Evaluation of admission and follow-up features of the patients with hyperthyroidism who applied to Outpatient Clinic of Pediatric Endocrinology Department

Aim: Hyperthyroidism is a disease that is less common in children compared to adults, therefore its diagnosis may be delayed and evidence-based recommendations for monitoring and treatment are lacking. Graves' disease is the most common cause of hyperthyroidism and its treatment can vary between countries and depending on different ages, preferences, severity of the disease and size of goiter. It was aimed to evaluate the admission and follow-up characteristics of patients who applied to Ankara University Faculty of Medicine (AUTF), Outpatient Clinic of Pediatric Endocrinology Department and were diagnosed with hyperthyroidism. Materials and methods: Patients who diagnosed with hyperthyroidism between September 2005-January 2023 and were between the ages of 0-18, were included. Patients characteristics, anthropometry, physical examination, laboratory and imaging findings were recorded retrospectively. Diagnosis of patients, treatment and follow-up period were evaluated. Statistical analysis was performed with Statistical Package for Social Sciences (SPSS, Version 26.0, Chicago, IL.). Results: Sixty-three patients were included and 65.1% of them the were female. The mean age was 11.7±4.95 years. While 48 of the patients (76.2%) were diagnosed with Graves' disease (GD), the second most common etiological cause was Hashitoxicosis (n=9, 14.3%). Thirthy-one (64.6%) of the patients with GD were girls (girl/boy ratio 1.82) and the mean age was 12.03±4.52 years. Eight patients with hashitoxicosis (88.9%) were female and the mean age was 14.94±3.44 years. The most common presenting complaint was palpitations. Ophthalmopathy was determined in 7 (11.1%) of the cases. Anti-TG in 38 (60.3%), Anti-TPO in 50 (79.4%) and TRAb in 45 (71.4%) of the cases were positive; while Anti-TPO was the most frequently detected thyroid autoantibody. Antithyroid drug (ATI) treatment was started in 60 of 63 patients who presented with hyperthyroidism. While the mean duration to achieve euthyroidism was 7±8.29 months; 71.4% of the patients reached euthyroidism within 6 months after the start of treatment. The mean treatment duration was 25.03±22.9 months. The duration of treatment was statistically significantly longer in those with GD compared to those with Hashitoxicosis (p=0.002). The mean follow-up period of 63 cases was 36.9±32.3 months. While the long-term remission rate in patients with GD who had receiving ATI treatment was 22.9%; relapse was determined in 15 of 48 cases (31.3%) during follow-up. In patients with first relapse, the mean duration from treatment discontinuation to relapse was 8.4±5.02 months and 76.9% relapsed within the first 12 months after stopping treatment. Total or partial thyroidectomy was performed in 11 (17.5%) of 63 patients with hyperthyroidism. The most common reason for surgical treatment (25%) was failure to achieve remission with long-term ATI treatment. Thyroidectomy was performed more frequently in the presence of large goiter (p=0.004), ophthalmopathy (p=0.018), large thyroid volume (p=0.044) and volume SDS (p=0.001). It was found that the time to reach euthyroidism (p=0.0015) and the time to TRAb negativity (p=0.022) were longer in those who underwent thyroidectomy compared to those who did not. Conclusions: In this study, we reported 63 cases with hyperthyroidism and 18 years of experience of our center. Euthyroidism can be achieved within the first 6 months with ATI treatment in the majority of children and adolescents with hyperthyroidism. It has been observed that long-term remission can be achieved at a low rate with ATI treatment in children with GD. Thus permanent treatment is likely to be required in the presence of large goiter, ophthalmopathy, and in patients in whom biochemical euthyroidism and TRAb negativity cannot be achieved with long-term treatment. Key words: Hyperthyroidism, Graves Disease, Thyroiditis