Cushing’s syndrome is the clinical picture produced by a chronic excess of glucocorticoids, the steroid hormones of the adrenal cortex, of which cortisol is the main one, whatever its source. The term Cushing’s disease is reserved for a pituitary corticotrope adenoma (a tumour of the pituitary cells that make ACTH), which is the most common endogenous cause, meaning a cause in which the patient’s own cortisol production is excessive.
The excess can originate in two ways, and that distinction organises the whole topic: a tumour that secretes adrenocorticotropic hormone (ACTH), the pituitary hormone that stimulates the adrenal cortex to make cortisol, and so drives both adrenal glands, or an adrenal gland that produces cortisol on its own. Which of the two is present decides where the tumour is sought and how it is treated.
Choose a route through the topic
Each topic answers the question that follows from the one before it: where the excess comes from, what it looks like, what it does to the heart and vessels, how it is proven and traced to its source, and how it is treated. A reader who is unfamiliar with the classification of the causes should start with the first topic, and the others then follow in the order listed.
- Causes and Classification of Cushing’s Syndrome explains where the excess comes from — the pituitary adenoma of Cushing’s disease, ectopic ACTH, the adrenal causes and the rare nodular adrenal forms — how the forms are grouped, and how common each one is.
- Clinical Manifestations of Cushing’s Syndrome describes what the excess looks like at the bedside, which findings are non-specific and which are specific, and the mineralocorticoid and central effects of a high cortisol level.
- Cardiovascular Complications of Cushing’s Syndrome explains why the cardiovascular system is the one most affected: how cortisol raises blood pressure, what it does to the heart, the prothrombotic state behind venous thromboembolism, and why cardiovascular disease dominates mortality.
- Diagnosis and Differential Diagnosis of Cushing’s Syndrome explains how the syndrome is suspected, confirmed by screening tests, and then separated into its ACTH-dependent and ACTH-independent causes.
- Treatment of Cushing’s Syndrome explains how the source is removed or controlled, the medical therapies available when surgery cannot do so, and the follow-up needed after remission.