Time course to hypothyroidism after fixed-dose radioablation therapy of Graves' disease in children

Approach to the Patient: Management and the Long-term Consequences of Graves' Disease in Children

In children, Graves' disease (GD) is the most common cause of hyperthyroidism. Most pediatric patients with GD will not go into lasting remission, even following many years of antidrug therapy. Thus, most pediatric patients will require radioactive iodine (RAI) or surgery. When antithyroid drugs are used, methimazole is the drug of choice. When methimazole is used in children, up to 20% will have minor adverse reactions and serious adverse events occur in up to 1%. RAI is an effective form of therapy when the thyroid size is less than 80 g. Because of concerns of whole-body radiation exposure, it is recommended that RAI be avoided in children under 5 years of age, and dosages less than 10 mCi be used between 5 and 10 years of age. Surgery is an effective treatment in children if performed by a high-volume thyroid surgeon. Because of the scarcity of high-volume pediatric thyroid surgeons, a multidisciplinary approach using pediatric surgeons and endocrine surgeons can be considered. Whereas there is a trend toward long-term antithyroid drug therapy in adults, for several reasons, this approach may not be practical for children. Determining the optimal treatment for the pediatric patient with GD, requires consideration of the risks and benefits relating to age and likelihood of remission.

The Efficacy and Short- and Long-Term Side Effects of Radioactive Iodine Treatment in Pediatric Graves' Disease: A Systematic Review

BACKGROUND

Graves's disease (GD) is the most common cause of hyperthyroidism. Maximal 30% of pediatric GD patients achieve remission with antithyroid drugs. The majority of patients therefore require definitive treatment. Both thyroidectomy and radioactive iodine (RAI) are often used as definitive treatment for GD. However, data on efficacy and short- and long-term side effects of RAI treatment for pediatric GD are relatively scarce.

METHODS

A systematic review of the literature (PubMed and Embase) was performed to identify studies reporting the efficacy or short- and long-term side effects of RAI treatment in pediatric GD.

RESULTS

Twenty-three studies evaluating 1,283 children and adolescents treated with RAI for GD were included. The treatment goal of RAI treatment changed over time, from trying to achieve euthyroidism in the past to aiming at complete thyroid destruction and subsequent hypothyroidism in the last 3 decades. The reported efficacy of a first RAI treatment when aiming at hypothyroidism ranged from 42.8 to 97.5%, depending on the activity administered. The efficacy seems to increase with higher RAI activities. When aiming at hypothyroidism, both short- and long-term side effects of treatment are very rare. Long-term side effects were mainly seen in patients in whom treatment aimed at achieving euthyroidism.

CONCLUSION

RAI is a safe definitive treatment option for pediatric GD when aiming at complete thyroid destruction. When aiming at hypothyroidism, the efficacy of treatment seems to increase with a higher RAI activity. Prospective studies are needed to determine the optimal RAI dosing regimen in pediatric GD.

Success rate of radioactive iodine treatment for children and adolescent with hyperthyroidism

PURPOSE

To assess the success rate of first dose radioiodine for treatment of hyperthyroidism in children and adolescent.

METHODS

This is a retrospective data analysis of children and adolescent with hyperthyroidism who received radioiodine (RAI) therapy from January 2013 to December 2017. Age, gender, family history of hyperthyroidism, duration of anti-thyriod drugs (ATDs) treatment, rapid turnover status, 2 h and 24 h I-131 radioiodine uptake (RAIU), thyroid volume, and treatment dose were also analyzed. The goal of RAI therapy was to achieve hypothyroidism within 3-6 months after treatment. Treatment result was evaluated at 6 months after treatment and divided into 2 groups: treatment success (hypothyroid and euthyroid) and treatment failure (hyperthyroid). The same parameters were compared between both groups.

RESULTS

32 hyperthyroid patients, 26 female with mean age at treatment of 13.84 ± 1.83 years. All patients had prior treatment with ATDs, with a median treatment duration of 32.5 months (range 2-108). The median estimated thyroid gland size was 24.62 g, range 9.29-72.8. RAI doses ranged from 4.1 to 29.9 mCi (median dose = 7.54 mCi). Significant difference in 24-h I-131 uptake and RI status was demonstrated. Successful treatment rate after single dose of therapeutic I-131 was 65.63%.

CONCLUSION

With the I-131 dose of 220 μCi/g of thyroid tissue, successful treatment rate after single dose of therapeutic I-131 was 65.63%. RAI therapy with I-131 dose of 250-400 μCi/g of thyroid tissue might be suitable in patients with medical failure from ATDs. Possible role of RI as the predictor for RAI therapy failure are needed to investigate in both adult and children clinical settings.

Long-Term Outcomes of Radioiodine Therapy for Juvenile Graves Disease with Emphasis on Subsequently Detected Thyroid Nodules: A Single Institution Experience from Japan

OBJECTIVE

To investigate the long-term outcomes of radioiodine therapy (RIT) for juvenile Graves disease (GD) and the ultrasonographic changes of the thyroid gland.

