditis, while no patient with Graves' disease was observed. A transient and rapid course with subsequent hypothyroidism was observed in nivolumab-induced thyroiditis. In addition, it was verified that PD-L1 and PD-L2 are expressed in normal thyroid tissue. This suggests that nivolumab therapy reduces immune tolerance, even in normal thyroid tissue, and leads to the development of thyroiditis. Treating thyrotoxicosis with only supportive care and considering levothyroxine replacement therapy once subsequent hypothyroidism occurs is proposed. Further investigations are required to confirm whether glucocorticoid therapy and discontinuation of nivolumab therapy prevent subsequent hypothyroidism.

Incidence of abnormal liver biochemical tests in hyperthyroidism

OBJECTIVE

Abnormal serum liver function tests are common in patients with untreated thyrotoxicosis, even prior to the initiation of antithyroidal medications that may worsen the severity of the abnormal serum liver biochemistries. There is a wide range of the incidence of these abnormalities in the published literature. The aim of this study was to assess the risks factors and threshold of thyrotoxicosis severity for developing an abnormal liver biochemical test upon the diagnosis of new thyrotoxicosis.

DESIGN

Single-institution retrospective cohort study.

PATIENTS

Patients of ≥18 years old receiving medical care at a large, academic, urban US medical centre between 2002-2016.

MEASUREMENTS

Inclusion criteria were a serum thyroid stimulating hormone (TSH) concentration of <0·3 mIU/l or ICD-9 code for thyrotoxicosis, with thyrotoxicosis confirmed by either a concurrent elevated serum triiodothyronine (T3) or thyroxine (T4) concentration ([total or free] within 3 months), and an available liver biochemical test(s) within 6 months of thyrotoxicosis. The biochemical liver tests assessed were serum aspartate transaminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AP), gamma-glutamyltransferase (GGT), total bilirubin, and conjugated bilirubin concentrations.

RESULTS

In this cohort of 1514 subjects, the overall incidence of any biochemical liver test abnormality within 6 months of thyrotoxicosis was 39%. An initial serum TSH concentration <0·02 mIU/l, male gender, and African-American race were significant predictors of an abnormal serum liver biochemical test within 6 months of the diagnosis of new-onset untreated thyrotoxicosis.

CONCLUSIONS

This study identifies risk factors for patients who develop an abnormal serum liver biochemical test result within 6 months of a diagnosis of untreated thyrotoxicosis.

Plasma proteome and metabolome characterization of an experimental human thyrotoxicosis model

BACKGROUND

Determinations of thyrotropin (TSH) and free thyroxine (FT4) represent the gold standard in evaluation of thyroid function. To screen for novel peripheral biomarkers of thyroid function and to characterize FT4-associated physiological signatures in human plasma we used an untargeted OMICS approach in a thyrotoxicosis model.

METHODS

A sample of 16 healthy young men were treated with levothyroxine for 8 weeks and plasma was sampled before the intake was started as well as at two points during treatment and after its completion, respectively. Mass spectrometry-derived metabolite and protein levels were related to FT4 serum concentrations using mixed-effect linear regression models in a robust setting. To compile a molecular signature discriminating between thyrotoxicosis and euthyroidism, a random forest was trained and validated in a two-stage cross-validation procedure.

RESULTS

Despite the absence of obvious clinical symptoms, mass spectrometry analyses detected 65 metabolites and 63 proteins exhibiting significant associations with serum FT4. A subset of 15 molecules allowed a robust and good prediction of thyroid hormone function (AUC = 0.86) without prior information on TSH or FT4. Main FT4-associated signatures indicated increased resting energy expenditure, augmented defense against systemic oxidative stress, decreased lipoprotein particle levels, and increased levels of complement system proteins and coagulation factors. Further association findings question the reliability of kidney function assessment under hyperthyroid conditions and suggest a link between hyperthyroidism and cardiovascular diseases via increased dimethylarginine levels.

CONCLUSION

Our results emphasize the power of untargeted OMICs approaches to detect novel pathways of thyroid hormone action. Furthermore, beyond TSH and FT4, we demonstrated the potential of such analyses to identify new molecular signatures for diagnosis and treatment of thyroid disorders. This study was registered at the German Clinical Trials Register (DRKS) [DRKS00011275] on the 16th of November 2016.

Mild Thyrotoxicosis Leads to Brain Perfusion Changes: An Arterial Spin Labelling Study

Hypo- and hyperthyroidism have effects on brain structure and function, as well as cognitive processes, including memory. However, little is known about the influence of thyroid hormones on brain perfusion and the relationship of such perfusion changes with cognition. The present study aimed to demonstrate the effect of short-term experimental hyperthyroidism on brain perfusion in healthy volunteers and to assess whether perfusion changes, if present, are related to cognitive performance. It is known that an interaction exists between brain perfusion and cerebral oxygen consumption rate and it is considered that neural activation increases cerebral regional perfusion rate in brain areas associated with memory. Measuring cerebral blood flow may therefore represent a proxy for neural activity. Therefore, arterial spin labelling (ASL) measurements were conducted and later analysed to evaluate brain perfusion in 29 healthy men before and after ingesting thyroid hormones for 8 weeks. Psychological tests concerning memory were performed at the same time-points and the results were correlated with the imaging results. In the hyperthyroid condition, perfusion was increased in the posterior cerebellum in regions connected with cerebral networks associated with cognitive control and the visual cortex compared to the euthyroid condition. In addition, these perfusion changes were positively correlated with changes of performance in the German version of the Auditory Verbal Learning Task [AVLT, Verbaler Lern-und-Merkfähigkeits-Test (VLMT)]. Cerebellar perfusion and function therefore appears to be modulated by thyroid hormones, likely because the cerebellum hosts a high number of thyroid hormone receptors.

