Radioiodine Therapy and Graves' Ophthalmopathy

Abstract

Appearances of and increases in Graves' ophthalmopathy (GO) have been reported after treatment of patients with hyperthyroidism with radioiodine. We sought to determine the rates of appearance or increase in manifestations of GO in American patients treated with radioiodine for hyperthyroidism. Methods: The study population, which consisted of 76 patients (range, 10.6-72 y), included 61 women and individuals of diverse ethnicity. The patients were followed for 1 y after radioiodine treatment. The clinical activity score (CAS) included 10 items of ophthalmic change that were evaluated at 2 and 6 mo and at 1 y; appearance of a new item scored 1 point. We evaluated interactions of 6 covariates-prolonged hyperthyroidism, prolonged hypothyroidism, smoking, treatment with an antithyroid drug (ATD), and serum levels of thyroid-stimulating immunoglobulin (TSI) and of high free T 3 (FT 3 )-with the numbers of patients with 2 or more CAS points and with exophthalmometer readings increased by at least 2 mm. In addition, patients completed a scored quality-of-life (QOL) questionnaire at baseline and at 1 y to assess eye symptoms. Results: The mean CAS points for all patients at 2 mo was 0.63 and was not significantly different at 1 y. In 9 of 10 CAS items, there were few patients affected at 1 y and for the most part there were fewer patients affected than at baseline. However, exophthalmometer readings increased in 39% of patients by a mean of 2.6 mm. Individual patients frequently exhibited increases and decreases in item manifestations. Exophthalmometer readings decreased by 2 mm or less in 13%. Of the covariates, only hyperthyroidism prolonged by at least 2.5 mo was significantly associated with 2 or more CAS points at 1 y; no covariate was significantly associated with the development of increased exophthalmometer readings. Eye symptoms recorded in the QOL were insignificantly improved over the year; symptoms did not correlate with CAS points or with exophthalmometer readings. Conclusion: After radioiodine treatment, no substantial change was seen in manifestations of CAS items except for a modest increase in exophthalmometer readings in 39% of patients. Manifestations of CAS items frequently appeared and disappeared. Prolonged hyperthyroidism is best avoided. Ocular symptoms were insignificantly fewer at 1 y after radioiodine therapy. The observed changes do not warrant prophylactic treatment of patients with steroids.

Greater Efficacy of Total Thyroidectomy versus Radioiodine Therapy on Hyperthyroidism and Thyroid-Stimulating Immunoglobulin Levels in Patients with Graves’ Disease Previously Treated with Antithyroid Drugs

“…However, the difference between both groups did not remain significant, likely because our study was not designed and powered enough to specifically address this question. It is now well established that worsening of GO may occur after RAI administration [6,7,8,9], but there is no clear consensus about the need for prophylactic use of glucocorticoids when RAI has to be given to patients with preexisting GO [25,26]. Some advocate steroid administration only in the presence of risk factors such as smoking, high TSI levels, severe preexisting GO or high levels of FT 3 before treatment [8,24,27].…”

Glucocorticoid Regimens for Prevention of Graves' Ophthalmopathy Progression Following Radioiodine Treatment: Systematic Review and Meta-Analysis

“…However, its use is limited by the potential risk of development or worsening of Graves' ophthalmopathy (GO) following therapy. While several reports did not demonstrate progression of GO following RAI (1,2), many more found a significant association between RAI and the development or the worsening of preexisting GO, including one systematic review (3)(4)(5)(6)(7). GO progression after RAI is more likely to occur in patients who already have GO prior to therapy, smoke, have severe hyperthyroidism, high levels of thyrotropin receptor antibody (TRAb), short duration of disease, or whose post-RAI hypothyroidism is not promptly corrected by levothyroxine replacement therapy (8,9).…”

Radioactive Iodine Therapy and Thyroid Eye Disease From an Ophthalmologist’s Perspective

“…24 Another group used the full 10-item CAS and designated an increase of 2 points as progression. 23 Träisk et al 17 used their own ''Clinical TAO Assessment Score'' with TAO points from 0 to 3 in chemosis, eyelid edema, redness, Hertel increase, impaired eye movement, corneal involvement, and visual impairment. A number of studies simply stated application of NOSPECS 12,19,22,38 and others described the components of the full ophthalmological evaluation.…”

“…The total change in CAS scores over the 1-year period was insignificant, however, and authors concluded that there is no evidence of progression of TAO attributable to RAI. 23 Subsequent studies included direct comparison with antithyroid medications. El-Kaissi et al 24 published a prospective study wherein no evidence of new occurrence or progression of TAO was found by CAS and MRI in 24 post-RAI patients compared with carbimazole-treated patients, despite significantly elevated TSH levels post-RAI.…”