METHODS

All of 117 juvenile patients (25 males and 92 females, aged 10 to 18 [median 16] years) who had undergone RIT for GD at our clinic between 1999 and 2018 were retrospectively reviewed. Each RIT session was delivered on an outpatient basis. The maximum 131I dose per treatment was 13.0 mCi, and the total 131I dose per patient was 3.6 to 29.8 mCi (median, 13.0 mCi). 131I administration was performed once in 89 patients, twice in 26, and three times in 2 patients. Ultrasonography of the thyroid gland was regularly performed after RIT. The duration of follow-up after the initial RIT ranged from 4 to 226 (median 95) months.

RESULTS

At the latest follow-up more than 12 months after RIT (n = 111), the patients' thyroid functions were overt hypothyroidism (91%), subclinical hypothyroidism (2%), normal (5%), or subclinical hyperthyroidism (2%). New thyroid nodules were detected in 9 patients, 4 to 17 years after initial RIT. Patients with newly detected thyroid nodules underwent RIT with lower doses of 131I and had larger residual thyroid volumes than those without nodules. None of the patients were diagnosed with thyroid cancer or other malignancies during the follow-up period.

CONCLUSION

Over a median follow-up period of 95 months (range, 4 to 226 months), RIT was found to be effective and safe in juvenile GD. However, cumulative evidence from further studies is required to confirm the long-term safety of RIT for juvenile GD.

ABBREVIATIONS

ATD = antithyroid drug; GD = Graves disease; KI = potassium iodide; LT4 = levothyroxine; MMI = methimazole; PTU = propylthiouracil; RAIU = radio-active iodine uptake; RIT = radioiodine therapy; 99mTc = technetium-99m; TSH = thyrotropin.

Management of thyrotoxicosis in children and adolescents: 35 years' experience in 304 patients

BACKGROUND

Diffuse toxic goiter accounts for about 15% of all childhood thyroid diseases. There is great controversy over the management of Graves' disease in children and adolescents. This article reports our experience in 304 children and juvenile patients with Graves' disease.

METHODS

Between 1981 and 2015, 304 patients aged 5-19 years with diffuse toxic goiter were studied, of whom 296 patients were treated with antithyroid drugs (ATD) for 18 months. Patients with persistent or relapsed hyperthyroidism who refused ablative therapy with surgery or radioiodine were managed with continuous methimazole (MMI) treatment.

RESULTS

In 304 patients (245 females and 59 males), the mean age was 15.6±2.6 years. After 18 months of ATD therapy, 37 remained in remission and of the 128 who relapsed, two, 29 and 97 patients chose surgery, continuous ATD and radioiodine therapy, respectively. Of the 136 patients who received radioiodine, 66.2% became hypothyroid. Twenty-nine patients received continuous ATD therapy for 5.7±2.4 years. The mean MMI dose was 4.6±12 mg daily, no serious complications occurred and all of them remained euthyroid during the follow-up. Less abnormal thyroid-stimulating hormone (TSH) values were observed in these patients, as compared to patients who were on a maintenance dose of levothyroxine after radioiodine induced hypothyroidism.

CONCLUSIONS

Original treatment with ATD and subsequent radioiodine therapy remain the mainstay of treatment for juvenile hyperthyroidism. Continuous ATD administration may be considered as another treatment modality for hyperthyroidism.

Guidelines for the treatment of childhood-onset Graves' disease in Japan, 2016

Purpose behind developing these guidelines: Over one decade ago, the “Guidelines for the Treatment of Graves’ Disease with Antithyroid Drug, 2006” (Japan Thyroid Association (JTA)) were published as the standard drug therapy protocol for Graves’ disease. The “Guidelines for the Treatment of Childhood-Onset Graves’ Disease with Antithyroid Drug in Japan, 2008” were published to provide guidance on the treatment of pediatric patients. Based on new evidence, a revised version of the “Guidelines for the Treatment of Graves’ Disease with Antithyroid Drug, 2006” (JTA) was published in 2011, combined with the “Handbook of Radioiodine Therapy for Graves’ Disease 2007” (JTA). Subsequently, newer findings on pediatric Graves’ disease have been reported. Propylthiouracil (PTU)-induced serious hepatopathy is an important problem in pediatric patients. The American Thyroid Association’s guidelines suggest that, in principle, physicians must not administer PTU to children. On the other hand, the “Guidelines for the Treatment of Graves’ Disease with Antithyroid Drug, 2011” (JTA) state that radioiodine therapy is no longer considered a “fundamental contraindication” in children. Therefore, the “Guidelines for the Treatment of Childhood-Onset Graves’ Disease with Antithyroid Drug in Japan, 2008” required revision.

