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.

A pregnant woman with an autonomously functioning thyroid nodule: a case report.

BACKGROUND: The epidemiology and natural history of autonomously functioning thyroid nodules (AFTNs) have not been elucidated. Here we report the pregnant Japanese woman with an AFTN. CASE PRESENTATION: The patient was a 31-year-old woman who was hospitalized due to the placenta previa associated with threatened abortion at the 16 weeks of her third pregnancy. At her second pregnancy, she was euthyroid but had a single, 2.3 cm nodule on her right thyroid lobe. Her thyroid hormone level was trended increased with her pregnancy progression, and the thyrotoxic state was remained after delivery. Before her third pregnancy, her hyper-vascular nodule enlarged to 3.4 cm at regular monitoring. When she visited our hospital, she was at 16 weeks of pregnancy and had thyrotoxicosis with negative TSH-receptor antibody. She delivered a baby weighing 2615 g without hypothyroidism at 39 weeks of pregnancy by natural delivery. After delivery, a 99mTc scintigram showed a hot spot in her right thyroid lobe. She was diagnosed with AFTN and treated with methimazole while nursing. CONCLUSIONS: This case showed that hCG stimulation during pregnancy caused thyroid nodule enlargement and enhanced thyroid hormone production. The pregnancy could be the pathological stimulus and provides chance to diagnosis for AFTNs.

Thyroid function related symptoms during levothyroxine monotherapy in athyreotic patients.

Previous reports by us and other investigators showed that among athyreotic patients on levothyroxine (LT4) following total thyroidectomy patients with normal serum thyroid-stimulating hormone (TSH) levels had mildly low serum free triiodothyronine (FT3) levels, whereas patients with mildly suppressed serum TSH levels had normal serum FT3 levels and patients with strongly suppressed serum TSH had elevated serum FT3 levels. The objective of this study was to clarify which of these three patient groups are closer to their preoperative euthyroid condition based on reported subjective symptoms. We prospectively studied 148 consecutive euthyroid patients with papillary thyroid carcinoma who underwent a total thyroidectomy. Symptoms reflecting thyroid function documented preoperatively and following 12 months of LT4 after thyroidectomy were compared. In 65 patients with strongly suppressed TSH levels significant changes in symptoms with tendencies towards thyrotoxicosis were seen with regards to heat and cold tolerance (p < 0.01), bowel movements (p < 0.05), and hand tremors (p < 0.05). In 33 patients with normal TSH levels, significant changes in symptoms with tendencies towards hypothyroidism were seen with regards to heat and cold tolerance (p < 0.05) and activity (p < 0.05). Lastly, in 50 patients with mildly suppressed TSH levels and FT3 levels equivalent to preoperative levels, all symptom items remained equivalent to their preoperative levels. Symptoms reflecting thyroid function in patients on LT4 following total thyroidectomy suggested that patients with mildly suppressed TSH levels were closest to a euthyroid status. These data provide useful findings regarding the management of patients following total thyroidectomy.

Thyroid diseases and bone health.

Thyroid hormones are essential for skeletal development and are important regulators of bone maintenance in adults. Childhood hypothyroidism causes delayed skeletal development, retarded linear growth and impaired bone mineral accrual. Epiphyseal dysgenesis is evidenced by classic features of stippled epiphyses on X-ray. In severe cases, post-natal growth arrest results in a complex skeletal dysplasia. Thyroid hormone replacement stimulates catch-up growth and bone maturation, but recovery may be incomplete dependent on the duration and severity of hypothyroidism prior to treatment. A severe phenotype characteristic of hypothyroidism occurs in children with resistance to thyroid hormone due to mutations affecting THRA encoding thyroid hormone receptor α (TRα). Discovery of this rare condition recapitulated animal studies demonstrating that TRα mediates thyroid hormone action in the skeleton. In adults, thyrotoxicosis is well known to cause severe osteoporosis and fracture, but cases are rare because of prompt diagnosis and treatment. Recent data, however, indicate that subclinical hyperthyroidism is associated with low bone mineral density (BMD) and an increased risk of fracture. Population studies have also shown that variation in thyroid status within the reference range in post-menopausal women is associated with altered BMD and fracture risk. Thus, thyroid status at the upper end of the euthyroid reference range is associated with low BMD and increased risk of osteoporotic fragility fracture. Overall, extensive data demonstrate that euthyroid status is required for normal post-natal growth and bone mineral accrual, and is fundamental for maintenance of adult bone structure and strength.

