Adverse events associated with methimazole therapy of graves' disease in children

Toxic Epidermal Necrolysis Secondary to Iodine Versus Methimazole in a Pediatric Patient With Complex Autoimmune Disease

We report a case of a 17-year-old girl who developed toxic epidermal necrolysis (TEN) secondary to preoperative iodine administration before thyroidectomy for Graves' disease. Past medical history was significant for COVID-19 and multisystem inflammatory syndrome in Children (MISC-C), with subsequent diagnoses of type 1 diabetes mellitus (T1DM), Addison disease, and Graves' disease. Her Graves disease was initially managed with methimazole. While there are reported cases of Stevens-Johnson syndrome (SJS) and TEN due to methimazole, the patient had discontinued methimazole over one month prior. Therefore, she likely represents the first case of TEN reported secondary to potassium iodide solution in a pediatric patient. Given the rarity of TEN in pediatric patients, our case highlights the challenges in managing complex autoimmune conditions and underscores the importance of careful medication choices in such cases.

The Role of Endoplasmic Reticulum Stress in Cell Injury Induced by Methimazole on Pancreatic Cells

Purpose: Methimazole is an anti-thyroid agent, especially as main therapy option for Graves' disease in children and adults. Drug induced pancreatitis is one of the known adverse effect of methimazole mentioned in case reports. However, the detailed molecular mechanisms of methimazole-induced pancreatitis are still unclear. In this study, the aim is to investigate the adverse effect of methimazole on pancreas cell stress mechanism and apoptosis. Methods: Cytotoxicity was evaluated in human pancreas/duct (PANC-1) cell line. Total oxidant (TOS) and antioxidant status (TAS) for oxidative stress index, glutathione (GSH) level and endoplasmic reticulum (ER) stress biomarkers were evaluated by ELISA. Reactive oxygen species (ROS) levels and apoptosis were evaluated by flow-cytometer. Results: The 30% inhibition rate concentration (IC₃₀) value was determined as 53 mM in PANC1 cells. The exposure concentrations were in the range of 0-40 mM for 48 hours. Methimazole might induce cellular stress conditions. ROS production increases depending on concentration, and this increase shows parallelism with the increase in ER stress biomarkers such as TOS, ERN1 and CASPASE12. Conversely, there was no significant difference between control and exposure groups in terms of apoptosis. Conclusion: In conclusion, methimazole might have triggered the mechanisms of inflammation or autophagy in the pancreatic cells. However, there is still a need for in vitro and in vivo studies including other cellular parameters related to apoptosis.

Hyperthyroidism in children and adolescents: Experience in a university hospital in Colombia

Introduction: Hyperthyroidism is a heterogeneous condition characterized by the excessive production of thyroid hormones. It represents a diagnostic and therapeutic challenge. Objective: To describe the clinical and paraclinical characteristics and the evolution and differences between the main etiologies in patients with hyperthyroidism treated by the Pediatric Endocrinology Service at the Hospital Universitario San Vicente Fundación in Medellín, Colombia, between July 1st., 2015, and June 30th., 2020. Materials and methods: We conducted a cross-sectional observational study with retrospective data collection. Results: We included 54 patients with a mean age of 11.9 years, 72.2% of whom were female; 85.2% had no history of comorbidities related to autoimmunity; 11.1% had a family history of Graves’ disease, and 29.6% of other thyroid diseases. Goiter was the most frequent clinical manifestation (83.3%) and 92.6% of the patients received treatment with methimazole, 79.6% required beta-blockers, and 11.2% additional drug therapy. Adverse drug reactions occurred in 16.7% of the patients and in 20.4% there was a resolution of hyperthyroidism (spontaneous: 9.3%; after radio-iodine ablation: 9.3%, and after surgery: 1.9%). Conclusion: Hyperthyroidism is a disease with diverse clinical manifestations. Its most frequent cause is Graves’ disease followed by hashitoxicosis, which in this study had a higher frequency than that reported in the literature. The duration and side effects of pharmacological treatment were similar to those previously reported, but the higher frequency of agranulocytosis is noteworthy.

