Long-term follow-up of treatment of thyrotoxicosis by three different methods

Effective Preoperative Plasmapheresis Treatment of Severe Hyperthyroidism in a Patient with Giant Toxic Nodular Goiter and Methimazole-Induced Agranulocytosis

Agranulocytosis is a rare but very serious complication of thyrostatic therapy. In severe hyperthyroidism, the removal of circulating thyroid hormones by plasmapheresis may be an effective therapeutic option. This report describes the therapeutic difficulties and successful preoperative treatment with plasmapheresis in a 63-year-old patient admitted to the Endocrinology Clinic with severe hyperthyroidism, during the course of giant toxic nodular goiter and agranulocytosis, which occurred after 2 weeks of taking methimazole. During hospitalization, methimazole treatment was discontinued and therapy with steroids, a beta blocker, propylthiouracil, Lugol’s solution, lithium carbonate, and antibiotics were initiated. Granulocyte colony growth stimulating factor was also used to resolve agranulocytosis. Due to the failure to achieve euthyreosis using this approach, we decided to conduct thyroid surgery, as a life-saving action, after preparation of the patient by plasmapheresis. Two plasmapheresis procedures were performed, resulting in a decrease in the concentration of free thyroid hormones. Total thyroidectomy was performed and there were no complications during surgery. We conclude that plasmapheresis may be considered as an effective alternative treatment option for the preparation of patients with hyperthyroidism for surgery, when the clinical situations prevent the use of conventional treatments for hyperthyroidism and when immediate life-saving surgery is necessary.

Safety of long-term antithyroid drug treatment? A systematic review

Continued low-dose MMI treatment for longer than 12-18 months may be considered in patients not in remission. However, ATDs are not free from adverse effects. We undertook a systematic review to clarify safety of long-term ATD treatment. Medline and the Cochrane Library for trials published between 1950 and Nov 2018 were systematically searched. We included original studies containing data for long-term (> 18 months) ATD treatment. Two reviewers independently extracted data from included trials and any disagreement was adjudicated by consensus. Of 615 related articles found, 12 fulfilled the criteria. Six articles had data for adults, five for non-adults and one article had data for both groups. The sample sizes ranged between 20 and 249 individuals, and the mean duration of ATD treatment ranged between 2.1 and 14.2 years. Considering all data from 1660 patients treated with ATD for a mean duration of 5.8 years (around 10,000 patient-years), major complications occurred only in 14 patients: 7 severe agranulocytosis, 5 severe liver damage, one ANCA-associated glomerulonephritis and one vasculitis with small cutaneous ulcerations. Minor complications rates were between 2 and 36%, while more complications were in higher doses and in the children. The most reported AE was cutaneous reaction; the other adverse events were elevated liver enzymes, leukocytopenia, arthritis, arthralgia, myalgia, thrombocytopenia, fever, nausea and oral aphthous. Long-term ATD treatment is safe, especially in low dose and in adults, indicating that it should be considered as an earnest alternative treatment for GD.

Systemic Thyroid Hormone Status in Treated Graves' Disease

OBJECTIVES

We aimed to compare the markers of thyroid hormone status in treated euthyroid Graves' patients and levothyroxine (LT4)-treated hypothyroid Graves' patients.

METHODS

We collected the data of 277 patients, including 140 radioiodine-treated hypothyroid Graves' patients on LT4 treatment (group 1), 83 euthyroid Graves' patients on methimazole (MMI) therapy (group 2), and 54 euthyroid Graves' patients off MMI or radioiodine therapy for > 2 years (group 3). After the exclusion of diabetic patients, 130, 73, and 52 patients remained for analysis in groups 1, 2, and 3, respectively. Pearson and Spearman correlation coefficients were employed to assess the relationships between T3:T4 ratio and variables in each group along with univariate and multivariate linear regression models.

RESULTS

The mean age and female/male ratio were similar in the three groups. Serum fT4 was significantly higher and T3, TSH, TPOAb, and TRAb were significantly lower in group 1 than in group 2 and combined groups 2 and 3, which translated to 27% lower serum T3:T4 ratio in group 1. Higher BMI, serum cholesterol, and LDL cholesterol and lower HDL cholesterol were observed in group 1 than in combined groups 2 and 3. In multivariate regression analysis, the T3:T4 ratio was significantly higher in combined groups 2 and 3 than in group 1 in the presence of BMI and serum fasting blood glucose, triglycerides, and TSH.

CONCLUSIONS

Hypothyroid Graves' patients using LT4 exhibited lower T3:T4 ratio despite lower TSH levels and their BMI and lipid parameters differed from those of euthyroid Graves' patients.

Cardiovascular Morbidity and Mortality After Treatment of Hyperthyroidism with Either Radioactive Iodine or Thyroidectomy

BACKGROUND

Hyperthyroid patients remain at an increased risk of cardiovascular diseases (CVDs) after restoring euthyroidism. The impact of the different treatment modalities of hyperthyroidism on future CVD risk remains unclear. The aims of this study were to assess cardiovascular morbidity and mortality in hyperthyroidism before and after treatment, and to compare the effects of two different treatment modalities: radioactive iodine (RAI) and thyroid surgery.

METHODS

A comparative cohort study was conducted among 6148 hyperthyroid patients treated with either RAI or thyroidectomy and 18,432 age- and sex-matched controls. First, hospitalizations due to CVDs prior to the treatment were analyzed. Second, the hazard ratios (HR) for any new hospitalization and mortality due to CVDs after treatment were estimated among all the hyperthyroid patients compared to the age- and sex-matched controls and also in the RAI-treated patients compared to the thyroidectomy-treated patients. The results were adjusted for prevalent CVDs at the time of treatment.

RESULTS

Before treatment for hyperthyroidism, hospitalizations due to all CVDs were more common in the hyperthyroid patients compared to the controls (odds ratio = 1.61 [confidence interval (CI) 1.49-1.73]). During the post-treatment follow-up, hospitalizations due to CVDs remained more frequent among the patients (HR = 1.15 [CI 1.09-1.21]), but there was no difference in CVD mortality (HR = 0.93 [CI 0.84-1.03]). Compared to the patients treated with thyroidectomy, the RAI-treated patients had a higher risk of hospitalization due to all CVDs (HR = 1.17), atrial fibrillation (HR = 1.28), as well as a higher CVD mortality rate (HR = 2.56). Yet, treatment with RAI resulting in hypothyroidism was not associated with increased CVD morbidity compared to thyroidectomy.

CONCLUSIONS

Hyperthyroidism increases the risk of CVD-related hospitalization, and the risk is sustained for up to two decades after treatment with RAI or surgery. Hyperthyroid patients treated with RAI remain at a higher CVD risk compared to patients treated with thyroidectomy. Hypothyroidism during follow-up, however, predicts better cardiovascular outcomes.

Radiation-related thyroid autoimmunity and dysfunction

The thyroid gland is vulnerable not only to external radiation but also to internal radiation, because the thyroid cells can incorporate radioactive iodine when synthesizing thyroid hormones. Since radiation-induction of thyroid neoplasia, including thyroid cancer, is well recognized, the data on radiation-related thyroid autoimmunity and dysfunction are summarized and reviewed. High-dose irradiation, irrespective of being external or internal, is strongly associated with a risk of hypothyroidism (with the prevalence ranging from 2.4% to 31%) and of Graves' hyperthyroidism (with the prevalence being up to 5%). It is easy to understand that high-dose irradiation induces hypothyroidism with some frequency, because high-dose irradiation destroys the thyroid gland. On the other hand, the basis for development of hyperthyroidism is mechanistically unclear, and it is merely speculative that autoantigens may be released from damaged thyroid glands and recognized by the immune system, leading to the development of anti-thyrotropin receptor antibodies and Graves' hyperthyroidism in subjects who are immunologically predisposed to this ailment. In contrast, the data on moderate to low-dose irradiation on thyroid autoimmunity and dysfunction are inconsistent. Although it is difficult to draw a definitive conclusion, some data may suggest a transient effect of moderate- to low-dose irradiation on hypothyroidism and autoimmune thyroiditis, implying that the effect, if it exists, is reversible. Finally, no report has shown a statistically significant increase in the prevalence of moderate- to low-dose irradiation-induced Graves' hyperthyroidism.

Long-Term Antithyroid Drug Treatment: A Systematic Review and Meta-Analysis

BACKGROUND

Several studies have reported inconsistent findings on the advantages and disadvantages of long-term treatment with antithyroid drugs (ATD). A systematic review and meta-analysis was undertaken to clarify the numerous aspects of long-term treatment with ATD.

METHODS

Medline and the Cochrane Library for trials published between 1950 and May 2016 were systematically searched. Studies containing data for long-term (>24 months) ATD treatment were included. Summary estimates of pooled prevalence, odds ratio, and weighted mean difference were calculated with a random effects model.

