A systematic review of drug therapy for Graves' hyperthyroidism

Lipid Profile Evolution in Graves' Disease Treated with Titration Regimen of Anti-Thyroid Drugs Versus Block and Replace Regimen

The aim was to compare the lipid profile of patients with GD treated with anti-thyroid drugs (ATDs) using a titration regimen versus a block and replace regimen. This is an 18-month prospective observational study. In this study were included 149 medically treated GD patients, aged+>+18 years. Pregnant women and patients treated with radioactive iodine therapy or partial/total thyroidectomy were excluded. Patients were divided into 2 subgroups: titration (A) and block and replace (B) therapy, according to the ATD regimen used. Thyroid and metabolic profile was measured at baseline and at least one visit during medical treatment. The whole group included 122 (81.87%) females (F) and 27 (18.12%) males (M), ratio F:M=4.5:1. As expected, at the time of diagnosis, thyrotoxic patients were with normal lipid profile. During medical treatment, in patients who achieved euthyroidism, the cholesterol levels increased as follows: in subgroup A: by 52.9 mg/dl (95% CI: 26.4-79.3), p<0.001 for total cholesterol (T-C), by 33.3 mg/dl (95% CI: 10.3-56.3), p=0.007 for low-density lipoprotein cholesterol (LDL-C) and by 11.44 mg/dl (95% CI: 3.08-19.79), p=0.009 for high-density lipoprotein cholesterol (HDL-C); in subgroup B T-C increased by 45.1 mg/dl (95% CI: 22.2-68), p<0.001 and for LDL-C by 33.57 mg/dl (95% CI: 12.72-54.42), p=0.003. No statistically significant increase in triglyceride levels was determined. Medical treatment of hyperthyroidism due to Graves' disease increased cholesterol levels regardless of the ATD regimen used.

Approach to the Patient Considering Long-term Antithyroid Drug Therapy for Graves' Disease

Antithyroid drugs (ATD) are the treatment of choice for the majority of patients with Graves' hyperthyroidism worldwide. However, relapse of hyperthyroidism after withdrawal of arbitrarily chosen conventional 12 to 18 months of therapy is very common. In the last 2 decades, many studies have shown that treatment with long-term ATD (LT-ATD) is effective and safe in the maintenance of euthyroidism. In addition, it has been reported that serum TSH receptor antibody may not decrease permanently before 5 to 6 years of ATD treatment, and clinical trials have shown that ≥5 years of ATD treatment is accompanied by remission in the majority of patients with Graves' hyperthyroidism. The objective of this article is to discuss the optimal time to withdraw of conventional ATD therapy, to illustrate the decision-making of the management of recurrent hyperthyroidism, to review the proper management of LT-ATD, and to generate suggestions for lifelong ATD treatment by discussing 4 scenarios of decision-making in patients with Graves' disease.

Dynamic Risk Model for the Medical Treatment of Graves' Hyperthyroidism according to Treatment Duration

BACKGRUOUND

Changes in thyrotropin receptor antibody (TRAb) levels are associated with the clinical outcomes of Graves' hyperthyroidism. However, the effects of the patterns of TRAb changes on patient prognosis according to the treatment duration of antithyroid drugs (ATDs) are not well established.

METHODS

In this retrospective cohort study, 1,235 patients with Graves' hyperthyroidism who were treated with ATDs for more than 12 months were included. Patients were divided into two groups according to treatment duration: group 1 (12-24 months) and group 2 (>24 months). Risk prediction models comprising age, sex, and either TRAb levels at ATD withdrawal (model A) or patterns of TRAb changes (model B) were compared.

RESULTS

The median treatment duration in groups 1 (n=667, 54%) and 2 (n=568, 46%) was 17.3 and 37.1 months, respectively. The recurrence rate was significantly higher in group 2 (47.9%) than in group 1 (41.4%, P=0.025). Group 2 had significantly more goiter, thyroid eye disease, and fluctuating and smoldering type of TRAb pattern compared with group 1 (all P<0.001). The patterns of TRAb changes were an independent risk factor for recurrence after adjusting for other confounding factors in all patients, except in group 1. Integrated discrimination improvement and net reclassification improvement analyses showed that model B performed better than model A in all patients, except in group 1.

CONCLUSION

The dynamic risk model, including the patterns of TRAb changes, was more suitable for predicting prognosis in patients with Graves' hyperthyroidism who underwent longer ATD treatment duration.

Serum autotaxin level: a promising diagnostic biomarker in differentiating Graves' disease and thyroiditis

BACKGROUND

Recent studies have suggested that serum autotaxin (ATX) may be a promising diagnostic biomarker in differentiating between Graves' disease (GD) and thyroiditis, as well as serving as a monitoring biomarker for GD. This study will evaluate the use of serum ATX as a diagnostic biomarker in these conditions.

METHODS

In this prospective interventional study, blood samples were collected from the patients who met both inclusion and exclusion criteria, and serum ATX levels were measured by using the MyBioSource human Autotaxin ELISA kit.

RESULTS

A total of 32 patients were enrolled, of which 18.8% were newly diagnosed with GD, 21.9% were thyroiditis, and 59.3% were on treatment for GD. Serum autotaxin antigen was significantly higher in GD patients than in thyroiditis (603.3217 ± 444.24 v/s 214.74 ± 55.91, P = <.005). Serum ATX measurement successfully discriminated GD patients from thyroiditis (AUC = 0.952, 95%CI: 0.00-1.00) with an optimal cutoff value of ≥257.20 ng/L (sensitivity = 100 and specificity = 81.71). Monitoring the efficacy of serum ATX was analyzed and showed a significant difference.

CONCLUSION

The serum ATX was higher in subjects with GD as compared to thyroiditis, and ATX levels were found to be decreased during the treatment period. In conclusion, serum ATX can be used as a diagnostic and monitoring biomarker in GD.

Enhanced predictive validity of integrative models for refractory hyperthyroidism considering baseline and early therapy characteristics: a prospective cohort study

BACKGROUND

A subset of Graves' disease (GD) patients develops refractory hyperthyroidism, posing challenges in treatment decisions. The predictive value of baseline characteristics and early therapy indicators in identifying high risk individuals is an area worth exploration.

METHODS

A prospective cohort study (2018-2022) involved 597 newly diagnosed adult GD patients undergoing methimazole (MMI) treatment. Baseline characteristics and 3-month therapy parameters were utilized to develop predictive models for refractory GD, considering antithyroid drug (ATD) dosage regimens.

RESULTS

Among 346 patients analyzed, 49.7% developed ATD-refractory GD, marked by recurrence and sustained Thyrotropin Receptor Antibody (TRAb) positivity. Key baseline factors, including younger age, Graves' ophthalmopathy (GO), larger goiter size, and higher initial free triiodothyronine (fT3), free thyroxine (fT4), and TRAb levels, were all significantly associated with an increased risk of refractory GD, forming the baseline predictive model (Model A). Subsequent analysis based on MMI cumulative dosage at 3 months resulted in two subgroups: a high cumulative dosage group (average ≥ 20 mg/day) and a medium-low cumulative dosage group (average < 20 mg/day). Absolute values, percentage changes, and cumulative values of thyroid function and autoantibodies at 3 months were analyzed. Two combined predictive models, Model B (high cumulative dosage) and Model C (medium-low cumulative dosage), were developed based on stepwise regression and multivariate analysis, incorporating additional 3-month parameters beyond the baseline. In both groups, these combined models outperformed the baseline model in terms of discriminative ability (measured by AUC), concordance with actual outcomes (66.2% comprehensive improvement), and risk classification accuracy (especially for Class I and II patients with baseline predictive risk < 71%). The reliability of the above models was confirmed through additional analysis using random forests. This study also explored ATD dosage regimens, revealing differences in refractory outcomes between predicted risk groups. However, adjusting MMI dosage after early risk assessment did not conclusively improve the prognosis of refractory GD.

CONCLUSION

Integrating baseline and early therapy characteristics enhances the predictive capability for refractory GD outcomes. The study provides valuable insights into refining risk assessment and guiding personalized treatment decisions for GD patients.

Comparison of Otsu and an adapted Chan-Vese method to determine thyroid active volume using Monte Carlo generated SPECT images

BACKGROUND

The Otsu method and the Chan-Vese model are two methods proven to perform well in determining volumes of different organs and specific tissue fractions. This study aimed to compare the performance of the two methods regarding segmentation of active thyroid gland volumes, reflecting different clinical settings by varying the parameters: gland size, gland activity concentration, background activity concentration and gland activity concentration heterogeneity.

