ESPE Abstracts

Introduction: Hypothyroidism in children and adolescents presents unique challenges to clinicians due to its diverse clinical manifestations, including important weight gain and growth deceleration. Hashimoto's Thyroiditis is the leading cause of thyroid disorders in the paediatric population.

Case report: A 9-year-old girl was referred to our endocrinology department for significant weight gain (15-20% over 6 months), growth deceleration, fatigue and snoring. She had no significant medical or family history of thyroid disorders. On examination, she appeared lethargic with a puffy face and bradypsychia. Her height was 123 cm (-1.64SDS; MPH -166cm; +0.41SDS) and she weighed 38 kg with BMI=25.1 kg/m2 (116% of 95th percentile) and a total of 13.72 kg of body fat. She had bradycardia and normal blood pressure. The thyroid gland was palpable and enlarged. She had Tanner stage I and her skin was dry without rash, striae or acanthosis. Laboratory evaluation revealed a markedly elevated TSH (636 uUI/ml), undetectable free thyroid hormones, and positive thyroid peroxidase and antithyroglobulin antibodies (ATPO > 600 UI/ml; ATG > 4000 UI/ml). Dyslipidaemia, insulin resistance (HOMA-IR = 3.2), and normal cortisol levels were also noted. Thyroid ultrasound showing an enlarged heterogeneous thyroid with increased vascularity confirmed severe hypothyroidism due to autoimmune thyroiditis. A wrist X-ray showed a delayed bone age. The patient was started on levothyroxine 1.5 mcg/kg daily, and dose was increased to 2.1 mcg/kg daily after 2 weeks.

Clinical Parameters and Treatment Regimen:

After one-month, improved TSH levels and reduced weight and fat mass were observed, allowing for a reduction in the levothyroxine dose. At six weeks, the patient's TSH levels were still slightly above normal, leading to a dosage adjustment. Weight and fat mass continued to decrease, showing overall improvement.

Conclusion: Treating hypothyroidism in children and adolescents presents challenges due to the dynamic nature of growth and development. While levothyroxine therapy effectively manages symptoms, the need for regular monitoring and dosage adjustments underscores the importance of continuous monitoring to adjust medication dosages appropriately. The fluctuations in TSH levels and the need for dose adjustments demonstrate the dynamic nature of thyroid hormone requirements in growing children.