Controversies in the management of Graves' disease in children

Graves' disease (GD) is the most prevalent cause of thyrotoxicosis in children. Because spontaneous and lasting resolution of this condition occurs in only a minority of patients, most pediatric patients with GD will need radioactive iodine treatment (¹³¹I) or thyroidectomy. Whereas the medication propylthiouracil (PTU) had been used in the past, only methimazole (MMI) should be now used in children, as PTU is associated with an unacceptable risk of liver failure. However, MMI may be associated minor and major side effects, which may be minimized using lower doses. An area of controversy involves the optimal duration of antithyroid drug (ATD) therapy. For some children, the prolonged use of antithyroid drugs is a valid approach, but for most, this will not increase the chance of remission. When ¹³¹I is administered, dosages should be greater than 150 uCi/gm of thyroid tissue, with higher dosages needed for larger glands. Considering that there will be low-level whole body radiation exposure associated with ¹³¹I, this treatment is viewed as controversial by some and should be avoided in young children. When surgery is performed, near-total or total thyroidectomy is the recommended procedure. Complications for thyroidectomy in children are considerably higher than in adults. Thus, an experienced thyroid surgeon is needed when children have surgery. Overall, when different treatment options for GD are considered, the benefits, risks and viewpoints of the family need to be considered and discussed in full.

2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis

BACKGROUND

Thyrotoxicosis has multiple etiologies, manifestations, and potential therapies. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions and patient preference. This document describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspecialty physicians and others providing care for patients with this condition.

METHODS

The American Thyroid Association (ATA) previously cosponsored guidelines for the management of thyrotoxicosis that were published in 2011. Considerable new literature has been published since then, and the ATA felt updated evidence-based guidelines were needed. The association assembled a task force of expert clinicians who authored this report. They examined relevant literature using a systematic PubMed search supplemented with additional published materials. An evidence-based medicine approach that incorporated the knowledge and experience of the panel was used to update the 2011 text and recommendations. The strength of the recommendations and the quality of evidence supporting them were rated according to the approach recommended by the Grading of Recommendations, Assessment, Development, and Evaluation Group.

RESULTS

Clinical topics addressed include the initial evaluation and management of thyrotoxicosis; management of Graves' hyperthyroidism using radioactive iodine, antithyroid drugs, or surgery; management of toxic multinodular goiter or toxic adenoma using radioactive iodine or surgery; Graves' disease in children, adolescents, or pregnant patients; subclinical hyperthyroidism; hyperthyroidism in patients with Graves' orbitopathy; and management of other miscellaneous causes of thyrotoxicosis. New paradigms since publication of the 2011 guidelines are presented for the evaluation of the etiology of thyrotoxicosis, the management of Graves' hyperthyroidism with antithyroid drugs, the management of pregnant hyperthyroid patients, and the preparation of patients for thyroid surgery. The sections on less common causes of thyrotoxicosis have been expanded.

CONCLUSIONS

One hundred twenty-four evidence-based recommendations were developed to aid in the care of patients with thyrotoxicosis and to share what the task force believes is current, rational, and optimal medical practice.

Nuclear Medicine in Thyroid Diseases in Pediatric and Adolescent Patients

Both benign and malignant diseases of the thyroid are rare in the pediatric and adolescent population, except congenital hypothyroidism. Nuclear medicine plays a major role, both in the diagnosis and therapy of thyroid pathologies. Use of radioactivity in pediatric population is strictly controlled due to possible side effects such as secondary cancers; therefore, management of pediatric patients requires detailed literature knowledge. This article aims to overview current algorithms in the management of thyroid diseases and use of radionuclide therapy in pediatric and adolescent population.

The treatment of Graves' disease in children and adolescents

Graves' disease (GD) accounts for 10%-15% of thyroid disorders in children and adolescents. The use of antithyroid drugs as the initial treatment option in GD is well accepted. An average two years remission is achieved in about 30% of children treated with antithyroid drugs. However, the optimal treatment duration and the predictive marker of remission after antithyroid drug therapy are still controversial. Additionally, (131)I therapy and surgery are considered the option for treatment in children and adolescents with GD. We review the treatment options for pediatric GD and the possible determinants of remission and relapse on antithyroid drug treatment in children and adolescents.

The Brazilian consensus for the diagnosis and treatment of hyperthyroidism: recommendations by the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism

INTRODUCTION

Hyperthyroidism is characterized by increased synthesis and release of thyroid hormones by the thyroid gland. Thyrotoxicosis refers to the clinical syndrome resulting from excessive circulating thyroid hormones, secondary to hyperthyroidism or due to other causes. This article describes evidence-based guidelines for the clinical management of thyrotoxicosis.

OBJECTIVE

This consensus, developed by Brazilian experts and sponsored by the Department of Thyroid Brazilian Society of Endocrinology and Metabolism, aims to address the management, diagnosis and treatment of patients with thyrotoxicosis, according to the most recent evidence from the literature and appropriate for the clinical reality of Brazil.

MATERIALS AND METHODS

After structuring clinical questions, search for evidence was made available in the literature, initially in the database MedLine, PubMed and Embase databases and subsequently in SciELO - Lilacs. The strength of evidence was evaluated by Oxford classification system was established from the study design used, considering the best available evidence for each question.

RESULTS

We have defined 13 questions about the initial clinical approach for the diagnosis and treatment that resulted in 53 recommendations, including the etiology, treatment with antithyroid drugs, radioactive iodine and surgery. We also addressed hyperthyroidism in children, teenagers or pregnant patients, and management of hyperthyroidism in patients with Graves' ophthalmopathy and various other causes of thyrotoxicosis.