RESULTS

Of 587 related articles found, six fulfilled the inclusion criteria. Long-term ATD treatment induced a remission rate of 57% [confidence interval (CI) 45-68%], a rate that was higher in adults than in non-adults (61% vs. 53%). The rate of complications was 19.1% [CI 9.6-30.9%], of which only 1.5% were major complications. The annual remission rate for each year of treatment was 16% [CI 10-27%], which was higher in adults than non-adults (19% vs. 14%). However, it should be noted that this is not a true linear correlation, but a positive relationship can be suggested between time and remission rate. Meta-regression revealed that smoking had a significant lowering effect on remission rate.

CONCLUSIONS

Long-term ATD treatment is effective and safe, especially in adults, indicating that it should be considered as an alternative treatment for Graves' disease.

Efficacy of Low-dose (2 millicurie) versus Standard-dose (4 millicurie) Radioiodine Treatment for Cats with Mild-to-Moderate Hyperthyroidism

Background

Radioiodine (¹³¹I) is effective treatment for hyperthyroidism in cats, but optimal dose to restore euthyroidism without inducing hypothyroidism is unclear. Treatment‐induced hypothyroidism can lead to azotemia and reduced duration of survival.

Objective

To compare efficacy and short‐term outcomes of low‐dose ¹³¹I versus higher, standard‐dose ¹³¹I as treatment for hyperthyroidism.

Animals

A total of 189 client‐owned cats undergoing ¹³¹I treatment for mild‐to‐moderate hyperthyroidism (serum T₄ ≥ 4.0 μg/dL and <13.0 μg/dL).

Methods

Prospective, nonrandomized, cohort study comparing treatment with either low‐dose (2 mCi, n = 150) or standard‐dose (4 mCi, n = 39) ¹³¹I. Serum T₄, thyroid‐stimulating hormone (TSH), and creatinine concentrations were measured after 1, 3, and 6 months to determine persistent hyperthyroidism, overt hypothyroidism (low T₄, high TSH), subclinical hypothyroidism (normal T₄, high TSH), and azotemia.

Results

There was no significant difference in prevalence of cats with persistent hyperthyroidism between standard‐ and low‐dose treatment groups at 3 (0% versus 5.3%; P = .34) and 6 (0% versus 3.3%; P = .51) months. Overt (18% versus 1%; P = .0005) or subclinical (46% versus 21%; P = .004) hypothyroidism was more common in cats at 6 months after standard‐dose ¹³¹I. No difference in incidence of azotemia existed between groups, but cats treated with standard‐dose ¹³¹I had higher creatinine concentrations (P < .05) and higher percent rises in creatinine (P < .0001).

Conclusions and Clinical Importance

Low‐dose ¹³¹I is safe and effective for cats with mild‐to‐moderate hyperthyroidism, as evidenced by a cure rate of >95% with reduced frequency of iatrogenic hypothyroidism and azotemia.

The Incidence of Hypothyroidism Following the Radioactive Iodine Treatment of Graves' Disease and the Predictive Factors Influencing its Development

The purpose of this study is to evaluate and compare the incidence of hypothyroidism following different fixed radioactive iodine-131 (¹³¹I) activities in the treatment of Graves’ disease (GD) and to investigate the predictive factors that may influence its occurrence. This retrospective analysis was performed on 272 patients with GD who were treated with ¹³¹I, among whom 125 received 370 MBq and 147 received 555 MBq. The outcome was categorized as hypothyroidism, euthyroidism, and persistent hyperthyroidism. Multiple logistic regression analysis was performed to identify significant risk factors that affect the development of hypothyroidism. The incidence of hypothyroidism following the first low activity was 24.8% with a high treatment failure rate of 58.4%, compared with 48.3% and 32% following high activity. The overall cumulative incidence of hypothyroidism following repeated activities was 50.7%, out of which 73.9% occurred after the first activity and 20.3% after the second activity. The higher ¹³¹I activity (P < 0.001) and average and mild enlargement of the thyroid gland (P = 0.004) were identified as significant independent factors that increase the rate of incidence of hypothyroidism (Odds ratios were 2.95 and 2.59). No correlation was found between the development of hypothyroidism and the factors such as age, gender, presence of exophthalmos, previous antithyroid medications, and the durations, and Technetium-99m (Tc-99m) pertechnetate thyroid uptake. In view of the high treatment failure rate after first low activity and lower post high activity hypothyroid incidence, high activity is recommended for GD patients, reserving the use of 370MBq for patients with average sized and mildly enlarged goiter; this increases patient convenience by avoiding multiple activities to achieve cure and long-term follow-up.

The effect of prior antithyroid drug use on delaying remission in high uptake Graves' disease following radioiodine ablation

Antithyroid drugs (ATDs) have been shown to attenuate the effectiveness of radioiodine (radioiodine ablation, RIA) therapy in Graves' disease. We undertook a study to look at the impact of iodine uptakes on the outcome of (131)I therapy. To determine the effect of prior ATD use on the duration of time to achieve cure in patients with high vs intermediate uptake Graves' disease who received a fixed dose (15 mCi) of (131)I radioiodine. In a retrospective study of patients with Graves' disease, 475 patients who underwent RIA were followed-up on a two-monthly basis with thyroid function tests. Of the 123 patients with a documented preablation RAIU and consistent follow-up it was observed that 40 patients had an intermediate RAIU (10-30%) and 83 subjects had a distinctly increased uptake (>30%). Successful cure was defined as the elimination of thyrotoxicosis in the form of low free thyroxin and rising TSH levels. When a standard dose of 15 mCi (131)I was administered, a cure rate of 93% was achieved. The median duration of time to cure (TC) was 129 days. Surprisingly, a direct proportional linear relationship (R(2)=0.92) was established between time to cure and radioiodine uptake (TC> 3 0%=172days, TC10 - 3 0%=105 days, P<0.001). Patients who used ATD medications took a proportionately longer duration to achieve remission (TCNO ATD=102days, TCATD=253days, P<0.001). The effect of prior ATD therapy in delaying remission was amplified in the subset of patients with higher uptakes (TC> 3 0% + ATD=310days, TC> 3 0% + NO ATD=102days, P<0.001) compared to those with the intermediate uptakes (TC10 - 3 0% + ATD=126 days, TC10 - 3 0% + NO ATD=99 days, P<0.001). RIA, using a dose of 15 mCi achieved a high cure rate. Higher uptakes predicted longer time to achieve remission, with prior ATD use amplifying this effect.

Predictive value of pyramidal lobe, percentage thyroid uptake and age for ablation outcome after 15 mCi fixed dose of radioiodine-131 in Graves' disease

PURPOSE

The purpose was to find out the efficacy of fixed 15 mCi radioactive iodine-131 (RAI) dose and predictive values of various factors for inducing hypothyroidism in Graves' disease (GD).

MATERIALS AND METHODS

Retrospective study conducted from January 2012 till August 2014. Patients with GD who had a technetium-99m thyroid scan, thyroid antibodies, received fixed 15 mCi RAI and did follow endocrine clinics for at least 6 months were selected. RAI was considered successful if within 6 months of RAI therapy patients developed hypothyroidism.

RESULTS

Of the 370 patients with GD who had RAI during study period, 210 (57%) qualified study criteria. Mean age of patients was 48 ± 15 years with female: male ratio of 69:31, positive thyroid antibodies in 61%, means thyroid uptake of 15.09 ± 11.23%, and presence of pyramidal lobe in 40% of total population. Hypothyroidism was achieved in 161 (77%) patients while 49 (23%) patients failed to achieve it (remained either hyperthyroid or euthyroid on antithyroid medication). Patients who became hypothyroid were significantly younger with higher proportion of presence of thyroid antibodies and pyramidal lobe and lower percentage thyroid uptake than those who failed. Multiple logistic regression analysis revealed that age (odds ratio; OR = 2.074), pyramidal lobe (OR = 3.317), thyroid antibodies (OR = 8.198), and percentage thyroid uptake (OR = 3.043) were found to be significant prognostic risk factors for post-RAI hypothyroidism. Gender was found to have nonsignificant association with the development of hypothyroidism. Receiver operating characteristic analysis revealed age <42 years and thyroid uptake <15% as threshold values for the development of post-RAI hypothyroidism.

CONCLUSION

We conclude that fixed (15 mCi) RAI dose is highly effective in rendering hypothyroidism in patients with GD. Age (≤42 years), thyroid uptake (≤15%) and presence of pyramidal lobe are strong predictors of hypothyroidism and must be considered for selecting optimal RAI dose.

