Hyperthyroidism in childhood: causes, when and how to treat

Graves’ Disease in a Young Patient With Turner’s Syndrome: The Genetic Association

INTRODUCTION

Autoimmune diseases occur more often in females, suggesting a key role for the X chromosome. Curiously, individuals with Turner syndrome (TS), with fewer copies of X-linked genes, are prone to develop autoimmune conditions. Hashimoto's thyroiditis (HT) is described with a relatively high frequency in patients with TS while the association with Graves' disease (GD) is rare. Here we report a rare case of TS with GD in a young patient.

METHOD

A 14-year-old girl presented with hyperthyroid symptoms and eye signs that developed over the past six months. She had somatic stigmata of TS. TS was diagnosed by karyotyping (45,XO/46,XX del Xq22) and GD was diagnosed by a thyroid function test and the presence of autoantibodies. She was treated effectively with carbimazole for GD. Estrogen replacement therapy was also initiated to induce the development of secondary sex characteristics.

CONCLUSION

X chromosome inactivation, an epigenetic process that establishes and maintains dosage compensation of X-linked genes, is especially vulnerable to disruption and may contribute to an autoimmune disease process. The occurrence of autoimmune diseases in patients with TS is discussed with regard to possible abnormalities in X-linked dosage compensation.

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.

Methimazole plus levothyroxine for treating hyperthyroidism in children: a systematic review and meta-analysis

BACKGROUND

Hyperthyroidism is a disease of excessive synthesis and secretion of thyroid hormones, and there is a lack of studies that have systematically evaluated the efficacy of the combination in treating hyperthyroidism. This study aimed to systematically evaluate the effectiveness and safety of methimazole combined with levothyroxine for treating hyperthyroidism in children.

METHODS

We searched PubMed, CNKI, Wanfang Database, EMBASE, Web of Science, and other online electronic databases to find correlation studies of methimazole combined with levothyroxine in treating hyperthyroidism in children from 2010 to 2021. Meta-analysis was performed using Stata 16 software.

RESULTS

Finally, 15 relevant articles were included comprising 1,718 pediatric patients. Meta-analysis results indicated that compared with methimazole alone (control group), the experimental group administered methimazole + levothyroxine had no evident difference in the level of thyroid-stimulating hormone [standardized mean difference (SMD) =-0.34, 95% confidence interval (CI): -1.02, 0.35, P=0.33], but notably improved the efficacy of clinical treatment of hyperthyroidism in children [odds ratio (OR) =5.77, 95% CI: 2.62, 12.74, P<0.001]. Meanwhile, the experimental group had lower adverse reaction rates (OR =0.28, 95%CI: 0.19, 0.40, P<0.001), free triiodothyronine (FT3) level (SMD =-0.85, 95% CI: -1.57, 0.13, P=0.02), free tetraiodothyronine (FT4) level (SMD =-0.94, 95% CI: -1.59, -0.30, P=0.004) and reduced thyroid volume (SMD =-1.3, 95% CI: -1.67, 0.93, P<0.001).

DISCUSSION

Using methimazole + levothyroxine to treat hyperthyroidism in children can raise the levels of FT3 and FT4, reduce the thyroid volume, improve clinical efficacy, and lower the adverse reaction rate of patients.

Report of a family with three generations of undiagnosed familial nonautoimmune hyperthyroidism

SUMMARY

Familial nonautoimmune hyperthyroidism (FNAH) is rare and occurs due to a constitutively activating thyroid-stimulating hormone receptor (TSHR) germline mutation. Forty-one families with FNAH have been reported so far. In the study, 17 of 41 families were not diagnosed with FNAH until three generations or more were described with hyperthyroidism. We report a case of FNAH diagnosed in the third generation. The index patient was diagnosed with hyperthyroidism at age 3. Large fluctuations in thyroid hormone levels occurred during anti-thyroid drug treatment, and he developed a goiter. The patient's mother had similar history, requiring two surgical interventions and radioiodine treatment. The younger brother of the index patient did not experience large thyroid hormone level fluctuations, nor increased thyroid growth. A heterozygous TSHR c.1357A>G mutation, resulting in a M453V amino acid exchange, was detected in all three patients leading to FNAH diagnosis, with complete genotype-phenotype segregation. Based on Sorting intolerant from tolerant (SIFT) and PolyPhen2 scores of 0.01 and 0.99, respectively, an effect on protein function can be assumed. As illustrated by this family with FNAH, total thyr oidectomy is necessary for patients with nonautoimmune hyperthyroidism. Development of goiter is common, anti-thyroid drug treatment is often difficult, and remission of hyperthyroidism does not occur after discontinuation of anti-thyroid drug treatment. Thus, early diagnosis and appropriate treatment of FNAH is necessary to avoid predictable, unnecessary complications and further surgical interventions.