CONCLUSIONS

The clinical diagnosis of hyperthyroidism usually offers no difficulty and should be made with measurements of serum TSH and thyroid hormones. The treatment can be performed with antithyroid drugs, surgery or administration of radioactive iodine according to the etiology of thyrotoxicosis, local availability of methods and preferences of the attending physician and patient.

Pediatric Graves' disease: management in the post-propylthiouracil Era

The most prevalent cause of thyrotoxicosis in children is Graves’ disease (GD), and remission occurs only in a modest proportion of patients. Thus most pediatric patients with GD will need treatment with radioactive iodine (RAI; ¹³¹I) or surgical thyroidectomy. When antithyroid drugs (ATDs) are prescribed, only methimazole (MMI) should be administered, as PTU is associated with an unacceptable risk of severe liver injury. If remission does not occur following ATD therapy, ¹³¹I or surgery should be contemplated. When ¹³¹I is administered, dosages should be greater than 150 uCi/gm of thyroid tissue, with higher dosages needed for large glands. Considering that there will be low-level whole body radiation exposure associated with ¹³¹I, this treatment should be avoided in young children. When surgery is performed near total or total-thyroidectomy is the recommended procedure. Complications for thyroidectomy in children are considerably higher than in adults, thus an experienced thyroid surgeon is needed when children are operated on. Most importantly, the care of children with GD can be complicated and requires physicians with expertise in the area.

Clinical Cerenkov luminescence imaging of (18)F-FDG

The aim of this study was to determine the feasibility of Cerenkov luminescence (CL) imaging of patients undergoing diagnostic (18)F-FDG scans to detect nodal disease.

METHODS

Patients undergoing routine (18)F-FDG PET/CT for various malignancies consented to being scanned for CL. White-light and Cerenkov images (5-min acquisition) of the surface of the patient contralateral to and at the site of nodal (18)F-FDG uptake were acquired using a cooled, intensified charge-coupled-device camera.

RESULTS

The camera demonstrated linear correlation between activity and counts into the low nanocurie range using (18)F-FDG. Imaging of patients revealed the presence of (18)F-FDG uptake in nodes that demonstrated uptake on PET. A correlation between maximum standardized uptake value from PET and counting rate per area on the CL imaging was established.

CONCLUSION

CL imaging with diagnostic doses of (18)F-FDG is feasible and can aid in detecting disease in the clinical setting.

Radioactive iodine for thyrotoxicosis in childhood and adolescence: treatment and outcomes

OBJECTIVE

The aim of the present study was to evaluate the outcome of radioiodine treatment in thyrotoxicosis in childhood and adolescence.

METHODS

This was a retrospective study of 27 patients (ages 7.2- 19.8 years) with a diagnosis of thyrotoxicosis who received iodine-131 (I-131) treatment from January 2007 to December 2011 in the Nuclear Medicine Division, Department of Radiology, Faculty of Medicine, Chiang Mai University. Gender, duration of antithyroid drug (ATD) treatment, 24-hour I-131 uptake, thyroid weight, total dose and number of treatments with I-131, and thyroid status at 6 months after treatment were recorded.

RESULTS

The outcomes of 27 patients (85.2% female, 14.8% male) treated with radioactive iodine were analyzed to assess the effectiveness of therapy as related to dose and gland size. All children and adolescents received 150 µCi of I-131/g of thyroid tissue (n=27). Six 6 months after treatment, 44.5% of the patients were hyperthyroid, 14.8% were euthyroid, and 40.7% were hypothyroid. Of the 12 cases with hyperthyroidism, 2 cases needed a second dose of I-131 treatment, and they finally reached a hypothyroid state. The patients were classified into 2 groups according to treatment success (euthyroid and hypothyroid) and treatment failure (hyperthyroid). There were no significant differences in age, gender, duration of ATD treatment, 2- and 24-hour I-131 uptake, thyroid weight, and total I-131 dose between these two groups.

CONCLUSIONS

Radioiodine treatment is safe and effective for thyrotoxicosis in childhood and adolescence. It is suitable as a good second-line therapy for patients with severe complications, those who show poor compliance, and those who fail to respond to ATD treatment.

Clinical experience with radioactive iodine in the treatment of childhood and adolescent Graves' disease

BACKGROUND/AIMS

Treatments for Graves' disease (GD) in children and adolescents include oral antithyroid drugs (ATDs), near total thyroidectomy, and radioactive iodine (RAI). ATDs remain the preferred choice in this age group, but because persistent remission occurs in 30% of cases, RAI is becoming a common option for definitive therapy.

METHODS

We performed a review of 65 medical records of GD patients under age 19 years who were followed between 1985 and 2005.

RESULTS

The prevalence of GD was higher in females (3:1) and during puberty (for both genders). If no remission was detected during ATD treatment, RAI was indicated when the following criteria were present: non-compliance, relapse, or side effects that were related to ATDs, large goiter, and long-term use of ATDs. The majority of patients developed hypothyroidism within 6 months after RAI. A progressive higher dose regimen was implemented in the last 10 years of the study period. A second RAI dose was necessary in eight cases. During the follow-up period, three pregnancies occurred. One patient with a thyroid nodule and benign cytology was detected.

