OBJECTIVETo study the changes in hormone levels and the therapy of pituitary hyperplasia secondary to primary hypothyroidism in children.

METHODSThe clinical data of 8 children with pituitary hyperplasia secondary to primary hypothyroidism (5 girls and 3 boys) at ages of 5 to 9 years were studied retrospectively. All of the children had a short stature. They were followed up 1 to 6 years.

RESULTSThe thyroid hormone levels decreased and the serum thyroid stimulating hormone (TSH) and prolactin (PRL) levels increased in the 8 children. After 2 to 6 months thyroxine replacement therapy, the levels of free triiodothyronine (FT3), free thyroxine (FT4) and serum TSH and PRL returned to normal, and the pituitary enlargement regressed to normal in the 8 children. Of them, 6 children's height growth rate increased significantly from 3.1+/-0.5 cm per year to 11.6+/-1.7 cm per year (p<0.01). The other 2 cases had low growth rate and then received additional recombinant human growth hormone (rhGH) therapy. Their height growth rate increased by 11 cm per year. Pituitary hyperplasia did not recur in the 8 children during the follow-up.

CONCLUSIONSThe thyroid function and pituitary examinations are necessary for children with a short stature. Thyroxine substitution therapy appears to be effective for primary hypothyroidism secondary to pituitary hyperplasia. rhGH replacement therapy after regression of the pituitary enlargement can result in a satisfactory height growth in children with low thyroid hormone levels and growth hormone deficiency.