Cushing's Syndrome: Screening and Diagnosis

Endogenous Cushing's syndrome (CS) is a rare disease, and usually characterized by hypertension, diabetes, obesity, osteoporosis, facial rounding, dorsocervical fat pad, thin skin, purple striae, hirsutism, and mood disorders. Efficient diagnostic and screening strategies lead to the diagnosis of a significantly higher number of cases of CS. As a screening test for CS, the Endocrine Society's Clinical Practice Guidelines recommend a single test with a high diagnostic accuracy, among the 1-mg dexamethasone suppression test (1-mg DST), late night salivary cortisol (LNSC), and 24 h urinary free cortisol (UFC). In normal subjects, administering a higher than physiological dose of glucocorticoids prompts the suppression of cortisol secretion. The 1-mg DST explores this normal feedback reaction from the hypothalamic-pituitary-adrenal axis (HPA). It is a simple dynamic test, usually performed in outpatients. A morning serum cortisol level