Hyperthyroidism.

Hyperthyroidism is characterised by increased thyroid hormone synthesis and secretion from the thyroid gland, whereas thyrotoxicosis refers to the clinical syndrome of excess circulating thyroid hormones, irrespective of the source. The most common cause of hyperthyroidism is Graves' disease, followed by toxic nodular goitre. Other important causes of thyrotoxicosis include thyroiditis, iodine-induced and drug-induced thyroid dysfunction, and factitious ingestion of excess thyroid hormones. Treatment options for Graves' disease include antithyroid drugs, radioactive iodine therapy, and surgery, whereas antithyroid drugs are not generally used long term in toxic nodular goitre, because of the high relapse rate of thyrotoxicosis after discontinuation. ß blockers are used in symptomatic thyrotoxicosis, and might be the only treatment needed for thyrotoxicosis not caused by excessive production and release of the thyroid hormones. Thyroid storm and hyperthyroidism in pregnancy and during the post-partum period are special circumstances that need careful assessment and treatment.

Protective effects of 5,7,4'-trihydroxy-6,3'dimethoxy-flavone 5-O-α-l-rhamnopyranoside, isolated from Annona squamosa leaves in thyrotoxicosis and in hepatic lipid peroxidation in rats.

Hitherto unknown protective effects of 5,7,4'-trihydroxy-6,3'dimethoxy-flavone 5-O-α-l-rhamnopyranoside (THDMF-Rha); isolated from Annona squamosa leaves were evaluated in l-thyroxine (l-T4)-induced thyrotoxicosis in rats. Administration of l-T4 at 500µg/kg body weight for 12days increased the levels of serum thyroid hormones, the activity of 5'-monodeiodinase-I (5'DI) and hepatic glucose-6-phosphatase (G-6Pase) as well as lipid peroxidation (LPO); with a parallel decrease in the levels of cellular antioxidants and serum lipids. However, administration of the isolated THDMF-Rha at a pre-standardized dose for 15days ameliorated the l-T4-induced alterations in the levels of thyroid hormones, hepatic LPO, G-6-Pase, 5'DI activity, and cellular levels of antioxidants and improved the status of different serum lipids, suggesting its antithyroidal and antioxidative potential. As compared to standard antithyroid drug, propylthiouracil, THDMF-Rha appeared to be more promising.

Effects of swimming training on tissue glycogen content in experimental thyrotoxic rats.

Thyrotoxicosis, a condition in which there is an excessive amount of circulating thyroid hormones, leads to reduced glycogen content in different tissues. In this study we analyzed the effects of aerobic swimming training on liver, heart, and skeletal muscle glycogen content in experimentally induced thyrotoxicosis. Wistar male rats were divided into euthyroid sedentary (ES, n = 12), euthyroid trained (ET, n = 11), thyrotoxic sedentary (TS, n = 12), and thyrotoxic trained (TT, n = 10) groups. Thyrotoxic groups received daily i.p. doses of T4 (sodium levothyroxine, 25 µg/100 g body mass) through the experimental period, and trained groups swam for 1 h at 80% of the aerobic-anaerobic transition intensity, 5 days/week for 4 weeks. Heart and liver glycogen stores were ∼30% lower in T4 treated compared with nontreated groups, but were not changed by training status. On the other hand, glycogen content in mixed fiber type gastrocnemius of TT was 1.5- to 2.3-fold greater than those in other groups, whereas no significant differences were found for the slow soleus muscle. Increased gastrocnemius but not soleus, liver, or heart glycogen indicates that in mild long-term thyrotoxicosis chronic swimming affects glycogen stores in a tissue-specific manner.

Bone disease in thyrotoxicosis.

Thyrotoxicosis, a clinical syndrome characterized by manifestations of excess thyroid hormone, is one of the commonly-recognised conditions of the thyroid gland. Thyrotoxicosis causes acceleration of bone remodelling and though it is one of the known risk factors for osteoporosis, the metabolic effects of thyroxine on bone are not well discussed. Studies show that thyroid hormones have effects on bone, both in vitro and in vivo. Treatment of thyrotoxicosis leads to reversal of bone loss and metabolic alterations, and decreases the fracture risk. There are limited studies in India as to whether these changes are fully reversible. In this review we discuss about the effects of thyrotoxicosis (endogenous and exogenous) on bone and mineral metabolism, effects of subclinical thyrotoxicosis on bone and mineral metabolism and effects of various forms of treatment in improving the bone mineral density in thyrotoxicosis.

