What are possible outcomes after Iodine 131 therapy for Graves disease?
There are three possible outcomes:
- 1. A patient may be hypothyroid if the dose is sufficient to destroy most of the thyroid tissue and function.
- 2. A patient may be euthyroid if the dose diminishes the function of the thyroid gland, but there is sufficient activity to maintain normal circulating levels of thyroid hormone.
- 3. A patient may be remain hyperthyroid if undertreated, with the thyroid gland continuing to produce high levels of thyroid hormone.
In the hypothyroid case, patients typically begin undergoing thyroid replacement therapy. In the hyperthyroid case, patients usually require retreatment with a higher dose of 131 I. The likelihood of each outcome depends on the range of doses given. Lower doses result in fewer hypothyroid patients, with more patients requiring retreatment for persistent hyperthyroidism. Higher doses result in more patients being hypothyroid and fewer needing to be retreated.