Background: After treating Graves’ disease (GD) with radioactive iodine (radioiodine) 15-20 % of patients experience worsening or occurrence of thyroid orbitopathy (TO), which can usually be prevented with glucocorticoids. In Europe there are different glucocorticoid regimens for the treatment or prevention of TO when treating patients with radioiodine, optimal regimen, however, is still unknown. Also, the optimal time for radioiodine treatment in TO patients and factors influencing the success of the first dose of radioiodine in GD patients is still not clear.
Aim: At the Department of Nuclear Medicine, UMC Ljubljana, patients with GD are often treated with radioiodine. Along with radioiodine, patients with TO or risk factors for TO are routinely given glucocorticoids in different regimens, which rather successfuly prevent TO deterioration. In our study we wanted to evaluate the effectiveness of our glucocorticoid regimens at the radioiodine treatment.
Patients and methods: In our retrospective study we collected data from medical records of all patients in whom GD first occurred between 2005 and 2009 and who were later treated with radioiodine at the Department of Nuclear Medicine, UMC Ljubljana. In a smaller group of patients with GD we also prospectively evaluated possible factors influencing the success of treatment with the first dose of radioiodine.
Results: The results of our study showed a higher success of the first dose of radioiodine in patients who were younger, had a smaller thyroid volume at the onset of GD and were less hyperthyroid at the onset of GD and at the time of radioiodine treatment. The results of our prospective study partially confirmed the results of our retrospective study – treatment with the first dose of radioiodine was more successful in patients with a smaller thyroid volume. In smokers/ex smokers, TO was active longer than in non smokers. Our short glucocorticoid regimen successfully prevented worsening of TO and decreased severity of TO after radioiodine treatment. Glucocorticoid treatment successfully prevented worsening of moderate-to-severe active TO after radioiodine treatment. The shorter the time until radioiodine treatment, the shorter the duration of TO activity, which was not influenced by number of radioiodine doses needed for successful GD treatment. After radioiodine treatment, de novo occurrence of TO was more frequent in GD patients who received several radioiodine doses.
Conclusions: Older patients and patients with a larger thyroid volume should receive higher radioiodine activity for successful treatment of GB with the first dose of radioiodine. Patients with TO should stop smoking as soon as possible. Our glucocorticoid regimens at the radioiodine treatment successfuly prevent worsening of TO and decrease severity of TO. Patients with TO should receive radioiodine as soon as possible.
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