From the Guidelines
Yes, exophthalmos can still develop or persist even when hyperthyroidism is being treated medically. This occurs because Graves' ophthalmopathy, which causes exophthalmos, is an autoimmune process that can progress independently of thyroid hormone levels 1. Medical treatments for hyperthyroidism such as methimazole, propylthiouracil (PTU), or radioactive iodine control the thyroid hormone production but don't directly address the orbital inflammation.
Key Points to Consider
- In fact, some patients develop eye symptoms before, during, or even after their thyroid function has been normalized with treatment.
- For patients with eye involvement, additional therapies may be needed, including:
- Lubricating eye drops
- Selenium supplements (200 mcg daily) in patients with selenium deficiency, as it has been shown to reduce some inflammatory symptoms in patients with milder TED 1
- Corticosteroids (such as prednisone)
- Orbital radiation
- Even surgery in severe cases, such as orbital decompression or strabismus repair
- Smoking cessation is crucial as smoking worsens eye disease and reduces treatment effectiveness 1.
- Regular monitoring of eye symptoms is important even when thyroid function tests are normal, and patients should report any changes in vision, eye pain, or increasing protrusion promptly to their healthcare provider.
- Teprotumumab, a human monoclonal antibody inhibitor of IGF-IR, has been shown to reduce proptosis and the clinical activity score of disease in many patients with active TED, and may be considered as a treatment option for patients with severe proptosis or compressive optic neuropathy 1.
From the Research
Development of Exophthalmos in Hyperthyroidism
- The development of exophthalmos in hyperthyroidism is a complex process that is not fully understood, and its relationship with medical treatment of hyperthyroidism is still being researched 2, 3, 4.
- According to a study published in 1996, the development or worsening of ophthalmopathy was not associated with relapse per se, but was associated with high serum T3 levels, especially when treated with iodine-131 4.
- Another study published in 2022 found that long-term continuation of low-dose methimazole therapy was effective and safe in preventing recurrent hyperthyroidism in patients with Graves' hyperthyroidism, but did not specifically address the development of exophthalmos 5.
- A review article published in 2016 noted that therapies for Graves' hyperthyroidism are largely imperfect, but did not provide specific information on the development of exophthalmos in patients receiving medical treatment for hyperthyroidism 6.
- A study published in 1993 found that the frequency of cases treated with radioiodine was considerably higher in patients with recurrence and in the elderly, and that the therapy duration was not pre-determined, but did not provide information on the development of exophthalmos in patients receiving medical treatment for hyperthyroidism 3.
Medical Treatment of Hyperthyroidism
- Medical treatment of Graves' hyperthyroidism is based on the use of thionamides, such as methimazole and propylthiouracil 2.
- Thionamides are effective for short-term control of Graves' hyperthyroidism, but a relatively high proportion of patients relapse after thionamide withdrawal 2.
- Other possible medical treatments for hyperthyroidism include iodine and compounds containing iodine, perchlorate, lithium, β-adrenergic antagonists, and glucocorticoids 2.