Incidence of Thyroid-Related Adverse Events in Melanoma Patients Treated With Pembrolizumab

CONTEXT

Immune checkpoint blockade is associated with endocrine-related adverse events. Thyroid dysfunction during pembrolizumab therapy, an anti-programmed cell death 1 (PD-1) receptor monoclonal antibody, remains to be fully characterized.

OBJECTIVE

To assess the incidence and characteristics of pembrolizumab-associated thyroid dysfunction.

DESIGN AND SETTING

Thyroid function was monitored prospectively in melanoma patients who initiated pembrolizumab within an expanded access program at a referral oncology center. 18Fluorodeoxyglucose uptake on positron emission tomography/computed tomography (18FDG-PET/CT) was reviewed in cases compatible with inflammatory thyroiditis.

PATIENTS

Ninety-nine patients with advanced melanoma (age, 26.3-93.6 years; 63.6% females) who received at least one administration of pembrolizumab.

MAIN OUTCOME MEASURES

Patient characteristics, thyroid function (TSH, free T4), thyroid autoantibodies, and 18FDG-PET/CT.

RESULTS

Eighteen adverse events of thyroid dysfunction were observed in 17 patients. Thyrotoxicosis occurred in 12 patients, of which nine evolved to hypothyroidism. Isolated hypothyroidism was present in six patients. Levothyroxine therapy was required in 10 of 15 hypothyroid patients. Thyroid autoantibodies were elevated during thyroid dysfunction in four of 10 cases. Diffuse increased 18FDG uptake by the thyroid gland was observed in all seven thyrotoxic patients who progressed to hypothyroidism.

CONCLUSIONS

Thyroid dysfunction is common in melanoma patients treated with pembrolizumab. Hypothyroidism and thyrotoxicosis related to inflammatory thyroiditis are the most frequent presentations. Serial measurements of thyroid function tests are indicated during anti-PD-1 monoclonal antibody therapy. Thyrotoxicosis compatible with inflammatory thyroiditis was associated with diffuse increased 18FDG uptake by the thyroid gland. The prospective role of thyroid autoantibodies should be further investigated, together with the histopathological correlates.

Partial prediction of postpartum Graves' thyrotoxicosis by sensitive bioassay for thyroid-stimulating antibody measured in early pregnancy

Graves' disease often occurs after delivery. However, it has been difficult to predict who will develop Graves' hyperthyroidism. We attempted to predict postpartum onset of Graves' disease by measuring anti-TSH receptor antibodies (TRAb) and thyroid-stimulating antibodies (TSAb) in early pregnancy. TRAb was measured by a third generation assay and TSAb was measured by a newly developed sensitive bioassay. In 690 early pregnant women, 2 showed borderline TRAb positive reactions. However, none of them developed Graves' disease after delivery. Thirty-eight of 690 pregnant women were positive for anti-thyroid peroxidase antibodies (TPOAb) and 4 were positive for TSAb. Two of these 4 women developed postpartum Graves' hyperthyroidism. These findings indicate that the third generation TRAb assay was not useful, but that the sensitive TSAb bioassay was moderately useful for predicting the postpartum onset of Graves' hyperthyroidism.

Testicular germ cell tumour presenting as thyrotoxicosis

A case is reported of a patient who presented to his family doctor with a short history of cough with signs and symptoms of thyrotoxicosis. Carbimazole treatment had little effect and his symptoms worsened to include severe shortness of breath. He was investigated further and found to have multiple lung and liver metastases from an unknown primary site. Biopsy and subsequent post-mortem investigations revealed a testicular tumour and a grossly elevated serum human chorionic gonadotrophin (hCG) concentration.

The biochemical and clinical thyrotoxicosis is presumed to be due to the thyrotrophic activity of excess hCG secretion, in a situation analogous to that seen in hydatidiform mole or in hyperemesis gravidarum.

Maternal First Trimester TSH Concentrations: Do They Affect Perinatal and Endocrine Outcomes?

We aimed to examine the distribution of 1(st) trimester TSH and evaluate its association with perinatal outcomes and future development of maternal thyrotoxicosis. This retrospective cohort study included data of all women without prior thyroid disease who delivered a singleton at our medical center from 1/2001 to 12/2011 and had a 1(st) trimester TSH<4.0 mU/l. Women were divided according to 1(st) trimester TSH concentrations into quartiles and by predefined TSH values (mU/l): 1) TSH<0.1; 2) TSH 0.11-0.2; 3) TSH 0.21-0.4; and 4) TSH 0.4-4. Obstetrical outcomes, hCG concentrations, and future thyroid status were collected from electronic medical records. A total of 13 841 women fulfilled the inclusion criteria. Mean maternal TSH concentration at 5 weeks of gestation was 2.09±0.83 mU/l and decreased to 1.29±0.87 mU/l in weeks 8-9 with an increase towards the end of the 1(st) trimester. Odds ratio for future thyrotoxicosis was 3.64 in the lowest compared to the highest TSH quartile and 10.03 in those with TSH<0.1 compared to TSH 0.41-4 mU/l. Rates of female fetuses were higher in the low TSH quartiles and in the lower TSH groups, however baby gender was not associated with increased risk of future thyrotoxicosis. Low maternal 1(st) trimester TSH quartiles or concentrations were not associated with adverse pregnancy outcome. Only a minor fraction of pregnant women with a low first tirmester TSH subsequently developed future thyrotoxicosis.

The presence of anti-thyroglobulin (TgAb) and/or anti-thyroperoxidase antibodies (TPOAb) does not exclude the diagnosis of type 2 amiodarone-induced thyrotoxicosis

PURPOSE

It is widely accepted that type 2 amiodarone-induced thyrotoxicosis (AIT) generally occurs in patients with a normal thyroid gland without signs of thyroid autoimmunity. However, it is currently unknown if the presence of anti-thyroglobulin (TgAb) and/or anti-thyroperoxidase antibodies (TPOAb) in AIT patients without other signs of an underlying thyroid disease may impair the response to glucocorticoid therapy.