CONCLUSIONS

RAI therapy is effective and safe in the treatment of GD in children and adolescents.

Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists

OBJECTIVE

Thyrotoxicosis has multiple etiologies, manifestations, and potential therapies. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions and patient preference. This article describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspeciality physicians and others providing care for patients with this condition.

METHODS

The development of these guidelines was commissioned by the American Thyroid Association in association with the American Association of Clinical Endocrinologists. The American Thyroid Association and American Association of Clinical Endocrinologists assembled a task force of expert clinicians who authored this report. The task force examined relevant literature using a systematic PubMed search supplemented with additional published materials. An evidence-based medicine approach that incorporated the knowledge and experience of the panel was used to develop the text and a series of specific recommendations. The strength of the recommendations and the quality of evidence supporting each was rated according to the approach recommended by the Grading of Recommendations, Assessment, Development, and Evaluation Group.

RESULTS

Clinical topics addressed include the initial evaluation and management of thyrotoxicosis; management of Graves' hyperthyroidism using radioactive iodine, antithyroid drugs, or surgery; management of toxic multinodular goiter or toxic adenoma using radioactive iodine or surgery; Graves' disease in children, adolescents, or pregnant patients; subclinical hyperthyroidism; hyperthyroidism in patients with Graves' ophthalmopathy; and management of other miscellaneous causes of thyrotoxicosis.

CONCLUSIONS

One hundred evidence-based recommendations were developed to aid in the care of patients with thyrotoxicosis and to share what the task force believes is current, rational, and optimal medical practice.

Prediction of post-treatment hypothyroidism using changes in thyroid volume after radioactive iodine therapy in adolescent patients with Graves' disease

BACKGROUND

The goal of iodine-131 therapy for pediatric Graves' disease is to induce hypothyroidism. However, changes in post-treatment thyroid volume have not been investigated in pediatric and/or adolescent patients.

OBJECTIVE

The aim of this retrospective study was to examine whether changes in thyroid volume predict post-treatment hypothyroidism in adolescent Graves' disease patients.

PATIENTS AND METHODS

We used ultrasonography to examine changes in thyroid volume, and also assessed thyroid functions, at 0, 1, 3, 5, 8 and 12 months after iodine-131 treatment in 49 adolescents ranging in age from 12 to 19 years retrospectively. Based on thyroid function outcome at 12 months, patients were divided into two groups: 29 patients with overt hypothyroidism requiring levothyroxine replacement and 20 without overt hypothyroidism. We compared changes in post-radioiodine thyroid volume between the two groups.

RESULTS

About 90% of patients whose thyroid volume at 3 months after iodine-131 administration was less than 50% of the original volume were hypothyroid by one year after treatment (positive predictive value 88%, sensitivity 75.9%, specificity 85.0%).

CONCLUSIONS

We believe ultrasonographic measurement of thyroid volume at 3 months after iodine-131 to be clinically useful for predicting post-treatment hypothyroidism in adolescent Graves' disease patients.

Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists

BACKGROUND

Thyrotoxicosis has multiple etiologies, manifestations, and potential therapies. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions and patient preference. This article describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspeciality physicians and others providing care for patients with this condition.

METHODS

The development of these guidelines was commissioned by the American Thyroid Association in association with the American Association of Clinical Endocrinologists. The American Thyroid Association and American Association of Clinical Endocrinologists assembled a task force of expert clinicians who authored this report. The task force examined relevant literature using a systematic PubMed search supplemented with additional published materials. An evidence-based medicine approach that incorporated the knowledge and experience of the panel was used to develop the text and a series of specific recommendations. The strength of the recommendations and the quality of evidence supporting each was rated according to the approach recommended by the Grading of Recommendations, Assessment, Development, and Evaluation Group.

RESULTS

Clinical topics addressed include the initial evaluation and management of thyrotoxicosis; management of Graves' hyperthyroidism using radioactive iodine, antithyroid drugs, or surgery; management of toxic multinodular goiter or toxic adenoma using radioactive iodine or surgery; Graves' disease in children, adolescents, or pregnant patients; subclinical hyperthyroidism; hyperthyroidism in patients with Graves' ophthalmopathy; and management of other miscellaneous causes of thyrotoxicosis.

CONCLUSIONS

One hundred evidence-based recommendations were developed to aid in the care of patients with thyrotoxicosis and to share what the task force believes is current, rational, and optimal medical practice.

Radioiodine treatment in pediatric Graves' disease and thyroid carcinoma

Graves' disease (GD) is the most common cause of hyperthyroidism in pediatric patients. Most pediatric thyroid cancer is differentiated thyroid cancer (DTC). The two diseases can be treated using different methods, such as antithyroid drug, radioactive iodine (RAI), and surgery for GD and surgery and RAI for DTC. RAI can be used to treat pediatric GD and DTC. In the article, we reviewed the RAI application in pediatric GD and DTC.