Cardiovascular morbidity and mortality in surgically treated hyperthyroidism - a nation-wide cohort study with a long-term follow-up

OBJECTIVE

Previous studies suggest that patients with hyperthyroidism remain at an increased risk of cardiovascular morbidity even after restoring euthyroidism. The mechanisms of the increased risk and its dependency on the different treatment modalities of hyperthyroidism remain unclear. The aim of this long-term follow-up study was to compare the rate of hospitalizations for cardiovascular causes and the mortality in hyperthyroid patients treated surgically with an age- and gender-matched reference population.

PATIENTS AND MEASUREMENTS

A population-based cohort study was conducted among 4334 hyperthyroid patients (median age 46 years) treated with thyroidectomy in 1986-2007 in Finland and among 12,991 reference subjects. Firstly, the hospitalizations due to cardiovascular diseases (CVD) were analysed until thyroidectomy. Secondly, the hazard ratios for any new hospitalization due to CVDs after the thyroidectomy were calculated in Cox regression analysis adjusted with the prevalent CVDs at the time of thyroidectomy.

RESULTS

The risk of hospitalization due to all CVDs started to increase already 5 years before the thyroidectomy, and by the time of the operation, it was 50% higher in the hyperthyroid patients compared to the controls (P < 0·001). After the thyroidectomy, the hospitalizations due to all CVDs (HR 1·15), hypertension (HR 1·23), heart failure (HR 1·17) and valvular diseases or cardiomyopathies (HR 1·55) remained more frequent among the patients than among the controls for 20 years after thyroidectomy. The increased morbidity was not clearly related to the aetiology of hyperthyroidism. Despite the increased CVD morbidity among the patients, there was no difference in cardiovascular mortality.

CONCLUSIONS

The present study shows that hyperthyroidism increases the risk of hospitalization due to CVDs and the risk is sustained up to two decades after effective surgical treatment. However, there was no excess CVD mortality in the middle-aged patient cohort studied.

The results of therapeutic plasma exchange in patients with severe hyperthyroidism: a retrospective multicenter study

Hyperthyroidism characterized by elevated serum levels of circulating thyroid hormones. The aim of hyperthyroidism treatment is to achieve a euthyroid state as soon as possible and to maintain euthyroid status. However, drug withdrawal and utilization of alternative therapies are needed in cases in which leucopenia or impairment in liver functions is observed during medical therapy. In the present study, we aimed to present our cases which underwent therapeutic plasma exchange (TPE) due to severe hyperthyroidism. The results of 22 patients who underwent therapeutic plasma exchange due to hyperthyroidism in Apheresis Units of Erciyes University and Gaziantep University, between 2006 and 2012, were retrospectively reviewed. These cases had severe thyrotoxic values despite anti-thyroid drug use. After TPE, we observed a significant decrease in free thyroxin (FT4) (p<0.001) and free triiodotyhronin (FT3) (p<0.004) levels. There was statistically significant increase in the mean values of TSH levels after TPE (p<0.001). Clinical improvement was achieved in hyperthyroidism by TPE in 20 cases (91%). Both FT3 and FT4 levels remained above the normal limits in two of 22 patients. TPE should be considered as an effective and safe therapeutic option to achieve euthyroid state before surgery or radioactive iodine treatment. TPE is a useful option in cases with severe hyperthyroidism unresponsive to anti-thyroid agents and in those with clinical manifestations of cardiac failure and in patients with severe adverse events during anti-thyroid therapy.

Avaliação do peso corporal em pacientes com doença de Graves durante o tratamento com metimazol

OBJETIVO: Avaliar a alteração de peso durante o tratamento do hipertiroidismo e correlacioná-la com IL-6 e TNF-alfa. SUJEITOS E MÉTODOS: Quarenta e dois pacientes foram incluídos. Peso corporal (PC), índice de massa corpórea (IMC), características clínicas e laboratoriais foram registrados. IL-6 e TNF-alfa foram determinados antes do tratamento com metimazol (MMI) e no estado de eutiroidismo. RESULTADOS: O PC foi de 59,62 ± 11,5 kg no estado de hipertiroidismo e de 69,91 ± 14,4 kg no estado de eutiroidismo (p < 0,001). O IMC aumentou de 23,1 ± 3,8 kg/m² para 27 ± 4,7 kg/m² durante o tratamento (p < 0,0001). Antes da terapia, 66,6% tinham IMC < 25 kg/m² e 33,3%, IMC > 25 kg/m². No estado de eutiroidismo, 38% dos pacientes apresentavam IMC < 25 kg/m² e 62%, IMC > 25 kg/m² (p = 0,01). No estado de eutiroidismo, encontrou-se significativa diminuição nos valores de IL-6 e TNF-alfa, mas nenhuma correlação entre IL-6 e TNF-alfa com PC ou IMC. CONCLUSÃO: Um importante aumento no PC e IMC foi observado durante o tratamento do hipertiroidismo e alterações de IL-6 e TNF-alfa relacionam-se somente com o retorno ao eutiroidismo.

Analysis of ¹³¹I therapy and correlation factors of Graves' disease patients: a 4-year retrospective study

OBJECTIVE

To analyze the correlation therapeutic effects of first sufficiency ¹³¹I therapy in Graves' disease patients and improve its one-time curative ratio.

METHODS

Seven hundred and sixty-six patients (age range 12-77 years, mean 40.46 ± 13.12 years), including 237 men (range 12-77 years, 40.98 ± 12.64 years) and 529 women (range 14-75 years, 40.22 ± 13.34 years), who received the first I treatment were studied. The relevant examinations were performed before ¹³¹I therapy: the maximal radioactive iodine uptake of thyroid (RAIUmax), the effective half-life (EHL), the ultrasound of thyroid to calculate its weight, thyroid imaging with single-photon emission computed tomography and serum-free triiodothyronine (FT₃), free thyroxine (FT₄), sensitive thyroid-stimulating hormone (sTSH), anti-thyrotrophin receptor antibody (TRAb), thyroid-stimulating immunoglobulin, thyroglobulin antibody (TgAb), and anti-thyroid microsome antibody (TMAb). After the ¹³¹I dosage was determined, all the patients took ¹³¹I once orally. The ¹³¹I dosage range was 74-592 MBq (221.63 ± 100.64 MBq). A clinical and laboratory assessment was performed at 1, 3, 6, and 12 months after ¹³¹I therapy. Patients were divided into the clinically recovered group (symptoms and signs disappeared, free thyroid hormone levels were within or below the normal range, and sTSH was within or above the normal range) and the clinically unhealed group (symptoms and signs disappeared partially, free thyroid hormone levels were still above the normal range or within the normal range for a time and then increased again, and sTSH was constantly below the normal range). Data were analyzed by the unpaired t-test, the independent samples t-test, the χ² test, logistic regression, and Pearson bivariate correlation.

RESULTS

The one-time curative ratio of ¹³¹I therapy was 78.7% (including euthyroidism and hypothyroidism). Multiplicity in healing patients fit the logistic regression equation. The accuracy of discrimination of the equation was 79.5%. The influential factors of ¹³¹I therapy were age, RAIUmax, EHL, TRAb, and TgAb. RAIUmax and EHL were the protecting factors. Age, TRAb, and TgAb were the risk factors. TRAb influenced the one-time curative ratio between patients with negative and positive TRAb, which was higher in men (2.836 times) than in women (1.438 times).

CONCLUSION

¹³¹I therapy is an effective intervention for Graves' disease. The higher the RAIUmax and (or) the longer the EHL, the higher the possibility of a one-time cure. Elder patients or patients with a positive TRAb and (or) TgAb have a lower possibility of a one-time cure. Women with a positive TRAb should be administered an increased ¹³¹I dose to improve the curative effect.

[Short-term results of treatment with 131I in patients with multinodular goiter: effect of the associated degree of hyperthyroidism and other variables]

OBJECTIVE

To assess the effectiveness of radioactive iodine (RAI) therapy and the incidence of hypothyroidism post RAI in patients with subclinical hyperthyroidism or clinical hyperthyroidism with Multinodular Goiter (MNG).

METHODS

A retrospective study of 69 consecutive patients treated with (131)I for MNG during the year 2008 observed for six months. All patients received a single fixed dose of 16 mCi (592 MBq) weighted by the gland size. They were categorized into two groups: subclinical hyperthyroidism or clinical hyperthyroidism. We compared the success rate and the incidence of hypothyroidism.

RESULTS

The thyroid dysfunction was corrected in 82.09% of the patients. Success rate was 100% in the clinical hyperthyroidism group and 78.13% in the subclinical hyperthyroidism group (P=0.105). The overall incidence of hypothyroidism was 16.42%; 25.00% of patients with clinical hyperthyroidism and 14.55% with subclinical hyperthyroidism developed this secondary effect (P=0.400). No statistically significant differences were found in the success rate in the incidence of hypothyroidism when the results were analyzed according to the thyrotropin decrease in patients with subclinical hyperthyroidism. Seven patients had positive anti-thyroid peroxidase antibodies (anti-TPO) before therapy. The incidence of hypothyroidism was significantly higher in them (57.14% vs 11.67%; P=0.011). Cardiac arrhythmias were four times more frequent in patients with clinical hyperthyroidism. Previous treatment with thiamazol positively affected the outcome.