METHODS

We performed a pilot retrospective cohort study with matched-subject design and an equivalence hypothesis, comparing the response to glucocorticoid therapy between 20 AIT patients with a normal thyroid gland, low radioiodine uptake, undetectable TSH receptor antibodies and positive TgAb and/or TPOAb (Ab+ group), and 40 patients with the same features and absent thyroid antibodies (Ab- group).

RESULTS

The mean cure time was 54 ± 68 days in the Ab+ group and 55 ± 49 days in the Ab- group (p = 0.63). The equivalence test revealed an equivalent cure rate after 60, 90 and 180 days (p = 0.67, 0.88 and 0.278, respectively). The occurrence of permanent hypothyroidism was higher in the Ab+ group than in the Ab- group (26.3 vs 5.13 %, p = 0.032).

CONCLUSIONS

The presence of TgAb and/or TPOAb does not affect the response to glucocorticoid therapy, suggesting that the patients with features of destructive form of AIT should be considered as having a type 2 AIT irrespective of the presence of TGAb or TPOAb. These patients have a higher risk of developing hypothyroidism after the resolution of thyrotoxicosis and should be monitored accordingly.

Lack of α2C-Adrenoceptor Results in Contrasting Phenotypes of Long Bones and Vertebra and Prevents the Thyrotoxicosis-Induced Osteopenia

A series of studies have demonstrated that activation of the sympathetic nervous system (SNS) causes osteopenia via β₂-adrenoceptor (β₂-AR) signaling. However, in a recent study, we found an unexpected and generalized phenotype of high bone mass in female mice with chronic sympathetic hyperactivity, due to double gene inactivation of adrenoceptors that negatively regulate norepinephrine release, α_2A-and α_2C-AR (α_2A/2C-AR^-/-). These findings suggest that β₂-AR is not the single adrenoceptor involved in bone turnover regulation and show that α₂-AR signaling may also mediate the SNS actions in the skeleton. In addition, we found that α_2A/2C-AR^-/- animals are resistant to the thyrotoxicosis-induced osteopenia, suggesting that thyroid hormone (TH), when in supraphysiological levels, interacts with the SNS to control bone mass and structure, and that this interaction may also involve α₂-AR signaling. In the present study, to further investigate these hypotheses and to discriminate the roles of α₂-AR subtypes, we have evaluated the bone phenotype of mice with the single gene inactivation of α_2C-AR subtype, which mRNA expression was previously shown to be down regulated by triiodothyronine (T3). A cohort of 30 day-old female α_2CAR^-/- mice and their wild-type (WT) controls were treated with a supraphysiological dose of T3 for 30 or 90 days, which induced a thyrotoxic state in both mouse lineages. The micro-computed tomographic (μCT) analysis showed that α_2C-AR^-/- mice present lower trabecular bone volume (BV/TV) and number (Tb.N), and increased trabecular separation (Tb.Sp) in the femur compared with WT mice; which was accompanied by decreased bone strength (determined by the three-point bending test) in the femur and tibia. The opposite was observed in the vertebra, where α_2C-AR^-/- mice show increased BV/TV, Tb.N and trabecular thickness (Tb.Th), and decreased Tb.Sp, compared with WT animals. In spite of the contrasting bone phenotypes of the femur and L5, thyrotoxicosis negatively regulated most of the micro architectural features of the trabecular bone in both skeletal sites of WT, but not of α_2C-AR^-/- mice. T3 treatment also decreased biomechanical properties (maximum load and ultimate load) in the femur and tibia of WT, but not of knockout mice. The mRNA expression of osteocalcin, a marker of mature osteoblasts, and tartrate-resistant acid phosphatase, which is expressed by osteoclasts and is involved in collagen degradation, was increased by T3 treatment only in WT, and not in α_2C-AR^-/- mice. Altogether, these findings suggest that α_2C-AR subtype mediates the effects of the SNS in the bone in a skeletal site-dependent manner, and that thyrotoxicosis depends on α_2C-AR signaling to promote bone loss, which sustains the hypothesis of a TH-SNS interaction to modulate bone remodeling and structure.

Postpartum thyroid dysfunction in women with autoimmune thyroiditis

INTRODUCTION

Autoimmune thyroiditis (AIT) is a predisposing factor for developing postpartum thyroid dysfunction (PPTD).

AIM

To study the characteristics of PPTD in women with AIT.

METHODS

Thirty-eight women with pre-existing AIT were included in the study. Thyroid-stimulating hormone, free triiodthyronine, free thyroxine, thyroid peroxidase antibodies, thyroglobulin antibodies were measured and ultrasound evaluation of the thyroid gland was performed in the first trimester of pregnancy and during the first year following delivery.

RESULTS

Thyroid dysfunction was recognized in 68.4% of the patients - 28.9% presented with hypothyroidism and 39.5 % with thyrotoxicosis. The immunological and morphological parameters did not differ between euthyroid women and those with thyroid dysfunction. At the end of the postpartum period restoration of euthyroid state (being on the treatment before pregnancy) was observed in 15.4% of patients with PPTD, while 84.6% required increase of the levothyroxine dose. The analysis found a significantly lower volume of the thyroid gland, shorter duration of the disease, a lower dose of levothyroxine before and during gestation in patients with impaired thyroid function at the end of the postpartum period.

CONCLUSION

The risk of PPTD in women with AIT predating pregnancy is higher among women with preserved thyroid functional capacity motivating a thorough assessment of thyroid hormone levels and close follow-up of those women during the postpartum period.