2022 European Thyroid Association Guideline for the management of pediatric Graves' disease

Hyperthyroidism caused by Graves' disease (GD) is a relatively rare disease in children. Treatment options are the same as in adults - antithyroid drugs (ATD), radioactive iodine (RAI) or thyroid surgery, but the risks and benefits of each modality are different. The European Thyroid Association guideline provides new recommendations for the management of pediatric GD with and without orbitopathy. Clinicians should be alert that GD may present with behavioral changes or declining academic performance in children. Measurement of serum TSH receptor antibodies is recommended for all pediatric patients with hyperthyroidism. Management recommendations include the first-line use of a prolonged course of methimazole/carbimazole ATD treatment (3 years or more), a preference for dose titration instead of block and replace ATD, and to avoid propylthiouracil use. Where definitive treatment is required either total thyroidectomy or RAI is recommended, aiming for complete thyroid ablation with a personalized RAI activity. We recommend avoiding RAI in children under 10 years of age but favor surgery in patients with large goiter. Pediatric endocrinologists should be involved in all cases.

Pre-treatment Neutropenia in Children and Adolescents with Autoimmune Hyperthyroidism

OBJECTIVE

Neutropenia can occur in untreated autoimmune hyperthyroidism (AIH) or in association with treatment with the anti-thyroid drug, methimazole (MMI). Starting MMI in children and adolescents with AIH and pre-existing neutropenia could thus be worrisome. The aim was to describe the prevalence of neutropenia in pediatric AIH, prior to antithyroid drug therapy and to assess the effect of antithyroid drugs on neutrophil count.

METHODS

Patients with AIH attending a pediatric endocrinology clinic were retrospectively reviewed. Absolute neutrophil count (ANC) data at presentation and during anti-thyroid treatment for up to 24 weeks was collected. AIH was defined as elevated free thyroxine (fT4) or free tri-iodothyronine (fT3), suppressed thyroid stimulating hormone, and positive thyroid autoantibodies. Neutropenia was defined as ANC <1500 cells/μL.

RESULTS

Thirty-one patients (71% female) were included with a median interquartile range (IQR) age of 14.71 (11.89-17.10) years. Neither fT4 nor fT3 levels correlated with ANC at presentation (r_s=0.22, p=0.24 and r_s=0.13, p=0.54, respectively). 26/31 (84%) had normal baseline ANC. None developed neutropenia with thionamides. 5/31 (16%) had baseline neutropenia (median ANC 1,200/μL; IQR 874-1200). Four of these five started MMI at diagnosis while one was started on propranolol only but MMI was started one week later. All five normalized ANC within 24 weeks.

CONCLUSION

In this cohort, 16% of AIH patients had neutropenia at presentation, but this resolved in the short term and did not worsen with thionamides. Thionamides may be used with caution in these patients with close monitoring of blood counts.

Methimazole Desensitization in a 4-Year-Old With Refractory Graves Disease

Objective

To describe a 4-year-old girl with Graves disease and methimazole allergy who underwent desensitization, allowing continued methimazole use when other treatments were contraindicated.

Methods

We formulated a desensitization plan utilizing cetirizine and prednisone for a patient with previously diagnosed Graves disease who developed urticaria and arthralgias from methimazole. She was admitted for monitoring of rash, urticaria, angioedema, and anaphylaxis. Her methimazole dose was increased as tolerated and then titrated as an outpatient.

Results

A 4-year-old girl presented with a heart rate of 195 beats/minute, blood pressure of 145/108, and subsequent labs of undetectable thyroid stimulating hormone (TSH), free T4 5.8 ng/dL, thyroid peroxidase antibody 11.5 IU/ml, and TSH receptor antibody 39.03 IU/L, consistent with Graves disease. She developed urticaria and arthralgias after 2.5 weeks on methimazole, which resolved with drug cessation. Because of her age, the risks of radioactive iodine ablation and surgery were concerning; therefore, methimazole desensitization was attempted. Prednisone (1 mg/kg/day) and cetirizine (5 mg/day) were started prior to low-dose methimazole reintroduction and continued for 7 days. Methimazole was then gradually increased to a final dose of 15 mg daily (0.8 mg/kg/day). Free T4 normalized within a month (1.12 ng/dL), and her TSH normalized within 10 months (4.61 mcU/mL). Except for 2 possible breakthrough allergic responses that resolved with pulse steroids, she continues to tolerate methimazole.

