The Physiology Of Hypercortisolism

内源性皮质醇增多症或库欣综合征与生活质量差、发病率和死亡率增加有关。早期诊断可能会减轻这种疾病的自然病史。库欣综合征的临床表现各不相同，部分与皮质醇过量的程度和持续时间有关。当皮质醇过多症严重时，其体征和症状是显而易见的。然而，库欣综合征的大多数体征和症状在普通人群中都很常见(例如高血压和体重增加)，并不是所有患者都有。除了糖皮质激素过多的典型特征，如近端肌肉无力和宽大的紫纹外，患者还可能出现由皮质醇增多引起的相关合并症。这些疾病包括心血管疾病、血栓栓塞症、精神和认知障碍以及感染。因此，内科医生和全科医生必须考虑库欣综合征是一个原因，内分泌科医生应该寻找和治疗这些并存。推荐的筛查库欣综合征的测试包括1毫克地塞米松抑制、尿游离皮质醇和深夜唾液皮质醇。在生理性皮质醇增多的患者中，这些指标可能会略有升高，这应该被排除在外，同时使用外源性糖皮质激素。每个筛查测试都有警告，测试的选择应该根据每个患者的特征和生活方式进行个性化。我们还发现，库欣综合征患者的甲状腺功能可能异常，在服用外源性糖皮质激素的患者中必须谨慎解释。

Endogenous pathologic hypercortisolism, or Cushing's syndrome, is associated with poor quality of life, morbidity, and increased mortality. Early diagnosis may mitigate against this natural history of the disorder. The clinical presentation of Cushing's syndrome varies, in part related to the extent and duration of cortisol excess. When hypercortisolism is severe, its signs and symptoms are unmistakable. However, most of the signs and symptoms of Cushing's syndrome are common in the general population (e.g., hypertension and weight gain) and not all are present in every patient. In addition to classical features of glucocorticoid excess, such as proximal muscle weakness and wide purple striae, patients may present with the associated comorbidities that are caused by hypercortisolism. These include cardiovascular disease, thromboembolic disease, psychiatric and cognitive deficits, and infections. As a result, internists and generalists must consider Cushing's syndrome as a cause, and endocrinologists should search for and treat these comorbidities. Recommended tests to screen for Cushing's syndrome include 1 mg dexamethasone suppression, urine free cortisol, and late night salivary cortisol. These may be slightly elevated in patients with physiologic hypercortisolism, which should be excluded, along with exogenous glucocorticoid use. Each screening test has caveats and the choice of tests should be individualized based on each patient's characteristics and lifestyle. We have also found that thyroid functions may be abnormal in Cushing's syndrome and must be interpreted with care in patients taking exogenous glucocorticoids.