Prospective population-based study of the association between vitamin D status and incidence of autoimmune disease

Beside its traditional role in skeletal health, vitamin D is believed to have multiple immunosuppressant properties, and low vitamin D status has been suggested to be a risk factor in the development of autoimmune disease. We investigated the association between vitamin D status and development of autoimmune disease. We included a total of 12,555 individuals from three population-based studies with measurements of vitamin D status (25-hydroxy vitamin D). We followed the participants by linkage to the Danish National Patient Register (median follow-up time 10.8 years). Relative risks of autoimmune disease were estimated by Cox regression and expressed as hazard ratios, HRs (95 % confidence intervals CIs). There were 525 cases of incident autoimmune disease. The risk for a 10 nmol/l higher vitamin D was: for any autoimmune disease (HR = 0.94 % CI 0.90, 0.98); thyrotoxicosis (HR = 0.83, 95 % CI 0.72, 0.96); type 1 diabetes (HR = 0.95, 95 % CI 0.88, 1.02), multiple sclerosis (HR = 0.89, 95 % CI 0.74, 1.07), iridocyclitis (HR = 1.00, 95 % CI 0.86, 1.17); Crohn's disease (HR = 0.95, 95 % CI 0.80, 1.13), ulcerative colitis (HR = 0.88, 95 % CI 0.75, 1.04); psoriasis vulgaris (HR = 0.99, 95 % CI 0.86, 1.13); seropositive rheumatoid arthritis (HR = 0.97, 95 % CI 0.89, 1.07), and polymyalgia rheumatica (HR = 0.94, 95 % CI 0.83, 1.06). We found statistically significant inverse associations between vitamin D status and development of any autoimmune disease and thyrotoxicosis in particular. Our findings suggest a possible protective role of a higher vitamin D status on autoimmune disease but warrant further studies to clarify causality.

Race/Ethnicity and the prevalence of thyrotoxicosis in young Americans

BACKGROUND

Race/ethnicity may be a newly recognized risk factor for Graves' disease.

OBJECTIVE

The aim of this study was to examine the prevalence of thyrotoxicosis by race/ethnicity in Americans aged 12-49 years using three National Health and Nutritional Examination Surveys (NHANES).

METHODS

Data were analyzed from 17,939 participants in NHANES III (1988-1994), NHANES 1999-2002, and NHANES 2007-2010 with available thyroid function test results. Thyrotoxicosis was defined as a serum thyrotropin (TSH) of ≤0.1 mIU/L or subjects taking methimazole or propylthiouracil, and overt thyrotoxicosis was defined as high serum thyroxine and a serum TSH of ≤0.1 mIU/L. Logistic regression was performed accounting for the complex sampling design of NHANES, and the results from all three NHANES surveys were combined using a random-effects model.

RESULTS

There were 75 study participants with point prevalent thyrotoxicosis, representing a pooled prevalence of 0.4% for Americans aged 12-49 years. Prevalent thyrotoxicosis was nearly three times more likely in non-Hispanic black subjects compared with non-Hispanic whites (OR=2.9 [CI 1.5-5.7]), while there was no difference between the prevalence of thyrotoxicosis in Mexican Americans compared to non-Hispanic whites (OR=1.2 [CI 0.6-2.4]; I2 for heterogeneity=0% for both). Among 27 patients with overt thyrotoxicosis, the odds ratio was 8.7 [CI 0.7-112.6] for non-Hispanic blacks and 4.6 [CI 0.4-59.3] for Mexican Americans compared with non-Hispanic whites.

CONCLUSIONS

The results suggest there are race/ethnicity differences in the prevalence of thyrotoxicosis. Future studies should address whether these differences are due to heritable factors, environmental exposures, or a combination of both.

Serum human chorionic gonadotropin levels and thyroid hormone levels in gestational transient thyrotoxicosis: Is the serum hCG level useful for differentiating between active Graves' disease and GTT?

Gestational transient thyrotoxicosis (GTT) is defined as transient thyrotoxicosis caused by the stimulating effect of human chorionic gonadotropin (hCG) during pregnancy. We attempted to identify the serum hCG level that causes GTT, and we compared the serum hCG levels and thyroid hormone levels of GTT patients according to whether they had a background of thyroid disease. We also evaluated serum hCG as a parameter for differentiating between active Graves' disease (GD) and GTT. We reviewed the 135 cases of pregnant women who came to our hospital to be evaluated for thyrotoxicosis during their 7th to 14th week of pregnancy, and their serum hCG level was measured at that time. Among the 135 pregnant women with thyrotoxicosis; 103 of the women had GTT, and the other 32 women had active GD. There were no correlations between their serum hCG levels and free thyroid hormone levels. There were no significant differences in thyroid hormone levels or hCG levels among the GTT groups with different thyroid disease backgrounds; i.e., the GTT group without thyroid disease, GTT group with chronic thyroiditis, GTT group with non-functioning thyroid nodules, and GTT group with GD in remission. The serum hCG level of the GTT group was significantly higher than in the active GD group, but it was not a good parameter for differentiating between the two groups. The FT3/FT4 ratio of the active GD was significantly higher than in GTT group, and was a better parameter for differentiation.

Serum Adiponectin Levels and Changes in Glucose Metabolism before and after Treatment for Thyroid Dysfunction

OBJECTIVE

Adiponectin is an adipokine which is known to decrease in individuals associated with obesity and insulin resistance. In this study, we aimed to investigate the serum adiponectin levels and glucose metabolism in patients with thyroid dysfunction before and after treatment.

METHODS

Newly diagnosed overt hypothyroid (n=20) and thyrotoxic (n=23) patients and healthy controls (n=20) with a body mass index of <30 kg/m(2) were evaluated prospectively. Patients with a known state of insulin resistance, including prediabetes and overt diabetes, and individuals with chronic diseases were excluded. Thyroid function and fasting plasma glucose (FPG), insulin, homeostatic model assessment (HOMA) insulin resistance (HOMA-IR) and HOMA-beta cell function (HOMA-beta), lipid and adiponectin levels were investigated in the basal state and after the restoration of euthyroidism.