METHODS

A computed tomography was performed on three playdough thyroid phantoms with volumes 20, 35 and 50 ml. The image data were separated into playdough and water based on Hounsfield values. Sixty single photon emission computed tomography (SPECT) projections were simulated by Monte Carlo method with isotope Technetium-99 m ([Formula: see text]Tc). Linear combinations of SPECT images were made, generating 12 different combinations of volume and background: each with both homogeneous thyroid activity concentration and three hotspots of different relative activity concentrations (48 SPECT images in total). The relative background levels chosen were 5 %, 10 %, 15 % and 20 % of the phantom activity concentration and the hotspot activities were 100 % (homogeneous case) 150 %, 200 % and 250 %. Poisson noise, (coefficient of variation of 0.8 at a 20 % background level, scattering excluded), was added before reconstruction was done with the Monte Carlo-based SPECT reconstruction algorithm Sahlgrenska Academy reconstruction code (SARec). Two different segmentation algorithms were applied: Otsu's threshold selection method and an adaptation of the Chan-Vese model for active contours without edges; the results were evaluated concerning relative volume, mean absolute error and standard deviation per thyroid volume, as well as dice similarity coefficient.

RESULTS

Both methods segment the images well and deviate similarly from the true volumes. They seem to slightly overestimate small volumes and underestimate large ones. Different background levels affect the two methods similarly as well. However, the Chan-Vese model deviates less and paired t-testing showed significant difference between distributions of dice similarity coefficients (p-value [Formula: see text]).

CONCLUSIONS

The investigations indicate that the Chan-Vese model performs better and is slightly more robust, while being more challenging to implement and use clinically. There is a trade-off between performance and user-friendliness.

The influence of thionamides on intra-thyroidal uptake of 131I during radioiodine-131 treatment of Graves' disease

Graves' disease is one of the most common causes of hyperthyroidism. Guideline recommendations advocate the intake of thionamides for at least 1 year. If hyperthyroidism persists, subsequent radioiodine-131 treatment (RIT) is a therapeutic option. Thionamides are known to influence intra-thyroidal bio-kinetics of iodine and should therefore be discontinued at least 3 days prior to RIT if possible. However, the required therapeutic activity has to be calculated individually by pre-therapeutic measurement of the uptake prior to RIT [radioiodine-131 uptake test (RIUT)] in Germany according to national guidelines. Therefore, the aim of this study was to quantify the influence of thionamides on intra-therapeutic uptake. A cohort of 829 patients with Graves' disease undergoing RIUT and RIT was analysed. Patients were subdivided into three groups. Group A: patients with carbimazole medication (n = 312), group B: patients with methimazole medication (n = 252) and group C: patients without thionamides (n = 265). Group A and B were further subdivided depending on the reduction of dosage of thionamides. In order to analyse the influence of thionamides, the variance of the determined individual extrapolated maximum intra-thyroidal uptake (EMU) between RIUT and RIT within the single groups and within the subgroups was statistically evaluated. When administering an equal dose of thionamides or no thionamides in RIUT and RIT (groups A1, B1 and C) no significant differences were detected when comparing EMU in RIT to EMU in RIUT (p > 0.05). In the subgroups A2-A4 (reduced dosage of carbimazole prior to RIT) EMU was significantly increased in RIT compared to RIUT [21% for a reduction of 0 to < 10 mg/d (A2), 39% for a reduction of 10-15 mg/d (A3) and 80% for a reduction of > 15 mg/d (A4)]. In the subgroups B2-B4 (reduced dosage of methimazole prior to RIT) EMU was as well significantly increased in RIT compared to RIUT [26% for a reduction of 0 to < 10 mg/d (B2), 36% for a reduction of 10-15 mg/d (B3) and 59% for a reduction of > 15 mg/d (B4)]. A significant dose-dependent increase of EMU in RIT compared to EMU in RIUT in patients discontinuing or reducing thionamides was detected. Therefore, thionamides should be discontinued at least 2 days prior to RIUT in order to achieve the designated target dose more precisely and to minimize radiation exposure of organs at risk.

Effect of Vitamin D Supplementation on Graves' Disease: The DAGMAR Trial

Objective: Treatment options in Graves' disease (GD) are limited and do not target the underlying autoimmunity, and relapse rates following a course of antithyroid drug (ATD) reach 50%. Previous research has shown promising results for a role of vitamin D in GD. We aimed to investigate whether vitamin D reduces failure to enter and sustain remission in patients with GD treated with ATD. Design: A multicenter, double-blinded, randomized placebo-controlled trial comparing vitamin D 70 mcg once daily (2800 IU) or placebo. The intervention was given first as add-on to ATD treatment, maximally 24 months, and then for 12 months after ATD cessation. Inclusion period was from 2015 to 2017 and study completion by December 2020. Patients included were adults with a first-time diagnosis of GD treated with ATD. Exclusion criteria included pregnancy and glucocorticoid treatment. The primary endpoint was failure to enter and sustain remission defined as relapse of hyperthyroidism within 12 months after ATD cessation, inability to stop ATD within 24 months, or radioiodine treatment or thyroidectomy. Two hundred seventy-eight patients were included in the study, and 4 patients withdrew consent. No adverse effects were found. Results: Participants were aged 44 ± 14 years at enrollment and 79% were female. The risk of failure to enter and sustain remission was 42% [95% confidence interval (CI) 33-50%] in the vitamin D group and 32% [CI 24-40%] in the placebo group corresponding to a relative risk of 1.30 [CI 0.95-1.78]. Conclusions: Vitamin D supplementation did not improve the treatment of GD in patients with normal or insufficient vitamin D status. Thus, supplementation with high-dose vitamin D cannot be recommended for GD. Study registration: ClinicalTrials.gov NCT02384668.

Prediction for recurrence following antithyroid drug therapy for Graves' hyperthyroidism

Objective

A common problem with antithyroid drugs (ATD) treatment in patients with Graves' disease (GD) is the high recurrence rate after drug withdrawal. Identifying risk factors for recurrence is crucial in clinical practice. We hereby prospectively analyze risk factors for the recurrence of GD in patients treated with ATD in southern China.

Subjects and methods

Patients who were newly diagnosed with GD and aged > 18 years were treated with ATD for 18 months and followed up for 1 year after ATD withdrawal. Recurrence of GD during follow-up was assessed. All data were analyzed by Cox regression with P values < 0.05 considered statistically significant.

Results

A total of 127 Graves' hyperthyroidism patients were included. During an average follow-up of 25.7 (standard deviation = 8.7) months, 55 (43%) had a recurrence within 1 year after withdraw of anti-thyroid drugs. After adjustment for potential confounding factors, the significant association remained for the presence of insomnia (hazard ratio (HR) 2.94, 95% confidence interval (CI) 1.47-5.88), greater goiter size (HR 3.34, 95% CI 1.11-10.07), higher thyrotrophin receptor antibody (TRAb) titer (HR 2.66, 95% CI 1.12-6.31) and a higher maintenance dose of methimazole (MMI) (HR 2.14, 95% CI 1.14-4.00).

Conclusion

Besides conventional risk factors (i.e., goiter size, TRAb and maintenance MMI dose) for recurrent GD after ATD withdraw, insomnia was associated with a 3-fold risk of recurrence. Further clinical trials investigating the beneficial effect of improving sleep quality on prognosis of GD are warranted.

Long-term thionamide antithyroid treatment of Graves' disease

Thionamide antithyroid drugs (ATD) are the treatment of choice for Graves' hyperthyroidism. The major drawback of ATD treatment for 1-2 years is the relapse of hyperthyroidism in about 50% of patients. Recently, it has been shown that ATD treatment for more than five years is accompanied by long-term remission in majority of patients without additional major side effects in both adults and children. Compared to radioactive iodine therapy, long-term ATD results in more favorable outcomes. This review summarizes the evidence on long-term ATD therapy regarding the remission rate of hyperthyroidism, efficacy and safety, indications and mode of therapy in patients with hyperthyroidism.

