Incidence of postradioiodine immunogenic hyperthyroidism/Graves' disease in relation to a temporary increase in thyrotropin receptor antibodies after radioiodine therapy for autonomous thyroid disease

[Guideline for Radioiodine Therapy for Benign Thyroid Diseases (6/2022 - AWMF No. 031-003)]

This version of the guideline for radioiodine therapy of benign thyroid disorders is an update of the version, which was published by the German Society of Nuclear Medicine (Deutsche Gesellschaft für Nuklearmedizin, DGN) in co-ordination with the German Society of Endocrinology (Deutsche Gesellschaft für Endokrinologie, DGE, Sektion Schilddrüse) and the German Society of General- and Visceral-Surgery (Deutsche Gesellschaft für Allgemein- und Viszeralchirurgie, DGAV) in 2015. This guideline was harmonized with the recommendations of the European Association of Nuclear Medicine (EANM). According to the German "Directive on Radiation Protection in Medicine" the physician specialised in nuclear medicine ("Fachkunde in der Therapie mit offenen radioaktiven Stoffen") is responsible for the justification to treat with radioiodine. Therefore, relevant medical indications for radioiodine therapy and alternative therapeutic options are discussed within the guideline. This procedure guideline is developed in the consensus of an expert group. This fulfils the level S1 (first step) within the German classification of Clinical Practice Guidelines.

The EANM guideline on radioiodine therapy of benign thyroid disease

This document provides the new EANM guideline on radioiodine therapy of benign thyroid disease. Its aim is to guide nuclear medicine physicians, endocrinologists, and practitioners in the selection of patients for radioiodine therapy. Its recommendations on patients' preparation, empiric and dosimetric therapeutic approaches, applied radioiodine activity, radiation protection requirements, and patients follow-up after administration of radioiodine therapy are extensively discussed.

123I Scintigraphy Mirror Image of Graves Disease Induced by Radioiodine Treatment for Toxic Adenoma

ABSTRACT

A 61-year-old woman presenting with hyperthyroidism received 131I therapy for a toxic adenoma diagnosed by 123I scintigraphy. Six months later, the patient had a relapse of hyperthyroidism, and 123I scintigraphy showed a mirror image of the first scintigraphy: a high and diffuse uptake in the thyroid gland except for the previously treated nodule. Graves disease was confirmed by elevated thyrotropin receptor antibodies. The patient was cured by a second radioiodine therapy. Radioiodine-induced Graves disease may occur within 6 months of 131I treatment of toxic adenoma and can be treated with a second line of 131I.

Long-term Effects of Radioiodine in Toxic Multinodular Goiter: Thyroid Volume, Function, and Autoimmunity

CONTEXT

Long-term studies evaluating the treatment of toxic multinodular goiter (TMNG) with fixed activities of radioiodine (RAI) are lacking.

OBJECTIVE

The objective of this work is to describe the effects of 15 mCi on thyroid volume, function, and autoimmunity in the long term.

DESIGN AND SETTING

A population-based, retrospective analysis with up to 12 years of follow-up was conducted in Siena, Italy.

PARTICIPANTS

Adult patients (n = 153) with TMNG, naive to RAI, were included.

METHODS

Evaluation was performed of thyroid function, antithyroid antibodies, and ultrasound scans before and yearly after RAI.

MAIN OUTCOME MEASURES

Evaluations included hyperthyroidism cure, hypothyroidism, volume reduction, nadir and regain, and antibody titer change.

RESULTS

The study revealed mean volume reductions greater than or equal to 50% at 3 years after RAI; the greatest annual reduction was observed during the first year (30 ± 17.8%; P < .001). Most patients (60%) achieved their volume nadir 3 to 6 years after RAI. Although 22% patients showed volume regain, the net reduction was statistically significant as late as 9 years after RAI (P = .005). The mean time to hypothyroidism was 2.7 ± 2.4 years, and it was associated with greater reductions in volume (P = .01). During the first 3 years after treatment, hyperthyroid patients decreased approximately by 50% per year without additional RAI. There was no statistically significant association of antibody titers with thyroid function except for antithyrotropin receptor antibodies and hyperthyroidism (P = .004). At the end of follow-up there were 61.6% euthyroid patients, 11% hyperthyroid (4.8% overt), and 27.4% hypothyroid patients (2.7% overt). Hyperthyroidism was cured in 89%.

