Should radioiodine now be first line treatment for Graves' disease?

Thyroid function test variability and cardiovascular morbidity in hyperthyroidism

OBJECTIVE

The variability of thyroid function tests (TFTs) during antithyroid drug (ATD) therapy and its association with adverse health outcomes have not been previously studied. The aim of this study was to evaluate the association of TFT variability and cardiovascular morbidity during ATD therapy.

DESIGN

Retrospective cohort study.

PATIENTS AND MEASUREMENTS

Hyperthyroid patients (n = 394) treated with ATD therapy at Tampere University Hospital between March 2016 and December 2018 were followed up for a median time of 1.5 years (interquartile range 0.8-2.0). The coefficients of variation (CVs) of the follow-up thyroid-stimulating hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3) measurements were determined. The associations of TFT variability and baseline clinical factors with cardiovascular disease (CVD) -associated hospital visits were assessed with logistic regression analyses.

RESULTS

In the multivariable analyses, age (odds ratio [OR]: 1.06, 95% confidence interval [CI]: 1.03-1.09), male gender (OR: 2.33, 95% CI: 1.03-5.28) and fT4-CV (OR: 1.02, 95% CI: 1.01-1.04) were independent risk factors for cardiovascular morbidity, whereas baseline positive thyrotropin receptor antibodies (TRAbs) were associated with lower cardiovascular morbidity (OR: 0.29, 95% CI: 0.14-0.61). When the patients with baseline TRAb positivity were studied separately, fT4-CV was associated with cardiovascular morbidity (OR: 1.03, 95% CI: 1.00-1.05).

CONCLUSIONS

During ATD therapy, fT4 variability is associated with an increased cardiovascular morbidity. Although positive TRAbs are associated with a lower cardiovascular morbidity compared with hyperthyroidism with negative autoantibodies, the variability of fT4 is associated with cardiovascular morbidity also in patients with positive TRAbs.

Non-thionamide antithyroid drug options in Graves' hyperthyroidism

INTRODUCTION

The thionamide anti-thyroid drugs namely carbimazole, methimazole, and propylthiouracil, have been the predominant therapy modality for Graves' hyperthyroidism for over 60 years. Although these agents have proven efficacy and favorable side-effect profiles, non-thionamide alternatives are occasionally indicated in patients who are intolerant or unresponsive to thionamides alone. This review examines the available non-thionamide drug options for the control of Graves' hyperthyroidism and summarizes their clinical utility, efficacy, and limitations.

AREAS COVERED

We reviewed existing literature on mechanisms, therapeutic utility, and side-effect profiles of non-thionamide anti-thyroid drugs. Established non-thionamide agents act on various phases of the synthesis, release, and metabolism of thyroid hormones and comprise historical agents such as iodine compounds and potassium perchlorate as well as drug repurposing candidates like lithium, glucocorticoids, beta-blockers, and cholestyramine. Novel experimental agents in development target key players in Graves' disease pathogenesis including B-cell depletors (Rituximab), CD40 blockers (Iscalimab), TSH-receptor antagonists, blocking antibodies, and immune-modifying peptides.

EXPERT OPINION

Non-thionamide anti-thyroid drugs are useful alternatives in Graves' hyperthyroidism and more clinical trials are needed to establish their safety and long-term efficacy in hyperthyroidism control. Ultimately, the promise for a cure will lie in novel approaches that target the well-established immunopathogenesis of Graves' disease.

[Thyrotoxicosis in a patient with Turner syndrome: radioactive iodine therapy]