Myopathy Associated with Acute Hypothyroidism following Radioiodine Therapy for Graves Disease in an Adolescent

We describe acute myopathy following I-131 treatment for hyperthyroidism due to Graves Disease (GD) in an adolescent. A 15 year-old diagnosed with GD required treatment with radioactive iodine (I-131) therapy. Six weeks post I-131, he developed generalized muscle cramps. The CK was 19.800 U/L, the total thyroxine was 2.3 mcg/dL (29.6 nmol/L SI) and the estimated free thyroxine (EFT) was 0.5 ng/dL (6.4 pmol/L SI). The ALT was 112 U/L and AST was 364 U/L (normal <35 U/L). The muscle cramps and CK elevation normalized five months after initiation of thyroid replacement therapy. This observation shows that acute myopathy can rarely occur in pediatric patients with GD following treatment with I-131.

Radioactive iodine for hyperthyroidism in children and adolescents: referral rate and response to treatment

OBJECTIVES

Radioactive iodine ((131)I) therapy is increasingly viewed as a safe and effective treatment for paediatric and adolescent hyperthyroidism. Our objective was to estimate treatment response and its predictors and describe current referral practices for (131)I therapy.

DESIGN

Retrospective study.

PATIENTS

One hundred and thirty-one children 30 days-21 years old with laboratory evidence of hyperthyroidism, seen in an academic paediatric and adolescent endocrinology practice.

MEASUREMENTS

Rate of referral, indications for (131)I, predictors of poor treatment response.

RESULTS

Thirty-eight of 102 patients with persistent hyperthyroidism (37%) received (131)I (160 μCi/g thyroid tissue/(131)I uptake), as did an additional 10 patients initially evaluated by adult thyroidologists. Primary indications were intolerance to (29%) or poor control on (19%) antithyroid drugs, patient preference (50%) and unknown (2%). Of 48 patients treated with (131)I, 89% and 11% became hypothyroid after one and two (131)I doses, respectively. The goal of (131)I therapy was attainment of hypothyroidism. 'Poor treatment response' (seen in 27%) was defined as requirement for a second (131)I dose or failure to achieve hypothyroidism after 6 months. Predictors of poor treatment response included: previous use of antithyroid drugs (37%vs. 0%, P = 0.02), ophthalmopathy (58%vs. 8%, P = 0.002), and an interval of ≥ 12 months from diagnosis to (131)I (50%vs. 10%, P = 0.003). A very elevated free T4 tended to be more prevalent in those with poor response.

CONCLUSIONS

In children and adolescents with hyperthyroidism, high rates of success after (131)I are achievable. Use of antithyroid drugs, pre-existing eye disease and prolonged time to (131)I may confer relative resistance to (131)I.

Radioiodine treatment for pediatric hyperthyroid Grave's disease

Grave's disease (GD) is an autoimmune disease in which excessive amounts of thyroid hormones circulate in the blood. Treatment for pediatric GD includes (1) antithyroid drugs (ATD), (2) radioiodine, and (3) thyroidectomy. Yet, the optimal therapy remains controversial. We collected studies from all electronically available sources as well as from conferences held in China. All studies using radioiodine and/or ATD and/or thyroidectomy were included. Information was found on 1,874 pediatric GD patients treated with radioiodine, 1,279 patients treated with ATD and 1,362 patients treated surgically. The cure rate for radioiodine was 49.8%; the incidence of hypothyroidism, 37.8%; of relapse, 6.3%; of adverse effects, 1.55%; and of drop outs, 0.6%. These data show that radioiodine treatment is safe and effective in pediatric GD with significant lower incidence of relapse and adverse effects but significantly higher incidence of hypothyroidism as compared with both ATD and thyroidectomy. For the time being, radioiodine treatment for pediatric GD remains an excellent first-line therapy and a good second-line therapy for patients with ATD failure, severe complications, or poor compliance.

Radioiodine treatment for pediatric Graves' disease

BACKGROUND

Pediatric Graves' disease (GD) is an autoimmune disease in which excessive amounts of thyroid hormones circulate in the blood. Treatments for pediatric GD include antithyroid drugs (ATD), thyroidectomy and radioiodine. Up to date, the optimal therapy remains controversial.

OBJECTIVES

To assess the effects of radioiodine treatment for pediatric GD.

SEARCH STRATEGY

Studies were obtained from computerized searches of MEDLINE, EMBASE, The Cochrane Library, China National Infrastructure (CNKI) and paper collections of conferences held in Chinese.

SELECTION CRITERIA

Randomised controlled trials, controlled clinical trials and prospective cohort studies comparing the effects of radioiodine with ATD or thyroidectomy with a duration of follow-up at least one year.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality, extracted data and interviewed authors of all potentially relevant studies by telephone or electronic mail to verify randomization procedures. One author entered data into a data extraction form and another author verified the results of this procedure.

MAIN RESULTS

Two prospective controlled clinical trials involving 167 patients were included. All of them were of low quality. Radioiodine treatment versus ATD showed benefits in achieving euthyroidism (relative risk (RR) 1.70, 95% confidence interval (CI) 1.29 to 2.24). Radioiodine treatment showed a higher incidence of hypothyroidism compared with ATD (RR 6.46, 95% CI 1.16 to 35.81). No significant differences in modifying Graves' opthalmopathy (worsening or appearance) between radioiodine treatment and ATD (RR 1.30, 95% CI 0.56 to 3.00) were observed. No trial evaluated mortality, health related quality of life, economic outcomes or compliance with treatments.