RESULTS

The basal fasting FPG levels were lower in the hypothyroid patients than the control subjects (p=0.02) and similar between the thyrotoxic patients and control subjects (p=0.127). The basal HOMA-beta levels were higher in the patients with hypothyroidism than in those with thyrotoxicosis (p=0.015). Following the restoration of euthyroidism, the FPG levels significantly increased in the hypothyroid patients (p=0.002) and decreased in the thyrotoxic (p=0.001) patients. The basal plasma adiponectin levels were 14.55±8.4 mcg/mL, 13.79±9.13 mcg/mL and 11.68±6.0 mcg/mL in the hypothyroid and thyrotoxic patients and healthy controls, respectively (p=0.503). The adiponectin levels decreased significantly in the patients with hypothyroidism (p=0.047), whereas they did not change in the patients with thyrotoxicosis (p=0.770) after achieving euthyroidism.

CONCLUSION

In this study, following the restoration of euthyroidism, the FPG levels increased in the hypothyroidism patients and decreased in the thyrotoxicosis patients, despite the lack of changes in the HOMA-IR and HOMA-beta levels. Meanwhile, the hypothyroid, thyrotoxic and euthyroid subjects had similar basal adiponectin levels, and a significant decrease in the adiponectin levels was observed after treatment for hypothyroidism, despite the absence of changes after treatment for thyrotoxicosis, indicating the need for further studies with a larger sample size.

Therapeutic particularities in amiodarone induced thyroid disorder in patients with underlying cardiac condition

AIM

the analysis of therapeutic approach in patients with basic heart condition and amiodarone induced thyroid dysfunction--correlations with the evolution and prognosis.

MATERIAL AND METHODS

The study included 215 patients, 90 men and 125 women aged between 35 and 87, with different cardiac pathologies hospitalized in the Cardiology Clinic between 2004-2014, who received amiodarone treatment, in most cases for prophylaxis of various arrhythmias, both supraventricular and ventricular. During the evolution, these patients have developed amiodarone-induced thyroid dysfunction (hypo- or hyper function).

RESULTS AND DISCUSSION

The evaluation of thyroid function after starting treatment was performed in 187 patients (86.97%). Diagnosis of amiodarone-induced thyroid dysfunction was based on hormonal dosages of TSH, FT4 and FT3, endocrinological examination and thyroid ultrasound. Thyroid dysfunction treatment was initiated, depending on the situation, in all patients during the hospitalization. Treatment included anti thyroid drugs or hormones substitution and in some cases a minimal dose of prednisone.

CONCLUSIONS

Thyroid dysfunction regardless of the type (with hypo- or hyper function) requires continuous changes of the cardiovascular treatment, and association, where appropriate, with thyroid dysfunction medication. In some cases the latter determines cardiovascular side effects, for instance corticotheraphy may become a factor of imbalance for the hemodynamic status of the patient (by fluid retention, increased blood pressure, hyper glycemia).

[Distribution of IgG subclasses of TgAb and TPOAb in sera from patients with Graves' disease, Graves' disease plus Hashimoto's thyroiditis and Hashimoto's thyrotoxicosis]

OBJECTIVE

To evaluate the distribution of IgG subclasses of TgAb and TPOAb in sera from patients with Graves' disease (GD), Graves' disease plus Hashimoto's thyroiditis (GH) and Hashimoto's thyrotoxicosis.

METHODS

Patients with GD (n = 33), GH (n = 31) or Hashimoto's thyrotoxicosis (n = 18) diagnosed by fine needle aspiration cytology at Department of Endocrinology of Peking University First Hospital, Beijing Haidian Hospital, China-Japan Friendship Hospital and Civil Aviation General Hospital during the period from January 2010 to May 2013 were enrolled. All of them had TgAb and TPOAb. The total serum IgG and IgG subclasses of TgAb and TPOAb were detected by antigen-specific enzyme-linked immunosorbent assay (ELISA). The prevalence and relative amount of IgG subclasses were calculated and compared among three groups.

RESULTS

The levels of TRAb in GD group (21.80(7.53, 40) U/L) were significantly higher than those in GH (7.30(3.10, 25.40) U/L) (P = 0.000) and Hashimoto's thyrotoxicosis groups (4.90(1.69, 16.43) U/L) (P = 0.003). And no significant differences were found in the levels of TgAb and TPOAb. The prevalence of TgAb IgG3 subclass in Hashimoto's thyrotoxicosis group (66.7%) was higher than GD group (35.5%) and GH group (36.4%) and the difference was close to significance (P = 0.066). There were significant differences of relative amount of TgAb IgG2 and TgAb IgG4 among three groups (P = 0.039 and 0.013), and GD patients had higher relative amounts of TgAb IgG2 (0.59(0.34, 0.94)) and TgAb IgG4 (0.57(0.28, 0.97)) than GH patients (TgAb IgG2, 0.31(0.23, 0.34); TgAb IgG4, 0.26(0.09, 0.48)) or patients with Hashimoto's thyrotoxicosis (TgAb IgG2, 0.32(0.24, 0.83); TgAb IgG4, 0.33(0.10, 0.65)) (for TgAb IgG2, P = 0.009 and 0.167; for TgAb IgG4, P = 0.005 and 0.041 respectively). No significant difference was found in the prevalence of each TPOAb IgG subclass. The difference of relative amount of TPOAb IgG2 among three groups was close to significance (P = 0.069). And the relative amount was higher in sera from GD patients (0.39 ± 0.04) than that in GH patients (0.29 ± 0.13) or patients with Hashimoto's thyrotoxicosis (0.26 ± 0.02) (P = 0.104 and 0.002 respectively).

CONCLUSION

The patients with high levels of TgAb IgG2, TgAb IgG4 and TPOAb IgG2 subclasses have a greater risk of GD. The IgG subclass distribution of TgAb and TPOAb might help to differentiate the causes of thyrotoxicosis in autoimmune thyroid diseases.