CONCLUSIONS

The treatment of TMNG with 15 mCi of RAI induced low hypothyroidism rates while providing high cure rates and significant volume reduction, which was maintained in the long term.

Radioiodine Therapy-Induced Conversion of Toxic Adenoma to Graves’ Disease

We present a 50-year-old female who was evaluated for the symptoms of thyrotoxicosis. She had low thyroid stimulating hormone (TSH) 0.02 with normal free thyroxine (FT4) 1.00 (0.61-1.76 ng/dL) and normal total triiodothyronine (TT3) 1.0 (0.60-2.20 ng/mL) levels. Her thyrotropin receptor antibody (TRAbs) and thyroid peroxidase antibody (TPOAb) titers were negative. Thyroid ultrasound revealed an ill-defined, heterogeneous, 1.8 cm x 0.8 cm x 0.7 cm nodule in the left lower lobe. 123-radioiodine (RAI) thyroid scan revealed 38.5% uptake, which was concentrated in the lower left thyroid lobe, a finding consistent with a solitary toxic adenoma of the thyroid.

The patient became clinically and biochemically euthyroid on methimazole (MMI). She then underwent 131-RAI therapy with 12 mCi, which cured her hyperthyroidism with normalization of TSH levels for four months. She then developed overt thyrotoxicosis with low TSH of 0.02, elevated TT3 of 3.2, and normal FT4 of 0.91. Repeat TRAbs and TPOAb were elevated along with diffusely increased uptake on the I-123 RAI thyroid uptake scan, consistent with Graves’ disease (GD). The patient was then placed on MMI again to bridge to definitive treatment with total thyroidectomy. Our case is a rare case where the patient with solitary toxic adenoma with negative TPOAb serology developed GD following I-131 RAI treatment.

Marine-Lenhart Syndrome: Case Report, Diagnosis, and Management

The coexistence of thyroid functioning nodules and Graves' disease is called Marine-Lenhart syndrome. This condition is estimated to occur in 0.8-2.7% of patients with Graves' disease with few cases reported in the literature. Criteria for the diagnosis are not well defined. Here, we present a case of hyperthyroidism characterized by the presence of stimulating TSH receptor antibodies and severe bilateral exophthalmos. A thyroid uptake and scan revealed an elevated 24-hour iodine-131 uptake and a discrete hot nodule in the upper pole of the right lobe which was also observed with a thyroid ultrasound. The patient was diagnosed with Marine-Lenhart syndrome complicated by thyroid eye disease and was treated with methimazole followed by thyroidectomy and orbital decompression. We review the existing literature and propose criteria for the diagnosis and treatment of this condition.

131I-Induced Graves' disease in patients treated for toxic multinodular goitre: systematic review and descriptive analysis

BACKGROUND

Graves' disease (GD) arising after the treatment of toxic multinodular goitre (TMNG) with radioiodine has long been described but it remained unclear whether GD was in fact iodine induced, its incidence, risk factors, natural history and treatment outcomes.

METHODS

A systematic search using The Cochrane Library, Medline and PubMed Central allowed the pooling of data from 3633 patients with thyroid autonomy, 1340 patients with TMNG, to fill gaps in knowledge, regarding the clinical expression of iodine-induced GD (131I-IGD) in adults.

RESULTS

131I-IGD developed in 0-5.3% of those with thyroid autonomy (first year) and in 5-5.4% of those with TMNG, 3-6 months after treatment. Patients with toxic adenoma were less affected. 131I-IGD was more common in patients with pre-treatment direct or indirect signs of autoimmunity: positive anti-TPO (p < 0.05), glandular hypoechogenicity, TRAbs within reference range, diffuse uptake on 99mTc-pertechnetate scans (p < 0.05), findings that may increase the risk tenfold. 131I-IGD manifested 3 months after 131I, justifying 15.4-29% of cases of relapse. The rate of spontaneous remission was 17-20% (6 months) and the rate of relapse after a second 131I treatment 22-25%. The use of an uptake-based administered 131I activity led to a greater proportion of euthyroid patients (78% compared to 25-50% with the mass-based approach).

