Case Description
A 43-year-old female presented with right eye redness and pain of gradual onset and insidious course. She had diabetes mellitus for 25 years controlled by insulin. Her best corrected vision was 20/20 bilaterally with 12/12 color vision and no afferent pupillary defect. She had mild right ocular motility limitation. External exam showed eyelid edema and 23 mm protrusion of the right eye compared to 20 mm in the left by exophthalmometry. There was also mild right upper eyelid retraction with increased inferior scleral show (Figure 1A). Slit-lamp examination showed dilated right conjunctival vessels with normal anterior and posterior segments. Orbital MRI revealed right extraocular muscle enlargement with tendon sparing (Figure 1B). Laboratory investigations showed normal free-T3, free-T4, and thyroid-stimulating hormone (TSH) levels but positive TSH-receptor antibodies and she was diagnosed with unilateral active thyroid-related eye disease (TED) and prescribed 60 mg/day of oral prednisone. After 2 weeks, however, she was intolerant to steroid due to uncontrollable blood sugar levels and was rapidly tapered off treatment and prescribed 10 mg of methotrexate weekly as monotherapy. Six months later she experienced marked improvement (Figure 1C) and was gradually tapered off methotrexate without relapse.
TED usually occurs with hyperthyroidism but can also rarely occur with hypothyroidism or euthyroidism.1 It can be unilateral or bilateral, and in cases of euthyroidism, requires the detection of anti-thyroid antibodies for diagnosis. The mainstay of treatment of moderate to severe active TED is glucocorticoids, however, methotrexate monotherapy can be safe and effective in cases of glucocorticoid intolerance.2