Turner syndrome (TS) is a chromosomal disorder affecting female and characterized by complete or partial monosomy of the X chromosome. These genetic changes lead to the abnormalities in growth and development and increase the risk of autoimmune diseases, including those affecting the thyroid. Thyroid pathology in TS may include autoimmune thyroiditis, hypothyroidism, thyrotoxicosis (Graves disease, AIT in the hyperthyroid state).Thyrotoxicosis is the clinical syndrome of excess circulating thyroid hormones. One of the main causes of thyrotoxicosis is Graves' disease (GD), an organ-specific autoimmune disease caused by the production of stimulating thyrotropin receptor antibodies. There are three treatment options for thyrotoxicosis: anti-thyroid drugs, radioactive iodine and thyroidectomy. A personalized approach to disease management is especially important in cases of genetic diseases.We present a clinical case of a patient with TS and GD, who has been referred to a radiologist at the Department of Radionuclide Therapy of Endocrinology Research Center. The patient was diagnosed with congenital hypothyroidism at neonatal screening, but thyroid hormones therapy was initiated aged three. Based on the survey, GD was diagnosed aged twenty one. Anti-thyroid drug therapy was started, which resulted in toxic hepatitis. Taking into account intolerance to anti-thyroid drugs, radioiodine therapy has been recommended, which led to hypothyroidism.

2022 Update on Clinical Management of Graves Disease and Thyroid Eye Disease

The management of hyperthyroidism and extrathyroidal manifestations of Graves disease remains complex. Considerations that include patient preference, age, comorbidity, pregnancy, tobacco smoking, and social determinants of health must all be weaved into a cohesive management plan. A multidisciplinary team is required to manage all aspects of Graves disease, particularly thyroid eye disease, for which new therapeutic options are now available.

Revisiting the role of surgery in the treatment of Graves' disease

Graves' disease (GD) can be managed by antithyroid drugs (ATD), radioactive iodine (RAI) and surgery. Thyroidectomy offers the highest success rates for both primary and persistent disease, yet it is the least recommended or utilized option reaching <1% for primary disease and <25% for persistent disease. Several surveys have found surgery to be the least recommended by endocrinologists worldwide. With the development of remote access thyroidectomies and intraoperative nerve monitoring of the recurrent laryngeal nerve, combined with current knowledge of possible risks associated with RAI or failure of ATDs, revaluation of the benefit to harm ratio of surgery in the treatment of GD is warranted. The aim of this review is to discuss possible reasons for the low proportion of surgery in the treatment of GD, emphasizing an evidence-based approach to the clinicians' preferences for surgical referrals, surgical indications and confronting traditional reasons and concerns relating to the low referral rate with up-to-date data.

Outcome of radioiodine therapy for feline hyperthyroidism: Fixed dose versus individualized dose based on a clinical scoring system

Background

Hyperthyroidism is the most frequent endocrinopathy in older cats. To date, there is no consensus on how to best calculate the dose of radioiodine to administer to hyperthyroid cats.

Aim

The goals of this study were to compare thyroid function, renal function, and survival time between hyperthyroid cats receiving a fixed dose of radioiodine and those receiving an individualized dose calculated using a clinical scoring system.

Methods

Medical records of 110 cats treated with radioiodine therapy at the University of Bern between 2010 and 2020 were reviewed. Thyroid function, renal function, and survival of cats treated with a fixed dose of radioiodine (2010-2015; n = 50) were compared to those of cats treated with an individualized dose (2015-2020; n = 60) at different time points after therapy.

Results

Treatment with a fixed dose of radioiodine (mean = 168 ± 26 MBq) was associated with 69% of euthyroidism, 19% persistent hyperthyroidism, and 12% hypothyroidism, whereas treatment with an individualized dose (mean = 120 ± 30 MBq) led to 54% euthyroidism, 23% hyperthyroidism, and 23% hypothyroidism (p = 0.73). More than 12 months after treatment, the incidence of azotemia was comparable between cats treated with a fixed dose (37%) and those treated with an individualized dose (31%) (p = 0.77). No factors were found to be predictive of treatment failure (hypothyroidism or hyperthyroidism) after therapy. Median survival time after radioiodine therapy was 44 months. In a multivariate analysis, persistent hyperthyroidism was the only variable independently associated with a shorter survival time (HR = 6.24, p = 0.002).

Conclusion

The method of calculating the dose of radioiodine (fixed vs. individualized) to treat feline hyperthyroidism does not appear to be decisive for posttreatment thyroid function, renal function, or survival.

A Clinical Debate: What Is the Therapeutic Choice for Recurrent Graves' Hyperthyroidism?

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