Conclusion

We describe a case of methimazole desensitization. In this patient, pretreatment with prednisone, coupled with daily cetirizine, successfully induced methimazole tolerance when other treatment modalities were contraindicated.

Clinical features and predictors of remission in children under the age of 7 years with Graves' disease

Importance

Graves' disease (GD) is rare in children under the age of 7 years. Children with this disease exhibit greater thyrotoxicity at diagnosis and require a longer course of medical therapy, compared with pubertal and postpubertal children and adults.

Objective

To investigate the clinical features and identify predictors of remission in children under the age of 7 years with GD.

Methods

This retrospective study included 77 children who were diagnosed with GD under the age of 7 years and were treated in the Department of Endocrinology, Beijing Children's Hospital from 2010 to 2018. Clinical manifestations, laboratory data, and follow-up records were collected for all patients. Children who achieved remission of treatment with methimazole were compared with those who had persistent disease to identify which variables were associated with remission; multiple logistic regression and Cox regression analyses were used to evaluate interactions among predictive variables.

Results

Sixty-three boys and 14 girls were included; the median age at diagnosis was 4.2 years (interquartile range: 3.2-5.3 years). Forty-six (56.7%) patients had no family history of thyroid disease, 17 patients had family history of thyroid disease and 14 patients with unknown family history. Of the 77 patients, 18 (23.4%) patients achieved remission of treatment with methimazole and 59 patients did not; moreover, 51 (66.2%) had Graves' ophthalmopathy. Univariate analyses revealed no significant differences between the remission group and non-remission group in terms of age at diagnosis, sex, initial goiter size, or initial thyroid hormone concentration. However, there were a trend of correlation between the initial level of thyroid peroxidase antibody (TPOAb) and remission status (univariate analysis OR 1.002, P = 0.038; multivariate analysis OR 1.004, P = 0.019). Similar results were observed in univariate analysis of the initial thyrotropin receptor antibody (TRAb) level, but this association was not significant in multivariate analysis. Cox regression analyses revealed that children with high TRAb level required longer duration of remission, compared with low TRAb level (OR 0.950, 95% CI 0.904-0.997, P = 0.037).

Interpretation

Initial TRAb level was an independent predictor of remission outcome in young children under the age of 7 years with GD. Initial TRAb level may predict the likelihood of remission in patients with young-age-of-onset GD.

Adjuvant rituximab, a potential treatment for the young patient with Graves' hyperthyroidism (RiGD): study protocol for a single-arm, single-stage, phase II trial

INTRODUCTION

Graves' disease (Graves' hyperthyroidism) is a challenging condition for the young person and their family. The excess thyroid hormone generated by autoimmune stimulation of the thyroid stimulating hormone receptor on the thyroid gland can have a profound impact on well-being. Managing the young person with Graves' hyperthyroidism is more difficult than in older people because the side effects of conventional treatment are more significant in this age group and because the disease tends not to resolve spontaneously in the short to medium term. New immunomodulatory agents are available and the anti-B cell monoclonal antibody rituximab is of particular interest because it targets cells that manufacture the antibodies that stimulate the thyroid gland in Graves'.

METHODS AND ANALYSIS

The trial aims to establish whether the combination of a single dose of rituximab (500 mg) and a 12-month course of antithyroid drug (usually carbimazole) can result in a meaningful increase in the proportion of patients in remission at 2 years, the primary endpoint. A single-stage, phase II A'Hern design is used. 27 patients aged 12-20 years with newly presenting Graves' hyperthyroidism will be recruited. Markers of immune function, including lymphocyte numbers and antibody levels (total and specific), will be collected regularly throughout the trial.

DISCUSSION

The trial will determine whether the immunomodulatory medication, rituximab, will facilitate remission above and beyond that observed with antithyroid drug alone. A meaningful increase in the expected proportion of young patients entering remission when managed according to the trial protocol will justify consideration of a phase III trial.Ethics and dissemination The trial has received a favourable ethical opinion (North East - Tyne and Wear South Research Ethics Committee, reference 16/NE/0253, EudraCT number 2016-000209-35). The results of this trial will be distributed at international endocrine meetings, in the peer-reviewed literature and via patient support groups.

