The Diagnosis and Differential Diagnosis of Cushing’s Syndrome and Pseudo-Cushing’s States

I. Introduction II. Definitions and Etiology III. Diagnostic Overview IV. Clinical Features V. Biochemical Diagnosis of Cushing’s Syndrome A. Cardinal features B. Urinary free cortisol (UFC) C. Low-dose dexamethasone testing D. Circadian rhythm assessment E. Cyclical Cushing’s syndrome VI. ACTH-Dependent vs. ACTH-Independent Cushing’s Syndrome VII. Differential Diagnosis of ACTH-Dependent Cushing’s Syndrome A. Overview B. Basal testing C. Dynamic noninvasive testing D. Invasive testing VIII. Other Causes of Cushing’s Syndrome IX. Imaging A. Pituitary B. Adrenal C. Ectopic secretion X. Differentiation from Pseudo-Cushing’s States XI. Conclusions