CONCLUSIONS

GD may be triggered by 131I. The incidence of the condition is low. Several risk factors were consistently identified; some have shown to raise the risk significantly. 131I-IGD seems more treatment resistant than iodine-independent GD and the best resolution rates were achieved with uptake-based selected iodine activities.

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.

Marine-Lenhart syndrome in two adolescents, including one with thyroid cancer: a case series and review of the literature

BACKGROUND

The coexistence of functional thyroid nodules and Graves' disease (GD) is a rare condition known as Marine-Lenhart syndrome. Thyroid cancer has been described in several adults, but never in children, with Marine-Lenhart syndrome. This paper discusses the challenges in diagnosis and the unique management of this condition in children, in the context of extant literature.

CONTENT

In this case report, two adolescent female patients with Marine-Lenhart syndrome, aged 15 and 16 years, exhibited biochemical evidence of hyperthyroidism, and were found to have unilateral hyperfunctioning thyroid nodules via thyroid scintigraphy. Additionally, both patients showed elevated thyroid-stimulating immunoglobulins (TSI) and increased glandular activity, confirming background GD. Notably, one patient was also diagnosed with intranodular thyroid cancer upon preoperative examination. Both patients were treated via surgical resection. Summary and outlook: Diagnosis of Marine-Lenhart syndrome can be made in patients with functional thyroid nodules and increased glandular activity on thyroid scintigraphy. Standard doses of radioiodine ablation are not effective in the majority of patients and should be avoided due to the increased risk for thyroid cancer, making thyroidectomy the preferred treatment.

Graves disease following radioiodine therapy for toxic adenoma: Clinical case report

RATIONALE

There is a low risk of developing Graves disease (GD) with elevated thyrotropin receptor antibodies (TRAbs) in patients undergoing radioiodine therapy for toxic adenoma.

PATIENT CONCERNS

An old female patient with a history of Hashimoto thyroiditis was referred to our department due to thyrotoxic symptoms. After the administration of radioiodine, a significant remission was achieved. However, after 4 months, she was referred to our department again due to recurrence of hyperthyroid symptoms.

DIAGNOSES

Based on the results of laboratory test, thyroid scan and ultrasound examination, she was diagnosed as thyrotoxicosis induced by toxic adenoma at the first visit. However, 4 months later, she was diagnosed as Graves' disease at the second visit.

INTERVENTIONS

She received radioiodine therapy two times with different doses of 15 mCi and 12 mCi.

OUTCOMES

After the administration of 15 mCi radioiodine, her thyroid hormones and clinical symptoms showed significant improvement. However, 4 months later, she presented thyrotoxicosis again. After the second radioiodine therapy with a lower dose, her clinical symptoms moved towards normalization during regular follow up.

LESSONS

Toxic adenoma and GD are considered as 2 distinct disease entities; however, radioiodine therapy for toxic adenoma may induce GD. We should learn to differentiate these 2 disorders prior to radioiodine therapy because of different treatment strategies and goals.

The thyroid, the eyes and the gut: a possible connection

INTRODUCTION

Graves' disease (GD) is an autoimmune disorder responsible for 60-90% of thyrotoxicosis, with an incidence of 1 to 2 cases per 1000 population per year in England. Graves' orbitopathy (GO) is the most frequent extrathyroidal manifestation, not provoked directly by abnormal thyroid hormone levels, but by the consequence of the underlying autoimmune process. The aetiology of autoimmune disorders is due to an interplay between susceptibility genes and environmental factors, such as infections and stress. What triggers the autoimmune reaction to a specific site of the body is not yet clearly understood. The lack of knowledge in GD and GO pathogenesis implicates therapies that only limit damage but do not prevent disease onset.

MATERIAL AND METHODS

We performed on PubMed and the Cochrane Library a literature search for the articles published until July 2016 by using the search terms 'graves disease' and 'microbiome', 'orbitopathy' and 'autoimmune pathogenesis'. Reference lists of relevant studies were hand-searched for additional studies.