LEARNING POINTS

In the study, 19/42 cases of familial nonautoimmune hyperthyroidism (FNAH), including the reported case, were not diagnosed as FNAH until the third generation; this lead to suboptimal treatment and frequent relapses of nonautoimmune hyperthyroidism (NAH). Detection of thyroid-stimulating hormone receptor (TSHR) mutations in patients with suspected FNAH to confirm diagnosis is essential to ensure proper treatment for the patient and further affected family members. NAH will persist without proper treatment by total thyroidectomy. Symptoms and age of onset may vary between family members All family members with a TSHR germline mutation should be monitored with thyroid-stimulating hormone and for symptoms throughout their lives.

Central TSH Dysregulation in a Patient with Familial Non-Autoimmune Autosomal Dominant Hyperthyroidism Due to a Novel Thyroid-Stimulating Hormone Receptor Disease-Causing Variant

Background and Objectives. Familial non-autoimmune autosomal dominant hyperthyroidism (FNAH) is a rare cause of childhood hyperthyroidism. It is caused by the thyroid-stimulating hormone receptor (TSHR) gene variants. So far, only around 40 families with FNAH have been reported. Patients with activating TSHR variants demonstrated the same classical signs and symptoms of hyperthyroidism as seen in patients with Graves' disease. Since 2012, ablative therapy is recommended to avoid relapses of hyperthyroidism and its consequences. Case Presentation. We presented a young adult male patient with a novel heterozygous TSHR disease-causing variant p.Arg418Lys (c.1253G>A) in the exon 10, who presented with a mild but progressive FNAH, with a follow-up since infancy. Discussion. Constantly suppressed TSH, including during the euthyreosis in childhood and hypothyreosis after iodine ablation therapy, suggested central dysregulation of the TSH secretion.

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.

Comprehensive Metabolomics Study in Children With Graves' Disease

OBJECTIVE

Graves' disease (GD) related hyperthyroidism (HT) has profound effects on metabolic activity and metabolism of macromolecules affecting energy homeostasis. In this study, we aimed to get a comprehensive understanding of the metabolic changes and their clinical relevance in GD children.

METHODS

We investigated serum substances from 30 newly diagnosed GD children and 30 age- and gender-matched healthy controls. We explored the metabolomics using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS) analysis, and then analyzed the metabolomic data via multivariate statistical analysis.

RESULTS

By untargeted metabolomic analysis, a total of 730 metabolites were identified in all participants, among which 48 differential metabolites between GD and control groups were filtered out, including amino acids, dipeptides, lipids, purines, etc. Among these metabolites, 33 were detected with higher levels, while 15 with lower levels in GD group compared to controls. Pathway analysis showed that HT had a significant impact on aminoacyl-transfer ribonucleic acid (tRNA) biosynthesis, several amino acids metabolism, purine metabolism, and pyrimidine metabolism.

CONCLUSION

In this study, via untargeted metabolomics analysis, significant variations of serum metabolomic patterns were detected in GD children.

Role of thyroid hormones in craniofacial development

The development of the craniofacial skeleton relies on complex temporospatial organization of diverse cell types by key signalling molecules. Even minor disruptions to these processes can result in deleterious consequences for the structure and function of the skull. Thyroid hormone deficiency causes delayed craniofacial and tooth development, dysplastic facial features and delayed development of the ossicles in the middle ear. Thyroid hormone excess, by contrast, accelerates development of the skull and, in severe cases, might lead to craniosynostosis with neurological sequelae and facial hypoplasia. The pathogenesis of these important abnormalities remains poorly understood and underinvestigated. The orchestration of craniofacial development and regulation of suture and synchondrosis growth is dependent on several critical signalling pathways. The underlying mechanisms by which these key pathways regulate craniofacial growth and maturation are largely unclear, but studies of single-gene disorders resulting in craniofacial malformations have identified a number of critical signalling molecules and receptors. The craniofacial consequences resulting from gain-of-function and loss-of-function mutations affecting insulin-like growth factor 1, fibroblast growth factor receptor and WNT signalling are similar to the effects of altered thyroid status and mutations affecting thyroid hormone action, suggesting that these critical pathways interact in the regulation of craniofacial development.