TRIAL REGISTRATION NUMBER

ISRCTN20381716.

Graves' disease in children in the two decades following implementation of an iodine prophylaxis programme

Grave’s disease (GD) is a form of thyroid autoimmune disease characterised by hyperthyroidism. It is a rare clinical problem in paediatrics. Development of disease is the result of genetic susceptibility and some environmental factors. One of the best-documented environmental factors involved in thyroid autoimmunity is iodine excess. The aim of our study was to analyse the clinical course and response to pharmacological treatment in children diagnosed with Graves’ disease in first two decades after mandatory salt iodination. Records of 94 children diagnosed with GD in the years 1998-2017 were analysed. Medical data of patients was compared between two decades following implementation of iodine prophylaxis: 1998-2007 (first-decade group – FDG) and 2008-2017 (second-decade group – SDG); 34 and 60 patients, respectively. Medical data of FDG was obtained from archival records and previous analysis performed in 2006. Data of 60 patients from SDG were obtained from currently available medical records. Results were statistically analysed using Microsoft Excel and Statistica 11 software. Results: In our study, after mandatory salt iodination, the tendency of an increase in newly diagnosed GD in children without family susceptibility was observed. The antibody profile indicates the significant contribution of the autoimmune process involving all thyroid antigens; therefore, the term “autoimmune hyperthyroidism” seems to be more appropriate than classical GD in this group of patients. The first-choice treatment with methimazole rarely causes adverse events during the therapy, and they have benign character.

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.

Fetal neonatal hyperthyroidism: diagnostic and therapeutic approachment

Fetal and neonatal hyperthyroidism may occur in mothers with Graves' disease. Fetal thyrotoxicosis manifestation is observed with the transition of TSH receptor stimulating antibodies to the fetus from the 17th-20th weeks of pregnancy and with the fetal TSH receptors becoming responsive after 20 weeks. The diagnosis is confirmed by fetal tachycardia, goiter and bone age advancement in pregnancy and maternal treatment is conducted in accordance. The probability of neonatal hyperthyroidism is high in the babies of mothers that have ongoing antithyroid requirement and higher antibody levels in the last months of pregnancy. Clinical manifestation may be delayed by 7-17 days because of the antithyroid drugs taken by the mother. Neonatal hyperthyroidism symptoms can be confused with sepsis and congenital viral infections. Herein, the diagnosis and therapeutic approach are reviewed in cases of fetal neonatal hyperthyroidism.

DYNAMIC CHANGES OF TRAb AND TPOAb AFTER RADIOIODINE THERAPY IN GRAVES' DISEASE

Context

To analyze the dynamic changes of serum thyrotrophin receptor antibody (TRAb) and thyroid peroxidase antibody (TPOAb) in Graves' disease (GD) patients before and after radioactive iodine (RAI) treatment and to investigate if TRAb and TPOAb play a role in the occurrence of early hypothyroidism after ¹³¹I therapy for Graves' hyperthyroidism.

Subjects and Methods

A total of 240 patients newly diagnosed with GD were selected to study. A clinical and laboratory assessment was performed before and at 3, 6, and 12 months after ¹³¹I therapy. Chemiluminescent immunoassays were used to detect serum free triiodothyronine (FT3), free thyroxine (FT4), sensitive thyroid-stimulating hormone (TSH) and TPOAb concentration. Radio-receptor assay was used to measure serum TRAb concentration. According to the early onset of hypothyroidism in a year after RAI therapy, patients were divided into early hypothyroidism group (group A) and non-early hypothyroidism group (group B).

Results

In both groups, serum TRAb and TPOAb increased at 3 months, reached the highest level at 6 months and returned to the baseline at 12 months after RAI therapy. TRAb showed a significant difference between the two groups at 6 months (P<0.01). Serum TPOAb in group A was higher than that in group B before and at 3, 6, 12 months after RAI therapy (P<0.05).

Conclusions

Serum TRAb and TPOAb are closely related to the occurrence of the early hypothyroidism, and play an important role in judging prognosis after ¹³¹I treatment in Graves' disease.

