Meinardi J R, Wolffenbuttel B H R, Dullaart R P F
Department of Internal Medicine, Canisius Wilhelmina Ziekenhuis, 6500 GS, Nijmegen, The Netherlands.
Eur J Endocrinol. 2007 Sep;157(3):245-54. doi: 10.1530/EJE-07-0262.
Cyclic Cushing's syndrome (CS) is a rare disorder, characterized by repeated episodes of cortisol excess interspersed by periods of normal cortisol secretion. The so-called cycles of hypercortisolism can occur regularly or irregularly with intercyclic phases ranging from days to years. To formally diagnose cyclic CS, three peaks and two troughs of cortisol production should be demonstrated. Our review of 65 reported cases demonstrates that cyclic CS originates in 54% of cases from a pituitary corticotroph adenoma, in 26% from an ectopic ACTH-producing tumour and in about 11% from an adrenal tumour, the remainder being unclassified. The pathophysiology of cyclic CS is largely unknown. The majority of patients with cyclic CS have clinical signs of CS, which can be either fluctuating or permanent. In a minority of patients, clinical signs of CS are absent. The fluctuating clinical picture and discrepant biochemical findings make cyclic CS extremely hard to diagnose. Clinicians should therefore be aware of this clinical entity and actively search for it in all patients with suspected CS but normal biochemistry or vice versa. Frequent measurements of urinary cortisol or salivary cortisol levels are a reliable and convenient screening tool for suspected cyclic CS. Cortisol stimulation or suppression tests may give spurious results owing to spontaneous falls or rises in serum cortisol at the time of testing. When cyclic CS is biochemically confirmed, further imaging and laboratory studies are guided by the presence or absence of ACTH dependency. In cases of suspected ectopic ACTH production, specific biochemical testing for carcinoids or neuroendocrine tumours is required, including measurements of serotonin in platelets and/or urine, chromogranin A and calcitonin.
周期性库欣综合征（CS）是一种罕见的疾病，其特征是皮质醇分泌过多反复发作，其间穿插着皮质醇分泌正常的时期。所谓的皮质醇增多症周期可规律或不规律地出现，周期间期从数天到数年不等。要正式诊断周期性CS，应证明皮质醇分泌有三个峰值和两个谷值。我们对65例报告病例的回顾表明，周期性CS在54%的病例中起源于垂体促肾上腺皮质激素腺瘤，26%起源于异位促肾上腺皮质激素分泌肿瘤，约11%起源于肾上腺肿瘤，其余病例未分类。周期性CS的病理生理学在很大程度上尚不清楚。大多数周期性CS患者有CS的临床体征，这些体征可能是波动的或持续的。少数患者没有CS的临床体征。临床症状的波动和生化检查结果的不一致使得周期性CS极难诊断。因此，临床医生应了解这种临床实体，并在所有疑似CS但生化检查正常的患者中积极寻找，反之亦然。频繁测量尿皮质醇或唾液皮质醇水平是疑似周期性CS的可靠且便捷的筛查工具。由于检测时血清皮质醇会自发下降或升高，皮质醇刺激或抑制试验可能会给出假结果。当生化检查确诊为周期性CS时，进一步的影像学和实验室检查根据是否存在促肾上腺皮质激素依赖性来指导。在疑似异位促肾上腺皮质激素分泌的病例中，需要对类癌或神经内分泌肿瘤进行特定的生化检查，包括测量血小板和/或尿液中的5-羟色胺、嗜铬粒蛋白A和降钙素。
