Thyroid Eye Disease: What's New

By Rebecca S. Bahn, MD

Graves’ disease is the most common cause of an overactive thyroid in the US. It is an autoimmune condition, which means the body creates antibodies against its own tissues or organs. In this case, antibodies attack the thyroid. This makes the thyroid produce too much thyroid hormone. This condition is called hyperthyroidism [hie-per-THIGH-roid-is-m]. About 25% to 50% of those with Graves’ disease develop thyroid eye disease (TED). In people with TED, antibodies attack the thyroid and tissues behind the eyes. Since TED is only seen in patients with Graves’ disease, it is also called Graves’ ophthalmopathy [ahf-thal-MOP-a-thee] or Graves’ orbitopathy [or-bit-OP-a-thee].

Preventing and Controlling Thyroid Eye Disease

Smoking is the most important risk factor for TED. It can make you get the disease, or it can make it worse. Second-hand smoke has a similar effect. All smokers with Graves’ hyperthyroidism should be referred to a medical program to help them stop smoking. All patients with TED, regardless of whether or not they are smokers, should also avoid secondhand smoke as much as possible.

People with hyperthyroidism due to Graves’ disease usually have three treatment options: the antithyroid drug methimazole [meh-THIM-uh-zole], surgery, or radioactive iodine. Surgery and radioactive iodine result in an underactive thyroid (hypothyroidism [hie-po-THIGH-roid-is-m]). However, radioactive iodine may worsen TED. Therefore, according to recent guidelines produced by the American Association of Clinical Endocrinologists and the American Thyroid Association, smokers who already have symptoms of mild TED and who choose to receive radioactive iodine instead of methimazole or surgery should take steroids—such as prednisone—with the radioactive iodine. This will keep the eye disease from getting worse. If patients already have severe TED, they should not undergo radioactive iodine therapy at all, but should instead be treated with either thyroid surgery or methimazole. In addition, since low thyroid hormone levels following any of these treatments puts a patient at risk for TED developing or worsening, the guidelines indicate that normal levels of thyroid hormone should be achieved and maintained no matter which treatment is chosen.

Treatment of Thyroid Eye Disease

Most patients with TED experience only mild eye redness or discomfort. However, about 20% of patients with TED develop more serious symptoms, including bulging eyes (known as proptosis [prop-TOH-sis]), double vision, swelling around the eyes, or eye pain.

Most patients can be treated by controlling TSH levels, using eye drops, and going to their doctor for periodic check-ups. TED tends to get better on its own over several years. However, about 3% to 5% of TED patients get intense pain and swelling or even loss of vision. Depending on the degree of inflammation, abnormal eye muscles, eyelid problems, and visual loss, steroids such as prednisone with or without radiation (directed at the part of the skull housing the eye), eye muscle and lid surgery, or more extensive surgery called orbital decompression may be necessary.

A New Approach: Rituximab Treatment of TED

For those who do develop severe disease, there is a study at Mayo Clinic in Rochester, Minnesota, to find out whether a medication called rituximab [ri-TUK-sih-mab] might be an effective and safe treatment for patients with TED. Though rituximab does not have FDA approval as a treatment for TED, and is considered investigational for this purpose, it is currently approved and used in the treatment of other medical conditions, including the autoimmune condition rheumatoid arthritis. Because patients with rheumatoid arthritis and those with TED have similar immune system issues, researchers at Mayo Clinic are studying whether rituximab will reverse abnormalities in TED patients and improve the disease. The rituximab study is open only to patients who have moderate to severe symptoms of TED because the medication sometimes causes serious side effects, including infections and severe skin rash.

Any patient with TED interested in discussing becoming part of this study or getting treatment for TED in general is encouraged to either call or email Dr. Rebecca Bahn (507-284-2462; bahn.rebecca@mayo.edu) or Dr. Marius Stan (507-284-2463; stan.marius@mayo.edu).

Dr. Rebecca Bahn is Professor of Medicine, Consultant in Endocrinology and Metabolism and Associate Dean of Research for Career Development at Mayo Clinic. She served as President of the American Thyroid Association in 2007-2008. Dr. Bahn obtained her medical degree from Mayo Clinic College of Medicine and completed postgraduate clinical training and a research fellowship in immunology at the same institution. Her clinical practice focuses on treating patients with Graves’ hyperthyroidism and ophthalmopathy and her NIH-funded research program