ESPE Abstracts

Background: Chronic autoimmune thyroiditis (AT) is a leading cause for acquired primary hypothyroidism in children. The prevalence of the AT in pediatric age is lower than in adults - approximately 2%. Familial predisposition is well established, however exact pathophysiologic mechanism is still not known. Since the first signs of Hashimoto thyroiditis are nonspecific and challenging to recognize, also the disease is not associated with pediatric age, the diagnosis in some cases is established late. In these cases decrease in height velocity and weight gain is one of the main causes for medical examination. The duration of unrecognized severe hypothyroidism is variable, often more than a year, therefore influences the final height of a patient.

Materials and Methods: A cohort of 85 children with Hashimoto thyroiditis aged 3-14 years were evaluated in our clinic in the period of 5 years. All showed signs of elevated antibodies, high TSH and diffuse hypoechogenicity of the thyroid on ultrasound scan. Main clinical findings were mild growth deficiency, weight gain, hair loss, dry skin, constipation and fatigue. Goiter was present in small number of the patients (17). In 6 patients where TSH levels were above 75 mIU/ml, short stature below 3th percentile curve was present which demanded further evaluation. Growth arrest persisted 1-3 years according previous growth curves in these patients. Diffuse pituitary enlargement of variable size mimicking macroadenoma was present. Growth velocity improved partially but didn’t reach the previous height curve within the next year in all. IGF levels were regularly tested, with improving results over time. Dynamic pituitary tests were performed one year after thyroxin replacement therapy (THR) is prescribed. In 3 of 6 patients GH peak remain below 3^rd percentile curve. In 2 patients with delayed puberty gonadotropin deficiency was present as well.

Discussion and Conclusion: Growth delay is a well-known feature in children with late recognized chronic autoimmune thyroiditis. Our experience and data in the literature showed that in most of the patients there is an improvement in growth velocity, IGF levels and GH secretion after 1 year of THR. Still, there is a small number of patients where, despite the THR therapy and normalization of TSH values, growth remain unsatisfied and GH therapy should be considered. In these children timing for reaching proper growth velocity is limited. Further guidelines are needed for starting with GH replacement therapy in these patients.

Key words: Hashimoto thyroiditis, growth hormone deficiency, pituitary enlargement