Radioiodine therapy of thyrotoxicosis in children and adolescents. Indications, efficacy and safety. Literature review

Болезнь Грейвса (БГ) – основная причина тиреотоксикоза у детей. В современной клинической практике применяется три метода лечения БГ: тиреостатики, радиоактивный йод и операция. Все эти методы лечения применяются давно, и в мире накоплен огромный опыт применения каждого из методов лечения. Лечение начинают практически всегда с тиреостатиков, непереносимость или неэффективность которых становится показанием к выбору альтернативных методов лечения. Для осознанного выбора метода лечения необходимо понимать его потенциальные параметры эффективности и безопасности, а также влияющие на них факторы. Цель обзора – критический анализ эффективности и безопасности радиойодтерапии в лечении тиреотоксикоза у детей и подростков в сравнении с аналогичными показателями других методов лечения, а также показания и противопоказания к данному виду лечения в современной клинической практике эндокринологов, радиологов и эндокринных хирургов. Выбор тактики лечения БГ у ребенка на каждом этапе осуществляется согласованно с ним и его родителями/опекунами путем информирования лечащим врачом об объективных преимуществах и недостатках методов лечения на основе имеющейся доказательной базы. Также приведены основные рекомендации эффективной и безопасной терапии радиоактивным йодом БГ у детей и подростков.

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.

Lateralized exanthem mimicking figurate inflammatory dermatosis of infancy after methimazole therapy

We reported a case of an 11-year-old girl admitted to our hospital for goiter, tachycardia, sweating, and visible and palpable thyroid. Thyroid function tests revealed a low thyrotropin level (<0.004 mIU/L) and elevated free thyroxine level (3.4 ng/ dL) diagnosed with Graves' disease and treated with methimazole. This anti-thyroid drug is recommended as first-line treatment in children with Graves' disease because it produces minor adverse effects with respect to propylthiouracil. She developed a lateralized exanthem mimicking figurate inflammatory dermatosis of infancy after methimazole therapy. The symptoms resolved after discontinuation of methimazole and treatment with an antihistamine and a corticosteroid. Furthermore, the treatment was changed to propylthiouracil without any adverse effects. According to current literature this is the first case of cutaneous figurate erythema related to methimazole, different from other well-known reactions such as skin eruption or urticaria.

Antithyroid drug-related hepatotoxicity in hyperthyroidism patients: a population-based cohort study

AIMS

The evidence of hepatotoxicity of antithyroid drugs (ATDs) is limited to case reports or spontaneous reporting. This study aimed to quantify the incidence and comparative risks of hepatotoxicity for methimazole (MMI)/carbimazole (CBM) vs. propylthiouracil (PTU) in a population-based manner.

METHODS

We conducted a cohort study of hyperthyroidism patients initially receiving MMI/CBM or PTU between 1 January 2004 and 31 December 2008 using the Taiwan National Health Insurance Research Database. The examined hepatotoxicity consisted of cholestasis, non-infectious hepatitis, acute liver failure and liver transplant, with the incidences and relative risks being quantified by Poisson exact methods and Cox proportional hazard models, respectively.

RESULTS

The study cohort comprised 71 379 ATD initiators, with a median follow-up of 196 days. MMI/CBM vs. PTU users had a higher hepatitis incidence rate (3.17/1000 vs. 1.19/1000 person-years) but a lower incidence of acute liver failure (0.32/1000 vs. 0.68/1000 person-years). The relative risk analysis indicated that any use of MMI/CBM was associated with a 2.89-fold (95% CI 1.81, 4.60) increased hepatitis risk compared with PTU, with the risk increasing to 5.08-fold for high dose MMI/CBM (95% CI 3.15, 8.18). However, any MMI/CBM use vs. PTU was not related to an increased risk of cholestasis (adjusted hazard ratio [HR] 1.14, 95% CI 0.40, 3.72) or acute liver failure (adjusted HR 0.54, 95% CI 0.24, 1.22).

CONCLUSIONS

MMI/CBM and PTU exert dissimilar incidence rates of hepatotoxicity. Compared to PTU, MMI/CBM are associated in a dose-dependent manner with an increased risk for hepatitis while the risks are similar for acute liver failure and cholestasis.