AUTHORS' CONCLUSIONS

The limited results in Chinese suggest that a gland specific lower dosage of radioiodine treatment is potentially effective for pediatric GD, but a significant higher incidence of hypothyroidism compared with ATD was observed. However, we could not identify a well-designed trial to provide strong evidence for radioiodine in the treatment of pediatric GD. High-quality randomised controlled clinical trials are needed to guide treatment choice.

Clinical course of pediatric and adolescent Graves' disease treated with radioactive iodine

The use of radioactive iodine (RAI) therapy in children and adolescents with Graves' disease is increasing; however, few data exist to guide dosing in this population. We aimed to determine the clinical course, failure rate and factors associated with failure of RAI for pediatric Graves' disease. A retrospective chart review from a tertiary care pediatric endocrinology clinic (1990-2003) identified 22 patients (12.7 +/- 4.0 years at diagnosis) with Graves' disease treated with RAI after initial pharmacological therapy. Patients received a calculated dose of RAI (0.1 mCi/g thyroid tissue, adjusted for 6-h radio-iodine uptake). Twenty-seven percent (95% CI 11-50%) remained hyperthyroid and required a second dose. If the first RAI was successful, the average time to hypothyroidism was 2.96 +/- 1.05 months. There were no statistically significant differences between those successfully treated with one dose and those requiring re-treatment. This high failure rate indicates a need to examine dosing of RAI in this age group.

An optimal treatment for pediatric Graves' disease is radioiodine

CONTEXT

Antithyroid medications, surgery, and radioactive iodine have been used for more than five decades for the treatment of hyperthyroidism due to Graves' disease in children, adolescents, and adults. Despite the widespread use of these different approaches, controversy still exists relative to the merits of each treatment, especially regarding the use of radioactive iodine.

OBJECTIVE

The objective of the study was to address the risk and benefits of (131)I therapy, as compared with other treatment approaches. POSITION: Long-term, spontaneous remission of Graves' disease occurs in less than 30% of children. Thus, the majority of children with Graves' disease will need definitive, curative therapy. There is little evidence that use of antithyroid medications beyond 1 or 2 yr increases the likelihood of spontaneous, long-term remission. Although the use of antithyroid medications is standard practice, the use of antithyroid medications involves definite risks. When used at sufficient doses, radioactive iodine is an effective cure for Graves' disease and is associated with few acute side effects. Potential long-term adverse side effects, including thyroid cancer and genetic damage, have yet to be observed in individuals treated as children or adolescents with (131)I.

CONCLUSION

Properly administered, radioactive iodine remains an ideal form of treatment for Graves' disease in the pediatric population. Because of the increased risk of thyroid cancer associated with low-dose thyroid irradiation in children, larger, rather than smaller, doses of (131)I should be given.

Effects of bone marrow cell transplant on thyroid function in an I131-induced low T4 and elevated TSH rat model

Background

We developed a study using low dose radioactive iodine creating an animal model of transient elevation of thyroid stimulating hormone (TSH). Male derived bone marrow cells were transplanted to asses their effect on thyroid function and their capability to repair the thyroid parenchyma.

Results

At 40 an 80 days after I¹³¹ treatment, the study groups TSH and T4 serum values both increased and decreased significantly respectively compared to the negative control group. Eight weeks after cell transplantation, neither TSH nor T4 showed a significant difference in any group. The mean number of SRY gene copies found in group I (Left Intracardiac Transplant) was 523.3 and those in group II (Intrathyroid Transplant) were only 73. Group III (No Transplant) and IV had no copies. Group I presented a partial restore of the histological pattern of rat thyroid with approximately 20% – 30% of normal-sized follicles. Group II did not show any histological differences compared to group III (Positive control).

Conclusion

Both a significant increase of TSH and decrease of T4 can be induced as early as day 40 after a low dose of I¹³¹ in rats. Restore of normal thyroid function can be spontaneously achieved after using a low dose RAI in a rat model. The use of BM derived cells did not affect the re-establishment of thyroid function and might help restore the normal architecture after treatment with RAI.

What Influences Early Hypothyroidism After Radioiodine Treatment for Graves' Hyperthyroidism?

OBJECTIVE

The objective of this study was to evaluate the factors influencing the occurrence of early hypothyroidism after radioiodine treatment of Graves' hyperthyroidism.

MATERIAL AND METHODS

Of 147 patients with Graves' disease (GD) treated with radioactive I-131 (RAI) in our thyroid clinic between July 2003 and December 2004, 84 were followed at 2 and 4 to 5 months after treatment. The age range was 12 to 75 years and the dosage range in these patients was 7.4 to 29.9 mCi. Twenty-four were males and 60 were females. Factors possibly contributing to post-RAI hypothyroidism are: dosage of I-131, age, gender, size of the gland, initial serum free T4, free T3, thyroid-stimulating hormone (TSH) levels, pretreatment with antithyroid drugs, radioactive iodine uptake, and duration of disease.