CONCLUSIONS

A single fixed weighted dose of (131)I is highly effective and safe for the control of clinical and subclinical hyperthyroidism due to MNG. Patients with anti-TPO antibodies may have a high risk of developing post-iodine hypothyroidism.

Male sex, African American race or ethnicity, and triiodothyronine levels at diagnosis predict weight gain after antithyroid medication and radioiodine therapy for hyperthyroidism

OBJECTIVE

To determine whether racial or ethnic differences affect weight gain after treatment of hyperthyroidism and to reassess established risk factors such as sex, age, and cause of hyperthyroidism.

METHODS

We conducted a retrospective review of medical records of 111 patients treated with radioiodine (RAI) for hyperthyroidism, with or without preceding antithyroid medication, during 2002 to 2005. We ascertained age, sex, race or ethnicity, insurance status, compliance with visits, serum triiodothyronine (T3) level at diagnosis, and cause of hyperthyroidism. Weights and serum thyroidstimulating hormone levels were obtained at diagnosis, at time of RAI therapy, and at 0 to 4 months, 4 to 8 months, 8 to 12 months, and 24 months after RAI treatment.

RESULTS

There was a significant weight increase after treatment of hyperthyroidism. Levels of T3 at initial diagnosis of hyperthyroidism, male sex, and black or Hispanic ethnicity were found to be independent predictors of weight gain after RAI treatment. We found a significant interaction between race or ethnicity and sex in multivariate models. There was no difference in thyroid function across racial or ethnic groups or the sexes. Age, cause of hyperthyroidism, posttreatment thyroid-stimulating hormone level, compliance, and insurance status were not found to be significant predictors of weight gain.

CONCLUSION

The T3 level at the time of diagnosis of hyperthyroidism is a strong predictor of weight gain after treatment of hyperthyroidism. Black race or ethnicity and male sex are also risk factors for weight gain.

Preoperative therapeutic plasma exchange in patients with thyrotoxicosis

The purpose of this report was to determine the effectiveness of therapeutic plasma exchange (TPE) in preoperative preparation of patients with thyrotoxicosis scheduled for either thyroid or nonthyroid surgery. We retrospectively reviewed 11 patients with thyrotoxicosis and those who prepared surgery with plasmapheresis between 1999 and 2008 at our institution. Ten patients underwent thyroid surgery and one patient was operated for femur fracture during antithyroid drug treatment. The indications for plasmapheresis in all patients with severe thyrotoxicosis were poor response to medical treatment (seven patients), agronulocytosis due to antithyroid drugs (three patients), iodine-induced thyrotoxicosis (Jodd Basedow effect in one patient), and rapid preparation for urgent orthopedic operation (one patient). After TPE, we observed a marked decrease in free thyroxin (FT3) and free triiodothyronin (FT4) levels; however, the decline in the biochemical values were not statically significant (P > 0.62, P > 0.15). Although both FT3 and FT4 levels remained above the normal limits in two of 11 patients, the signs and symptoms of thyrotoxicosis improved in all patients and no thyroid storm observed during the perioperative period. TPE can be considered a safe and effective alternative to prepare patients with thyrotoxicosis for surgery when drug treatment fails or is contraindicated and when emergency surgery is required.

Radiometabolic treatment of hyperthyroidism with a calculated dose of 131-iodine: results of one-year follow-up

Oral administration of radioactive iodine (131I) is a well-known and effective procedure for the treatment of hyperthyroidism. However, the optimal dose is still a matter of debate, as is the frequency of recurrence and hypothyroidism. The aim of our study was to evaluate the 1-yr outcome of a calculated dose of 131I activity in the treatment of hyperthyroidism, following the guidelines published jointly by the Italian Society of Endocrinology and the Italian Society of Nuclear Medicine.We studied 84 patients affected with hyperthyroidism (55 with Graves' disease and 29 with toxic adenoma), who were treated with a dose of 131I activity obtained by using the formula from the guidelines. In all patients serum free T4, free T3, and TSH were measured before, and 2, 6, and 12 months after radiometabolic therapy. A thyroid scan and thyroid uptake with 131I were also performed before treatment, and a thyroid ultrasound scan was obtained before and 1 yr after treatment. One year after treatment, 22 out of 55 patients with Graves' diseases (40.0%) had persistence/ recurrence of hyperthyroidism, whereas only 1 patient of the 29 with toxic adenoma (3.4%) was still in a hyperthyroid state. The frequency of hypothyroidism in patients responsive to therapy was higher in subjects with Graves' disease (45.5%), than in those with toxic adenoma (17.3%, p=0.02). Overall size reduction of the target lesion was 56.2+/-23.1%. In conclusion, the dose calculation suggested by the guidelines represents an effective method for treating thyroid toxic adenoma. In subjects with Graves' disease, we propose using a pre-determined 131I activity, which is higher than that derived from the guidelines. Such an approach would reduce the incidence of recurrent/persistent hyperthyroidism. On the other hand, an increase in post-131I hypothyroidism should not be regarded as a negative effect in these patients, since hypothyroidism is easily corrected, and the risk of worsening ophthalmopathy is reduced.

Prediction of cure and risk of hypothyroidism in patients receiving 131I for hyperthyroidism

CONTEXT

There is little consensus regarding the most appropriate dose of radioiodine ((131)I) to be administered to patients with hyperthyroidism.

OBJECTIVE

To compare the efficacy of fixed dose regimens of (131)I in curing hyperthyroidism and to define simple clinical and biochemical factors that predict outcome in individual patients.

DESIGN

Consecutive series of hyperthyroid subjects treated with (131)I.

SETTING

Single Secondary/Tertiary Care Hospital Clinic.

PARTICIPANTS

A total of 1278 patients (1013 females and 262 males, mean age 49.7 years) presenting with hyperthyroidism between 1984 and 2006.

INTERVENTION

Treatment with (131)I using a fixed dose regimen.

MAIN OUTCOME MEASURES

Probability of cure and risk of development of hypothyroidism following a single dose of (131)I.

RESULTS

Patients given a single dose of (131)I of 600 MBq (n = 485) had a higher cure rate (84.1%) compared with those receiving either 370 MBq (74.9%, P < 0.001) or those given 185 Bq (63%, P < 0.001). An increased incidence of hypothyroidism by 1 year was evident with higher doses (600 MBq: 60.4%; 370 MBq: 49.2%, P = 0.001; 185 Bq: 38.1%, P < 0.001). Binary logistic regression analysis identified a 600 Bq dose of (131)I [adjusted odds ratio, AOR 3.33 (2.28-4.85), P < 0.001], female gender [AOR 1.75 (1.23-2.47), P = 0.002], lower presenting serum free T4 concentration [AOR 1.01 (1.01-1.02), P < 0.001] and absence of a palpable goitre [AOR 3.33 (2.00-5.56), P < 0.001] to be independent predictors of cure. Similarly, a 600 MBq dose [AOR 3.79 (2.66-5.38), P < 0.001], female gender [AOR 1.46 (1.05-2.02), P = 0.02], younger age [AOR 1.03 (1.02-1.04), P < 0.001], absence of a palpable goitre [AOR 3.85 (2.38-5.88), P < 0.001] and presence of ophthalmopathy [AOR 1.57 (1.06-2.31), P = 0.02] were identified as independent factors predicting the probability of development of hypothyroidism at one year. Based on these findings, formulae to indicate probability of cure and risk of hypothyroidism for application to individual patients were derived.

CONCLUSIONS

Simple clinical/biochemical criteria can be used to predict outcome after (131)I treatment. These factors determine that males, those with severe biochemical hyperthyroidism, and those with a palpable goitre require larger doses (600 MBq) in order to achieve cure.

Thyroid echogenicity predicts outcome of radioiodine therapy in patients with Graves' disease

CONTEXT

Despite accounting for variations in gland size and iodine kinetics, the success of radioiodine therapy in patients with Graves' disease remains moderately common and unpredictable.

OBJECTIVES

We hypothesized that hypoechogenic glands, with large, densely packed cells, are more radiosensitive than normoechogenic glands, in which much radiation is wasted on more abundant colloid. We evaluated this hypothesis in a cohort of patients with Graves' disease.

DESIGN

This was a prospective trial of patients recruited during 4 yr and followed up 1 yr after radioiodine therapy.

SETTING

This trial was held in a university hospital-outpatient clinic.