[Application of herbal medicine alba in treatment of patients with the pathology of thyroid].

High prevalence of hyperplastic and autoimmune diseases of thyroid in Ukrainian population is determined by endemic deficit of iodine and selenium. The aim of this research was to assess the place of biologically-active additions on the basis of herbal material containing an iodine and selenium in prophylaxis and treatment of thyroid pathology. During the six month period 55 patients received herbal preparation Alba twice a day. The levels of TSH, volume of thyroid, the sizes of nodular goiter (ultrasound investigation) were measured before and at the end of the investigation. The levels of thyroid stimulating antibodies to TSH receptor (AB-r TSH) were evaluated in patients with hyperthyroidism. The results of Alba application showed that in patients with thyroid pathology (diffuse nontoxic goiter, hyperthyroidism and chronic thyroiditis) it was possible to reduce the volume of thyroid, normalize its function, and decrease the level of AB-r TSH in diffuse toxic goiter. We also found approximately 20 % shortening of the time needed to get target level of TSH and finally the duration of treatment of thyrotoxicosis.

Subclinical Thyrotoxicosis and Cardiovascular Risk: Assessment of Circulating Endothelial Progenitor Cells, Proangiogenic Cells, and Endothelial Function.

Background: Subclinical thyrotoxicosis (SCT) is defined by low or undetectable thyroid-stimulating hormones and normal thyroid hormones. The treatment of SCT is uncertain despite being associated with increased cardiovascular risk (CVR) and mortality. Circulating endothelial progenitor cells (cEPCs) and circulating angiogenic cells (CACs) have been found to be reduced in conditions with CVR. We aimed to evaluate whether endothelial function and cEPC and CAC counts were reduced in SCT and to study the in vitro effect of triiodothyronine (T3) on proangiogenic cell (PAC) function from young healthy controls. Methods: cEPCs (quantified by flow cytometry, 20 SCT/20 controls), CACs following in vitro cultures (15 SCT/14 controls), paracrine function of CACs, endothelial function by flow-mediated dilation (FMD, 9 SCT/9 controls), and the effect of T3 on apoptosis and endothelial nitric oxide synthase (eNOS) expression in PACs were studied. Results: p < 0.001, CD133+/VEGFR-2+ 0.4 (0.0-0.7) vs. 0.6 (0.0-4.6), p = 0.009, CD34+/VEGFR-2+ 0.3 (0.0-1.0) vs. 0.7 (0.1-4.9), p = 0.002; while CAC count was similar. SCT predicted a lower cEPC count after adjustment for conventional CVR factors. FMD was lower in SCT subjects versus controls (% mean ± SD, 2.7 ± 2.3 vs. 6.1 ± 2.3, p = 0.005). In vitro studies showed T3 increased early apoptosis and reduced eNOS expression in PACs. Conclusions: In conclusion, SCT is associated with reduced cEPC count and FMD, confirming increased CVR in SCT. Future outcome trials are required to examine if treatment of this subclinical hyperactive state improves cardiovascular outcome. Clinical Trial Registration: http://www.controlled-trials.com/isrctn/, identifier ISRCTN70334066.

Determinants and outcome of amiodarone-associated thyroid dysfunction.