RESULTS

All patients had low TSH, elevated FT4, and elevated radioactive iodine uptake (RAIU) at 4 and/or 24 hours. Of the 84 patients followed, 46% of the males and 62% of the females became hypothyroid at 4 to 5 months (57% of the total). Twenty-one patients remained hyperthyroid and 14 patients became euthyroid. Multivariate analysis of these 84 patients showed no statistically significant single contributing factor for the development of early hypothyroidism.

CONCLUSION

The early onset of hypothyroidism after RAI in GD is very common (57%) and unpredictable. Thus, after RAI treatment, all patients must be closely monitored for the development of this disorder.

Graves' disease in children and adolescents: response to long-term treatment

BACKGROUND

Optimal treatment of Graves' disease in paediatric patients is still a matter of controversy. Antithyroid drugs, radioiodine and thyroidectomy are the three therapeutic options available.

AIM

To report our experience of long-term medical treatment and outcome of paediatric Graves' disease.

METHODS

A 5-y-long medical protocol was implemented in 20 children and adolescents with Graves' disease. All patients received antithyroid drugs as the first therapeutic option; patients who did not enter long-term remission received I(131) and/or surgery as the definitive treatment.

RESULTS

The mean age at diagnosis was 12.1+/-4 y. Only two patients were males, both presenting concomitant type 1 diabetes. Mean follow-up was 13.8+/-5.5 y. Forty per cent of patients achieved long-term remission with low antithyroid drugs doses (mean treatment time: 5.4+/-1.4 y). Six patients received I(131) as definitive treatment and another six underwent surgery after completing medical treatment for 6.8+/-4.1 and 5.1+/-2 y, respectively. No patients requiring high antithyroid drugs doses to maintain euthyroidism reached long-term remission and needed I(131) and/or surgery.

CONCLUSION

Implementation of a long-term antithyroid drug protocol achieved 40% long-term remissions in paediatric patients with Graves' disease. Need for maintained high doses of antithyroid drugs could be considered a predictive factor for no remission. When permanent remission was not obtained by medical treatment, I(131)and/or surgery allowed healing in all cases.

Enfermedad de Graves-Basedow en el niño preescolar

Graves' disease, which is the main cause of hyperthyroidism in the pediatric age group, is very rare in pre-school children. We describe the cases of four girls, aged less than 6 years old, out of a total of 30 patients diagnosed with Graves' disease between 1985 and 2004. Investigations were motivated by tachycardia, chronic diarrhea, language development delay or thyroid nodules detected by cervical ultrasonography. In three of the four patients height and bone age were advanced. In all patients goiter was small or absent. None of the patients had ophthalmic disease. In all patients free T3 and T4 were elevated and thyroid-stimulating hormone was suppressed. Three patients were positive for thyroid-stimulating immunoglobulins (the method was not available for the oldest case). Two patients showed complete resolution after 5 years of treatment with carbimazole. The remaining two patients are still under treatment and no adverse effects have been documented.

Juvenile thyrotoxicosis; can we do better?

Thyrotoxicosis remains a frustrating condition for the young person, family, and health professionals involved. The associated symptoms do not always suggest thyroid disease and patients can be unwell for many months before the diagnosis is made. The antithyroid drug regimen used to treat children and adolescents with thyrotoxicosis varies from one unit to another and yet the potentially life threatening side effects and remission rates post-treatment may be related to the regimen used. Most patients with thyrotoxicosis will need many years of drug therapy if the thyroid gland is not removed surgically or destroyed by radioiodine. Even "definitive" treatment will typically necessitate thyroxine replacement for life.

Radioiodine therapy in patients with hyperthyroid disorder: standard versus dosimetric activity application

Due to its high success rate and non-invasive character, an increasing demand for radioiodine therapy can be seen. This study was conducted to determine whether standardized 131I activities can be used to facilitate management of patients with hyperthyroid disorder or whether a pre-therapeutic radioiodine test is advisable to determine an adequate therapeutic activity. The therapeutic uptake of 218 patients with benign thyroid disorders were determined and compared with 24 h and 48 h test uptake measurements as well as with calculated standard uptake values. Since there is a linear relationship between iodine uptake and delivered radiation dose, the effect of the different therapeutic approaches on the latter parameter was analysed. Special care was taken to assess possible differences between the various thyroid disorders. A mean deviation between pre-therapeutic test uptake and actual therapeutic uptake of 14.7% was observed in contrast to one of 29.1% when using disease specific standard values per millilitre of thyroid tissue. Furthermore, the proportion of patients with large deviations of more than 40% increased drastically when using standard uptake values (with radioiodine test, 4.1%; with standard values, 18.8%). In conclusion, the dosimetric approach with a pre-therapeutic radioiodine test proved to be the most accurate therapeutic procedure. Both the 24 h and 48 h test uptake measurements gave analogous results and yielded a correlation coefficient of 0.91 when compared with the therapeutic uptake. While it may be tempting to use standard activities to facilitate patient management, the findings of this study confirm that, for precise therapy planning, a pre-therapeutic radioiodine test is advised. Since no significant difference could be found between the 24 h and 48 h test uptake values, an early measurement 24 h after administration of the test activity is recommended.