Section of Endocrinology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA.
Thyroid. 2010 Feb;20(2):213-6. doi: 10.1089/thy.2009.0175.
Resistance to thyroid hormone (RTH) is a rare disorder in which an abnormality in the binding domain of the thyroid hormone receptor results in end-organ insensitivity to the actions of thyroid hormones. This disorder is sometimes misdiagnosed as Graves' disease due to the presence of a goiter with high Iodine-123 thyroid uptake and high levels of total and free thyroid hormones. Additionally, some patients with RTH may experience palpitations or tachycardia. There is a previous report of a patient with pituitary RTH and concurrent Graves' disease.
We describe a patient who was found to have a goiter with signs and symptoms of hyperthyroidism by his primary care physician. Work-up revealed a low thyroid stimulating hormone (TSH), high thyroid-stimulating immunoglobulins, high Iodine-123 thyroid uptake, as well as increased homogenous activity in both thyroid glands on nuclear scan and a suppressed TSH. Diagnosis of Graves' disease was made, and the patient underwent radioactive ablation of the thyroid gland. The patient subsequently developed hypothyroidism and required a much higher dose of levothyroxine than his weight-based estimate of a full replacement dose to maintain euthyroidism. On 325 micog of daily levothyroxine the patient was clinically euthyroid and had a normal TSH although his levels of T3 and T4 were high. Work-up revealed a mutation in the thyroid hormone beta-receptor gene, consistent with diagnosis of RTH.
RTH is often misdiagnosed as Graves' disease. However, these disorders can coexist, and the concurrent presence of both disorders in a patient can present diagnostic challenges. A previous report of a patient with Graves' disease associated with RTH was published before gene sequencing could be used to confirm diagnosis of RTH. We present a patient with Graves' disease and concurrent RTH that was confirmed by gene sequencing, showing a mutation in the thyroid hormone receptor beta gene.
甲状腺激素抵抗（RTH）是一种罕见的疾病，其特征是甲状腺激素受体结合域的异常导致甲状腺激素的靶器官不敏感。由于存在高碘-123 甲状腺摄取和总甲状腺激素及游离甲状腺激素水平升高的甲状腺肿，这种疾病有时会被误诊为格雷夫斯病。此外，一些 RTH 患者可能会出现心悸或心动过速。此前有一份关于垂体 RTH 合并格雷夫斯病的患者报告。
我们描述了一位被初级保健医生发现患有甲状腺肿且伴有甲亢体征和症状的患者。检查结果显示甲状腺刺激激素（TSH）低、甲状腺刺激免疫球蛋白高、碘-123 甲状腺摄取高、核扫描显示双侧甲状腺均匀活性增加且 TSH 受抑制。诊断为格雷夫斯病，患者接受了甲状腺放射性消融。随后，患者出现甲状腺功能减退，需要比根据体重估计的完全替代剂量高出很多的左旋甲状腺素剂量来维持甲状腺功能正常。在每天 325 微克左旋甲状腺素的治疗下，患者的临床甲状腺功能正常且 TSH 正常，尽管 T3 和 T4 水平升高。检查结果显示甲状腺激素β受体基因存在突变，符合 RTH 的诊断。
RTH 常被误诊为格雷夫斯病。然而，这些疾病可以同时存在，在同一位患者中同时存在这两种疾病会带来诊断挑战。此前一份关于与 RTH 相关的格雷夫斯病患者的报告是在基因测序可用于确认 RTH 诊断之前发表的。我们报告了一例 Graves 病和并发 RTH 的患者，该患者通过基因测序得到确认，显示甲状腺激素受体β基因突变。
