Cushing syndrome (CS) is a combination of symptoms and signs caused by chronic high blood levels of cortisol. Cushing disease is a type of Cushing syndrome that results from excessive pituitary production of adrenocorticotropic hormone (ACTH) by pituitary adenoma and is the most common cause of endogenous hypercortisolism. Typical symptoms and signs of CS include moon face and truncal obesity, easy bruising, wide purple striae and proximal muscle weakness. Many patients will also have type 2 diabetes and hypertension. Diagnosis is made by confirming elevated serum cortisol levels using a dexamethasone suppression test, serum or salivary mid-night cortisol levels or elevated 24 hours urinary free cortisol concentration. When endogenous hypercortisolism is confirmed, ACTH level guides further investigations. An elevated ACTH suggests pituitary or ectopic source of hypercortisolism and CRH (corticotrophin releasing hormone) stimulation test and inferior petrosal sinus sampling helps differentiate the source of elevated ACTH and guides appropriate imaging modality. Treatment of Cushing disease depends on the cause of disease and includes pituitary surgery, radiotherapy, medical treatment with mainly steroidogenesis inhibitors, or bilateral adrenalectomy in very unwell patients.
See Cushing syndrome in The Manuals.
References
Jaemeson JL, de Groot LJ. Handbook of Endocrinology, Adult and Pediatric, 7th ed., Vol 2. Philadelphia, PA: Saunders; 2015:227-256.
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