Thyroid-associated Ophthalmopathy

Abstract

Thyroid-associated ophthalmopathy is the most frequent extrathyroidal involvement of Graves' disease but it sometimes occurs in euthyroid or hypothyroid patients. Thyroid-associated ophthalmopathy is an autoimmune disorder, but its pathogenesis is not completely understood. Autoimmunity against putative antigens shared by the thyroid and the orbit plays a role in the pathogenesis of disease. There is an increased volume of extraocular muscles, orbital connective and adipose tissues. Clinical findings of thyroid-associated ophthalmopathy are soft tissue involvement, eyelid retraction, proptosis, compressive optic neuropathy, and restrictive myopathy. To assess the activity of the ophthalmopathy and response to treatment, clinical activity score, which includes manifestations reflecting inflammatory changes, can be used. Supportive approaches can control symptoms and signs in mild cases. In severe active disease, systemic steroid and/or orbital radiotherapy are the main treatments. In inactive disease with proptosis, orbital decompression can be preferred. Miscellaneous treatments such as immunosuppressive drugs, somatostatin analogs, plasmapheresis, intravenous immunoglobulins and anticytokine therapies have been used in patients who are resistant to conventional treatments. Rehabilitative surgeries are often needed after treatment.

Keywords: Radiotherapy; Thyroid ophthalmopathy; decompression surgery; proptosis; steroid therapy.

Figure 1. Right upper lid retraction in a 38-year-old male patient. Upper lid retraction (Dalrymple’s sign) may be one of the initial signs of thyroid-associated ophthalmopathy

Figure 2. Bilateral infiltrative thyroid-associated ophthalmopathy in a 33-year-old female patient. Hertel exophthalmometer values were 28 mm for both eyes

Figure 3. Orbital computed tomography images showing enlarged inferior and medial rectus muscles in a patient with thyroid-associated ophthalmopathy. The inferior rectus muscle is enlarged, mimicing an orbital tumor

Figure 4. Internal rotation of the left eye due to fibrosis of the left medial rectus muscle in a 55-year-old patient with thyroid-associated ophthalmopathy

Figure 5. A 61-year-old female patient with infiltrative thyroid-associated ophthalmopathy. The patient exhibted significant palpebral and conjunctival edema and reported severe pain (A). The same patient showed substantial regression of clinical signs after 3 months of intravenous corticosteroid therapy (B)

Figure 6. Coronal computed tomography of a patient with thyroid-associated ophthalmopathy (A). Coronal computed tomography images from the same patient after orbital decompression surgery (B). Postoperative images show the absence of the medial orbital wall and thinning of the cortical bone in the lateral wall