大剂量地塞米松抑制试验不同抑制率的库欣病患者临床和生化特点分析

Clinical and biochemical characteristics of Cushing＇s disease with different suppression rates by high-dose dexamethasone

目的 分析经典大剂量地塞米松抑制试验（high-dose dexamethasone suppression test，HDDST）不同抑制率的库欣病患者临床和生化特点。方法 回顾性分析1991至2011年在解放军总医院诊治的202例库欣病患者临床资料，根据HDDST结果将患者分为抑制组（抑制率≥50%）和非抑制组（抑制率〈50%），抑制组又根据抑制率再分为A组（≥80%）和B组（50%～80%），比较3组间临床、生化和影像特点的异同。结果 （1）本组资料中，23.3%的患者HDDST中不被抑制，抑制组中A、B亚组分别占53.4%和23.3%。与抑制组-A和B比较，非抑制组病程更短、血钾水平更低。（2）库欣病常见体征中，非抑制组紫纹和下肢水肿较抑制组-A更多见；高血压和低钾血症的发生率明显高于抑制组（包括A、B亚组，P〈0.01），但糖代谢紊乱仅较抑制组-A更多见（P〈0.05）。抑制组的亚组中，抑制组-B低钾血症更多见（P〈0.05）。（3）非抑制组血清ACTH、游离皮质醇和24 h尿游离皮质醇均显著高于抑制组（包括A、B亚组），对抑制组的亚组进一步分析只有8∶00的血清皮质醇以抑制组-B更高（P〈0.05）。（4）3组垂体MRI阴性率无明显差异，阳性改变中以垂体瘤直接征象更常见；肾上腺影像特点中以双侧增生最多见，非抑制组有增多的趋势，但无显著性；肾上腺没有明显增生样改变在各组也没有显著差异，当表现为单侧增生时3组均以左侧多见，尤其是抑制组-A。结论 尽管抑制率不同，除抑制组-B的8∶00血清皮质醇更高和低钾血症多见外，抑制组各亚组间的其他临床、生化和影像特点相似，而非抑制组则具有更高的激素水平、更短的病程、更突出的体征和严重的生化异常。

Objective To analyze the clinical and biochemical characteristics of Cushing′s disease with different suppression rates by high-dose dexamethasone. Methods Two hundred and two consecutive patients with Cushing′s disease were divided into three groups according to the response to the high-dose dexamethasone suppression test（HDDST）： non-suppressed group （suppression rate 〈50%）, suppressed group A （suppression rate ≥80%） and suppressed group B （suppression rate 50%-80%）. Results （1）Of the 202 patients, non-suppressed group was seen in 23.3%（47/202）, meanwhile suppressed group A and B accounted for 53.4% and 23.3% respectively. Compared with both suppressed group A and B, non-suppressed group had shorter duration and lower serum potassium level（P〈0.01）. （2）Patients in non-suppressed group presented a higher prevalence of striae, edema of lower limbs and disorder of glucose metabolism as compared with the patients in suppressed group A. On the other hand, patients in non-suppressed group were more likely to suffer from hypertension and hypokalemia than those in both suppressed group A and B. Further analysis of prevalence of hypokalemia in suppressed group revealed significantly higher prevalence rate of hypokalemia in suppressed group B（P〈0.05）. （3）Patients in non-suppressed group also had significantly higher baseline plasma ACTH, cortisol, and 24 h urinary free cortisol than those in both suppressed group A and B. Patients in suppressed group A presented significantly higher baseline plasma cortisol levels （8∶00） as compared with patients in suppressed group B. （4）Pituitary MRI revealed no significant difference among the 3 groups, and the direct signs of pituitary tumor were more common in patients with positive pituitary imaging. Bilateral hyperplasia was the most common imaging feature of adrenal glands, and it tended to be more common of patients in non-suppressed group. No significant difference was found in findings of normal-like adrenal gland among three groups. However, unilateral hyperplasia was more common on the left, especially in the suppressed group A. Conclusion There were no significant differences in the clinical and biochemical characteristics of Cushing′s disease in both suppressed group A and B, except for a significant higher serum cortisol at 8∶00 and prevalence of hypokalemia in suppressed group B. The patients in non-suppressed group presented higher levels of the hormone, shorter duration, more typical signs of Cushing′s disease and severe biochemical abnormalities as compared with suppressed groups.