Boscaro Marco, Arnaldi Giorgio
Division of Endocrinology, Polytechnic University of Marche, 60126 Ancona, Italy.
J Clin Endocrinol Metab. 2009 Sep;94(9):3121-31. doi: 10.1210/jc.2009-0612.
Clinical decision making for patients with suspect hypercortisolism involves a complex diagnostic assessment. Cushing's syndrome remains one of the most challenging endocrine pathologies. Most clinical features overlap with those of common diseases found in the general population, and some patients have an atypical clinical presentation with only isolated symptoms. Recently, several studies have suggested that the prevalence of Cushing's syndrome is higher than previously thought. Therefore, efficient screening tests are needed to identify the few uncovered patients also among unselected high-risk ambulatory patients with disorders potentially related to cortisol excess. The recommended diagnostic tests are 24-h urinary free cortisol, 1-mg overnight dexamethasone suppression test, and late-night salivary cortisol. Once the diagnosis of Cushing's syndrome is established, the next step is the measurement of plasma ACTH. Then, dynamic test and appropriate imaging procedures are the most useful noninvasive investigations for the differential diagnosis. Patients with Cushing's disease are generally responsive to the CRH test and to high-dose glucocorticoid feedback. Bilateral inferior petrosal sinus sampling is considered the gold standard for establishing the origin of ACTH secretion, and it is recommended in patients with ACTH-dependent Cushing's syndrome whose clinical, biochemical, or radiological studies are discordant or equivocal. The present clinical case shows that even if rare, the ectopic ACTH secretion should be considered also in those cases where the pretest probability is low. The management of Cushing's syndrome depends on the exact knowledge of its various causes, paying attention to the many potential diagnostic pitfalls. The choice of test, the modality of specimen collection (blood, urine, and saliva), the quality of measurement (assay methodology and standardization), and close dialogue among endocrinologists, chemical pathologists, and neuroradiologists are key factors for optimal care of patients.
对于疑似皮质醇增多症患者的临床决策需要进行复杂的诊断评估。库欣综合征仍然是最具挑战性的内分泌疾病之一。大多数临床特征与普通人群中常见疾病的特征重叠，一些患者临床表现不典型，仅有孤立症状。最近，多项研究表明库欣综合征的患病率高于此前认为的水平。因此，需要有效的筛查试验来识别那些未被发现的患者，即使是在未经过选择的、患有可能与皮质醇过量相关疾病的高危门诊患者中。推荐的诊断试验包括24小时尿游离皮质醇、1毫克过夜地塞米松抑制试验和午夜唾液皮质醇测定。一旦确诊为库欣综合征，下一步是测定血浆促肾上腺皮质激素（ACTH）。然后，动态试验和适当的影像学检查是鉴别诊断最有用的非侵入性检查。库欣病患者通常对促肾上腺皮质激素释放激素（CRH）试验和高剂量糖皮质激素反馈有反应。双侧岩下窦采血被认为是确定ACTH分泌来源的金标准，推荐用于临床、生化或影像学研究结果不一致或不明确的促肾上腺皮质激素依赖性库欣综合征患者。本临床病例表明，即使罕见，在那些预先测试概率较低的病例中也应考虑异位ACTH分泌。库欣综合征的治疗取决于对其各种病因的确切了解，同时要注意许多潜在的诊断陷阱。检查的选择、标本采集方式（血液、尿液和唾液）、测量质量（检测方法和标准化）以及内分泌学家、化学病理学家和神经放射学家之间的密切沟通是为患者提供最佳治疗的关键因素。
