RADIOIODINE UPTAKE IN THE STUDY OF DIFFERENT TYPES OF HYPOTHYROIDISM IN CHILDHOOD

A method for demonstrating small uptakes of radioiodine by the thyroid gland has been described. The study suggests that in some cases of cretinism iodine-accumulating thyroid tissue may be completely absent while in others a small amount may be present. In cretins in whom a small amount of thyroid tissue can be demonstrated, the symptoms, even though appearing during the first year of life develop more insidiously. In cases of hypothyroidism developing later in childhood, small amounts of thyroid tissue capable of taking up iodine usually can be demonstrated. In addition to the cases of hypothyroidism in which there is absence of the gland or marked diminution in the amount of thyroid tissue, two patients (Nos. 13 and 14) with definite hypothyroidism showed a normal uptake of I131. One of those patients had a thyroid gland of normal size, the other a moderately enlarged gland. They lived in regions in which there was no likelihood of deficient iodine intake (see Addendum). One patient (No. 15) with acquired hypothyroidism took up no iodine when first studied but after injection of thyrotropic hormone showed a normal uptake. The problem of whether acquired hypothyroidism may be due to deficiency of thyrotropic hormone is discussed.