OBJECTIVE: Amiodarone is frequently associated with thyroid dysfunction. Identifying predictors for amiodarone-associated thyroid dysfunction and assessing treatment outcome may aid clinicians in daily practice. METHODS: We included 303 consecutive patients with amiodarone therapy for cardiac arrhythmias (260 with atrial fibrillation and 43 with ventricular arrhythmias). Thyroid function tests were performed every 6 months. RESULTS: Mean age was 63 ± 12 years and 66% was male. After median follow-up of 3·3 (0·1-24) years, 23 (8%) patients developed amiodarone-associated thyrotoxicosis (incidence rate 1·9 per 100 person years) and 18 (6%) hypothyroidism (incidence rate 1·1 per 100 person years). The only predictor for amiodarone-associated thyrotoxicosis was age <62 years [HR = 2·4 (95% CI 1·0-5·7), P = 0·05]. Predictors for amiodarone-associated hypothyroidism were thyroid stimulating hormone >1·4 mU/l at baseline [HR = 5·1 (95% CI 1·1-22·4), P = 0·03], left ventricular ejection fraction <45% [HR = 3·8 (95% CI 1·1-13·3), P = 0·04] and diabetes mellitus at baseline [HR = 3·3 (95% CI 1·1-10·3), P = 0·04]. Gender was not a predictor for amiodarone-associated thyroid dysfunction. Five out of 12 (42%) patients with thyrotoxicosis exhibited spontaneous normalization of thyroid function on continuation of amiodarone therapy. Mean time to normalization in the total group was 6·2 ± 3·3 months, with no difference between continuing or discontinuing amiodarone (6·6 ± 3·8 vs 5·8 ± 2·8 months, P = 0·5). CONCLUSIONS: During median follow-up of 3·3 years, the incidence of amiodarone-associated thyrotoxicosis was higher compared to hypothyroidism. Only general predictors for amiodarone-associated thyroid dysfunction were observed. Discontinuation of amiodarone did not influence treatment outcome.

Estrogens modulate RANKL-RANK/osteoprotegerin mediated interleukin-6 effect on thyrotoxicosis-related bone turnover in mice.

Interleukin-6 has been shown to cause imbalance between bone resorption and formation in thyrotoxicosis. The aim of the present study was an attempt to estimate the influence of estrogens on thyrotoxicosis-related disturbances in bone turnover in relation to RANKL-RANK/osteoprotegerin system in IL-6 deficient mice. The study was performed on 56, 12-13 weeks old, female mice: C57BL/6J (wild-type; WT) and C57BL/6J (IL6-/-Kopf) (IL-6 knock-out; IL6KO). The mice were randomly divided into 8 groups with 7 mice in each one: 1. WT controls, 2. IL6KO controls, 3. WT mice with thyrotoxicosis, 4. IL6KO mice with thyrotoxicosis, 5. WT ovariectomized, 6. IL6KO ovariectomized, 7. WT ovariectomized mice with thyrotoxicosis, and 8. IL6KO ovariectomized mice with thyrotoxicosis. Experimental model of menopause was evoked by bilateral ovariectomy carried out in 8-9 weeks old mice. Thyrotoxicosis was induced by intraperitoneal injection of levothyroxine at a dose of 1 µg/g daily over 21 days. The serum levels of TRACP5b, osteocalcin, OPG, and RANKL were determined by ELISA. RANKL serum concentrations were elevated significantly in all groups of ovariectomized mice as compared to respective controls, however, in a minor degree in IL6KO thyrotoxic mice as compared to wild-type animals. Osteoprotegerin serum levels were significantly increased in all thyrotoxic groups of mice except ovariectomized IL6KO animals. To sum up, the results of the present study suggest that IL-6 plays a key role in stimulation of RANKL-RANK/OPG system and this effect is strongly enhanced in conditions of accelerated bone turnover such as thyrotoxicosis and/or estrogen depletion.

[Cardiometric data as indications to surgical treatment of elderly and senile patients suffering from thyrotoxicosis].

On the basis of studying clinical symptoms of thyrotoxicosis in elderly patients and an analysis of results of investigation of the heart the authors marked out additional indications to surgical treatment of this category of patients. Results of surgical treatment of elderly and senile patients suffering from thyrotoxicosis are also described.

[Quality of life of patients before and after surgical treatment of diffuse toxic goiter].

Quality of life of 89 patients with diffuse toxic goiter was analyzed before surgical intervention and at different terms after thyroidectomy or terminal subtotal resection of the thyroid gland using questionnaire SF-36. It was found that quality of life of patients with diffuse toxic goiter was lower than that of respondents without such pathology. The indices of quality of life one year after thyroidectomy (terminal subtotal resection of the thyroid gland) remained depending on the duration of the disease and complications of thyrotoxicosis, became reliably larger as compared with preoperative level due to social activity and emotional state.

Behavioral assessment of children and adolescents with Graves' disease: A prospective study.

