Methimazole is most appropriate for this patient with Graves ophthalmopathy (GO). GO may be manifested by lateral gaze palsy, scleral injection, periorbital edema, and pressure sensation behind the eyes. Additional manifestations include proptosis, lid lag, and, if severe, decreased visual acuity. Excess deposition of glycosaminoglycans in the retro-orbital space results in increased pressure; the ensuing compression of the muscles and cranial nerves causes the ocular palsy. Most patients with GO have mild, nonprogressive symptoms that do not require specific treatment. The decision to treat depends upon the severity and activity of the disease. For patients who need treatment, initial therapy should target controlling the hyperthyroidism. Methimazole will rapidly lower circulating thyroid hormone levels, may reduce serum thyroid autoantibody titers, and may assist in controlling GO symptoms. Additional therapy to control symptoms includes use of ocular lubricants and taping of the eyelids at night (if the lids are unable to completely cover the eye). Because cigarette smoking increases the activity of GO and impairs the response to therapy, smoking cessation is of paramount importance.
External-beam radiotherapy is reserved for treatment of severe GO but typically is employed if symptoms persist or worsen in spite of return to the euthyroid state.
Because radioactive iodine (RAI) treatment has been associated with (at least transient) worsening of GO due to an initial increase in circulating antibody levels, its use is not recommended in patients with moderate to severe GO. When RAI is used, pretreatment with a glucocorticoid to mitigate the rise in antibody levels is recommended prior to RAI therapy.
Total thyroidectomy is typically recommended for long-term control of Graves disease in patients with active GO when medical therapy fails to induce a remission. However, returning the patient to a state of euthyroidism is advisable before surgery. Surgical decompression is also an option to control active GO, particularly if there is compression of the optic nerve.