ESPE Abstracts

Introduction: Thyrotoxicosis is a clinical manifestation that arises due to excessive amounts of circulating thyroid hormone in the body with a subsequent hypermetabolic state. The condition has multiple aetiologies of which Graves’ disease accounts for the most cases in children and adolescence. Symptoms in children are often more obscure than those seen in adults which may contribute to diagnostic delay of the condition. The aim of the study is to assess the incidence of thyrotoxicosis in children and adolescents in Iceland over the span of two decades (2001-2021), furthermore to investigate if the incidence rate has increased as well as to describe treatment options and disease recurrence.

Material/Methods: This retrospective descriptive study included all children and adolescents diagnosed with thyrotoxicosis in the years 2001-2021 in Iceland. Information was obtained from the Directorate of Health's drug database and from ICD-10 diagnoses at Landspítali – The National University Hospital.

Results: In total, 77 children and adolescents were diagnosed with thyrotoxicosis during the study period, with an overall incidence rate of 4.6/100,000 person-years for people younger than 18. Graves’ disease accounted for 55 of the cases (77,5 %), Hashitoxicosis for 13 (18,3 %), two suffered from neonatal thyrotoxicosis at birth (2,8 %) and one developed post-operative thyrotoxicosis following a removal of ACTH producing pituitary adenoma (1,4 %). The gender ratio was 1:2.8 (male : female) and the mean age at diagnosis was 13.7 for boys and 14.2 for girls. Patients included in this study diagnosed with Graves’ disease were the primary focus of therapeutic intervention, of which 8 individuals (14.5%) are currently receiving antithyroid drugs (ATD), 13 reached an euthyroid state with medication (23.7%), four relapsed and are currently receiving medication (7.3%), 25 received treatment with radioactive iodine (45.5%) and 5 underwent surgery (9.1%). Boys were more likely relapse and relapsed sooner following ATD although the difference was not significant. Disease relapse during the study period was 31.8%.

Conclusions: The incidence of both thyrotoxicosis and Graves' disease did not increase during the study period. The disease was more common in girls although gender ratio was lower than expected. ATD were the first choice in treatment. Recurrence of the disease was common and radioactive iodine treatment was the most common permanent treatment option. A possible relationship between the duration of ATD therapy and disease relapse should be investigated.