Effects of hyperthyroidism in the development of the appendicular skeleton and muscles of zebrafish, with notes on evolutionary developmental pathology (Evo-Devo-Path)

The hypothalamus-pituitary-thyroid (HPT) axis plays a crucial role in the metabolism, homeostasis, somatic growth and development of teleostean fishes. Thyroid hormones regulate essential biological functions such as growth and development, regulation of stress, energy expenditure, tissue compound, and psychological processes. Teleost thyroid follicles produce the same thyroid hormones as in other vertebrates: thyroxin (T4) and triiodothyronine (T3), making the zebrafish a very useful model to study hypo- and hyperthyroidism in other vertebrate taxa, including humans. Here we investigate morphological changes in T3 hyperthyroid cases in the zebrafish to better understand malformations provoked by alterations of T3 levels. In particular, we describe musculoskeletal abnormalities during the development of the zebrafish appendicular skeleton and muscles, compare our observations with those recently done by us on the normal developmental of the zebrafish, and discuss these comparisons within the context of evolutionary developmental pathology (Evo-Devo-Path), including human pathologies.

[Hyperthyroidism in children at the University Hospital in Dakar (Senegal)]

Introduction

L'hyperthyroïdie de l'enfant semble rare et constitue un problème de par son retentissement psychosomatique. L’objectif était de faire le point sur ses aspects épidémiologiques et diagnostiques chez l’enfant à Dakar.

Méthodes

Il s'agissait d'une étude multicentrique, descriptive sur 15 ans. Etaient analysés les aspects épidémiologiques, cliniques et étiologiques.

Résultats

239 patients sélectionnés avec une prévalence de 2.4%, un sex ratio (H/F) de 0.36, un âge moyen de 10.8 ans. À l'inclusion, il s'agissait d'un ainé de famille (26.3%), d'une croissance avancée (36.9%), retardée (12.5%), d'une corpulence insuffisante (40.1%). L'étiologie était la maladie de Basedow dans 90.3% avec un facteur psychoaffectif dans 22.1%. Sur le plan clinique, prédominaient la tachycardie (92.4%), le goitre (91.1%), l'exophtalmie (81.8%), l'amaigrissement (69.8%) avec cependant une énurésie (30.2%) et des manifestations psychiques (3.1%). Les manifestations cardiovasculaires et cutanées étaient positivement associées avec l'âge (p < 0.05). Le goitre était associé au sexe féminin (p = 0.005), aux signes cardiovasculaires (p = 0.02), neuropsychiques (p = 0.03), cutanées (p = 0.03) et à la diarrhée (p = 0.03). La T4 libre était corrélée à l'âge (p = 0.007), la diarrhée (p = 0.021), l'anxiété (p = 0.024), la fréquence cardiaque (p = 0.00) et la maladie de Basedow (p = 0.04). Plus le goitre était volumineux, plus était augmentée la T4 libre (p = 0.007).

Conclusion

Conclusion: L'hyperthyroïdie de l'enfant se différencie de celle de l'adulte par les facteurs d'induction, les perturbations sur la croissance et l'énurésie. L’âge et le sexe semble favoriser le tableau clinique de thyrotoxicose et les signes associés.

Change in BMI after radioactive iodine ablation for graves disease

Background

We aimed to determine the extent of post-treatment weight gain that occurs in pediatric patients in the first year following radioactive iodine (RAI) therapy for Graves disease (GD) and its relationship to clinical characteristics.

Methods

A retrospective chart review of patients receiving RAI therapy for GD between 1998–2015 was performed. Change in BMI SDS (∆BMI SDS) from baseline to one year after treatment was determined. We also investigated whether individual clinical and/or biochemical factors were associated with the weight trajectory in these patients.