Previous studies have identified frequent comorbid neuropsychiatric disorders and conditions in adults with thyrotoxicosis. These studies are scarce or even lacking in pediatric population. This work aimed to study the behavior of children and adolescents with Graves' disease (GD). This study included 35 children with GD (boys = 15; girls = 25; mean age: 11.45±1.50yrs) and 40 healthy children (boys = 20; girls = 20; mean age: 12.54±1.62yrs). Behavior was assessed using Child Behavior Checklist (CBCL). Children with GD were assessed during periods of thyroid hormone elevation (active disease) and normalized thyroid hormones (with anti-thyroid drugs or ATDs). Compared to healthy children, patients during periods of thyroid hormone elevation (74.29%) and normalized thyroid hormones (31.43%) had higher frequencies of behavioral abnormalities and scorings of total CBCL scale (P = 0.01; P = 0.04, respectively) and its subscales' [Anxious/Depressed (P = 0.02; P = 0.04), Withdrawn/Depressed (P = 0.03; P = 0.04) and Somatic Complaints (P = 0.03; P = 0.127) and Social (P = 0.01; P = 0.225), Thought (P = 0.01; P = 0.128) and Attention (P = 0.01; P = 0.01) problems], indicating internalizing and externalizing problems. The majority of patients had at least two different behavioral problems. Marked improvement was found during period of normalized thyroid hormones (P = 0.001). Correlation analyses showed significant associations between total CBCL scoring and age at onset (P = 0.01; P = 0.001) and lower concentrations of thyroid stimulating hormone (TSH) (P = 0.001; P = 0.04) and higher concentrations of free thyroxine (fT4) (P = 0.01; P = 0.02), triiodothyronine (fT3) (P = 0.01; P = 0.03) and thyrotropin receptor antibodies (TRAbs) (P = 0.001; P = 0.01) during periods of thyroid hormone elevation and normalized thyroid hormones, respectively. Multiple linear regression analysis showed that "at presentation" lower concentrations of TSH (P = 0.001; P = 0.03) and higher concentrations of fT4 (P = 0.001, P = 0.01), fT3 (P = 0.01; P = 0.06) and TRAbs (P = 0.001; P = 0.001) were predictors of behavioral problems during periods of active disease and normalized thyroid hormones. We conclude that GD is associated with higher frequencies and severities of anxiety, depression and inattention during periods of thyroid hormone elevation as well as normalized thyroid hormones with ATDs. Therefore, early diagnosis and optimizing management are required to improve children's social life.

INa and IKir are reduced in Type 1 hypokalemic and thyrotoxic periodic paralysis.

We evaluated voltage-gated Na(+) (I(Na)) and inward rectifier K(+) (I(Kir)) currents and Na(+) conductance (G(Na)) in patients with Type 1 hypokalemic (HOPP) and thyrotoxic periodic paralysis (TPP). We studied intercostal muscle fibers from five subjects with HOPP and one with TPP. TPP was studied when the patient was thyrotoxic (T-toxic) and euthyroid. We measured: (1) I(Kir), (2) action potential thresholds, (3) I(Na), (4) G(Na), (5) intracellular [Ca(2+)], and (6) histochemical fiber type. HOPP fibers had lower I(Na), G(Na), and I(Kir) and increased action potential thresholds. Paralytic attack frequency correlated with the action potential threshold, G(Na) and I(Na), but not with I(Kir). G(Na), I(Na), and [Ca(2+)] varied with fiber type. HOPP fibers had increased [Ca(2+)]. The subject with TPP had values for G(Na), I(Na), action potential threshold, I(Kir), and [Ca(2+)] that were similar to HOPP when T-toxic and to controls when euthyroid. HOPP T-toxic TPP fibers had altered G(Na), I(Na), and I(Kir) associated with elevation in [Ca(2+)].

Mutations of GNAS and TSHR genes in subclinical toxic multinodular goiter.