Long-term management of Graves disease: a narrative review

Graves disease (GD) is the most common cause of hyperthyroidism, accounting for more than 90% of cases in Korea. Patients with GD are treated with any of the following: antithyroid drugs (ATDs), radioactive iodine (RAI) therapy, or thyroidectomy. Most patients begin treatment with ATDs, and clinical guidelines suggest that the appropriate treatment period is 12 to 18 months. While RAI treatment and surgery manage thyrotoxicosis by destroying or removing thyroid tissue, ATDs control thyrotoxicosis by inhibiting thyroid hormone synthesis and preserving the thyroid gland. Although ATDs efficiently control thyrotoxicosis symptoms, they do not correct the main etiology of GD; therefore, frequent relapses can follow. Recently, a large amount of data has been collected on long-term ATDs for GD, and low-dose methimazole (MMZ) is expected to be a good option for remission. For the long-term management of recurrent GD, it is important to induce remission by evaluating the patient's drug response, stopping ATDs at an appropriate time, and actively switching to surgery or RAI therapy, if indicated. Continuing drug treatment for an extended time is now encouraged in patients with a high possibility of remission with low-dose MMZ. It is also important to pay attention to the quality of life of the patients. This review aimed to summarize the appropriate treatment methods and timing of treatment transition in patients who relapsed several times while receiving treatment for GD.

Audit of long-term treatment outcomes of thyrotoxicosis in a single-centre virtual clinic: The utility of long-term antithyroid drugs

OBJECTIVE

To investigate the long-term outcomes and prognosis of thyrotoxicosis in a large number of patients in a single UK county (Leicestershire).

DESIGN

Retrospective cohort analysis of 56,741 thyroid function test (TFT) results, treatment modalities and outcomes in a well-established virtual thyrotoxicosis clinic database.

PATIENTS

One thousand four hundred and eighty-nine patients were included with a median length of follow-up of 10.9 years. The aetiology of thyrotoxicosis was autoimmune (85.9%), nodular (9.1%) and mixed (5.0%). Treatment modalities included antithyroid drugs (ATDs), radioiodine (RAI; 555 MBq fixed dose) and thyroidectomy.

METHODS

We analysed both individual TFTs and groups of sequential TFTs on or after the same thyroid treatment(s), which we describe as 'phase of thyroid care' (POTC). Patients studied entered the virtual clinic between 1 January 1995 and 1 January 2010; we exported data on every TFT sample up to April 2020.

RESULTS

ATD had been used in 99.2% (median 2, maximum seven courses) with long-term ATD (&gt;2 years) in 48%. RAI and thyroidectomy were used more commonly with nodular and mixed aetiology. Overall, T4 was more often controlled than thyroid-stimulating hormone (TSH), and at the latest follow-up, T4 was normal in &gt;96%, TSH in &gt;79% and both in &gt;76% of different aetiologies. The mean percentage control of T4 was 85% and TSH 50%; in long-term ATD courses, this improved to 89% and 62%, respectively. In the latest POTC, control of T4 and TSH was best in cases off treatment (95%/87%) and on T4 without ablative therapy (94%/72%), but was broadly similar in patients on long-term ATD (90%/68%), after RAI (92%/60%) or after thyroidectomy (91%/58%). After the first course of ATD, remission or hypothyroidism was seen in 47.3% autoimmune, 20.9% nodular and 32.5% mixed, with 90% relapses seen within 4 years. Relapse was more common in patients with ophthalmopathy, but there was no difference between the sexes.

CONCLUSIONS

Thyrotoxicosis can be well controlled with minimal specialist clinic attendance using a software-supported virtual shared-care scheme. Long-term ATD appears to be a valid patient choice achieving TFT control comparable to that seen after RAI or surgery. In patients with autoimmune disease, relapse is more common in patients with ophthalmopathy, and hypothyroidism is common after RAI. In nodular disease, we found that spontaneous remission may occur.

Appropriate duration of antithyroid drug treatment as a predictor for relapse of Graves' disease: a systematic scoping review

BACKGROUND

Following the conventional 12-18 month antithyroid drug (ATD) treatment in Graves' disease (GD), 50% of patients experience relapse of hyperthyroidism.

OBJECTIVE

The aim of this systematic scoping review was critical appraisal of duration of ATD therapy in the last 80 years.

METHODS

Articles were identified through the search of PubMed from January 1, 1941 to April 30, 2021. All study types were included. Articles were eligible if they reported data on the length of ATD treatment, particularly thyroid hormones and TSH receptor antibodies (TRAb) concentrations and specifically those with data on the remission and/or relapse rates.

RESULTS

We described major progress regarding the duration of ATD therapy and related outcomes at every 20 years. Articles of 1941-1960 were mainly concerned with determination of favorable treatment, minimal effective dose, side effects and rate of remission after < 12-month ATD therapy. Studies with larger number of patients and longer follow-ups appeared in 1961-1980; higher remission rate after 18-24 months versus 6 months of ATD therapy was reported. Articles of 1981-2000 focused on identification of factors associated with high relapse rates after discontinuation of ATD. In 2001-2021, ATD became the first choice of treatment in many countries. However, 12-18 months of ATD therapy was arbitrarily chosen as the appropriate option. According to recent studies, persistent normalization of TRAb occurs after 5 years of methimazole therapy and ATD treatment of > 60 months could offer a 4-year remission rate of 85%.

CONCLUSION

Long-term ATD treatment for more than 60 months is safe and effective, has the highest remission rate and cures most patients with GD; hence, it should be considered as the most appropriate duration for ATD therapy in these patients.

Management of Graves' hyperthyroidism: present and future

INTRODUCTION

Graves' disease (GD) is an autoimmune disorder due to loss of tolerance to the thyrotropin receptor (TSHR) and ultimately caused by stimulatory TSHR antibodies (TSHR-Ab). GD may be associated with extrathyroidal manifestations, mainly Graves' orbitopathy. Treatment of GD relies on antithyroid drugs (ATDs), radioactive iodine (RAI), thyroidectomy. The major ATD limitation is the high recurrence rate after treatment. The major drawback of RAI and thyroidectomy is the inevitable development of permanent hypothyroidism.

AREAS COVERED

Original articles, clinical trials, systematic reviews, meta-analyses from 1980 to 2021 were searched using the following terms: Graves' disease, management of Graves' disease, antithyroid drugs, radioactive iodine, thyroidectomy, Graves' orbitopathy, thyroid-eye disease.

EXPERT OPINION

ATDs are the first-line treatment worldwide, are overall safe and usually given for 18-24 months, long-term treatment may decrease relapses. RAI is safe, although associated with a low risk of GO progression, particularly in smokers. Thyroidectomy requires skilled and high-volume surgeons. Patients play a central role in the choice of treatment within a shared decision-making process. Results from targeted therapies acting on different steps of the autoimmune process, including iscalimab, ATX-GD-59, rituximab, blocking TSHR-Ab, small molecules acting as antagonists of the TSHR, are preliminary or preclinical, but promising in medium-to-long perspective.

The longer the antithyroid drug is used, the lower the relapse rate in Graves' disease: a retrospective multicenter cohort study in Korea

PURPOSE

Current literature suggests 12-18 months of antithyroid drug (ATD) treatment for patients with Graves' disease, but the risk of relapse is high. Although some studies reported better outcomes of long-term ATD treatment, recent data that suggest the optimal treatment duration are limited.

METHODS

We performed a multicenter retrospective cohort study of 908 patients newly diagnosed with Graves' disease between 2006 and 2013. The relapse rate according to ATD treatment duration was analyzed.

RESULTS

After initial ATD treatment, 338 patients (37.2%) had relapsed. The relapse rate according to ATD treatment duration was 42.4% at 1 year, 38.5% at 2 years, 33.8% at 3 years, 31.7% at 4 years, 30.2% at 5 years, 27.8% at 6 years, and 19.1% at more than 6 years, respectively, demonstrating a significant decreasing trend (p = 0.003). In a multivariable Cox regression analysis, ATD treatment duration was an independent risk factor for relapse (p = 0.043).

CONCLUSIONS

The longer that ATD therapy is used, the lower the relapse rate is in patients with Graves' disease. Long-term ATD treatment may be considered in Graves' patients who do not show complications or an economic burden from hyperthyroidism.

Hiccups as a Rare Presentation of Thyrotoxicosis Triaged by an Epidural Steroid Injection

Thyrotoxicosis manifests when excess levels of thyroid hormone act on different tissues throughout the body. Excess hormone levels can be related to endogenous production or exogenous ingestion and can present differently in patients. It has been theorized that high levels of thyroxine can irritate the neuroanatomical hiccup center leading to persistent hiccups. Although extremely rare, physicians should be aware of this entity to allow for proper diagnosis and management. Here, we discuss a rare case of thyrotoxicosis after an epidural steroid injection presenting with intractable hiccups.