Anti-thyroid drugs in pediatric Graves' disease

Graves' disease is the most common cause of hyperthyroidism in children. Most children and adolescents are treated with anti-thyroid drugs as the initial modality. Studies have used Methimazole, Carbimazole and Propylthiouracil (PTU) either as titration regimes or as block and replacement regimes. The various studies of anti-thyroid drug (ATD) treatment of Graves' disease in pediatric patients differ in terms of the regimes, remission rate, duration of therapy for adequate remission, follow up and adverse effects of ATD. Various studies show that lower thyroid hormone levels, prolonged duration of treatment, lower levels of TSH receptor antibodies, smaller goiter and increased age of child predicted higher chance of remission after ATD. A variable number of patients experience minor and major adverse effects limiting initial and long term treatment with ATD. The adverse effects of various ATD seem to more in children compared to that of adults. In view of liver injury including hepatocellular failure need of liver transplantation associated with PTU, the use has been restricted in children. The rate of persistent remission with ATD following discontinuation is about 30%. Radioactive iodine therapy is gaining more acceptance in older children with Graves's disease in view of the limitations of ATD. For individual patients, risk-benefit ratio of ATD should be weighed against benefits of radioactive iodine therapy and patient preferences.

An overview on the proposed mechanisms of antithyroid drugs-induced liver injury

Drug-induced liver injury (DILI) is a major problem for pharmaceutical industry and drug development. Mechanisms of DILI are many and varied. Elucidating the mechanisms of DILI will allow clinicians to prevent liver failure, need for liver transplantation, and death induced by drugs. Methimazole and propylthiouracil (PTU) are two convenient antithyroid agents which their administration is accompanied by hepatotoxicity as a deleterious side effect. Although several cases of antithyroid drugs-induced liver injury are reported, there is no clear idea about the mechanism(s) of hepatotoxicity induced by these medications. Different mechanisms such as reactive metabolites formation, oxidative stress induction, intracellular targets dysfunction, and immune-mediated toxicity are postulated to be involved in antithyroid agents-induced hepatic damage. Due to the idiosyncratic nature of antithyroid drugs-induced hepatotoxicity, it is impossible to draw a specific conclusion about the mechanisms of liver injury. However, it seems that reactive metabolite formation and immune-mediated toxicity have a great role in antithyroids liver toxicity, especially those caused by methimazole. This review attempted to discuss different mechanisms proposed to be involved in the hepatic injury induced by antithyroid drugs.

Methimazole Associated Neutropenia in a Preterm Neonate Treated for Hyperthyroidism

Maternal Graves' disease is relatively uncommon with an estimated incidence of 0.4%–1% of all pregnancies, but only 1–5% of newborns delivered to mothers with Graves' disease develop overt clinical signs and symptoms of hyperthyroidism. Here, we describe a case of a 1380-gram female neonate who was born at 30-week gestation to a mother with Graves' disease. Our patient presented with hyperthyroidism followed by transient hypothyroidism requiring treatment with levothyroxine. While hyperthyroid, she was treated with methimazole, iodine, and a beta-blocker. 20 days after the initiation of methimazole, she developed neutropenia. The neutrophil counts started to improve immediately after the initiation of the weaning of methimazole. To the best of our knowledge, this is the first case reported in the literature of methimazole induced neutropenia in a preterm infant being treated for neonatal Graves' disease.

Factors affecting drug-induced liver injury: antithyroid drugs as instances

Methimazole and propylthiouracil have been used in the management of hyperthyroidism for more than half a century. However, hepatotoxicity is one of the most deleterious side effects associated with these medications. The mechanism(s) of hepatic injury induced by antithyroid agents is not fully recognized yet. Furthermore, there are no specific tools for predicting the occurrence of hepatotoxicity induced by these drugs. The purpose of this article is to give an overview on possible susceptibility factors in liver injury induced by antithyroid agents. Age, gender, metabolism characteristics, alcohol consumption, underlying diseases, immunologic mechanisms, and drug interactions are involved in enhancing antithyroid drugs-induced hepatic damage. An outline on the clinically used treatments for antithyroid drugs-induced hepatotoxicity and the potential therapeutic strategies found to be effective against this complication are also discussed.

