甲状腺激素抑制试验对甲状腺肿大的鉴别诊断

The Differential Diagnosis of Thyroid Enlargement by Thyroid Hormones Suppression Test

目的:探寻应用甲状腺激素抑制试验对甲状腺肿大的病因进行鉴别诊断的意义。方法:对101例甲状腺肿大患者行甲状腺摄^(131)I率测定后,口服“左旋甲状腺素钠”片7d,然后口服3倍剂量^(131)I,再次测定甲状腺摄^(131)I率。以第24h摄^(131)I率计算抑制率,以抑制率是否大于50％作为判断摄^(131)I率是否明显受抑制的标准。结果:101例患者第1次摄^(131)I率均高于本地正常值水平,甲状腺激素抑制试验显示抑制率>50％共59例,占58.42％;抑制率<50％共42例,占41.58％。化验甲状腺激素正常67例中,抑制率<50％共17例,占25.37％;抑制率>50％共50例,占74.63％。甲状腺激素升高34例中抑制率<50％共25例,占73.53％;抑制率>50％共9例,占26.47％。第1次摄^(131)I率高峰前移6例中抑制率>50％及<50％各3例。结论:甲状腺激素抑制试验对甲状腺肿大的病因的鉴别诊断安全可靠,可确定是否为甲亢所致。但费时及麻烦,建议在诊断困难时选择性地开展此项检查。

Objective: To explore the significance of thyroid hormones suppression test in finding the cause of thyroid enlargement in differential diagnosis. Method: 101 cases with thyroid enlargement took sodium levothyroxine tablets in the next 7 days ofter the first131 I uptake rate test was done, then took131 I three times as much as the dose of the first one, and gave another 131 I uptake test, the rate of suppression is counted from the131 I intake rate 24 hours later. Result: The131 I uptake rale shown in the first time was higher than the auerage of the locality, and suppression test of thyroid hormones shows that in 59 cases (58. 42% of the total cases) suppression rate is greater than 50% , and in the rest 42 cases(41.58% of the total cases) the suppression rate is less than 50%, The test in 67 cases with normal thyroid hormones shows that 17 of them (25.37% ) haue a suppression rate of less than 50%, and the other 50 cases (74. 63%) have a suppression rate of over 50% . In 34 cases with higher thyroid hormone, 25 cases (43.53% ) of them have a sup-presion rate of less than 50% , and the rest 9 cases (26.47%) have a suppression rate of higher than 50% . In the 6 cases with apex time earlier than usual in the first131 I uptake rate, half of them have a suppression rate of over 50% , and the other half, less than 50% . Conclusion: The suppression test on thyroid hormone is safe and reliable in making differential diagnosis on thyroid enlargement so as to determine whether the enlargement is caused by hyperparathyroidism. It is, however, time-taking and inconvenient. Therefore, it is advisable to do this test only when confirmed diagnosis is hard to get by other methods.