Dual attack: targeting the rare co-occurrence of myasthenia gravis and Graves' disease with radioactive iodine therapy

SUMMARY

Occasionally, autoimmune disorders can come in twos. This double trouble creates unique challenges. Myasthenia gravis co-existing with autoimmune thyroid disease occurs in only about 0.14-0.2% of cases. The patient is a 27-year-old man with a 2-month history of bilateral ptosis, diplopia, with episodes of easy fatigability, palpitations, and heat intolerance. On physical exam, the patient had an enlarged thyroid gland. Myasthenia gravis was established based on the presence of ptosis with weakness of the intraocular muscles, abnormal fatigability, and a repetitive nerve stimulation study indicated neuromuscular junction disease. Episodes of fluctuating right shoulder weakness were also noted. He was also found to have elevated FT3, FT4, and a suppressed TSH. Thyroid ultrasound revealed thyromegaly with diffused parenchymal disease. Thyroid scintigraphy showed increased uptake function at 72.4% uptake at 24 h. TRAb was positive at 4.1 U/L. Patient was started on pyridostigmine which led to a significant reduction in the frequency of ocular muscle weakness. Methimazole was also initiated. Radioactive iodine at 14.9 mci was instituted for the definitive management of hyperthyroidism. After RAI, there was abatement of the hyperthyroid symptoms, as well as improvement in the status of the myasthenia gravis, with ptosis, diplopia, and right arm weakness hardly occurring thereafter despite the reduction of the pyridostigmine dose based on a symptom diary and medication intake record. Two distinct autoimmune conditions displayed a markedly improved clinical course with the institution of radioactive iodine therapy for Graves' disease.

LEARNING POINTS

The presence of ptosis, diplopia, and fluctuating muscle weakness are atypical in Graves' disease and should prompt an investigation on the existence of concurrent myasthenia gravis. A prompt diagnosis of both conditions will enable the institution of appropriate management that would target both rare and challenging autoimmune diseases. Selecting the therapeutic options with minimal risk of morbidity and mortality, which could lead to maximal benefit especially in a resource-limited setting is paramount. Targeted non-surgical management can lead to the remission of two autoimmune diseases which can result in patient satisfaction and improved quality of life.

Antithyroid Drug Treatment in Graves' Disease

Graves' disease is associated with thyrotropin (TSH) receptor stimulating antibody, for which there is no therapeutic agent. This disease is currently treated through inhibition of thyroid hormone synthesis or destruction of the thyroid gland. Recurrence after antithyroid drug (ATD) treatment is common. Recent studies have shown that the longer is the duration of use of ATD, the higher is the remission rate. Considering the relationship between clinical outcomes and iodine intake, recurrence of Graves' disease is more common in iodine-deficient areas than in iodine-sufficient areas. Iodine restriction in an iodine-excessive area does not improve the effectiveness of ATD or increase remission rates. Recently, Danish and Korean nationwide studies noted significantly higher prevalence of birth defects in newborns exposed to ATD during the first trimester compared to that of those who did not have such exposure. The prevalence of birth defects was lowest when propylthiouracil (PTU) was used and decreased by only 0.15% when methimazole was changed to PTU in the first trimester. Therefore, it is best not to use ATD in the first trimester or to change to PTU before pregnancy.

Hemodynamic Instability during Thyroidectomy in Graves' Disease

BACKGROUND

The aim of this study was to investigate the changes in vital signs and hemodynamic status that occur in patients during the intraoperative course of thyroidectomy in Graves' Disease (GD).

METHODS

A total of 71 patients were included in the study. Patients were directed to surgery when they had large goiters with compressive symptoms or suspicious nodules, were pregnant or lactating, were unresponsive or intolerant to antithyroid drugs (ATDs), or expressed a preference to have surgery. All patients scheduled for operations underwent surgery while in the euthyroid state.

RESULTS

Hemodynamic instability was observed in 18 patients during thyroidectomy. Disease duration, sample weight, and thyroid-stimulating hormone receptor antibodies (TRAb) levels were found to be effective on hemodynamic instability. Logistic regression analysis revealed an 11-fold increase in the instability risk in patients with a period of disease shorter than 21 months (P = 0.037). A TRAb value >11.5 increased the risk by 235fold (p < 0.001).

CONCLUSION

High levels of TRAb values and new onset of disease with shorter periods of ATDs use may be risk factors for hemodynamic instability during thyroidectomy. Patients with larger thyroid glands are at greater risk for instability during surgery. Those risks should be taken into account during surgery, and the surgical and anesthetic management of the patient should be made more carefully in concordance with the anesthesia team.

Graves' orbitopathy: a multidisciplinary approach

Orbitopathy is the main extra thyroidal manifestation of Graves' disease. It is a very challenging condition, which requires a cooperation between many specialists (endocrinologists, ophthalmologists, radiologists, radiotherapeutic, orbital surgeons) for an optimal clinical management. An accurate diagnostic assessment is required, in order to plan an adequate treatment of Graves' orbitopathy. Medical therapy, radiotherapy or surgery may be necessary to control the disease. In this review, the authors analyze the various therapeutic strategies, as well the more recent therapies based on pharmacologic immunomodulation.

Autoimmune switch from hyperthyroidism to hypothyroidism in Graves’ disease

We report a case of a 21-year-old young woman who was initially diagnosed with hyperthyroidism secondary to Graves’ disease and spontaneously switched to hypothyroidism in a year. While most autoimmune hypothyroidism is due to Hashimoto’s disease, in her case, we suspect that her hypothyroidism is due to a switch of antibody dominance from thyroid stimulating hormone (TSH) receptor-stimulating antibody (TS Ab) to TSH receptor-blocking antibody (TB Ab). Switching from dominant TS Ab activity to dominant TB Ab activity is a rare phenomenon. Optimal management of this condition is not known. Loss of follow-up and medication non-adherence has made medical management in this young woman of reproductive age further challenging.

Hyperthyroidism is associated with breast cancer risk and mammographic and genetic risk predictors

BACKGROUND

Despite the biological link between thyroid hormones and breast cancer cell proliferation shown in experimental studies, little is known about the association between hyperthyroidism and breast cancer, as well as its association with the most common mammographic and genetic risk predictors for breast cancer.

METHODS

This study estimates the incidence rate ratios (IRRs) of breast cancer among women diagnosed with hyperthyroidism, compared to those who are not, using two cohorts: a Swedish national cohort of the general female population (n = 3,793,492, 2002-2011) and the Karolinska Mammography Project for Risk Prediction of Breast Cancer (KARMA, n = 69,598, 2002-2017). We used logistic regression to estimate the odds ratios (ORs) of hyperthyroidism according to the mammographic and genetic risk predictors for breast cancer.

RESULTS

An increased risk of breast cancer was observed in patients in the national cohort with hyperthyroidism (IRR = 1.23, 95% CI = 1.12-1.36), particularly for toxic nodular goiter (IRR = 1.38, 95% CI = 1.16-1.63). Hyperthyroidism was associated with higher body mass index, early age at first birth, and lower breastfeeding duration. Higher mammographic density was observed in women with toxic nodular goiter, compared to women without hyperthyroidism. Additionally, among genotyped women without breast cancer in the KARMA cohort (N = 11,991), hyperthyroidism was associated with a high polygenic risk score (PRS) for breast cancer overall (OR = 1.98, 95% CI = 1.09-3.60) and for estrogen receptor-positive specific PRS (OR = 1.90, 95% CI = 1.04-3.43).

CONCLUSION

Hyperthyroidism is associated with an increased risk of breast cancer, particularly for patients with toxic nodular goiter. The association could be explained by higher mammographic density among these women, as well as pleiotropic genetic variants determining shared hormonal/endocrine factors leading to the pathology of both diseases.

Prediction of Relapse After Antithyroid Drugs Withdrawal: A Narrative Review

Context: Antithyroid drugs (ATD) are the first-line treatment for Graves’ disease (GD); however, relapse following treatment is approximately 30% - 40% in the first year, and 50% - 60% in the long term. Identification of risk factors that predict relapse, after discontinuing ATD, plays an important role in guiding therapeutic options. Evidence Acquisition: PubMed was used to search for studies published in English between 1995 and 2019. The following search terms were used: Graves’ disease, antithyroid drugs, relapse, recurrence, and outcome. The reference lists from review articles were also included in the search in order to find older journals. Results: Factors associated with a high recurrence rate, as reported in most studies, were divided into phenotype and genotype predictors. Phenotype factors included large goiter size, persistence of high TSH receptor antibody (TRAb), severe hyperthyroidism, smoking, younger age, male sex, and prior history of recurrence. Genotype factors included human leukocyte antigen (HLA), CD40, CTLA-4, PTPN22, Tg, and TSHR genes. In a subgroup analysis by age, genetic factors were better predictors in the younger group, while clinical signs were more useful in the older group. The reliability of using individual baseline risk factors to predict subsequent relapse is poor; however, predictive scores calculated by grouping single risk factors might help to predict future outcomes. Conclusions: Longer normalization time of TRAb, the persistence of a palpable goiter, and harboring genetic risk factors in younger patients are associated with high recurrence rate of GD. Multi-marker prediction models have been proposed and validated to improve the predictive value of relapse after ATD withdrawal.