OBJECTIVES: This study aimed to detect the mutations of the GNAS and TSHR genes in subclinical toxic multinodular goiter (sTMG) and to evaluate the relationship between these mutations and sTMG. METHODS: Forty-four patients with sTMG and 20 matched controls (multinodular goiter) were recruited into this study. All of the patients underwent subtotal thyroidectomy. Gene mutations were analyzed by direct DNA sequencing of the polymerase chain reaction-amplified part of exons. RESULTS: In the sTMG group, 3 mutations of the GNAS gene were identified in 7 patients (15.9%), and 6 mutations of the TSHR gene were identified in 14 patients (31.8%). The mutation rate of the TSHR gene in patients with sTMG was significantly higher than that in the control group. Furthermore, in the sTMG group, statistical analysis indicated that mutations were significantly correlated with the serum level of thyroid-stimulating hormone for the TSHR gene, but no significant difference was found for the GNAS gene. Also, no significant difference was found in mutation positivity of the 2 genes between patients with nodules who were born before universal salt iodization and patients with nodules who were born afterward (p > 0.05). CONCLUSIONS: The results indicate that a mutation of the TSHR gene may be related to sTMG. The serum thyroid-stimulating hormone level plays an important role in the mutagenesis.

Thyroid hormones, their carrier proteins, and thyroid antibodies in the pleural effusion of two patients with graves' disease-induced thyrotoxicosis.

INTRODUCTION: Concentrations of thyroid hormones, their carrier proteins, and thyroid antibodies in plasma have been extensively investigated, but those in pleural effusion have not. PATIENTS AND MEDTHODS: In the present study, we report, for the first time, the concentrations of thyroid hormones, their carrier proteins, and thyroid antibodies in the pleural effusion of two thyrotoxicosis patients with Graves' disease. RESULTS: The pleural effusions were transudates. The concentrations of thyroid hormone carrier proteins, such as thyroxine-binding globulin (TBG), thyroxine-binding prealbumin (TBPA), and albumin (Alb) were approximately 30-50% of the plasma. The concentrations of total triiodothyronine (TT3), total tetraiodothyronine (TT4), free triiodothyronine (FT3), and free tetraiodothyronine (FT4) were approximately 15-40%, 45-55%, 45-75%, and 80-85% of the plasma, respectively. The concentration of thyroid stimulating hormone receptor antibody (TRAb) (equal to TSH-binding inhibitory immunoglobulins%; TBII%) was approximately 90% of the plasma. CONCLUSION: If the pleural effusions were treated with diuretics, substantial quantity of thyroid hormones and thyroid antibodies in the pleural effusion may have returned to the plasma, and might exacerbate thyrotoxicosis. For patients with thyrotoxicosis and pleural effusion, thoracentesis should be considered. The present findings will contribute to the understanding and treatment of hyperthyroidism-induced pleural effusion.

Contribution of radioiodine uptake measurement and thyroid scintigraphy to the differential diagnosis of thyrotoxicosis.

Both clinical and subclinical thyrotoxicosis can result from a wide range of disorders. Establishing the correct etiology underlying thyrotoxicosis is essential to direct treatment towards its specific pathophysiologic process. Based on clinical experience and guideline recommendations, radioiodine iodine uptake (RAIU) measurement and scintigraphy are often requested as the first-line investigation in thyrotoxic patients; however, their specific individual contribution to the differential diagnosis of thyrotoxicosis has not been previously investigated. In our study we aimed at evaluating the diagnostic role of RAIU measurement and scintigraphy in the management of thyrotoxicosis. A total of 108 patients with clinical and 42 patients with subclinical thyrotoxicosis were included in this retrospective study. All patients had RAIU measured at 24 hours after (131)I-iodide administration, followed by thyroid scintigraphy. Based on the combination of RAIU and scintigraphy, patients were classified as having diffuse toxic goiter (DTG) in 44% (the most common diagnosis), toxic adenoma in 15.9%, thyroiditis in 14%, and toxic multinodular goiter in 2.7%, while the pattern was inconclusive in 22.7% of all patients. When considering only patients with clinical thyrotoxicosis, the scan was inconclusive in 12.9% of patients whereas it was inconclusive in 47.6% of patients with subclinical thyrotoxicosis. There was a highly significant association between thyrotoxic status and scan result, with a statistically significant better performance of RAIU and scintigraphy in patients with clinical thyrotoxicosis when compared to patients with subclinical thyrotoxicosis considered as a whole (P<0.001). Instead, no statistically significant difference was observed between patients with subclinical thyrotoxicosis and TSH <0.1 mU/L and patients with TSH between 0.1 mU/L and 0.4 mU/L (P=0.191). In conclusion, we confirm the key role of RAIU and scintigraphy in the management of thyrotoxicosis and document its better performance in patients with clinical thyrotoxic status.