Alexander Erik K, Larsen P Reed
Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
J Clin Endocrinol Metab. 2002 Mar;87(3):1073-7. doi: 10.1210/jcem.87.3.8333.
Radioactive iodine ((131)I) has become the most widely used therapy for patients with hyperthyroidism caused by Graves' disease in the United States. There remains, however, significant variability among (131)I dosing regimens, and it is clear that most patients ultimately develop hypothyroidism after therapy. To avoid persistent hyperthyroidism, we adopted a high dose (131)I therapy protocol based on measurement of 24-h thyroid (123)I uptake designed to deliver 8 mCi (296 MBq) to the thyroid gland 24 h after (131)I administration. To evaluate the efficacy of this protocol, we reviewed our clinical experience over a 7-yr period. We treated 261 patients (219 women and 42 men) with hyperthyroidism caused by Graves' disease with (131)I [mean dose, 14.6 mCi (540 MBq)] between 1993 and 1999. Before treatment, 207 (79%) had received an antithyroid drug (109 propylthiouracil and 98 methimazole). We determined their thyroid status 1 yr after treatment in relation to age, pretreatment with an antithyroid drug, pretreatment thyroid size, and dose of (131)I retained in the thyroid 24 h after treatment. Among the 261 patients, 225 (86%) were euthyroid or hypothyroid 1 yr after treatment, and 36 patients (14%) had persistent hyperthyroidism and required a second treatment. The patients who had persistent hyperthyroidism were younger (P < 0.01), had larger thyroid glands (P < 0.01), higher pretreatment thyroid (123)I uptake values (P < 0.01), and higher serum T(4) concentrations (P < 0.01) and were more likely to have taken antithyroid medication before administration of (131)I (P = 0.01). Five of these patients developed transient hypothyroidism, followed by thyrotoxicosis. There was an asymptotic, inverse relationship between the retained dose of (131)I at 24 h and persistent hyperthyroidism, revealing a 5-10% failure rate despite delivery of up to 400 microCi (14.8 MBq)/g. A dose of (131)I that results in accumulation of 8 mCi (296 MBq) in the thyroid gland 24 h after administration is an effective treatment for the majority of patients with Graves' hyperthyroidism. Young patients with larger thyroid glands, higher serum T(4) concentrations, and higher 24-h thyroid (123)I uptake values, and those pretreated with antithyroid medication for greater than 4 months are at higher risk for treatment failure. A higher dose of (131)I may be advisable in such patients.
放射性碘（¹³¹I）已成为美国治疗格雷夫斯病所致甲状腺功能亢进症患者最广泛使用的疗法。然而，¹³¹I给药方案之间仍存在显著差异，并且很明显大多数患者在治疗后最终会发展为甲状腺功能减退。为避免持续性甲状腺功能亢进，我们采用了基于24小时甲状腺¹²³I摄取量测量的高剂量¹³¹I治疗方案，旨在¹³¹I给药后24小时向甲状腺输送8毫居里（296兆贝可）。为评估该方案的疗效，我们回顾了7年期间的临床经验。1993年至1999年期间，我们用¹³¹I[平均剂量，14.6毫居里（540兆贝可）]治疗了261例格雷夫斯病所致甲状腺功能亢进症患者（219名女性和42名男性）。治疗前，207例（79%）曾接受过抗甲状腺药物治疗（109例服用丙硫氧嘧啶，98例服用甲巯咪唑）。我们在治疗1年后根据年龄、抗甲状腺药物预处理情况、治疗前甲状腺大小以及治疗后24小时甲状腺内保留的¹³¹I剂量来确定他们的甲状腺状态。在这261例患者中，225例（86%）在治疗1年后甲状腺功能正常或减退，36例（14%）有持续性甲状腺功能亢进，需要进行第二次治疗。有持续性甲状腺功能亢进的患者更年轻（P<0.01），甲状腺更大（P<0.01），治疗前甲状腺¹²³I摄取值更高（P<0.01），血清T₄浓度更高（P<0.01），并且在¹³¹I给药前更有可能服用过抗甲状腺药物（P = 0.01）。其中5例患者出现短暂性甲状腺功能减退，随后发生甲状腺毒症。治疗后24小时¹³¹I的保留剂量与持续性甲状腺功能亢进之间存在渐近的反比关系，这表明尽管每克输送高达400微居里（14.8兆贝可），仍有5 - 10%的失败率。给药后24小时甲状腺内积聚8毫居里（296兆贝可）的¹³¹I剂量对大多数格雷夫斯甲状腺功能亢进症患者是一种有效的治疗方法。甲状腺更大、血清T₄浓度更高、24小时甲状腺¹²³I摄取值更高的年轻患者以及接受抗甲状腺药物预处理超过4个月的患者治疗失败风险更高。对于此类患者，可能建议使用更高剂量的¹³¹I。