Long-term outcomes of graves disease in children treated with anti-thyroid drugs

BACKGROUND

Graves disease (GD) is the most common cause of thyrotoxicosis in children and adolescents, accounting for 15% of all thyroid diseases during childhood. Anti-thyroid drugs (ATD) are recommended as the first-line treatment in children and adolescents. However, the remission rate is lower in children than in adults, and the optimal treatment duration and favorable factors associated with remission remain unknown. We aimed to investigate long-term outcomes of pediatric GD patients receiving ATD.

METHODS

We retrospectively reviewed medical charts of 396 GD subjects from 1985 to 2017 at MacKay Children's Hospital. Ninety-six patients were excluded from the analyses, including 71 patients followed for less than one year, 6 patients who received radioactive therapy and 19 patients who received surgery. The remaining 300 patients initially treated with ATD and followed up for more than 1 year constituted our study population.

RESULTS

The 300 patients comprised 257 (85.7%) females and 43 (14.3%) males. Their median age at diagnosis was 11.6 (range 2.7-17.8) years with 11 patients (3.7%) younger than 5 years. Their median follow-up period was 4.7 (range 1.1-23.9) years. Overall, 122 patients achieved the criteria for discontinuing ATD treatment, and seventy-nine (39.9%) patients achieved remission, with a median follow-up period of 5.3 (range 1.5-20.1) years. Patients in the remission group were more likely to be aged <5 years (remission vs. relapse vs. ongoing ATD; 11.4 vs. 0 vs. 2.6%, P = 0.02), less likely to have a family history of thyroid disease (24.1 vs. 42.1 vs. 52.6%, P = 0.001), and had lower TSH receptor antibody (TRAb) levels (42.8 vs. 53.6 vs. 65.1%, P = 0.02) at the time of diagnosis.

CONCLUSION

Long-term ATD remains an effective treatment option for GD in children. Pediatric GD patients aged <5 years, having no family history of thyroid disease and having initial lower TRAb levels were more likely to achieve remission.

Impact of surgery versus medical management on cardiovascular manifestations in Graves disease

BACKGROUND

Graves disease is well known to have multiple adverse effects on the cardiovascular system. We compared the cardiovascular outcomes after surgical intervention versus medical treatment in patients with Graves disease.

METHODS

We performed a retrospective study of all Graves disease patients with a cardiovascular comorbidity who underwent either surgical or medical management (N = 151). Perioperative biochemical and cardiovascular outcomes from the surgical versus the medical groups were analyzed.

RESULTS

Of 151 patients, 69 (45.6%) patients underwent total thyroidectomy and 82 (54.3%) patients received medical treatment. Hypertension resolved in 44.7% of the patients from the surgical group vs 18% in the medical group (P = .03). Tachyarrhythmias, including atrial fibrillation and tachycardia, improved in 85.9% of patients in the surgical group vs 66% in the medical group (P = .01). All cardiovascular manifestations examined, hypertension, tachyarrhythmias, and heart failure, improved in 69% of patients in the surgical group and 42.6% of patients in the medical group during the follow-up period (P < .01).

CONCLUSION

Surgical treatment offers a significant and rapid clinical improvement of cardiovascular manifestations in Graves disease patients, such as hypertension, tachyarrhythmias, and heart failure. Surgery should be considered and recommended in Graves disease patients with known cardiovascular manifestations.

"Block-and-replace" treatment in Graves' disease: experience in a cohort of pediatric patients

PURPOSE

The "block-and-replace" (BR) method involves the use of a high dose of antithyroid drugs (ATD) with levothyroxine (L-T4). Its use in the management of Graves' disease (GD) is still debated mainly because the frequency of side effects of ATD is dose dependent. We retrospectively studied the effect of medium dose of ATD with L-T4 versus monotherapy with ATD in pediatric patients with unstable GD.

METHODS

28 pediatric patients with GD with unstable response to ATD were treated with L-T4 and medium dose of ATD. We compared the rate of euthyroidism, hypothyroidism and hyperthyroidism episodes observed during treatment with methimazole alone with those observed during the BR approach. We evaluated the occurrence of side effects and the rate of remission in patients treated with ATD + L-T4 therapy and the efficacy of combination therapy to postpone a definitive treatment (radioiodine and thyroidectomy).

RESULTS

Patients showed a better control of thyroid function during the BR therapy, presenting fewer episodes of hyperthyroidism and hypothyroidism. No serious side effects during the BR approach were observed. Only one patient went into remission with the ATD + L-T4 therapy. Fifteen patients required a definitive therapy (4 radioiodine, 11 thyroidectomy). The use of BR method has delayed radioiodine treatment for 4.9 years and surgery for 2.9 years.

CONCLUSIONS

The BR method does not increase the remission rates. It may be useful to combine L-T4 with a medium dose of methimazole when GD is difficult to manage with methimazole alone. It may represent a therapeutic option to postpone definitive treatments to a suitable age.

Risk Factors for the Relapse of Graves' Disease Treated With Antithyroid Drugs: A Systematic Review and Meta-analysis

PURPOSE

Antithyroid drugs (ATDs) are the first-line treatment for Graves' disease (GD). A common problem with ATD treatment is the high relapse rate after drug withdrawal. The goal of this study was to analyze the influencing factors for the relapse of GD patients treated with ATD by using a systematic review and meta-analysis, provide some predictive indexes for the susceptibility of GD recurrence, and then further explore some useful methods to decrease the GD relapse rate after ATD treatment.

METHODS

Articles published in PubMed, EMBASE, The Cochrane Library, China National Knowledge Infrastructure, Wan Fang, and Chinese Biomedical Literature databases before January 2019 were collected. Patients newly diagnosed with GD, who were aged >16 years, were treated with ATD. Follow-up was then conducted for at least 12 months after ATD withdrawal. Only prospective or retrospective studies were eligible. The primary end point was the recurrence of GD during follow-up. All the data from the trials were analyzed via meta-analysis and meta-regression. p values < 0.05 were considered statistically significant, and statistical heterogeneity was assessed by using I² statistics.

FINDINGS

A total of 20 studies and 3242 patients were involved in this meta-analysis, with 1681 patients relapsed (incidence rate, 51.9%) during the follow-up time. Analysis of risk factors suggested that younger age (weighted raw mean difference [RMD], -3.51; 95% CI, -5.74 to -1.29), larger thyroid volume (RMD, 4.38; 95% CI, 1.68 to 7.08), bigger goiter size (1.94% risk; 95% CI, 0.43 to 3.46), higher free triiodothyronine level (RMD, 5.09; 95% CI, 4.42 to 5.77), and higher free thyroxine level (RMD, 4.21; 95% CI, 0.54 to 7.89) were associated with the higher relapse rate of GD. The block-replace ATD regimen (a fixed high dose of an ATD with levothyroxine supplementation to maintain euthyroidism) (risk ratio, 0.64; 95% CI, 0.52 to 0.78) exhibits a lower relapse rate than the titration regimen (an ATD used alone and dose adjusted according to thyroid function tests).

IMPLICATIONS

This analysis revealed that certain risk factors were associated with GD relapses such as younger age, larger goiter size or thyroid volume, and the higher free triiodothyronine or free thyroxine level in the diagnosing phase of GD. For patients with these clinical characteristics, early definitive treatment with radioactive iodine or surgery should be offered to those who are unlikely to achieve remission with ATDs only. In addition, more prospective cohort studies with different ATD regimens would help to determine the optimum ATD treatment for patients with GD. PROSPERO identifier: CRD 42019146825.

