10 Years of Successful Treatment with Dextrothyroxine in a Girl with TSH-Induced Hyperthyroidism

Abstract

14 years ago, a 5.7-year-old healthy girl was treated with desiccated thyroid for a goiter and elevated TSH levels. The goiter disappeared and TSH levels were normalized. However, hyperthyroidism appeared. Without therapy, the goiter reappeared and hyperthyroidism aggravated. Based on hormone values, TSH-induced hyperthyroidism was diagnosed. After exclusion of neoplastic TSH secretion, treatment with dextrothyroxine (DT₄) was initiated at age of 10 years and continued during the last 10 years (except for short periods). The girl became euthyroid, has no goiter and normal TSH values. Since thyrotrophs and peripheral tissues are probably normally sensitive to T₄, we postulate that her hypothalamopituitary-thyroid control is operating on a higher set point level for T₄.

Large somatostatin-insensitive thyrotrophin-secreting pituitary tumour responsive to d-thyroxine and dopamine agonists

“…The different potencies of d-and lthyroxine (9) on various tissues might reflect differences in the cellular uptake of the isomers or be due to different deiodination pathways (10). The selective effect of D-thyroxine has been utilized in a small number of non-neoplastic patients with pituitary resistance to thyroid hormones (13)(14)(15). The selective effect of D-thyroxine has been utilized in a small number of non-neoplastic patients with pituitary resistance to thyroid hormones (13)(14)(15).…”