CONCLUSION

In this scenario, a Marie Sklodowska-Curie funded project INDIGO ( http://www.indigo-iapp.eu/ ) is investigating the role of the gut bacteria in GD and GO pathogenesis. The gut is the first and the widest area of bacteria access, with the highest concentration of T cells in the human body and trained to react to microorganisms. Interestingly, all the environmental factors involved in GD and GO pathogenesis can alter the balance within the microorganisms located in the gut, and influence the immune system, in particular the proportions of regulatory Treg and inflammatory TH17 cells. It is hoped that investigating GD and GO pathogenesis from this novel aspect will identify new targets for prevention and treatment.

[Radioiodine therapy for benign thyroid diseases (version 5). German Guideline]

The version 5 of the guideline for radioiodine therapy of benign thyroid disorders is an update of the version 4, which was published by the German Society of Nuclear Medicine (Deutsche Gesellschaft für Nuklearmedizin, DGN) in co-ordination with the German Society of Endocrinology (Deutsche Gesellschaft für Endokrinologie, DGE, Sektion Schilddrüse) and the German Society of General- and Visceral-Surgery (Deutsche Gesellschaft für Allgemein- und Viszeralchirurgie, DGAV) in 2007. This guideline was harmonized with the recommendations of the European Association of Nuclear Medicine (EANM). According to the German "Directive on Radiation Protection in Medicine" the physician specialised in nuclear medicine ("Fachkunde in der Therapie mit offenen radioaktiven Stoffen") is responsible for the justfication to treat with radioiodine. Therefore, relevant medical indications for radioiodine therapy and alternative therapeutic options are discussed within the guideline. This procedure guideline is developed in the consensus of a representative expert group. This fulfils the level S1 (first step) within the German classification of Clinical Practice Guidelines.

Graves Disease Induced by Radioiodine Therapy for Toxic Nodular Goiter: A Case Report

Graves’ disease (GD) may be observed as an infrequent adverse effect after radioiodine therapy (RAIT) for toxic thyroid adenoma (TA) and toxic multi nodular goiter (MNG). We present a case of a 55-year-old male with a toxic nodule who was treated with RAI. After therapy, the patient’s serum free triiodothyronine (fT3) and free thyroxine (fT4) levels gradually increased. Antithyroid peroxidase (TPOAb), antithyroglobulin (TgAb) and TSH-receptor antibodies (TRAb) were also positive. Thyroid scintigraphy revealed diffuse intense uptake after four months of RAIT. Radiation-induced GD should be considered in patients with aggravated hyperthyroidism 3-4 months after therapy.

An uncommon case of Marine-Lenhart syndrome

The term Marine-Lenhart syndrome describes the association between Graves' disease and autonomously functioning thyroid nodules (AFTN), such as toxic adenoma or toxic multinodular goiter. The two diseases may coexist or may be present at different moments in the same patient. In the literature, there are many reports on the development of Graves' disease after radioiodine treatment for AFTN, but very little information may be found on the occurrence of AFTN after radioiodine therapy for Graves' disease. We describe here the case of a female patient with Graves' disease who was successfully treated with radioiodine for Graves' disease, returning to normal thyroid function. Three years later, biochemical analysis and ultrasound examination identified a thyroid nodule that progressively increased in size. The 99mTc-pertechnetate scintigraphy showed avid uptake in the right lobule, which corresponded to a nodular lesion consistent with AFTN.

Radioiodine therapy in benign thyroid diseases: effects, side effects, and factors affecting therapeutic outcome