Hyperthyroidism

Hyperthyroidism is a condition where the thyroid gland produces and secretes inappropriately high amounts of thyroid hormone which can lead to thyrotoxicosis. The prevalence of hyperthyroidism in the United States is approximately 1.2%. There are many different causes of hyperthyroidism, and the most common causes include Graves' disease (GD), toxic multinodular goiter and toxic adenoma. The diagnosis can be made based on clinical findings and confirmed with biochemical tests and imaging techniques including ultrasound and radioactive iodine uptake scans. This condition impacts many different systems of the body including the integument, musculoskeletal, immune, ophthalmic, reproductive, gastrointestinal and cardiovascular systems. It is important to recognize common cardiovascular manifestations such as hypertension and tachycardia and to treat these patients with beta blockers. Early treatment of cardiovascular manifestations along with treatment of the hyperthyroidism can prevent significant cardiovascular events. Management options for hyperthyroidism include anti-thyroid medications, radioactive iodine, and surgery. Anti-thyroid medications are often used temporarily to treat thyrotoxicosis in preparation for more definitive treatment with radioactive iodine or surgery, but in select cases, patients can remain on antithyroid medications long-term. Radioactive iodine is a successful treatment for hyperthyroidism but should not be used in GD with ophthalmic manifestations. Recent studies have shown an increased concern for the development of secondary cancers as a result of radioactive iodine treatment. In the small percentage of patients who are not successfully treated with radioactive iodine, they can undergo re-treatment or surgery. Surgery includes a total thyroidectomy for GD and toxic multinodular goiters and a thyroid lobectomy for toxic adenomas. Surgery should be considered for those who have a concurrent cancer, in pregnancy, for compressive symptoms and in GD with ophthalmic manifestations. Surgery is cost effective with a high-volume surgeon. Preoperatively, patients should be on anti-thyroid medications to establish a euthyroid state and on beta blockers for any cardiovascular manifestations. Thyroid storm is a rare but life-threatening condition that can occur with thyrotoxicosis that must be treated with a multidisciplinary approach and ultimately, definitive treatment of the hyperthyroidism.

The Role of Surgery in Autoimmune Conditions of the Thyroid

The two most common autoimmune conditions of the thyroid include chronic lymphocytic (Hashimoto's) thyroiditis and Graves' disease. Both conditions can be treated medically, but surgery plays an important role. Hashimoto's thyroiditis and Graves' disease are mediated by autoantibodies that interact directly with the thyroid, creating inflammation and impacting thyroid function. Patients may develop large goiters with compressive symptoms or malignancy requiring surgical intervention. In addition, there are several surgical indications specific to Hashimoto's and Graves' Disease.

Thyroid diseases increased the risk of type 2 diabetes mellitus: A nation-wide cohort study

Thyroid function may alter carbohydrate metabolism via influence of insulin, which may in terms of derangement of thyroid function and insulin function result in the development of type 2 diabetes mellitus (T2D). We investigated the association of thyroid disorders with T2D by a cohort study of the Taiwan nationwide health insurance database.A sub-dataset of the National Health Insurance Research Database (NHIRD) was used in this study. The thyroid disease (both hyper- and hypo-thyroidism) group was chosen from patients older than 18 years and newly diagnosed between 2000 and 2012. The control group consisted of randomly selected patients who never been diagnosed with thyroid disease and 4-fold size frequency matched with the thyroid disease group. The event of this cohort was T2D (ICD-9-CM 250.x1, 250.x2). Primary analysis was performed by comparing the thyroid disease group to the control group and the second analysis was performed by comparing the hyperthyroidism subgroup, hypothyroidism subgroup, and control group.The occurrence of T2D in the thyroid disease group was higher than the control group with hazard ratio (HR) of 1.23 [95% confidence interval (CI) = 1.16-1.31]. Both hyperthyroidism and hypothyroidism were significantly higher than control. Significantly higher HR was also seen in female patients, age category of 18 to 39-year-old (y/o) and 40 to 64 y/o subgroups. Higher occurrence of T2D was also seen in thyroid disease patients without comorbidity than in the control group with HR of 1.47 (95% CI = 1.34-1.60). The highest HR was found in the half-year follow-up.There was a relatively high risk of T2D development in patients with thyroid dysfunctions, especially in the period of 0.5 to 1 year after presentation of thyroid dysfunctions. The results suggest performing blood sugar tests in patients with thyroid diseases for early detection and treatment of T2D.

MANAGEMENT OF THYROTOXICOSIS AMONG GENERAL PRACTITIONERS IN TRINIDAD COMPARED WITH 2016 AMERICAN THYROID ASSOCIATION GUIDELINES FOR HYPERTHYROIDISM

Objective: A previous Trinidadian survey highlighted the investigative and therapeutic approaches selected by general practitioners (GPs) in managing thyrotoxicosis. The main objective of this study was to compare practice with existing guidelines. Methods: In this cross-sectional study a pretested de novo questionnaire was self-administered to GPs throughout Trinidad. The survey evaluated GPs' choices in management of thyrotoxicosis cases and compared their responses to the 2016 American Thyroid Association guidelines as well as with those previously reported locally. Results: A total of 159 completed questionnaires were analyzed (59% response rate). Thyroid stimulating hormone was the preferred (94%) biochemical test to confirm thyrotoxicosis etiology. A combination of ultra-sound and thyroid scintigraphy, thyroid ultrasound alone, and scintigraphy only were the testing options selected by 41%, 38%, and 12%, respectively. Generally medical therapy with antithyroid drugs was the preferred treatment option with 86% of respondents selecting this option for the index case of newly diagnosed female Graves disease. The greatest proportion of respondents that selected radioactive iodine (RAI) was 35% for both the index case as well as the male equivalent. Surgery was the most popular option at 25% for patients with a toxic multinodular goiter. Having access to RAI and scintigraphy was reported by 32% and 28%, respectively. Conclusion: GPs appear to be constrained to making rational choices based upon availability rather than what the guidelines recommend. In the absence of formal continuing medical education for GPs on thyrotoxicosis, dissemination of guidelines at the primary care level may reduce this gap. Abbreviations: ATA = American Thyroid Association; ATD = antithyroid drugs; CME = continued medical education; GP = general practitioner; RAI = radioactive iodine; SURG = surgery; T4 = thyroxine; TSH = thyroid-stimulating hormone.

Graves' Disease: Can It Be Cured?

Whether or not Graves' hyperthyroidism can be really cured, depends on the definition of "cure." If eradication of thyroid hormone excess suffices for the label "cure," then all patients can be cured because total thyroidectomy or high doses of ¹³¹I will abolish hyperthyroidism albeit at the expense of creating another disease (hypothyroidism) requiring lifelong medication with levothyroxine. I would not call this a "cure," which I would like to define as a state with stable thyroid stimulating hormone (TSH), free thyroxine, and triiodothyronine serum concentrations in the normal range in the absence of any thyroid medication. Surgery and radioiodine are unlikely to result in so-defined cures, as their preferable aim as stated in guidelines is to cause permanent hypothyroidism. Discontinuation of antithyroid drugs is followed by 50% recurrences within 4 years; before starting therapy the risk of recurrences can be estimated with the Graves' Recurrent Events After Therapy (GREAT) score. At 20-year follow-up about 62% had developed recurrent hyperthyroidism, 8% had subclinical hypothyroidism, and 3% overt hypothyroidism related to TSH receptor blocking antibodies and thyroid peroxidase antibodies. Only 27% was in remission, and might be considered cured. If the definition of "cure" would also include the disappearance of thyroid antibodies in serum, the proportion of cured patients would become even lower.

Long-term remission following antithyroid drug withdrawal in patients with Graves' hyperthyroidism: parameters with prognostic value

OBJECTIVE

To assess the predictive value of some clinical and biochemical parameters, and of the +49 A/G polymorphism of the CTLA-4 gene, for long-term remission following the withdrawal of antithyroid drugs before starting antithyroid drug therapy.

STUDY DESIGN

Observational, prospective and longitudinal study.

METHODS

Seventy-two patients (11 of whom were men) with newly diagnosed Graves' hyperthyroidism who had been attended consecutively at a University Clinic in a population with sufficient iodine intake were included in the study.

EXCLUSION CRITERIA

patients under the age of 18, pregnant women and non-Caucasian patients. All subjects were treated following a well-defined protocol. Long-term remission was calculated at 12 and 36 months following withdrawal of the antithyroid drug.

RESULTS

Thirty-six of the 72 study subjects experienced a remission of at least 12 months following withdrawal of methimazole, with no differences according to their age or sex. A comparison made between the remission rates seen in both groups yielded significant differences regarding the presence of Graves' orbitopathy, the duration of the treatment with methimazole and the absence of the CTLA-4 G/G genotype. In the univariate and multivariate analyses performed, only lower frequencies of Graves' orbitopathy and an absence of the CTLA-4 G/G genotype were considered independent predictors of long-term remission.

