Endocrine Abstracts

Introduction: Thyroid-associated ophthalmopathy (TAO) represents a common extrathyroidal manifestation of Graves’ disease, however 2-7.5% of primary hypothyroid patients can experience a form of TAO as well. This condition is a rare autoimmune disease, where auto-antibodies (anti-TSH receptor antibodies or TRAb) target antigens shared by the thyroid and the orbit. This results in the inflammation, swelling and bulging of the eyes and surrounding orbital tissues. There are no clear guidelines on how to treat TAO in hypothyroid patients, making it a challenging case to manage. However, based on the current Graves’ disease associated ophthalmopathy guidelines, there are several treatments available.

Case presentation: We present a case of a 41 year old female patient, who was admitted to our hospital in March 2023 after experiencing an acute episode of periorbital swelling of both eyes, lagophthalmos, pain, decreased ocular mobility, epiphora and chemosis. The patient, who is also suffering from a severe mental disability and is a non-smoker, was diagnosed with primary hypothyroidism one month prior, and was started on levothyroxine. The patient had no previous hyperthyroid state or radioactive iodine therapy. Laboratory investigations confirmed the primary hypothyroidism with positive thyroid peroxidase antibodies (ATPO) and anti-TSH receptor antibodies (TRAb). The orbital CT scan showed bilateral exophthalmos and some signs of optic nerves degeneration. The examination describes asymmetric involvement (left eye being more affected), chemosis, periorbital edema, exposure keratopathy.

Discussions: The ophthalmologist started the patient on an IV steroid course. After the symptoms have significantly improved, the steroid course was paused, however the condition persists even under euthyroid state. The constant high TRAb values from our patient and a lack of clear guidelines on how to treat TAO in hypothyroid patients, can explain the delay in achieving a remission. Other immunosuppressants such as the addition of oral mycophenolate to the regimen, were not taken into consideration due to the side-effects of the substances and the pre-existing anemia and altered liver function diagnoses our patient had.

Conclusion: TAO in hypothyroid patients is a rare condition, therefore early detection and treatment can help prevent sight-threatening complications. Such cases can be successfully treated with steroids, however in rare cases like this, the addition of other immunomodulatory therapy may be indicated. This step requires a close collaboration between endocrinologists and ophthalmologists.