Findling James W, Kehoe Michael E, Raff Hershel
Endocrine-Diabetes Center, St. Luke's Medical Center, Milwaukee, Wisconsin 53215, USA.
J Clin Endocrinol Metab. 2004 Dec;89(12):6005-9. doi: 10.1210/jc.2004-1378.
Inferior petrosal sinus sampling for ACTH differentiates pituitary ACTH-dependent Cushing's (CD) from the ectopic ACTH syndrome (EAS). Petrosal sinus to peripheral (IPS:P) ACTH ratios greater than 2.0 in the basal state or a peak greater than 3.0 after CRH are diagnostic of CD. However, false-negative rates of 1-10% have been reported. We report three patients with features of CD with peak IPS:P ACTH ratios less than 3.0 after CRH suggesting EAS. We compared IPS:P prolactin (PRL) as an index of pituitary venous effluent in these three index cases with 44 patients with CD and five with EAS. The dominant basal IPS:P PRL ratio was greater than 1.8 in all 49 patients but was less than 1.2 in the three index cases. The IPS:P ACTH ratio normalized to IPS:P PRL was greater than 0.8 in all CD patients but was less than 0.6 in EAS patients. The IPS:P ACTH ratios normalized to IPS:P PRL were greater than 1.2 in the index cases, which was similar to those with CD. The three index cases had clinical and biochemical remissions after pituitary surgery.PRL is an index of pituitary venous effluent during inferior petrosal sinus sampling in patients with CD who fail to have a peak IPS:P ACTH ratio greater than 3.0 after CRH. IPS:P PRL should be measured when results indicate EAS.
岩下窦采血检测促肾上腺皮质激素（ACTH）可区分垂体ACTH依赖性库欣综合征（CD）与异位ACTH综合征（EAS）。基础状态下岩下窦与外周血ACTH比值（IPS:P）大于2.0或促肾上腺皮质激素释放激素（CRH）刺激后峰值大于3.0可诊断为CD。然而，已有报道假阴性率为1% - 10%。我们报告了3例具有CD特征的患者，CRH刺激后IPS:P ACTH峰值小于3.0，提示为EAS。我们将这3例患者作为索引病例，与44例CD患者和5例EAS患者比较了IPS:P催乳素（PRL），以此作为垂体静脉流出指标。49例患者中，所有患者基础状态下IPS:P PRL优势比值均大于1.8，但3例索引病例小于1.2。CD患者中，IPS:P ACTH比值与IPS:P PRL的标准化比值均大于0.8，而EAS患者小于0.6。索引病例中IPS:P ACTH比值与IPS:P PRL的标准化比值大于1.2，与CD患者相似。这3例索引病例垂体手术后临床及生化指标均缓解。对于CRH刺激后IPS:P ACTH峰值未大于3.0的CD患者，PRL是岩下窦采血时垂体静脉流出指标。当结果提示为EAS时，应检测IPS:P PRL。