PATIENTS

A total of 177 consecutive patients with first presentation of Graves' disease (28 males), 23-76 yr old, who relapsed after antithyroid therapy were included in the study.

INTERVENTION

The patients were assigned to an ablative target-absorbed dose of 200 Gy (n = 78) or randomly to 100 or 120 Gy of nonablative dose (n = 99).

MAIN OUTCOME MEASURES

The measures were incidences of hyperthyroidism, euthyroidism, and hypothyroidism at 12-month follow-up.

RESULTS

At follow-up there were 25 hyperthyroid, 44 euthyroid, and 108 hypothyroid patients. Compared with 96 patients with a hypoechogenic gland, in 81 patients with a normoechogenic gland, there were more hyperthyroid (22 vs. 7%) and euthyroid (41 vs. 11%), but less hypothyroid outcomes (37 vs. 81%; P < 0.0001). The other independent predictor of increased radioresistance was the large gland volume.

CONCLUSION

In patients with Graves' disease, normoechogenic and large glands are associated with increased radioresistance.

Hypothyroidism

Hypothyroidism is one of the most common disorders encountered in an endocrine office practice. This article reviews the epidemiology, etiology, clinical presentation, diagnosis, and treatment of hypothyroidism. We emphasize some of the more recent issues, such as combination thyroid hormone therapy, management of hypothyroidism during pregnancy, and the management of subclinical hypothyroidism.

Ultrasonography thyroid volume estimation in hyperthyroid patients treated with individual radioiodine dose

Radioiodine (RAI) therapy is a safe and effective treatment for hyperthyroidism and individual doses are frequently administered. Initial thyroid volume (TV) is an important parameter for RAI therapy. Ultrasonography (US) is considered the most reliable method of determining TV. The aim of this study was to evaluate TV by means of US in a cohort of 75 hyperthyroid patients before and after RAI therapy. According to clinical examination, thyroid US and technetium-99m (99mTc)-pernechnetate scintiscan, the diagnosis of hyperthyroidism was multinodular goiter (MNG) in 27, diffuse goiter (DG) in 32 and uninodular goiter (UNG) in 16 patients. The RAI dose to be administered was calculated according to TV and RAI uptake, up to a maximum of 600 MBq. TV was further evaluated 1, 3 and 6-12 months after RAI therapy. The initial TV was 42.3+/-4.0 ml for MNG, 29.7+/-2.8 ml for DG and 34.5+/-3.7 ml for UNG. After 6-12 months a non-significant TV reduction was observed in the MNG group even though the fraction of initial TV was 53.3+/-6.5%. Moreover, a significant TV reduction was noticed in the DG group (8.8+/-2.3 ml; p<0.001). In this group the fraction of initial TV was 28.6+/-3.2% at 6-12 month evaluation. A less marked, though still significant (p=0.04) TV reduction (19.6+/-3.2 ml) was also observed in the UNG group, the fraction of initial TV being 57.8+/-5.3% 6-12 months after RAI. In the whole patient population there was no significant correlation between TV reduction or TV at the last examination and initial TV, RAI dosage, baseline free T4 and TSH levels. No correlation was found between clinical condition at the last examination and TV reduction. In conclusion, these data justify TV estimation by means of US in the protocol of individual RAI dose for the therapy of hyperthyroidism. Our follow-up documents a poorly predictable TV reduction in all clinical conditions, but this is more pronounced and predictable in patients with diffuse toxic goiter.

131I induced hematological alterations in rat blood: protection by zinc

The present study was planned to determine the potential of zinc in attenuating the toxicity induced by 131I in rat blood. Female wistar rats were segregated into four main groups. Animals in Group I served as normal controls; Group II animals were administered a dose of 3.7 Mbq of 131I (carrier free) intraperitoneally, Group III was supplemented with Zinc in the form of ZnSo4.7H2O (227 mg/l drinking water), and Group IV was given a combined treatment of Zinc as well as 131I, in a similar way as was given to Groups IV and II animals, respectively. The effects of different treatments were studied on various parameters in rat blood including hemoglobin (Hb) levels, % hematocrit, zinc protoporphyrins (ZPP), activities of enzymes which included aminolevulinic acid dehydratase (delta-ALAD) and Na+ K+ ATPase and uptake of 65Zn in blood. The study revealed an increase in the levels of hemoglobin, % hematocrit, activities of delta-ALAD, Na+ K+ ATPase and uptake of 65Zn, 7 days after the 131I treatment. On the contrary, the levels of ZPP were found to be significantly decreased after 131I treatment. However, zinc treatment to 131I-treated animals significantly attenuated the various biochemical and hematological indices. Moreover, zinc treatment to the 131I-treated animals could significantly decrease the uptake of 65Zn, which was increased after 131I treatment. Based upon these data, the present study suggests that zinc has the potential to attenuate 131I induced toxicity by restoring the altered hematological indices and biochemical changes.

Subtotal Thyroidectomy: A Reliable Method to Achieve Euthyroidism in Graves’ Disease. Prognostic Factors

BACKGROUND

Subtotal thyroidectomy is a widely accepted surgical procedure for Graves' disease. The purpose of this work is to evaluate functional long-term results and determine predictive prognostic factors of postoperative thyroid function.

STUDY DESIGN

This is a retrospective study conducted on 202 patients with Graves' disease undergoing subtotal thyroidectomy during the period 1979-2002. Predictive prognostic factors of final thyroid status were investigated by logistic ordinal regression, and probability of hypothyroidism during the years of follow-up was obtained by the Kaplan-Meier method.

RESULTS

Surgery controlled hyperthyroidism in 196 out of 202 patients (97%). The probability of hypo-, eu-, and hyperthyroidism at 5 years was 62.1%, 35.5%, and 2.4%, respectively. No statistical change in thyroid function occurred in the follow-up after 60 months. Multivariate analysis by a logistic ordinal regression analysis showed that weight of the remnant, age, and gender seemed to influence long-term thyroid function. The higher rates of euthyroidism were obtained when the remnant weight was between 6 and 8 g. No recurrence or persistence of hyperthyroidism occurred with remnant weights under 5 g.

CONCLUSIONS

Subtotal thyroidectomy controlled hyperfunction symptoms in 97% of our patients. Cure (euthyroidism) of Graves' disease patients should be attempted by leaving a thyroid tissue remnant between 6 and 8 g. Even more significant, our results suggest that euthyroidism rates could be improved by leaving a smaller remnant in elderly women and greater remnants in young men.

Variability of the administered radioiodine doses for the treatment of hyperthyroidism in Belgium

OBJECTIVE

When using radioiodine for hyperthyroidism there is no consensus regarding the administration of fixed or calculated doses. Guidelines do not specify the preferable approach or the parameters to use to calculate the dose. Therefore, the dose might be quite different with regard to the chosen procedure. This study was undertaken to evaluate the variability of the amount of radioiodine administered in Belgium in various cases of hyperthyroidism.

DESIGN AND PATIENTS

Twenty-one Belgian nuclear medicine physicians received summarized clinical files from 10 patients suffering from overt hyperthyroidism (n = 7) or subclinical hyperthyroidism (n = 3). Five patients had homogeneous goiters, one had multinodular goiter, and four had hot nodule. Participants had to determine the radioiodine dose (millicuries, mCi) they would give in each case.

RESULTS

Proposed doses varied between 2 mCi and 25 mCi. Mean proposed dose for nodular disease was 10.71 mCi; it was 6.79 mCi for homogeneous goiter. For individual cases, a difference between the lowest and the highest dose of more than 17 mCi was observed in more than 50% of the cases.

CONCLUSIONS

We believe that more precise guidelines are mandatory, underlying uncertainties, controversies but recommending however, as minimal and maximal doses to administer, as well as clinical and biological parameters, if any, to be taken into account in order to modulate these doses.

Optimized radioiodine therapy for Graves?? disease: Two MIRD-based models for the computation of patient-specific therapeutic 131I activity

AIM

(131)I therapy is increasingly used for Graves' hyperthyroidism. Debate remains about the best method for calculating the activity to administer, as well as about the potential benefit of such computed activity. Several arguments plead, nevertheless, in favour of a personalized computation, such as inter-individual variations of thyroid volume and biokinetics.

METHODS

A MIRD-based dosimetric approach, with an additional extension that takes into account the variation of thyroid mass during the treatment, has been developed. This approach includes the benefits of a personalized determination of biokinetics. Results were compared with those of six methods widely used in routine practice. Forty-one patients were enrolled (34 women, seven men; mean age +/-SD: 48.11 +/- 6.4 years). (131)I uptakes were measured at 4, 24 and 96 h (36.2 +/- 14.6%, 42.8 +/- 9.7% and 27.6 +/- 6.8%, respectively), following administration of the tracer. The kinetics of iodine in the thyroid were evaluated using a two-compartment model (effective half-life of 5.1 +/- 1.6 days). Computations of activities to deliver the doses prescribed by the physician were done with the eight formalisms.

