Endocrine Abstracts

Introduction: Grave’s disease is a rare disease in children. Treatment options are the same as in adults but remission rate with antithyroid drugs (ATD) appears to be lower in children and more prolonged courses of ATD are recommended. We aimed to evaluate the outcome of ATD treatment and to identify factors associated with remission.

Methods: Retrospective study of 36 pediatric patients diagnosed with Grave’s disease at the Pediatric Department of a tertiary hospital in Portugal between 2002 and 2023. Remission was defined as euthyroidism for more than 12 months after stopping ATD treatment. Patients who achieved remission were compared to those treated for more than 2 years with ATD without remission. Statistic results are expressed as median (interquartile range) or frequency (percentage).

Results: Twenty-eight patients (77.8%) were female and median age at diagnosis was 14 (5.50) years. Twenty-four patients were sypmtomatic at diagnosis, mostly presenting with tachycardia (35.3%) and unintentional weight loss (26.5%). The median thyroid-stimulating hormone (TSH), free T4 (fT4), free T3 (fT3) and TSH-receptor antibodies (TRAbs) at diagnosis were 0.002 (0.01) µUI/ml, 2.49 (1.57) ng/dl, 8.76 (11.62) ng/dl and 14.35 (36.90) U/l, respectively. All patients started methimazole with a median initial dose of 10 (5) mg/day and a median treatment duration of 24 (28.50) months. Mild side effects were reported for only one patient. During follow-up, 9 patients achieved remission, 2 patients experienced relapse after discontinuation of ATD and 13 patients were treated for more than 2 years with ATD without remission. The ATD course duration for both patients who had a relapse was less than 2 years. In patients who achieved remission, the fT4 at diagnosis [1.80 (0.72) vs 2.91 (1.66) ng/dl, P=0.020], the time for fT4 normalization [24.5 (13.5) vs 49.0 (107.5) days, P=0.010], the time for TSH normalization [4.5 (6.8) vs 12.9 (11.0) months, P=0.010] and TRAbs levels at diagnosis [3.30 (12.65) vs 40.00 (25.35) U/l, P=0.002] were significantly lower than the non-remission group.

Conclusion: The overall remission rate after ATD treatment in our cohort was 25%, which is in accordance with previously reported rates. Lower fT4 and TRAbs levels at diagnosis and lower time for fT4 and TSH normalization were associated with higher chances of remission.