Prospective and Controlled Study of Ophthalmopathy After Radioiodine Therapy for Graves' Hyperthyroidism

Abstract

The effects of radioiodine (131I) therapy for hyperthyroidism on the ocular process of Graves' disease is controversial. In order to evaluate the outcome of ophthalmopathy after radioiodine therapy for thyrotoxicosis we studied prospectively 30 Graves' hyperthyroid patients, 22 submitted to radioiodine (131I) treatment (group A) and 8 treated with antithyroid drugs (group B). All patients were evaluated by clinical ophthalmologic examination, and ocular proptosis (OP) was measured with both a Hertel exophthalmometer (HE) and computed tomography (CT) before and 4 to 7 months after therapy. No statistical difference was obtained between pre- and post-treatment OP measurements in each eye in either group, and we did not observe worsening in the ophthalmopathy of patients treated with drugs or radioiodine. After therapy, there was an improvement in the clinical signs of ophthalmopathy in 59% of group A and in 37.5% of group B patients. We found a significant correlation between OP measured by HE and by CT. CT findings showed an increase in orbital fat and/or muscle thickening in all patients at baseline, proving to be a useful procedure for ophthalmologic diagnosis in doubtful cases. No patient in either group developed hypothyroidism or elevated TSH levels during the study period; this may explain our good results in the evolution of Graves' ophthalmopathy after treatment with 131I and antithyroid drugs. Euthyroidism seems to be an important factor in the outcome of ophthalmopathy after therapy, whatever the mode of treatment chosen to achieve it.

Tratamento do hipertireoidismo da Doença de Graves

“…Alguns estudos descreveram agravamento da doença ocular possivelmente secundário à liberação dos antígenos tireoidianos na circulação, favorecendo reação cruzada entre esses antígenos e fibroblastos da órbita, com infiltração da mesma pelas células T ativadas (60). No entanto outros autores observaram que o 131 I não influencia (61) tireoidismo, assim como a redução do volume glandular foi similar nos pacientes que utilizaram doses padronizadas de 131 I comparado com o uso de doses calculadas de forma mais elaborada.…”

Controversies in radioiodine therapy: relation to ophthalmopathy, the possible radioprotective effect of antithyroid drugs, and use in large goitres

“…In this last study, the course of the ophthalmopathy was worse after 131 I therapy than after subtotal thyroidectomy. Manso et al (26), in a prospective, nonrandomised study enrolling 22 patients, found no progression of the ophthalmopathy. The results of non-randomised studies, summarised in Fig.…”

Análise retrospectiva do resultado do tratamento com iodo radioativo em 120 pacientes tirotóxicos por doença de Basedow-graves

“…Posteriormente, em trabalho complementar (52) demonstraram que a reposição precoce com T4 reduz a ocorrência de oftalmopatia após emprego de radioiodo. Estudo de nossa unidade, controlado, prospectivo e empregando mensurações objetivas, não demonstrou agravamento da oftalmopatia com o radioiodo comparado ao tratamento com anti-tiroideanos (53). Recentemente, porém, outro trabalho num grande número de pacientes, apresenta resultados diferentes, indicando piora da oftalmopatia com o emprego do iodo radioativo (54).…”