An unusual case of hypopituitarism and transient thyrotoxicosis following asymptomatic pituitary apoplexy

Although pituitary function is often impaired in pituitary apoplexy, the development of thyrotoxicosis is rare. We describe an unusual case of hypopituitarism due to pituitary apoplexy coexisting with transient hyperthyroidism. A 74-year-old woman presented with severe fatigue, palpitation, appetite loss, hypotension, and hyponatremia. Endocrine studies showed hyperthyroidism and anterior pituitary hormone deficiencies. A magnetic resonance imaging suggested recent-onset pituitary apoplexy in a pituitary tumor, although the patient had no apoplectic symptoms such as headache and visual disturbance. Thyrotoxicosis and adrenal insufficiency worsened her general condition. Glucocorticoid supplementation improved her clinical symptoms and hyponatremia. Serum anti-thyrotropin receptor and thyroid-stimulating antibody titers were negative, and her thyroid function was spontaneously normalized without antithyroid medication, suggesting painless thyroiditis. Thereafter, her thyroid function decreased because of central hypothyroidism and 75 µg of levothyroxine was needed to maintain thyroid function at the euthyroid stage. The pituitary mass was surgically removed and an old hematoma was detected in the specimen. Considering that painless thyroiditis develops as a result of an autoimmune process, an immune rebound mechanism due to adrenal insufficiency probably caused painless thyroiditis. Although the most common type of thyroid disorder in pituitary apoplexy is central hypothyroidism, thyrotoxicosis caused by painless thyroiditis should be considered even if the patient has pituitary deficiencies. Because thyrotoxicosis with adrenal insufficiency poses a high risk for a life-threatening adrenal crisis, prompt diagnosis and treatment are critical.

Determinants of serum T4 and T3 at the time of diagnosis in nosological types of thyrotoxicosis: a population-based study

OBJECTIVE

To characterize thyroid hormone levels at the time of diagnosis in the nosological types of thyrotoxicosis diagnosed in the population and to analyze determinants for serum thyroxine (T4) and tri-iodothyronine (T3).

DESIGN

Population-based study of thyrotoxicosis at disease onset.

METHODS

In the period 1997-2000, we prospectively identified all patients diagnosed with incident primary overt thyrotoxicosis in a Danish population cohort and classified patients into ten well-defined nosological types of disease (n=1082). Untreated levels of serum T3, T4, and T3:T4 ratio were compared and related to sex, age, level of iodine deficiency, smoking status, alcohol intake, iodine supplement use, co-morbidity, and TSH receptor antibodies (TRAbs) in multivariate models.

RESULTS

Graves' disease (GD) patients had much higher levels of T3 and higher T3:T4 ratio at diagnosis compared with other thyrotoxic patients, but with a profound negative association between hormone levels and age. In GD, patients diagnosed in the area with more severe iodine deficiency had lower levels of T3 and T4. TRAb-negative GD patients had biochemically mild thyrotoxicosis. Higher age was also associated with lower degree of biochemical thyrotoxicosis in nodular toxic goiter. We found no association between serum T3 and T4 and sex, smoking habits, iodine supplements, alcohol intake, or co-morbidity in any type of thyrotoxicosis.

CONCLUSIONS

The study gives new insight into the hormonal presentation of thyrotoxicosis and showed that young age, positive TRAb levels, but also residency in the area with higher iodine intake was positively associated with biochemical disruption in GD.

Thyroid profiles in a patient with resistance to thyroid hormone and episodes of thyrotoxicosis, including repeated painless thyroiditis

BACKGROUND

Thyrotoxic disease can be difficult to recognize in patients with resistance to thyroid hormone (RTH) because the clinical symptoms of thyrotoxicosis cannot be observed, and thyrotropin (TSH) may not be suppressed because of hormone resistance. Painless thyroiditis is a relatively common cause of thyrotoxicosis, but its occurrence in RTH has not been reported. We assessed the thyroid profile in a patient with RTH and episodes of thyrotoxicosis who experienced repeated painless thyroiditis.

PATIENT FINDINGS

A 44-year-old Japanese woman with RTH, which was confirmed by the presence of a P453A mutation in the thyroid hormone receptor β (TRβ) gene, showed a slight elevation of the basal levels of thyroid hormones, which indicated that her pituitary RTH was mild. She experienced a slight exacerbation of hyperthyroxinemia concomitant with TSH suppression. A diagnosis of painless thyroiditis was made because of the absence of TSH receptor antibodies, low Tc-99m pertechnetate uptake by the thyroid gland, and transient suppression followed by a slight elevation of TSH following the elevation of thyroid hormones. The patient's complaints of general malaise and occasional palpitations did not change throughout the course of painless thyroiditis. Three years later, painless thyroiditis occurred again without any deterioration of the clinical manifestations.

CONCLUSIONS

Mild pituitary RTH can be overcome by slight exacerbation of hyperthyroxinemia during mild thyrotoxicosis. When pituitary resistance is severe and TSH is not suppressed, thyrotoxicosis may be overlooked.

Lithium toxicity precipitated by thyrotoxicosis due to silent thyroiditis: cardiac arrest, quadriplegia, and coma

BACKGROUND

Lithium is widely used to treat bipolar disorders. Lithium toxicity is generally caused by inappropriately high doses of lithium or impaired lithium excretion. Most lithium is eliminated via the kidneys and, since thyroid hormone increases tubular reabsorption of lithium, thyrotoxicosis could contribute to the development of lithium toxicity. We report a case of severe lithium toxicity that was apparently precipitated by the onset of thyrotoxicosis resulting from silent thyroiditis and dehydration.

