库欣综合征中2mg地塞米松抑制试验两种诊断标准的准确性研究

Accuracy of two cut-off points in 2 mg dexamethasone suppression test in diagnosis of Cushing's syndrome

目的评价2mg地塞米松抑制试验(DST)以血清皮质醇水平或抑制率为切点诊断库欣综合征的准确性。方法收集经手术后病理学检查明确病因的163例库欣综合征患者的临床资料。回顾并记录患者基础8:00血清皮质醇水平及2mgDST后血清皮质醇绝对值,计算抑制率。分别以血清皮质醇绝对值和抑制率作为2mgDST对库欣综合征的诊断切点,分析两者与患者术后病理学诊断的符合率,评价诊断的准确性。结果经术后病理学检查证实,163例库欣综合征患者中库欣病94例,肾上腺皮质瘤63例,异位促肾上腺皮质激素(ACTH)综合征6例。以2mgDST后血清皮质醇>5μg/dL为切点,诊断库欣病88例,肾上腺皮质瘤63例,异位ACTH综合征6例,与病理学诊断的符合率为96.3%;以2mgDST后抑制率<50%为切点,诊断库欣病68例,肾上腺皮质瘤63例,异位ACTH综合征6例,与病理学诊断的符合率为84.0%。结论与2mgDST后抑制率<50%相比,以血清皮质醇>5μg/dL为切点诊断库欣综合征的准确性更高。

Objective To evaluate the accuracy of 2 mg dexamethasone suppression test（DST）with serum cortisol or inhibition rate as cut-off points in diagnosis of Cushing＇s syndrome.Methods The clinical data of 163 patients with Cushing＇s syndrome confirmed by pathological examinations after operation were collected.The baseline serum cortisol levels at 8：00 and serum cortisol levels after 2 mg DST were recorded,and inhibition rates were calculated.Serum cortisol level and inhibition rate were served as cut-off points for diagnosis of Cushing＇s syndrome in 2 mg DST,and coincidence with pathological diagnosis was analysed.Results Pathological examinations after operation confirmed that there were 94 cases of Cushing disease,63 cases of corticosuprarenaloma and 6 cases of ectopic adrenocorticotropic hormone（ACTH）syndrome among 163 cases of Cushing syndrome.With serum cortisol 5 g/dL after 2 mg DST as cut-off point,88 cases of Cushing disease,63 cases of corticosuprarenaloma and 6 cases of ectopic ACTH syndrome were diagnosed,and coincidence with pathological diagnosis was 96.3%.With inhibition rate 50% after 2 mg DST as cut-off point,68 cases of Cushing disease,63 cases of corticosuprarenaloma and 6 cases of ectopic ACTH syndrome were diagnosed,and coincidence with pathological diagnosis was 84.0%.Conclusion Compared with inhibition rate 50% after 2 mg DST as cut-off point,serum cortisol 5 g/dL after 2 mg DST as cut-off point may yield higher accuracy in diagnosis of Cushing＇s sydrome.