Controversies in the pharmacological treatment of Graves' disease in children

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.

Hyperthyroidism in adolescents

The term 'hyperthyroidism' refers to a form of thyrotoxicosis due to inappropriate high synthesis and secretion of thyroid hormone(s) by the thyroid. The leading cause of hyperthyroidism in adolescents is Graves' disease (GD); however, one should also consider other potential causes, such as toxic nodular goitre (single or multinodular), and other rare disorders leading to excessive production and release of thyroid hormones. The term 'thyrotoxicosis' refers to a clinical state resulting from inappropriate high thyroid hormone action in tissues, generally due to inappropriate high tissue thyroid hormone levels. Thyrotoxicosis is a condition with multiple aetiologies, manifestations, and potential modes of therapy. By definition, the extrathyroidal sources of excessive amounts of thyroid hormones, such as iatrogenic thyrotoxicosis, factitious ingestion of thyroid hormone, or struma ovarii, do not include hyperthyroidism. The aetiology of hyperthyroidism/and thyrotoxicosis should be determined. Although the diagnosis is apparent based on the clinical presentation and initial biochemical evaluation, additional diagnostic testing is indicated. This testing should include: (1) measurement of thyroid-stimulating hormone receptor (TSHR) antibodies (TRAb); (2) analysis of thyroidal echogenicity and blood flow on ultrasonography; or (3) determination of radioactive iodine uptake (RAIU). A 123I or 99mTc pertechnetate scan is recommended when the clinical presentation suggests toxic nodular goitre. A question arises regarding whether diagnostic workup and treatment (antithyroid drugs, radioiodine, surgery, and others) should be the same in children and adolescents as in adults, as well as whether there are the same goals of treatment in adolescents as in adults, in female patients vs in male patients, and in reproductive or in postreproductive age. In this aspect, different treatment modalities might be preferred to achieve euthyroidism and to avoid potential risks from the treatment. The vast majority of patients with thyroid disorders require life-long treatment; therefore, the collaboration of different specialists is warranted to achieve these goals and improve patients' quality of life.

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.

Update on pediatric hyperthyroidism

PURPOSE OF REVIEW

This review is intended to highlight recent studies which provide new data on the epidemiology and management of children with hyperthyroidism, including neonates.

RECENT FINDINGS

A French study demonstrates differences in age-related trends in incidence of hyperthyroidism in males versus females and suggests the overall incidence may be increasing. New studies confirm the effectiveness and safety of long-term medical therapy (up to 10 years), including from the first randomized trial of short-term versus long-term therapy. Radioiodine ablation (RAI) is the main alternative therapy, though surgery may have some advantages if done in a high-volume center; using higher weight-based doses of I-131 (250 μCI/g thyroid tissue) could increase proportion of patients achieving hypothyroidism and decrease repeat ablations. Maternal or neonatal thyroid-stimulating hormone (TSH) receptor antibodies in children of mothers with Graves' disease, and TSH at 3-7 days of age are good predictors of which neonates will have problems.

SUMMARY

More research is needed on the epidemiology of Graves' disease. Long-term medical therapy well past two years should be considered an option in compliant patients to decrease the number who need definitive therapy. For those receiving RAI, a dose of about 250 μCI/g thyroid tissue should result in fewer cases of persistent hyperthyroidism than lower doses.

The Incidence of Childhood Thyrotoxicosis Is Increasing in Both Girls and Boys in Sweden

BACKGROUND

We found an increase in the incidence rate (IR) of childhood thyrotoxicosis (CT) during the 1990s in central Sweden. The optimal treatment method for CT is a subject that is still debated upon.

OBJECTIVES

To investigate whether the increase in IR of CT in Sweden persists and to study the treatment outcome.

METHOD

Children <16 years of age diagnosed with CT during 2000-2009 and living in 1 of 5 counties in central Sweden were identified retrospectively using hospital registers. Data on clinical and biochemical characteristics and outcomes of treatment were collected from medical records. The corresponding data from 1990 to 1999 were pooled with the new data.

RESULTS

In total, 113 children were diagnosed with CT during 1990-2009 in the study area. The overall IR was 2.2/100,000 person-years (95% CI 1.2-2.5/100,000 person-years). The IR was significantly higher during 2000-2009 than during 1990-1999 (2.8/100,000 [2.2-3.6] vs. 1.6/100,000 person-years [1.2-2.2], p = 0.006). The increase was significant for both sexes. Seventy percent of the patients who completed the planned initial treatment with antithyroid drugs (ATDs) and were not lost to follow-up relapsed within 3 years. Boys tended to relapse earlier than girls (6.0 months after drug withdrawal [95% CI 1.9-10.0] vs. 12.0 months [95% CI 6.8-17.3], p = 0.074).

CONCLUSIONS

The IR of CT is increasing in both girls and boys. Relapse rate after withdrawal of ATD treatment is 70%. Boys tend to relapse earlier than girls, and this needs to be further investigated.