Radioiodine ((131)I) therapy of benign thyroid diseases was introduced 70 yr ago, and the patients treated since then are probably numbered in the millions. Fifty to 90% of hyperthyroid patients are cured within 1 yr after (131)I therapy. With longer follow-up, permanent hypothyroidism seems inevitable in Graves' disease, whereas this risk is much lower when treating toxic nodular goiter. The side effect causing most concern is the potential induction of ophthalmopathy in predisposed individuals. The response to (131)I therapy is to some extent related to the radiation dose. However, calculation of an exact thyroid dose is error-prone due to imprecise measurement of the (131)I biokinetics, and the importance of internal dosimetric factors, such as the thyroid follicle size, is probably underestimated. Besides these obstacles, several potential confounders interfere with the efficacy of (131)I therapy, and they may even interact mutually and counteract each other. Numerous studies have evaluated the effect of (131)I therapy, but results have been conflicting due to differences in design, sample size, patient selection, and dose calculation. It seems clear that no single factor reliably predicts the outcome from (131)I therapy. The individual radiosensitivity, still poorly defined and impossible to quantify, may be a major determinant of the outcome from (131)I therapy. Above all, the impact of (131)I therapy relies on the iodine-concentrating ability of the thyroid gland. The thyroid (131)I uptake (or retention) can be stimulated in several ways, including dietary iodine restriction and use of lithium. In particular, recombinant human thyrotropin has gained interest because this compound significantly amplifies the effect of (131)I therapy in patients with nontoxic nodular goiter.

The Marine-Lenhart syndrome revisited

The coexistence of thyroid autonomy (Plummer's disease) and Graves' disease has been termed "Marine-Lenhart syndrome". During the last years, several papers have been published on the development of Graves' disease shortly after radioiodine therapy of Plummer's disease (autonomy). Especially in patients with elevated thyroid antibodies, the incidence of this event is significantly higher after radioiodine therapy of autonomy. A review of the literature dating back to 1911 is discussed in this paper. The original paper published by Marine and Lenhart comes to the conclusion that the two diseases are different expressions of one disease. Looking at the literature, we have to state now that the Marine-Lenhart syndrome has never existed: With Plummer we know now that Plummer's and Graves' disease are different diseases. They may develop in the same patient but independent from each other.

Therapy of large multinodular goitre using repeated doses of radioiodine

OBJECTIVE

To evaluate the efficacy of radioiodine therapy using I in a group of patients with large multinodular goitre (LMG).

METHODS

The study was carried out in patients with goitre volume greater than 100 cm and in patients with LMG who were disqualified from surgery. The study included 34 female participants (age range: 62-84 years) with LMG: 26 patients were hyperthyroid and eight patients had a nontoxic goitre. The patients were treated with 800 MBq of radioiodine administered four times at 3-month intervals (total activity of 3.2 GBq). Before each therapy course, serum thyrotropin, free thyroxin, free triiodothyronine and antithyroid antibodies were measured, ultrasonography and thyroid scan were performed. Patients were followed up for a minimum of 24 months. Fine-needle biopsy was done before qualification to the study.

RESULTS

Before therapy, median thyroid volume was 145 cm. It decreased during therapy to 65-76 cm after 12 months and to 50-62 cm after 24 months. After 24 months, 60% of patients were euthyroid and 40% of patients were hypothyroid. During therapy, significant increases in TSHRAb, TPOAb and TgAb levels were observed. No correlation between the levels of antithyroid antibodies, radioiodine uptake, reduction of goitre volume and hormonal status was found.

CONCLUSION

In most cases of LMG, repeated administration of radioiodine is safe and effective. The highest response of the thyroid volume is observed after the first course of treatment. On account of a high incidence of hypothyroidism, the patients should be monitored during and after therapy.

Radioiodine treatment for benign thyroid diseases

Radioiodine has been in use for over 60 years as a treatment for hyperthyroidism. Major changes in clinical practice have occurred with the realization that accurate dosimetry is incapable of avoiding the risks of hypothyroidism, while more accurate assessment of the risks of other adverse effects of radioiodine such as ophthalmopathy and carcinogenesis have become available. More is also known of the potential for pretreatment with an antithyroid drug to affect the outcome of radioiodine treatment. However, we are still uncertain of the benefits of radioiodine treatment in subclinical hyperthyroidism. During the last two decades there has been wider acceptance of radioiodine as a safe and effective therapy for benign, nontoxic goitre, coupled with waning enthusiasm for the use of levothyroxine, as the risks and benefits of this option have become more apparent. The use of recombinant TSH offers the prospect that radioiodine treatment of nontoxic goitre can be simplified and improved, although more studies of this strategy are urgently required.