PATIENT FINDINGS

The patient was a 64-year-old woman who was admitted for muscle weakness in the lower extremities, diarrhea, and palpitations. She had bipolar disorder and was being treated with lithium carbonate, which she discontinued one week before admission. Her circulating lithium levels had been monitored yearly. Early in her admission she was dehydrated and had febrile episodes, paroxysmal atrial fibrillation, and muscle weakness. Initially, fluid therapy was started, but she lost consciousness and had a cardiac arrest for 2 minutes due to prolonged sinus arrest. Chest compression and manual artificial ventilation were performed, and body surface pacing was started. Serum lithium was markedly elevated to 3.81 mEq/L (therapeutic range, 0.4-1.0 mEq/L), and thyroid hormone levels were increased (free triiodothyronine, 8.12 pg/mL; free thyroxine, 4.45 ng/dL), while thyrotropin (TSH) was suppressed (<0.01 μIU/mL). Hemodialysis was performed, and a temporary pacemaker was inserted for severe sinus bradycardia. The serum thyroglobulin was 4680 ng/mL (reference range, <32.7 ng/mL). A TSH receptor antibody test was negative. Glucocorticoid therapy and inorganic iodine (100 mg) were administered and continued until day 11. However, her neurological symptoms deteriorated with floppy quadriplegia and deep coma. She gradually recovered. On day 36, she was discharged without any neurological symptoms or thyrotoxicosis.

SUMMARY

A 64-year-old woman taking lithium for bipolar disorder developed lithium toxicity in the setting of what seemed likely to be a recent onset of thyrotoxicosis due to silent thyroiditis.

CONCLUSIONS

Thyrotoxicosis may be a contributing cause of lithium toxicity, particularly if it is abrupt in onset and even with cessation of lithium therapy if renal function is compromised. Thyroid function should be assessed immediately in patients with suspected lithium toxicity.

The first case of association between postpartum thyroiditis and thyroid hormone resistance in an Italian patient showing a novel p.V283A THRB mutation

BACKGROUND

Postpartum thyroiditis (PPT) is characterized by the development of postpartum thyroid dysfunction, which may occur up to 12 months after delivery. The syndrome usually presents with transient thyrotoxicosis, followed by transient hypothyroidism. The association of this condition with resistance to thyroid hormones (RTH) has never been described.

PATIENT FINDINGS

In this report, we describe a 30-year-old patient affected by RTH due to a novel p.V283A thyroid hormone receptor-β (THRB) heterozygous mutation in exon 8, which affects the ligand-binding domain, never before described in literature. A simple polymorphism was excluded through screening of 100 healthy controls.

SUMMARY

The patient became pregnant twice (in 2008 and in 2009) and developed PPT after both deliveries. Two months after her first pregnancy and one month after her second pregnancy, she presented with severe endogenous thyrotoxicosis and concomitant suppressed thyrotropin (TSH) levels, which represents an unusual finding in patients affected by RTH. Other causes of hyperthyroidism were excluded. After the hyperthyroid phase, she became hypothyroid (TSH >75 mU/L and low free-thyroxine and free-tri-iodothyronine levels), and eventually returned to her usual euthyroid status. During the course of PPT, no specific treatment was required, except for β-blockers used to treat tachycardia during the hyperthyroid phase.

CONCLUSIONS

We report a unique case of a woman affected by RTH, due to a novel mutation V283A in THRB, who experienced PPT with a severe thyrotoxic phase after both her pregnancies. The association between RTH and PPT has never been reported in the literature. In particular, the marked suppression of TSH occurring when levels of TH are particularly elevated is not a frequent condition during RTH.

Episodes of paralysis in Chinese men with thyrotoxic periodic paralysis are associated with elevated serum testosterone

BACKGROUND

The strong predilection for thyrotoxic periodic paralysis (TPP) to occur in males suggests androgen may contribute to its pathogenesis. We therefore sought to determine if serum total and free testosterone (TT and FT) concentrations differed among patients with TPP during episodes of paralysis, patients with TPP between episodes of paralysis, and patients with Graves' disease (GD) not having TPP.

METHODS

A total of 105 Chinese men were included in the study, and were divided into three groups. Group 1 consisted of men with TPP who were studied during episodes of paralysis; group 2 consisted of men with TPP who were studied between episodes of paralysis; group 3 consisted of men with GD not having TPP. Patients in each were different persons. Serum electrolytes, free triiodothyronine (FT3), free thyroxine (FT4), TT, and FT were measured. Multiple regression analyses and analysis of covariance were performed to analyze the relationship of serum parameters, group status, and age.

RESULTS

One multiple regression analysis was used to determine if serum TT concentrations were associated with age, FT3, FT4, or group status. This analysis indicated that age, FT4 level, and group status were significantly and independently associated with serum TT concentrations. With regard to group status, patients in group 1 had serum TT concentrations 0.92 ng/mL higher than patients in group 3 (p=0.033). As to FT4 level, TT concentrations increased by 0.016 ng/mL for each additional pmol/L of FT4 (p=0.002). Another multiple regression analysis was used to determine if serum FT concentrations were associated with age, FT3, FT4, group status, or serum TT concentrations. This analysis revealed that serum TT concentrations and group status were significantly and independently associated with serum FT concentrations. In terms of group status, patients in group 1 had serum FT concentrations of 2.11 pg/mL greater on average than patients in group 3 (p=0.006).

CONCLUSIONS

We infer that episodes of paralysis in Chinese men with TPP are associated with elevated serum testosterone. We also found serum TT and FT concentrations of men with GD are both affected by group status; serum TT rather than FT concentrations are associated with thyroid function.

Prevalance of gestational diabetes mellitus in patients with gestational transient thyrotoxicosis

OBJECTIVE

To investigate prevalence of gestational diabetes mellitus (GDM) in patients with gestational transient thyroxicosis (GTT).

METHODS

Fifty two patients with GTT and 100 age matched healthy pregnant women were included. Fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), LDL-cholesterol, HDL-cholesterol, triglyceride, thyrotrophin (TSH) and thyroid hormones were measured at thyrotoxic state in GTT patients and at 6-12th weeks of pregnancy in control group. Oral glucose tolerance test (OGTT) with 100 g glucose was performed and laboratory parameters were re-evaluated at 24-28th weeks of pregnancy in all subjects.

