Non-toxic diffuse goitre. Factors influencing the effect of thyroid medication.

The use of thyroid preparations to reduce the size of non-toxic goitres is well established, as is their use in differentiating between high 1311 uptake rates due to thyrotoxicosis and those occurring in non-toxic goitres (Greer and Smith, 1954; Werner and Spooner, 1955). It would seem reasonable to expect that the amount by which the thyroidal 1311 uptake can be suppressed by thyroid preparatio9s might be an index of the likelihood of reducing goitre size by their administration. Other factors which might affect the response to the thyroid medication are duration of the goitre, the initial 1311 uptake rate, and the size of the goitre. The aim of this study was to assess the significance of these factors in the response of goitres to thyroid preparations.