RESULTS

There was no statistical difference between results of the two MIRD-based formalisms (227 +/- 148 MBq and 213 +/- 124 MBq), which were also not significantly different from those obtained with the majority of the other methods (from 128 +/- 95 MBq to 275 +/- 223 MBq). However, a large intra-individual difference up to a factor of 2 between two given methods was found.

CONCLUSION

The formalism developed appears to be a good compromise between all the common formalisms already used in many institutions. Furthermore, it allows the exposures of target volumes and non-target volumes to be planned individually and practical individual radiation protection recommendations to be implemented.

The cost effectiveness of treatment modalities for thyrotoxicosis in a U.K. center

OBJECTIVE

This study determined the cost effectiveness of treating thyrotoxicosis using thionamide therapy, radioiodine or surgery in the United Kingdom.

DESIGN

One hundred thirty-five patients diagnosed with thyrotoxicosis (62% Graves' disease, 7% nodular disease, 5% thyroiditis, and 27% unknown aetiology) referred in 12 months were offered a fully informed choice of treatment modality. Thirteen patients with transient thyrotoxicosis were subsequently excluded from the analysis. Seventy-four patients (61%) received an 18-month course of thionamide therapy, 43 received radioiodine therapy (35%), and 5 had a thyroidectomy (4%) within the first year of diagnosis as their primary treatment. A successful outcome ("cure") was defined as euthyroidism 12 months after thionamide therapy or euthyroidism or hypothyroidism on thyroxine replacement at 24 months following radioiodine or thyroidectomy. Costs were calculated for outpatient attendances, laboratory tests, and initial and subsequent treatments.

MAIN OUTCOME

In the thionamide group 73% were "cured" at 30 months after initiating treatment compared to 95% in the radioiodine group and 100% treated by thyroidectomy at 24 months. Cost per "cure" was calculated to be 3,763 pounds (5,644 dollars) per patient who received thionamides, 1,375 pounds (2,063 dollars) per patient given radioiodine and 6,551 pounds (9,826 dollars) per patient who underwent thyroidectomy.

CONCLUSION

The most cost-effective primary treatment modality for thyrotoxicosis is radioiodine.

Optimisation of thyroid hormone replacement using an automated thyroid register

The high prevalence of thyroid dysfunction requires an efficient and effective means of monitoring and adjustment. We compared the current network of 12,524 patients with thyroid dysfunction with register data prior to 1991 to examine the precision of thyroxine replacement in patients with hypothyroidism and assess locally changing trends in treatment of hyperthyroidism. Since 1991, due to the associated adverse effects of a suppressed thyroid-stimulating hormone (TSH) (<0.03 mU/l), the network has facilitated a significant reduction in the proportion of thyroxine-treated patients with TSH suppression from 58.5% before 1991 to 9.2 +/- 3.8% thereafter. Since 1991, there has been an increased use of radioiodine by 14.3% [95% confidence interval (95% CI): 10.6-17.8] and a reduced use of thyroidectomy by 12.3% (95% CI: 8.8-15.8) to treat hyperthyroid patients compared with before 1991. Between the two treatments, there were no differences in subsequent rates of hypothyroidism or mean thyroxine dosage.

Subnormal energy expenditure: a putative causal factor in the weight gain induced by treatment of hyperthyroidism

AIMS

To examine the causes of weight gain occurring as an adverse effect of treatment of hyperthyroidism.

METHODS

We measured 24-h energy expenditure (EE), body composition and spontaneous physical activity (SPA) in eight patients before and 1 year after treatment of hyperthyroidism was initiated, and eight controls.

RESULTS

One year after initiation of treatment thyrotropin was normalized, thyroid hormones had fallen to the lower end of the reference range and fat mass had increased by 3.5 kg (p < 0.001). Twenty-four hour EE adjusted for fat-free mass (FFM) was 15% higher in hyperthyroid patients before treatment than in controls (p = 0.003), and treatment decreased 24-h EE by 1.9 MJ/day (p = 0.001). After treatment, 24-h EE, adjusted for FFM, was similar to the controls. Multiple regression analyses showed that the suppressed EE could partly be attributed to an iatrogenic suppression of thyroid hormones, resulting in lower sleeping EE. Twenty-four hour SPA was normal in the hyperthyroid state, but decreased after treatment by 21% (p = 0.045), to a level not significantly different, but still below that of the controls.

CONCLUSIONS

The study suggests that weight gain during treatment of hyperthyroidism might be due to subnormal levels of EE and SPA caused by a suppression of the thyroid hormone to a level in the lower end of the normal range.

Antithyroid drug therapy of Graves' hyperthyroidism: realistic goals and focus on evidence

Only a minority of patients with hyperthyroidism caused by Graves' disease will experience cure of disease with a permanent euthyroid state without medication. Antithyroid drugs are useful in attaining euthyroidism, and most patients will gradually enter remission of the autoimmune abnormality after becoming euthyroid. A stable euthyroid state may be sustained by prolonged low-dose medication. The risk of relapse of hyperthyroidism after withdrawal of medication seems to be independent of duration of therapy, once remission has been induced. A number of risk factors influence the outcome of therapy and they should be evaluated when planning duration of therapy with antithyroid drugs.

The incidence of recurrence and hypothyroidism after radioiodine treatment in patients with hyperthyroidism in Trakya, a mild iodine deficiency area, during the period 1991–2003

OBJECTIVE

The purpose of this retrospective study was to evaluate the incidence of recurrence and the success of radioiodine treatment (RIT) in the Trakya region of Turkey, an area with mild iodine deficiency, and to compare the effect of dose regimen selection (fixed (FD) or calculated dose (CD)) on treatment success.

MATERIAL AND METHODS

The study sample included 148 patients (40 male, median age 50) treated with radioiodine between the years 1991-2003. Patients were categorized into three diagnostic groups: Graves' disease (GD) (n = 65), solitary toxic adenoma (TA) (n = 29), and toxic multinodular hyperthyroidism (TMH) (n = 54), and each divided into two subgroups according to treatment method; the first group was treated with a FD of 370 MBq (10 mCi), and the second with CD.

RESULTS

The largest group was GD (44%), followed by TMH (36%). Median duration of follow-up was 28 months (range 6-147). FD was given to 52.7% of all patients and CD was given to 47.3%. There was a partial difference in the dose regimen between all groups, but did not reach statistically significant levels (FD vs. CD: 65%-35%; 38%-62%; 46%-54%; GD, TA, TMH respectively, p > 0.05). Total cure rate in FD and CD was 46 (59%) and 37 (52.9%), respectively. The rates of hypothyroidism for GD, TA, and TMH groups were 28 (43.1%), 6 (20.7%) and 16 (29.6%), respectively. The incidence of hypothyroidism did not vary significantly between any groups (p > 0.05). At the end of the follow-up period, a total of 104 patients (70.3%) were treated successfully. There was no significant difference in the cure rate between any groups (p > 0.05).

CONCLUSIONS

The treatment success in all groups and subgroups did not differ significantly between FD and CD. Our lower cure rate than in previous studies may be related to iodine deficiency. Higher doses of radioiodine may be required to increase final treatment success in endemic goiter areas. If this true, dosimetry and calculated dose regimen would be required in all groups of patients instead of an FD concept. However, our findings should be verified in larger series of patients, with longer follow-up period, and urinary iodine concentration measurements.

Graves' disease with moderate-severe endocrine ophthalmopathy-long term results of a prospective, randomized study of total or subtotal thyroid resection

The optimal thyroid surgery to be performed in patients with Graves' disease and concomitant endocrine ophthalmopathy is a matter of debate. We randomly assigned 44 patients with moderate-severe eye signs in a trial of treatment with subtotal, leaving a small (approximately 2 g) thyroid remnant, or total thyroidectomy. At inclusion, the patients had been treated with antithyroid drugs, and corticosteroids been given to 12 (27%). All received postoperative thyroxine supplementation and were followed for 3 years at regular examinations. The eye disease improved in all cases, and throughout the study, the two groups did not differ with regard to subjective and objective eye symptoms and laboratory findings. At the study start, motility disturbances were present in 8 and 11 of the cases in the subtotal and total resection group and proptosis in 16 and 17, respectively. After 3 years, the corresponding data were 3 and 6 cases with motility defects and 16 and 15 cases with proptosis. Thyrotropin (TSH)-receptor antibody levels gradually fell and became nondetectable in 21 (49%). The surgical complication rate (permanent recurrent laryngeal nerve paresis and permanent hypoparathyroidism) was significantly higher in the total thyroidectomy group. The data indicate that in patients with Graves' disease and active endocrine ophthalmopathy, subtotal thyroidectomy, leaving a small thyroid remnant, will reduce the risk of surgical complications but not the beneficial effect of surgery.

