Pseudo-Cushing's syndrome

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Overview
Pseudo-Cushing's syndrome is a medical condition in which patients display the signs, symptoms, and abnormal hormone levels seen in Cushing's syndrome. Pseudo-Cushing's syndrome, however, is not caused by a problem with the hypothalamic-pituitary-adrenal axis as Cushing's is. It is an idiopathic condition.

Investigations

 * Levels of cortisol and ACTH are both high
 * 24-hour urinary cortisol levels are high
 * Dexamethasone suppression test fails to suppress serum cortisol
 * Loss of diurnal variation in cortisol levels- Loss of Diurnal Variation is seen only in true Cushing's Syndrome or Disease.
 * High mean corpuscular volume and gamma-glutamyl transferase may be clues to alcoholism
 * Polycystic Ovarian Syndrome should be ruled out, since PCOS has similar symptoms.

Differential diagnosis

 * Differentiation from Cushing's is extremely difficult
 * Causes of Cushing's should be excluded with imaging of the lungs, adrenal glands, and pituitary gland - but these often appear normal in Cushing's anyway
 * In the alcoholic patient with pseudo-Cushing's, admission to hospital (and avoidance of alcohol) will result in normal midnight cortisol levels within 5 days, excluding Cushing's

Prognosis

 * Blood results and symptoms normalise rapidly on cessation of drinking or remission of depression