Endocrine Abstracts

Thyrotoxicosis is a common disorder affecting up to 3% of the UK population and Graves’ disease is the most common aetiology. Clinically relevant thyroid eye disease is present in 25–50% of patients with Graves’ disease causing significant disfigurement and morbidity in 5–10% of patients. At the onset of ophthalmopathy, 80–90% of patients have hyperthyroidism, with the rest having euthyroidism or hypothyroidism. Risk factors for development of eye complications include severe biochemical hyperthyroidism and cigarette smoking.

The treatment options for Graves’ disease include a prolonged course of antithyroid drugs, the administration of radioiodine and total thyroidectomy. Radioiodine therapy has been associated with development or worsening of Graves’ ophthalmopathy and steroid prophylaxis is effective in prevention of progression of pre-existing ophthalmopathy. Development of hypothyroidism is another risk factor for development or worsening of thyroid eye disease and should be avoided through prompt T₄ replacement therapy.

Radioiodine treatment is not recommended for patients with active eye disease, whereas steroid prophylaxis is recommended for patients with clinically apparent but stable or quiescent eye disease. Typical steroid regimens involve a high dose of oral glucocorticoids for 2 months, but lower doses given for 6 weeks could be equally effective. Prophylactic steroid treatment is not recommended for patients without evidence of ophthalmopathy because of the low absolute risk of developing severe eye disease after radioiodine.

Patients who smoke are at a higher risk of worsening of Graves’ ophthalmopathy than non-smokers, regardless of the type of treatment given. A consensus statement recommends routine steroid prophylaxis in smokers given radioiodine treatment, even if signs of eye disease are absent. This symposium will review the current evidence and international guidance regarding the prevention of thyroid eye disease following radioiodine administration.