Graves’ disease is an autoimmune condition where the body’s immune system mistakenly attacks the thyroid gland, leading it to produce an excess of thyroid hormones. This overactivity, known as hyperthyroidism, can cause symptoms like weight loss, rapid heartbeat, and tremors. While several approaches exist to manage this condition, radioactive iodine (RAI) therapy is a common and effective treatment option for many individuals.
How Radioactive Iodine Works
Radioactive iodine therapy utilizes a specific isotope, Iodine-131 (I-131), which is administered orally. The thyroid gland naturally absorbs iodine from the bloodstream to produce thyroid hormones. This physiological process allows the radioactive iodine to be selectively taken up by the overactive thyroid cells.
Once absorbed by the thyroid cells, the I-131 emits beta particles, short-range radiation. These particles destroy the overactive thyroid cells, reducing the gland’s ability to produce excessive hormones. The localized action of the radiation ensures that surrounding tissues are largely unaffected. Over several weeks to months, the destruction of these cells leads to a decrease in thyroid hormone production, alleviating the symptoms of hyperthyroidism.
Preparing for Treatment
Before undergoing RAI therapy, specific preparation steps are necessary. Patients are advised to follow a low-iodine diet for one to two weeks prior to the procedure. This dietary restriction helps deplete the body’s iodine stores, making the thyroid cells more receptive to the radioactive iodine.
It is also required to stop certain thyroid medications, such as anti-thyroid drugs like methimazole or propylthiouracil, several days before treatment. These medications can interfere with the uptake of radioactive iodine by the thyroid gland. A pregnancy test is mandatory for women, as RAI therapy is not safe during pregnancy or breastfeeding. A thyroid uptake scan may also be performed to assess how well the thyroid gland absorbs iodine, which helps in determining the appropriate dose of RAI.
The Treatment Process and Immediate Aftercare
On the day of treatment, the radioactive iodine is administered orally, either as a capsule or a liquid solution. The dose is determined by a medical professional, often based on factors like the size of the thyroid gland and the degree of hyperthyroidism. After receiving the RAI, patients are discharged with specific instructions for immediate aftercare and radiation safety.
For several days to a week following treatment, precautions are necessary to limit radiation exposure to others. This includes maintaining a safe distance from family members, especially children and pregnant individuals. Patients are advised to sleep in a separate bed and avoid prolonged close contact. Special care is also required for waste disposal, such as flushing the toilet multiple times after use and washing laundry separately. These measures are in place because the patient’s body temporarily emits small amounts of radiation, which gradually decreases over time.
Long-Term Outcomes and Considerations
The full effects of radioactive iodine therapy are not immediate and manifest over several weeks to a few months. While some individuals may experience a gradual improvement in symptoms within a few weeks, the maximum benefit takes about three to six months to become apparent. Regular follow-up appointments with blood tests are necessary to monitor thyroid hormone levels during this period.
An expected long-term outcome of RAI therapy is the development of hypothyroidism, an underactive thyroid. This occurs because the treatment effectively destroys a significant portion of the thyroid cells, leading to insufficient hormone production. If hypothyroidism develops, lifelong thyroid hormone replacement medication, such as levothyroxine, will be necessary to maintain normal hormone levels. This replacement therapy is straightforward and effective in managing the condition. While well-tolerated, some individuals may experience mild and temporary side effects, such as neck tenderness or a temporary worsening of hyperthyroid symptoms in the initial days following treatment. Overall, RAI therapy has a high success rate in treating Graves’ disease.