Results

One hundred fifty seven patients aged 12.7 ± 3 years (80% girls) were included in the analysis. Average ∆BMI SDS was 0.70 ± 0.71 (p < 0.001) at 1 year. Patients with weight loss at presentation had a greater ∆BMI SDS than those without (0.92 vs 0.56, p = 0.005), whereas no association was seen with gender, pubertal status, use of antithyroid drugs, history of ADHD, or Down syndrome. Baseline BMI SDS was negatively correlated with ∆BMI SDS, with a stronger correlation in males. From baseline to 1 year, the proportion of overweight and obese patients increased from 9.6% to 18.5% and from 6.4% to 21%, respectively. In a subset of 81 patients, a positive correlation was noted between time to euthyroidism and ∆BMI SDS, particularly in boys.

Conclusions

The number of our patients in the overweight category doubled and the number in the obese category more than tripled in the first year following RAI treatment for GD. Anticipatory guidance regarding this important issue is badly needed.

Pediatric Reference Intervals for Free Thyroxine and Free Triiodothyronine by Equilibrium Dialysis-Liquid Chromatography-Tandem Mass Spectrometry

OBJECTIVE

Thyroid hormone concentrations fluctuate during growth and development. To accurately diagnose thyroid disease in pediatric patients, reference intervals (RIs) should be established with appropriate age groups from an adequate number of healthy subjects using the most exact methods possible. Obtaining statistically useful numbers of healthy patients is particularly challenging for pediatric populations. The objective of this study was to determine non-parametric RIs for free thyroxine (fT4) and free triiodothyronine (fT3) using equilibrium dialysis-high performance liquid chromatography-tandem mass spectrometry with over 2200 healthy children 6 months-17 years of age.

METHODS

Subjects were negative for both thyroglobulin and thyroid peroxidase autoantibodies and had normal thyrotropin concentrations. The study included 2213 children (1129 boys and 1084 girls), with at least 120 subjects (average of 125) from each year of life, except for the 6 month to 1 year age group (n=96).

RESULTS

Non-parametric RIs (95th percentile) for fT4 were: 18.0-34.7 pmol/L (boys and girls, 6 months-6 years) and 14.2-25.7 pmol/L (boys and girls, 7-17 years). RIs for fT3 were: 5.8-13.1 pmol/L (girls, 6 months-6 years); 5.7-11.8 pmol/L (boys, 6 months-6 years); 5.7-10.0 pmol/L (boys and girls, 7-12 years); 4.5-8.6 pmol/L (girls, 13-17 years); and 5.2-9.4 pmol/L (boys, 13-17 years).

CONCLUSION

Numerous significant differences were observed between pediatric age groups and previously established adult ranges. This emphasizes the need for well-characterized RIs for thyroid hormones in the pediatric population.

A new family with an activating mutation (G431S) in the TSH receptor gene: a phenotype discussion and review of the literature

Germline nonautoimmune hyperthyroidism due to an activating mutation in the thyroid stimulating hormone receptor gene is an uncommon disease. To date 32 different mutations have been described. The severity of the hyperthyroid symptoms is variable and phenotype differences have been described in subjects harboring the same mutation. This paper describes a family with a mutation in codon 431 of the thyroid stimulating hormone receptor gene. This is the most common activating mutation in the thyroid stimulating hormone receptor gene with total of 13 patients harboring the mutation in four families. The similarities and differences among patients with the mutation in codon 431 are discussed. Furthermore all previously reported activating mutations in the thyroid stimulating hormone receptor gene are reviewed.

A 3-year-old girl with Graves' disease with literature review

Graves' disease, the main cause of hyperthyroidism in the pediatric age group, is very rare in children younger than 4 years old but can seriously interfere with growth and development if not recognized and treated. Here we report a case of a 3-year-old girl with Graves' disease who presented with goiter, exophthalmos, heat intolerance, and hyperactivity. At her first visit, her serum concentrations of triiodothyronine (T3) and free thyroxine (free T4) were normal, whereas that of thyroid-stimulating hormone (TSH) was decreased. Antimicrosomal antibody was 7,053.94 IU/mL, and TSH-binding inhibitory immunoglobulin was 31.62%. A thyroid scan showed diffuse enlargement with markedly increased uptake of both thyroid glands. Although T3 and free T4 levels were initially normal, she developed hyperthyroidism 3 months later. She was finally diagnosed with Graves' disease and treated with methimazole for 6 months. This is the first report of Graves' disease in children younger than 4 years old in Korea.

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.