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  • • Due to chronic glucocorticoid excess

    • Facial plethora, dorsocervical fat pad, supraclavicular fat pad, truncal obesity, easy bruisabilility, purple striae, hirsutism, impotence or amenorrhea, muscle weakness, and psychosis

    • Hypertension

    • Hyperglycemia

    • Includes Cushing disease (excess adrenocorticotropic hormone [ACTH] produced by pituitary adenomas) and Cushing syndrome (ectopic ACTH syndrome or primary adrenal disease resulting in glucocorticoid secretion independent of ACTH stimulation)

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Epidemiology

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  • • In children, Cushing syndrome is most commonly caused by adrenal cancers

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Symptoms and Signs

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  • • Truncal obesity, hirsutism, moon facies, acne, buffalo hump, purple striae

    • Hypertension

    • Hyperglycemia

    • Weakness

    • Depression

    • Growth retardation or arrest in children

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Laboratory Findings

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  • • Overnight, low-dose dexamethasone suppression test and measurement of urinary free cortisol establishes diagnosis

    • -No suppression and elevated urinary cortisol suggest Cushing syndrome

    • Detection of elevated midnight cortisol level suggests Cushing syndrome (midnight plasma level or late-night salivary cortisol sampling)

    • Once Cushing syndrome established, measure plasma ACTH level

    • -A repeatedly normal or elevated ACTH level suggests pituitary adenoma or ectopic ACTH secretion

      -Suppressed ACTH is diagnostic of hyperadrenocorticism due to primary adrenal disease

    • If ACTH-dependent Cushing disease and no clear pituitary lesion on MRI, may proceed to petrosal sinus sampling with corticotropin-releasing hormone (CRH) stimulation: a central to peripheral ACTH gradient suggests Cushing disease, while no gradient suggests ectopic ACTH secretion

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Imaging Findings

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  • • MRI finding of pituitary lesion suggests Cushing disease

    Cushing syndrome caused by primary adrenal diseases: Thin-section CT scan or MRI can detect virtually all adrenal tumors and hyperplasia

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  • • Rare forms of ACTH-independent Cushing syndrome include macronodular hyperplasia

    • Pigmented micronodular hyperplasia is associated with the syndrome of Carney complex (also includes cardiac myxomas and lentigines)

    • Rarely, ectopic adrenal tissue can be the source for excess cortisol secretion; most common location is along the abdominal aorta

    • Ectopic ACTH syndrome usually caused by small-cell lung cancers or carcinoids but can result from tumors of the pancreas, thyroid, thymus, prostate, esophagus, colon, ovaries, pheochromocytoma, and malignant melanoma

    • False-positive dexamethasone suppression tests seen in patients with depression, physiologic stress, marked obesity, renal failure, or taking drugs that accelerate dexamethasone metabolism (phenytoin, rifampin, phenobarbital); estrogens increase cortisol binding globulins and elevate total plasma cortisol concentrations

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  • • Complete history and physical exam

    • Overnight, low-dose dexamethasone suppression test

    • 24-hour urinary cortisol measurement

    • Plasma ACTH level

    • Directed imaging including pituitary MRI or abdominal CT or MRI

    • Potential role for petrosal sinus sampling to delineate nonvisualized pituitary source for excess ACTH

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  • • Resection is best treatment for cortisol-producing adrenal tumors or ACTH-producing tumors

    • Pituitary irradiation may be necessary if pituitary surgery fails

    • Medical treatment may be indicated to control hypercortisolism, or when patients not cured by resection or when complete resection is impossible

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Surgery

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