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.