Thyroid disorders in children from birth to adolescence.

Thyroid hormones play a crucial role as a regulator of growth, of nervous system myelination, of metabolism, and of organ functions. Disorders affecting the thyroid gland represent the most common endocrinopathies in childhood. The etiology and clinical presentation of thyroid disorders in children and adolescents substantially differ from that in adults. Thus, pediatric medical care requires an appreciation of distinct characteristics of thyroid function and dysfunction in childhood and adolescence. Early diagnosis and treatment are essential to prevent irreversible and permanent nervous system damage and developmental delay, especially in infants as they are extremely vulnerable to thyroid dysfunction. Therefore, as well as reviewing distinct features of disorders with hypothyroidism, hyperthyroidism and normal thyroid function in childhood and adolescence, this article will also focus on important aspects of pre- and postnatal thyroid development and physiology.