CONCLUSIONS

The absence of Graves' orbitopathy and of the CTLA-4 G/G genotype are independent predictors of long-term remission following a first course of antithyroid drugs.

Predictors of Initial and Sustained Remission in Patients Treated with Antithyroid Drugs for Graves' Hyperthyroidism: The RISG Study

Purpose. To study predictors of attaining (part 1) and sustaining (part 2) remission in patients with Graves' hyperthyroidism (GH) treated with antithyroid drugs (ATD). Methods. In the prospective first part, the included patients were treated with ATD until a prespecified definition of remission (thyrotropin > 0.4 mU/L and TSH-receptor antibodies (TRAb) ≤ 1. 0 IU/L in a patient receiving a methimazole dose ≤ 5 mg/day, on two occasions two months apart) was met, or for 24 months. In the second part, patients attaining remission in part 1 were randomized to treatment or observation and followed until relapse or for 24 months. Results. 173 patients completed study 1 and 53% attained remission. TRAb and age were the only significant predictors of remission. Patients with baseline TRAb below vs above 10 IU/L attained remission in 63% compared to 39%, and 5 months priorly (p<0.001). In study 2, 96.4% of the patients randomized to treatment (n=33) sustained remission compared to 66% in the observation group (n=33). Treatment arm was the only significant parameter (p<0.001) of sustained remission. Conclusion. Baseline TRAb was prognostic for attaining remission in GH. Consecutive TRAb measurements during treatment were not worthwhile, but a single measurement after 6-8 months in patients with initial TRAb < 10 IU/L could substantially shorten the treatment period in a subgroup of patients. Only 3.6% of the patients in remission experienced relapse during follow-up when treated with a combination of fixed low dose methimazole and L-T4. ClinTrial.gov registration number is  NCT00796913.

Antithyroid Drugs

The thionamide drugs, i.e. carbimazole and its metabolite methimazole (MMI), and propylthiouracil (PTU) have extensively been used in the management of various forms of hyperthyroidism over the past eight decades. This review aims to summarize different aspects of these outstanding medications. Thionamides have shown their own acceptable efficacy and even safety profiles in treatment of hyperthyroidism, especially GD in both children and adults and also during pregnancy and lactation. Of the antithyroid drugs (ATDs) available, MMI is the preferred choice in most situations taking into account its better efficacy and less adverse effects accompanied by once-daily dose prescription because of a long half-life and similar cost. Considering the more severe teratogenic effects of MMI, PTU would be the selected ATD for treatment of hyperthyroidism during pre-pregnancy months and the first 16 weeks of gestation. Recent studies have confirmed the efficacy and safety of long-term MMI therapy with low maintenance doses for GD and toxic multinodular goiter. Despite the long-term history of ATD use, there is still ongoing debate regarding their pharmacology and diverse mechanisms of action, viz. their immunomodulatory effects, and mechanisms and susceptibility factors to their adverse reactions.

DISEASE PRESENTATION AND REMISSION RATE IN GRAVES DISEASE TREATED WITH ANTITHYROID DRUGS: IS GENDER REALLY A FACTOR?

OBJECTIVE

Male gender is considered an adverse prognostic factor for remission of Graves disease treatment with antithyroid drugs (ATDs), although published data are conflicting. This often results in early consideration of radioiodine treatment and surgery for men. Our objective was to compare disease presentation and outcome in men versus women treated with ATDs.

METHODS

Retrospective study of 235 patients (64 men, 171 women) with Graves disease who were evaluated for features at presentation and outcome at the end of follow-up between 2010 and 2015.

RESULTS

Disease presentation was similar in men and women for age at diagnosis (41.4 ± 14 years vs. 40 ± 15 years), duration of follow-up (6.6 ± 7 years vs. 7.7 ± 6 years), rates of comorbid autoimmune diseases, and rate of Graves ophthalmopathy. Smoking was more prevalent in males (31% vs. 15%; P = .009). Free thyroxine and triiodothyronine levels were comparable. ATDs were first-line treatment in all males and in 168 of 171 females, for a median duration of 24 and 20 months, respectively ( P = .55). Remission rates were 47% in men and 58% in women ( P = .14). Males had fewer adverse events (9% vs. 18%) and treatment discontinuation (5% vs. 16%). Disease recurrence was comparable (14% vs. 20%; P = .32), as was requirement for second-line treatment, either radioiodine therapy or thyroidectomy.

CONCLUSION

Graves disease presentation is similar in men and women. Men treated with ATDs have high remission rates and similar recurrence rates compared to women, with fewer adverse events and less discontinuation of treatment. ATDs are an attractive first-line treatment for both genders.

ABBREVIATIONS

ATA = American Thyroid Association; ATD = antithyroid drug; GO = Graves ophthalmopathy; T3 = triiodothyronine; T4 = thyroxine; TSH = thyroid-stimulating hormone.

ANNIVERSARY REVIEW: Antithyroid drug therapy: 70 years later

The thionamide antithyroid drugs were discovered in large part following serendipitous observations by a number of investigators in the 1940s who found that sulfhydryl-containing compounds were goitrogenic in animals. This prompted Prof. Edwin B Astwood to pioneer the use of these compounds to treat hyperthyroidism in the early 1940s and to develop the more potent and less toxic drugs that are used today. Despite their simple molecular structure and ease of use, many uncertainties remain, including their mechanism(s) of action, clinical role, optimal use in pregnancy and the prediction and prevention of rare but potentially life-threatening adverse reactions. In this review, we summarize the history of the development of these drugs and outline their current role in the clinical management of patients with hyperthyroidism.

Treatment of adult Graves' disease

Treatment strategy in Graves' disease firstly requires recovery of euthyroid status by antithyroid therapy. Treatment modalities, precautions, advantages and side-effects are to be discussed with the patient. No particular treatment modality has demonstrated superiority. Pregnancy or pregnancy project affects choice of treatment and monitoring. Graves' orbitopathy is liable to be aggravated by iodine-131 treatment and requires pre-treatment assessment. Iodine-131 treatment aims at achieving hypothyroidism. Thyroid surgery for Graves' disease should preferably be performed by an expert team. In case of recurrence of hyperthyroidism, the various treatment options should be discussed with the patient. Empiric treatment of thyroid dermopathy uses local corticosteroids in occlusive dressing.

Long-term outcome of thyrotoxicosis in childhood and adolescence in the west of Scotland: the case for long-term antithyroid treatment and the importance of initial counselling

BACKGROUND

Thyrotoxicosis is both rarer and more severe in children than in adults, rendering management difficult and often unsatisfactory.

OBJECTIVE

To ascertain outcome in a geographically defined area of Scotland between 1989 and 2014.

METHOD

Retrospective case note review with follow-up questionnaire to family doctors for patients with Graves' disease and Hashimoto's thyroiditis.

RESULTS

Sixty-six patients (58 females:8 males) comprising 53 with Graves' disease and 13 with Hashimoto's thyroiditis were diagnosed at median 10.4 (2.9-15.8) years and followed up for 11.8 (2.6-30.2) years. Antithyroid drug (ATD) therapy was stopped electively in 35 patients after 4.5 (1.5-8.6) years, resulting in remission in 10/13 Hashimoto's thyroiditis and 10/22 Graves' disease. Side effects occurred in 12 patients receiving carbimazole, six of whom changed to propylthiouracil; no adverse events occurred in the latter patients.Second-line therapy was given to 37 patients (34 with Graves' disease), comprising radioiodine (22) at 15.6 (9.3-24.4) years for relapse (6), poor control/adherence (14) or electively (2); and surgery (16) at 12 (6.4-21.3) years for relapse (4), poor control/adherence (5) and electively (7). Adherence problems with thyroxine replacement were reported in 10/33 patients in adulthood.

CONCLUSIONS

Hashimoto's thyroiditis should be distinguished from Graves' disease at diagnosis since the prognosis for remission is better. Remission rates for Graves' disease are low (10/53 patients), time to remission variable and adherence with both ATD and thyroxine replacement often problematic. We recommend (a) the giving of long-term ATD rather than a fixed course of treatment in GD and (b) meticulous and realistic counselling of families from the time of diagnosis onwards.