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 Trial of Four Weeks of Combination Therapy with Low-dose Methimazole and a Cholesterol Absorption Inhibitor as the Initial Treatment for Childhood-onset Graves' Disease

The initial treatment of childhood-onset Graves' disease is based on the result of clinical trials of adult-onset disease. The major adverse events associated with methimazole, the only medication approved for childhood-onset disease in Japan, are considered to depend on the dose, and the risk of adverse events is increased in patients requiring higher doses for initial treatment. The serum levels of thyroid hormones are partially dependent on the enterohepatic circulation, especially under thyrotoxicosis. Cholesterol absorption inhibitors suppressing the enterohepatic circulation have the possibility of controlling thyrotoxicosis. In this clinical trial, 13 patients with childhood-onset Graves' disease (5.5 to 15.3 yr old) were divided into three treatment groups: low-dose (0.25 mg/kg/d) methimazole monotherapy, high-dose (1.0 mg/kg/d) methimazole monotherapy, and combination (low-dose methimazole + a cholesterol absorption inhibitor) therapy. The therapeutic efficacy was determined based on the rates of decrease of thyroid hormones for four weeks. The high-dose methimazole regimen was superior in efficacy to the low-dose methimazole regimen, while the combination therapy demonstrated effects equal to those of the high-dose monotherapy. Therefore, combination therapy with a cholesterol absorption inhibitor can improve thyrotoxicosis, and the dose of methimazole can be reduced in the initial treatment of child-onset Graves' disease.

Hyperthyroidism in childhood: causes, when and how to treat

Graves' disease (GD) is the most common cause of hyperthyroidism in children. This review gives an overview and update of management of GD. Antithyroid drugs (ATD) are recommended as the initial treatment, but the major problem is the high relapse rate (30%) as remission is achieved after a first course of ATD. More prolonged medical treatment may increase the remission rate up to 50%. Alternative treatments, such as radioactive iodine or thyroidectomy, are considered in cases of relapse, lack of compliance, or ATD toxicity. Therefore, clinicians have sought prognostic indicators of remission. Relapse risk decreases with longer duration of the first course of ATD treatment, highlighting the positive impact of a long period of primary ATD treatment on outcome. The identification of other predictive factors such as severe biochemical hyperthyroidism at diagnosis, young age, and absence of other autoimmune conditions has made it possible to stratify patients according to the risk of relapse after ATD treatment, leading to improvement in patient management by facilitating the identification of patients requiring long-term ATD or early alternative therapy. Neonatal autoimmune hyperthyroidism is generally transient, occurring in only about 2% of the offspring of mothers with GD. Cardiac insufficiency, intrauterine growth retardation, craniostenosis, microcephaly and psychomotor disabilities are the major risks in these infants and highlight the importance of thyroid hormone receptor antibody determination throughout pregnancy in women with GD, as well as highlighting the need for early diagnosis and treatment of hyperthyroidism.

A Report of Three Girls with Antithyroid Drug-Induced Agranulocytosis; Retrospective Analysis of 18 Cases Aged 15 Years or Younger Reported between 1995 and 2009

Agranulocytosis is an extremely serious, although rare, adverse effect of antithyroid drugs (ATDs), including methimazole (MMI) and propylthiouracil (PTU), in children and adolescents. There are few reports about the characteristics of ATD-induced agranulocytosis in Japanese children and adolescents. This report presents the cases of three girls with ATD-induced agranulocytosis and a retrospective analysis of 18 patients with ATD-induced agranulocytosis, whose cases had been referred to the drug manufacturer, Chugai Pharmaceutical Co., Ltd. Our 3 patients, ranging in age from 12 to 14 yr, developed ATD-induced agranulocytosis between the 15th and 57th day of ATD treatment for hyperthyroidism. Fever and sore throat were the earliest symptoms of agranulocytosis. The patients were rescued by ceasing ATD therapy and administering antibiotics, potassium iodide, glucocorticoid, immunoglobulin and granulocyte colony-stimulating factor (G-CSF). We retrospectively analyzed 18 cases of ATD-induced agranulocytosis treated with MMI in 16 cases and PTU in 2 cases. Twelve patients were treated with 20–45 mg/d MMI. Agranulocytosis developed between the 15th and 1,344th day of therapy. In conclusion, considering the risk of ATD-induced agranulocytosis, we recommend low-dose MMI therapy for treatment of Graves’ disease.