Effect of long-term continuous methimazole treatment of hyperthyroidism: comparison with radioiodine

OBJECTIVE

To investigate the long-term effects of continuous methimazole (MMI) therapy.

DESIGN AND METHODS

Five hundred and four patients over 40 years of age with diffuse toxic goiter were treated with MMI for 18 months. Within one year after discontinuation of MMI, hyperthyroidism recurred in 104 patients. They were randomized into 2 groups for continuous antithyroid and radioiodine treatment. Numbers of occurrences of thyroid dysfunction and total costs of management were assessed during 10 years of follow-up. At the end of the study, 26 patients were still on continuous MMI (group 1), and of 41 radioiodine-treated patients (group 2), 16 were euthyroid and 25 became hypothyroid. Serum thyroid and lipid profiles, bone mineral density, and echocardiography data were obtained.

RESULTS

There was no significant difference in age, sex, duration of symptoms and thyroid function between the two groups. No serious complications occurred in any of the patients. The cost of treatment was lower in group 1 than in group 2. At the end of 10 years, goiter rate was greater and antithyroperoxidase antibody concentration was higher in group 1 than in group 2. Serum cholesterol and low density lipoprotein-cholesterol concentrations were increased in group 2 as compared with group 1; relative risks were 1.8 (1.12-2.95, P<0.02) and 1.6 (1.09-2.34, P<0.02) respectively. Bone mineral density and echocardiographic measurements were not different between the two groups.

CONCLUSION

Long-term continuous treatment of hyperthyroidism with MMI is safe. The complications and the expense of the treatment do not exceed those of radioactive iodine therapy.

Comparison of Different Thyroid Committed Doses in Radioiodine Therapy for Graves' Hyperthyroidism

Despite vast worldwide experience in the use of 131I for treating Graves' disease (GD), no consensus of opinion exists concerning the optimal method of dose calculation. In one of the most popular equations, the administered (131)I dose is directly proportional to the estimated thyroid gland volume and inversely proportional to the measured 24-hour radioiodine uptake. In this study, we compared the efficiency of different tissue-absorbed doses to induce euthyroidism or hypothyroidism within 1 year after radioiodine therapy in GD patients. The study was carried out in 134 GD patients (age, 53 +/- 14 year; range, 16-82 year; thyroid volume, 28 +/- 18 mL; range, 6-95 mL; average 24-hour thyroid uptake, 72%) treated with (131)I therapy. The average radioiodine activity administered to patients was 518 +/- 226 MBq (range, 111-1110). The corresponding average thyroid absorbed dose, calculated by a modified Medical Internal Radiation Dose (MIRD) equation was 376 +/- 258 Gy (range, 99-1683). One year after treatment, 58 patients (43%) were hypothyroid, 57 patients (43%) were euthyroid, and 19 patients (14%) remained hyperthyroid. The patients were divided into 3 groups: 150 Gy (n = 32), 300 Gy (n = 58) and >300 Gy (n = 44). No significant difference in the rate of recurrent hyperthyroidism was found among the 3 groups (150 Gy: 15%; 300 Gy: 14%; and > or =300 Gy: 14%; chi-square test, p = 0.72). Whereas, the rate of hypothyroidism in the 3 groups was significantly correlated with the dose (150 Gy: 30%; 300 Gy: 46%; >300 Gy: 71%; chi-square test, p = 0.0003). The results obtained in this study show no correlation between dose and outcome of radioiodine therapy (in terms of persistent hyperthyroidism) for thyroid absorbed doses > or =150 Gy, while confirming the relation between the thyroid absorbed dose and the incidence of hypothyroidism in GD patients.

Long-term follow-up study of radioiodine treatment of hyperthyroidism

OBJECTIVE

To determine the cumulative incidence of hypothyroidism during long-term follow-up in patients treated for hyperthyroidism by radioactive iodine (131)I (RAI) therapy, the significance of clinical factors in predicting the development of hypothyroidism, and the outcome after a fixed 7 mCi (259 MBq) dose of RAI.

DESIGN

Prospective cohort study of patients treated for hyperthyroidism by RAI.

PATIENTS AND MEASUREMENTS

Since 1965, details on 2043 patients treated by RAI therapy in Tampere University Hospital were entered into a computerized register. Following RAI treatment, thyroid status was monitored every 1-3 months during the first year, and subsequently at 1-3-year intervals until June 2002 or until the patient died or moved out of the Tampere University Hospital district. results The cumulative incidence of hypothyroidism in patients with Graves' disease and toxic multinodular goitre at 1, 10 and 25 years was 24%vs. 4%, 59%vs. 15% and 82%vs. 32%, respectively. In a Cox regression model, previous partial thyroidectomy [risk ratio (RR) = 1.63 in patients with Graves' disease and RR = 1.59 in those with toxic multinodular goitre] and age at the first RAI treatment (RR = 0.998 and RR = 0.996 per year) were statistically significantly associated with the development of hypothyroidism both in patients with Graves' disease and in those with toxic multinodular goitre. Antithyroid medication preceding RAI therapy (RR = 0.47) decreased and female gender (RR = 1.53) increased the risk of hypothyroidism only in patients with Graves' disease. Administration of a single dose of RAI resulted in the control of hyperthyroidism in 75% of patients, while two to six RAI treatments were needed in 25% of patients to achieve either a hypothyroid or a euthyroid state in both groups. None of the clinical factors studied was associated with the remission rate either in patients with Graves' disease or in those with toxic multinodular goitre. The remission rate did not differ between the patients who received a dose of RAI calculated according to the uptake of RAI and thyroid size and those who received an empirical dose of RAI. The fixed 7 mCi (259 MBq) dose of RAI cured 80% of patients.

CONCLUSION

RAI treatment is effective in treating hyperthyroidism in patients with Graves' disease, but hypothyroidism will develop in 82% of patients in 25 years. Because the development of hypothyroidism seems to be inevitable and unpredictable by any clinical factors, the objective of RAI treatment should be to minimize the persistence of hyperthyroidism with the simplest possible form of treatment. We recommend a fixed 7 mCi dose of RAI to be used as the first empirical dose in the treatment of hyperthyroidism, at least in Graves' disease.

[Results of treatment with calculated doses of radioiodine depending on gland size and morphology in graves' disease. Analysis of variables]

OBJECTIVE

To assess the efficacy of the administered doses of Radioiodine (RAI) in the treatment of patients with hyperthyroidism in Graves' disease, calculated on the basis of gland size and morphology (assessment by palpation and scintigraphy), analyzing which variables influence the final result of our sample, and on the early development of hypothyroidism.

METHODS

99 patients treated with RAI between april 1996 and november 2000 were evaluated retrospectively, 77 women and 22 men, mean age 44 years (range: 18-76). 67 patients received treatment with oral antithyroid drugs. The administered dose range was: 185-629 MBq. Mean follow-up time was 13.4 months. Success was defined as elimination of hyperthyroidism; and early hypothyroidism which appeared in the six months after therapy.

RESULTS

30 patients remained with euthyroidism, 53 patients had hypothyroidism and 16 had recurrent hyperthyroidism. A total of 84% of the patients were controlled with one dose of RAI. Only the time of evolution influenced the final results. The rest of the variables (gender, age, doses and antithyroid drugs) did not influence them. No relationship was found between the appearance of early/late hypothyroidism and the administered doses. A certain tendency was found for early hypothyroidism to appear in the youngest patients (p = 0.111).

CONCLUSIONS

The administered doses in our department have been shown to be effective in controlling thyrotoxicosis. In our sample, only time of evolution influenced on the final results of the patients. Only the age factor showed a certain tendency in the evolution to early/late hypothyroidism.

Epidemiology and prevention of clinical and subclinical hypothyroidism

Iodine deficiency is the most common cause of hypothyroidism worldwide. In persons living in iodine-replete areas, causes are congenital, spontaneous because of chronic autoimmune disease (atrophic autoimmune thyroiditis or goitrous autoimmune thyroiditis [Hashimoto's thyroiditis]), or iatrogenic because of goitrogens, drugs, or destructive treatment for thyrotoxicosis. Screening for congenital hypothyroidism exists and its use prevents mental retardation. The prevalence of spontaneous hypothyroidism is between 1% and 2% and is more common in older women and 10 times more common in women than in men. A significant proportion of subjects have asymptomatic chronic autoimmune thyroiditis and 8% of women (10% of women over 55 years of age) and 3% of men have subclinical hypothyroidism. Approximately one third of patients with newly diagnosed overt hypothyroidism have received destructive therapy for hyperthyroidism and indefinite surveillance is required. There is not much that can be done to prevent the occurrence of spontaneous autoimmune hypothyroidism, but if identified early, something can be done to prevent progression to overt disease. Controversy exists as to whether healthy adults would benefit from screening for autoimmune thyroid disease because a significant proportion of subjects tested will have evidence of mild thyroid failure. Case finding in women at menopause or visiting a primary care physician with nonspecific symptoms appears justified.