Optimal iodine supplementation during antithyroid drug therapy for Graves' disease is associated with lower recurrence rates than iodine restriction

OBJECTIVE

A relationship between iodine intake and the effectiveness of antithyroid drug (ATD) therapy for Graves' disease (GD) has been suggested, and strict restriction of iodine intake has been tried in the treatment of GD in some studies. However, it is unclear whether dietary iodine supplementation improves the prognosis of ATD therapy for GD. This study aimed to clarify whether optimal iodine supplementation during antithyroid drug therapy for GD is associated with lower recurrence rates than iodine restriction.

METHODS

This was a prospective randomized trial of newly diagnosed patients with GD. Patients with newly diagnosed GD were recruited. After ATD therapy and strict dietary iodine restriction for 1 month, patients (n = 459) were randomly assigned to iodine-supplemented and iodine-restricted groups. After exclusion, 405 patients finally completed the study. The iodine-supplemented group included 203 patients (61 males and 142 females) with an average age of 32.2 ± 10.5 years (17-65 years), and the iodine-restricted group included 202 patients (61 males and 141 females) with an average age of 31.9 ± 11.8 years (16-64 years). Patients in the iodine-supplemented group were given about 10 grams of iodized salt every day, while the iodine-restricted group received noniodized salt with low-iodine or noniodine diet. The dietary iodine intervention lasted for 24 months. Urinary iodine concentration (UIC), thyrotropin receptor antibody (TRAb), free T3 (FT3), free T4 (FT4) and thyrotropin (TSH) of 2 groups were measured every 3 months. The recurrence rates within 12 months after withdrawal of ATD were evaluated.

RESULTS

UIC in the iodine-supplemented group was within the recommended range for optimal iodine intake (135-162 μg/L) and was significantly higher than that in iodine-restricted group (30-58 μg/L). Within 12 months of withdrawal of ATD, the total recurrence rate in the iodine-supplemented group was 35.5%, significantly lower than in the iodine-restricted group, which was 45.5%.

CONCLUSION

Optimal dietary iodine supplementation during antithyroid drug therapy for GD is associated with lower recurrence rates than iodine restriction, and therefore, diet control with strict iodine restriction might be an adverse factor in the management of GD.

Evidence for the possible occurrence of Grave's disease in a blue-eyed black lemur (Eulemur flavifrons)

The blue-eyed black lemur (Eulemur flavifrons) is classified by the International Union for Conservation of Nature (IUCN) as critically endangered. A 23-year-old male housed at Mulhouse Zoo presented with lethargy, polyphagia, alopecia, and chronic weight loss. Clinical examination suggested an endocrine pathology such as hyperthyroidism. Secondary examinations included cervical ultrasound, thyroid biopsy, and scintigraphy. The latter revealed elevated thyroid activity. Blood analysis was performed to measure the level of anti-receptor thyroid-stimulating hormone antibodies, which allowed us to test the autoimmune hypothesis. The high level of antibodies together with levels of thyroid-stimulating hormone and the scintigraphy images led to the diagnosis of Grave's disease. Carbimazole treatment followed by thyroidectomy resulted in a quick weight gain and general improvement in health status. The following breeding season, the treated individual sired an offspring. To the authors' knowledge, this is the first report of likely Grave's disease in a non-human primate.

Electrochemical versus Enzymatic in Vitro Oxidations of 6-propyl-2-thiouracil: Identification, Detection, and Characterization of Metabolites

6-Propylthiouracil, PTU, is a well-known antithyroid drug that has been the mainstay of treatment of Graves' disease. It is, however, also associated with liver toxicity and idiosyncratic toxicity. These toxicities are generally associated with metabolites derived from its bioactivation. In this manuscript, bioactivation of PTU was studied via two separate techniques: electrochemical oxidation and through the use of human liver microsomes. The aim of this work was to compare the bioactivation products of these two techniques. The electrochemical technique was studied online with a mass spectrometer, EC/ESI/MS. The microsomal oxidations were studied in tandem with liquid chromatography. The EC/ESI/MS technique was devoid of the normal reducing biological matrix prevalent in microsomal incubations. The predominant product at 400 mV was the dimeric PTU species with negligible formation of other metabolites. At higher potentials, complete desulfurization of PTU was observed with formation of sulfate. No sulfonic acid was observed, suggesting that the cleavage of the C-S bond was effected at the sulfinic acid stage, releasing a highly reducing sulfur species which is known to give rise to genotoxicity. The microsomal oxidations, surprisingly, showed formation of the unstable sulfenic acid, the S-oxide. Further incubation showed both the sulfinic and sulfonic acids. None of the systems showed any adducts with nucleophiles such as glutathione, showing that none of the reactive metabolites were stable enough to be adducted to nucleophiles in both the biological matrix and the electrochemical oxidizing environment.

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.

Serum 25-hydroxyvitamin D might be an independent prognostic factor for Graves disease recurrence

Graves disease is the most common cause of thyrotoxicosis. Although medical intervention with antithyroid drugs (ATDs) is commonly the first choice of treatment in Korea, the remission rate associated with this approach is not satisfactory. During ATD therapy, low or undetectable serum levels of thyroid-stimulating hormone (TSH) receptor antibodies (TRAbs) have been reported to affect the incidence of Graves disease remission. This study evaluated the correlation between serum 25-hydroxyvitamin D levels and TRAb levels, as well as the effect of 25-hydroxyvitamin D on the recurrence of Graves disease.A total of 143 patients, who were diagnosed with Graves disease and treated with ATDs, were retrospectively included in our observational study. These patients were followed for more than 1 year after ATD discontinuation. The levels of serum 25-hydroxyvitamin D and TRAb (ie, thyroid-stimulating antibody [TSAb], as detected by bioassay, and TSH-binding inhibitory immunoglobulins [TBIIs]) were measured, and a thyroid function test was performed upon ATD discontinuation. Recurrence was evaluated every 3 months, and was defined as an occurrence of overt thyrotoxicosis during the follow-up period.A total of 95 patients (66.4%) experienced recurrence with a median latency period of 182 days (ranging 28-1219 days). The serum 25-hydroxyvitamin D levels at the time of ATD discontinuation were not correlated with either TBII or TSAb. In the Cox proportional hazard regression analysis, higher free T4 levels (>1.4 ng/dL; hazard ratio [HR], 3.252; 95% confidence interval [CI], 1.022-10.347) and low levels of 25-hydroxyvitamin D (≤14.23 ng/mL) were associated with a higher probability of Graves disease recurrence (HR, 3.016; 95% CI, 1.163-7.819).Lower serum 25-hydroxyvitamin D levels were associated with a higher incidence of Graves disease recurrence. Therefore, serum 25-hydroxyvitamin D might be an independent risk factor for predicting Graves disease recurrence after ATD discontinuation.

Growth hormone and insulin-like growth factor 1 affect the severity of Graves' disease

Graves' disease, the most common form of hyperthyroidism in iodine-replete countries, is associated with the presence of immunoglobulins G (IgGs) that are responsible for thyroid growth and hyperfunction. In this article, we report the unusual case of a patient with acromegaly and a severe form of Graves' disease. Here, we address the issue concerning the role of growth hormone (GH) and insulin-like growth factor 1 (IGF1) in influencing thyroid function. Severity of Graves' disease is exacerbated by coexistent acromegaly and both activity indexes and symptoms and signs of Graves' disease improve after the surgical remission of acromegaly. We also discuss by which signaling pathways GH and IGF1 may play an integrating role in regulating the function of the immune system in Graves' disease and synergize the stimulatory activity of Graves' IgGs.

LEARNING POINTS

Clinical observations have demonstrated an increased prevalence of euthyroid and hyperthyroid goiters in patients with acromegaly.The coexistence of acromegaly and Graves' disease is a very unusual event, the prevalence being <1%.Previous in vitro studies have showed that IGF1 synergizes the TSH-induced thyroid cell growth-activating pathways independent of TSH/cAMP/PKA cascade.We report the first case of a severe form of Graves' disease associated with acromegaly and show that surgical remission of acromegaly leads to a better control of symptoms of Graves' disease.

Thyrotoxicosis - investigation and management

Graves' disease (GD) and toxic nodular (TN) goitre account for most cases of thyrotoxicosis associated with hyperthyroidism. Hyperthyroidism is confirmed with measurement of a suppressed serum thyrotropin concentration (TSH) and elevated free thyroid hormones. The three therapeutic options are antithyroid drugs, radioactive iodine and surgery. Thionamides achieve long-term remission in 35% of cases. Many centres administer fixed doses of iodine-131; larger doses result in improved rates of cure at the cost of hypothyroidism. Surgery is usually considered for patients who have a large goitre, compressive symptoms or significant ophthalmopathy.