Clinical management of childhood hyperthyroidism with and without Down syndrome: a longitudinal study at a single center.

Background The approach to the clinical management of Graves' disease (GD) is debatable. This study aimed to identify predictors of remission in pediatric GD. Methods A longitudinal study of 36 children and adolescents with GD followed from 1997 to 2017 at a single tertiary hospital was performed. Clinical and biochemical parameters, including comorbidities, treatment with anti-thyroid drugs (ATD) or definitive therapy (radioiodine [RIT] and thyroidectomy), and remission as the main outcome were collected. We performed a multivariable logistic regression analysis to identify likely predictors of remission. Results Among patients, most were female, in late puberty, with exuberant symptoms at onset. Eleven also suffered from Down syndrome (DS). Thirty-four patients (94%) started on methimazole from disease onset, and 25 (69%) received it as the only therapy, with a mean duration of 2.7±1.8 years. Six changed to RIT and three underwent thyroidectomy; no DS patient received definitive therapy. Remission was higher in DS patients (45% vs. 25%, p=0.24), but afterwards (3.9±2.5 vs. 2.3±1.4 years, p<0.05); there was no significance in relapsing (20% vs. 15%). Females were less likely to reach remission (p<0.05); serum free thyroxine at onset was higher (p<0.05) in patients who required definitive therapy. Thyroid-stimulating immunoglobulin (TSI) values normalized in exclusively ATD therapy, especially from 2 years on (p<0.05). Conclusions Males were more likely to achieve remission. TSI values may normalize in GD, notably from the second year of treatment. DS children may benefit with conservative management in GD.