RESULTS

Mean age of patients with GTT was 28.46 ± 5.45 and control group was 27.78 ± 3.75(p = 0.085). Patients with GTT had significantly higher HbA1c, LDL-cholesterol and HDL-cholesterol at 6-12th weeks of pregnancy (p < 0.01, p < 0.01 and p = 0.034, respectively). TSH was negatively correlated with HbA1c and LDL-cholesterol in thyrotoxic state in GTT patients (r = -0.393, p < 0.001 and r = -0.293, p < 0.001, respectively). OGTT showed GDM in 7 (13.5%) GTT patients and 4 (4%) healthy pregnants (p = 0.047). HbA1c, LDL-cholesterol and HDL-cholesterol were higher in GTT patients compared to healthy pregnants also at 24-28th weeks of pregnancy (p < 0.001, p < 0.001 and p = 0.024).

CONCLUSION

Although GTT is known to be a transient state that can resolve spontaneously, it might have negative effect on carbohydrate metabolism like other causes of hyperthyroidism.

Inappropriate elevation of serum thyrotropin levels in patients treated with axitinib

BACKGROUND

Although anticancer treatment with the tyrosine kinase inhibitor (TKI) axitinib frequently causes thyroid dysfunction, the associated mechanism and clinical features have not been elucidated.

METHODS

Six patients were treated with axitinib for metastatic renal cell carcinoma at the Hamamatsu University School of Medicine between 2008 and 2010. We reviewed their thyroid function results and compared them to those of patients treated with two other TKIs, sunitinib or sorafenib, and to those of subjects with normal hypothalamic-pituitary-thyroid (HPT) function.

RESULTS

Axitinib-induced thyroid dysfunction was observed in all patients, and two patterns were observed: increased serum thyrotropin (TSH) levels within one month after administration occurred in five patients and transient thyrotoxicosis due to destructive thyroiditis occurred in five patients within 7 months of treatment. Four patients exhibited both. When the relationship between the serum TSH and thyroid hormones was evaluated using plots of TSH versus both free thyroxine and free triiodothyronine, four patients showed an inappropriate elevation of serum TSH during administration of axitinib. Their values apparently shifted against the regression line compared to data from patients with a normal HPT function. A similar tendency, though weaker, was observed in some patients treated with sunitinib or sorafenib.

CONCLUSION

This is the first study to report an inappropriate elevation of serum TSH levels in patients treated with axitinib.

Thyroid function and prevalence of anti-thyroperoxidase (TPO) and anti-thyroglobulin (Tg) antibodies in outpatients hospital setting in an area with sufficient iodine intake: influences of age and sex

In order to examine the prevalence of thyroid disease in a hospital outpatient setting, in an area of sufficient iodine intake, serum levels of TSH, T4, T3, anti-Tg and anti-TPO antibodies were examined in 909 individuals with an age range of 12.4 to 88.5 years, participating in a checkup outpatient setting. The study was conducted in Henry Dynant Hospital located in the metropolitan area of Athens, Greece, during a 2 year period. Hormonal parameters were determined by chemiluminescence immunoassay. Overt thyrotoxicosis was found in 4.95% of the total population and subclinical thyrotoxicosis in 5.5%. Overt hypothyroidism was found in 1.43% and subclinical hypothyroidism in 4.51%. In male population, overt thyrotoxicosis was found in 4.4 % and subclinical thyrotoxicosis was also found in 4.4%. On the other hand, overt hypothyroidism was found in 1.4% and subclinical hypothyroidism was found in 3.7% in males. In female population, overt thyrotoxicosis was found in 5.2% whereas subclinical thyrotoxicosis was found in 6.0%. Overt hypothyroidism was found in 1.5% and subclinical hypothyroidism was found in 4,9% in females. Positive anti-TPO antibodies were detected more often (30.4%) than anti-Tg (15.4%) in the tested population. The positivity in both anti-TPO and anti-Tg antibodies was correlated with abnormally high TSH concentrations after the age of 50 years, especially in female population. In conclusion distinct profile of thyroid hormonal parameters was observed in inhabitants in the metropolitan area of Athens, with overt thyrotoxicosis strikingly overcome overt hypothyroidism while subclinical forms of each dysfunction also exhibit analogous results.

Thyroid diseases and female reproduction

Thyroid diseases are very common in women of reproductive age. The aim of this study was to review the current evidence on physiology, pathophysiology, diagnosis and management of women with thyroid disorders that are currently seeking fertility, undergoing assisted reproduction technologies (ART) or being pregnant. Normal thyroid function is essential for normal function of the gonadal axis, thus important in maintaining normal reproductive capacity. On the contrary, any type of thyroid dysfunction may reduce the likelihood of pregnancy; the latter can be restored to normal after appropriate treatment. Over eight million children have been born as a result of assisted reproduction techniques (ART) since 1978. As these procedures are becoming more common in clinical practice, the exact impact of thyroid status on reproductive outcomes as well as that of drugs used in ART on thyroid function has to be fully elucidated. Maternal thyroid function is crucial, especially during the first weeks of gestation, for offspring's wellness and brain development. On the other hand, normal physiological mechanisms during gestation can have a major impact on maternal thyroid function. As human chorionic gonadotropin (hCG) has a thyroid stimulating hormone (TSH)-like effect, high hCG concentrations are associated with thyroid stimulation, both functionally (lower serum TSH concentrations) and anatomically (increased thyroid volume). Although the association between maternal hypothyroidism and increased perinatal morbidity has been described for over a century, more recently, even the presence of anti-thyroid antibodies has been associated with adverse pregnancy outcomes, such as recurrent abortions and placental abruption. This is of major clinical significance, as anti-thyroid antibodies are surprisingly prevalent in pregnancy, especially during the first two trimesters.