Tratamento do hipertireoidismo da Doença de Graves

A Doença de Graves constitui a forma mais comum de hipertireoidismo e três abordagens terapêuticas são atualmente utilizadas: drogas antitireoidianas (DAT), cirurgia e iodo radioativo (131I). As DAT continuam como tratamento de primeira escolha em pacientes com doença leve, bócios pequenos, crianças e adolescentes, e em situações especiais como na gravidez. Por outro lado, o 131I tem sido cada vez mais utilizado, porque é considerado um tratamento seguro, definitivo e de fácil aplicação. O risco de exacerbação do hipertireoidismo após administração do 131I, os fatores prognósticos de falência e o cálculo da dose administrada têm sido alguns dos aspectos discutidos na literatura recentemente, e são particulamente comentados nesta revisão. O tratamento cirúrgico constitui quase um tratamento de exceção, com indicação para os casos em que as terapias anteriores não possam ser utilizadas.

Radioiodine treatment of hyperthyroidism-prognostic factors for outcome

There is little consensus regarding the most appropriate dose regimen for radioiodine (131I) in the treatment of hyperthyroidism. We audited 813 consecutive hyperthyroid patients treated with radioiodine to compare the efficacy of 2 fixed-dose regimens used within our center (185 megabequerels, 370 megabequerels) and to explore factors that may predict outcome. Patients were categorized into 3 diagnostic groups: Graves' disease, toxic nodular goiter, and hyperthyroidism of indeterminate etiology. Cure after a single dose of 131I was investigated and defined as euthyroid off all treatment for 6 months or T4 replacement for biochemical hypothyroidism in all groups. As expected, patients given a single dose of 370 megabequerels had a higher cure rate than those given 185 megabequerels, (84.6% vs. 66.6%, P < 0.0001) but an increase in hypothyroidism incidence at 1 yr (60.8% vs. 41.3%, P < 0.0001). There was no difference in cure rate between the groups with Graves' disease and those with toxic nodular goiter (69.5% vs. 71.4%; P, not significant), but Graves' patients had a higher incidence of hypothyroidism (54.5% vs. 31.7%, P < 0.0001). Males had a lower cure rate than females (67.6% vs. 76.7%, P = 0.02), whereas younger patients (<40 yr) had a lower cure rate than patients over 40 yr old (68.9% vs. 79.3%, P < 0.001). Patients with more severe hyperthyroidism (P < 0.0001) and with goiters of medium or large size (P < 0.0001) were less likely to be cured after a single dose of 131I. The use of antithyroid drugs, during a period 2 wk before or after 131I, resulted in a significant reduction in cure rate in patients given 185 megabequerels 131I (P < 0.01) but not 370 megabequerels. Logistic regression analysis showed dose, gender, goiters of medium or large size, and severity of hyperthyroidism to be significant independent prognostic factors for cure after a single dose of 131I. We have demonstrated that a single fixed dose of 370 megabequerels 131I is highly effective in curing toxic nodular hyperthyroidism as well as Graves' hyperthyroidism. Because male patients and those with more severe hyperthyroidism and medium or large-sized goiters are less likely to respond to a single dose of radioiodine, we suggest that the value of higher fixed initial doses of radioiodine should be evaluated in these patient categories with lower cure rates.

Weight gain following treatment of hyperthyroidism

OBJECTIVE

Patients frequently express concern that treating hyperthyroidism will lead to excessive weight gain. This study aimed to determine the extent of, and risk factors for, weight gain in an unselected group of hyperthyroid patients.

DESIGN AND SUBJECTS

We investigated 162 consecutive hyperthyroid patients followed for at least 6 months. Height, weight, clinical features, biochemistry and management were recorded at each clinic visit.

RESULTS

Documented weight gain was 5.42 +/- 0.46 kg (mean +/- SE) and increase in BMI was 8.49 +/- 0.71%, over a mean 24.2 +/- 1.6 months. Pre-existing obesity, Graves' disease causing hyperthyroidism, weight loss before presentation and length of follow-up each independently predicted weight gain. Patients treated with thionamides or radioiodine gained a similar amount of weight (thionamides, n = 87, 5.16 +/- 0.63 kg vs. radioiodine, n = 62, 4.75 +/- 0.57 kg, P = 0.645), but patients who underwent thyroidectomy (n = 13) gained more weight (10.27 +/- 2.56 kg vs. others, P = 0.007). Development of hypothyroidism (even transiently) was associated with weight gain (never hypothyroid, n = 102, 4.57 +/- 0.52 kg, transiently hypothyroid, n = 29, 5.37 +/- 0.85 kg, on T4, n = 31, 8.06 +/- 1.42 kg, P = 0.014). This difference remained after correcting for length of follow-up. In the whole cohort, weight increased by 3.95 +/- 0.40 kg at 1 year (n = 144) to 9.91 +/- 1.62 kg after 4 years (n = 27) (P = 0.008), representing a mean weight gain of 3.66 +/- 0.44 kg/year.

CONCLUSION

We have demonstrated marked weight gain after treatment of hyperthyroidism. Pre-existing obesity, a diagnosis of Graves' disease and prior weight loss independently predicted weight gain and weight continued to rise with time. Patients who became hypothyroid, despite T4 replacement, gained most weight.

Drug therapy for hyperthyroidism in pregnancy: safety issues for mother and fetus

Hyperthyroidism (thyrotoxicosis) in pregnancy and the child bearing years is usually attributable to Graves' disease. This is an autoimmune condition in which thyroid-stimulating immunoglobulins (TSI) cause hyperthyroidism. As a rule, pregnancy complicates the management of hyperthyroidism, rather than vice versa. However, patients who remain thyrotoxic during pregnancy are at increased risk of maternal and fetal complications, particularly miscarriage and stillbirth. Therefore, bodyweight loss, eye signs and a bruit over the thyroid gland in a pregnant woman warrant thyroid investigation. Investigations should include measurement of serum free thyroid hormone levels [free thyroxine (T4) and free triiodothyronine (T3)] rather than total T4 and T3 levels, because total T4 and T3 levels may be raised in euthyroid pregnancies due to the presence of increased levels of thyroxine binding globulin (TBG). By 20 weeks' gestational age, the fetal thyroid is fully responsive to TSI and to antithyroid drugs. Maternal T4 and T3 and thyrotropin pass across the placenta in small and decreasing amounts as gestation progresses, but thyrotropin releasing hormone, TSI, antithyroid drugs, iodides and beta-blockers are readily transferred to the fetus from the mother. Hyperthyroidism is usually treated throughout pregnancy with an antithyroid drug, preferably propylthiouracil. The smallest dose which controls the disease is given with careful monitoring of free T4 and T3 levels to minimise the risk of fetal hypothyroidism and goitre. Bilateral subtotal thyroidectomy may be an option for a small number of patients with hyperthyroidism in pregnancy.

Accuracy considerations when using early (four- or six-hour) radioactive iodine uptake to predict twenty-four-hour values for radioactive iodine dosage in the treatment of Graves' disease

Although literature has offered methods to predict 24-hour radioactive iodine uptake values from early (4- to 6-hour) measurements, the resultant dosage errors have not been examined. Potential errors include underdosage, overdosage, and a failure to recognize rapid turnover patients (early-to-late uptake ratios > or = 1) who are at high risk for treatment failure and full-body radiation exposure. We developed and tested a novel method for minimizing error involved in using a single early uptake measurement to derive late uptake. From a retrospective analysis of 203 Graves' disease patients, receiver operating characteristic (ROC) curve analysis enabled us to identify patients likely to experience rapid turnover and therefore should receive 24-hour studies. Twenty-four-hour uptake measurements are necessary with 77% or more 4-hour uptake values and 80% or more 6-hour values. After eliminating these patients, we developed linear regression equations to predict the 24-hour uptake from 4-hour (n = 61) and 6-hour (n = 22) rule groups, testing their efficacy on separate 4-hour (n = 61) and 6-hour (n = 21) patient groups. We also used our test population to measure error in four early-to-late uptake conversion formulas presented in the literature. Error involved in these predictions ranged from a 10.6% overestimate for 4-hour calculations to a 5.9% underestimate for 6-hour calculations. When applied to two dosage formulas incorporating gland size, absorbed dose, and 24-hour uptake, average dosage error was 7%. In comparison to the other sources of error radioactive iodine (131I) dosimetry, potential error in predicting 24-hour uptake from 4- or 6-hour uptake values is low.