Graves’ Disease: Radioactive Iodine As A Treatment Option

Graves’ disease (GD) is an autoimmune condition that affects approximately 1% to 1.5% of the US population.¹ It’s the most common cause of hyperthyroidism² and affects about 3% of women and 0.5% of men.

Graves’ disease results in hyperthyroidism, where the overactive thyroid can cause weight loss, fast heart rate, sweating, diarrhea, tremors, mood swings, and changes in sexual function.   

Additionally, GD can affect the eyes, resulting in eye-bulging, sensitivity to light, and vision changes.

With adequate treatment, it’s possible to enter remission and have your symptoms largely improve. Here we review treatment options, focusing on one in particular: radioactive iodine (RAI) therapy.

How Graves’ disease develops

Hyperthyroidism occurs when the thyroid gland produces an oversupply of thyroid hormones, and this causes thyroid enlargement, which can cause a goiter. 

Researchers think that the likelihood of developing Graves’ disease has a very strong genetic component², heightened by environmental factors² such as smoking, stressful life events, pregnancy, infection, and high amounts of dietary iodine. 

Treatment options for Graves’ disease

Graves ' disease has three treatment options: antithyroid medication, radioactive iodine therapy, and surgery. 

In Western countries, patients are usually given an initial course of antithyroid medication before starting RAI. 

Antithyroid medication

Antithyroid medication includes methimazole and propylthiouracil (PTU). 

Methimazole is the most commonly used medication, while PTU is used in women in the first trimester of pregnancy and those unable to take methimazole.  

These medications are designed to prevent thyroid hormone production. 

RAI and Surgery

If normalized thyroid hormone levels are not maintained 12 to 18 months² after completing a course of antithyroid medication, then radioactive iodine therapy and surgery should be considered. 

Surgery involves a total thyroidectomy (removing the thyroid gland) and is a very effective way to reach Graves’ disease remission. However, as with any procedure, you’ll have a few risks to consider. 

A general anesthetic is required, which in itself poses risks. Also, possible nerve injury can occur, causing vocal cord paralysis. 

In some cases, the surgery results in temporary or even permanent hypoparathyroidism, which can cause muscle, hair, and nail abnormalities. 

The surgical option is usually only recommended if you can’t tolerate the antithyroid medication, RAI therapy, if you have quite a large goiter, or if you have nodules suspicious of being malignant. 

Endocrinologists in North America rarely recommend surgery as the first treatment for Graves’ disease.

How radioactive iodine treats Graves’ disease

This brings us to RAI therapy, where radioactive iodine is taken to destroy the thyroid gland gradually and cause hypothyroidism, or an underactive thyroid, which you can then manage with daily medication. 

How well and how fast this treatment works depends on the goiter size, the uptake of the iodine, and the degree of hyperthyroidism. 

Usually, people become hypothyroid within two to three months³ of receiving a single dose of RAI. About 10% of⁴ people require a second dose before reaching hypothyroid status.

Risks of radioactive iodine treatment

Despite radioactive iodine therapy being a second-line treatment in the USA, it still comes with some risks and complications you should consider. 

RAI's early side effects can include a sore throat; thyroiditis occurs in about 1% of patients.² This causes a temporary increase in thyroid hormone production and requires medication. 

It’s generally thought that RAI can worsen thyroid eye disease, which can result in bulging of the eye, double vision, and sensitivity to light. Vision loss can occur in severe cases. 

Radioactive iodine treatment is not recommended during pregnancy or for women trying to conceive. 

You should wait a minimum of six months² following treatment before trying to conceive. 

If you’re breastfeeding or have ceased breastfeeding within the previous six weeks, you are advised not to have radioactive iodine treatment. 

You should speak with your obstetrician about these issues for specific guidance.

The lowdown

Graves’ disease is a common autoimmune condition that should be diagnosed and treated quickly to avoid long-term complications. 

There are three treatment options for Graves’ disease: antithyroid medications, surgery, and radioactive iodine therapy, which is used to destroy the thyroid gland. 

Talk to your doctor if you want to understand more about radioactive iodine therapy, its efficacy, and the possible risks it might present to determine the best treatment plan.