The difference between Cushing’s disease and other forms of Cushing’s syndrome

There are important chemicals in your body called glucocorticoids, which are steroid hormones produced in your adrenal glands. Glucocorticoids – particularly one called cortisol help with many bodily processes, such as metabolism and your ability to fight infection.1-3 Glucocorticoids (both natural and synthetic) are also used in medicines for conditions such as allergies, respiratory problems, and skin problems.4

Cushing’s syndrome is a hormonal disorder

Cushing’s syndrome is the term used to describe a group of signs and symptoms that occur when a persons’ cortisol levels are too high (known as hypercortisolism) for too long.1-3 The majority of people have Cushing’s syndrome because they are regularly taking certain medicine(s) that continually add too much cortisol to the body. Doctors call this an “exogenous” (outside the body) cause of Cushing’s syndrome.1,5 Other people have Cushing’s syndrome because something is causing the adrenal gland(s) to overproduce cortisol.5 Doctors call this an “endogenous” (inside the body) cause of Cushing’s syndrome.1

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Cushing’s disease is a form of Cushing’s syndrome

Cushing’s disease is the most common form of endogenous Cushing’s syndrome. It is caused by a tumor in the pituitary gland that secretes excessive amounts of a hormone called Adrenocorticotropic hormone, or ACTH.1,4 Fortunately, this type of tumor is typically benign. Unlike a cancerous (malignant) tumor, a benign tumor stays in its original location and will not spread.1,3,6 After you are diagnosed with Cushing’s syndrome, it is important that your doctor continues the diagnostic process to determine the cause of hypercortisolism.

How a pituitary tumor causes Cushing’s disease

ACTH is a hormone produced in your pituitary gland. ACTH travels to your adrenal glands and signals them to produce cortisol (see diagram below).4

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Tumor grows within the pituitary gland and produces excessive amounts of ACTH. ACTH travels through the blood to the adrenal glands, located above the kidneys.

Adrenal glands release excessive amounts of cortisol, which travels throughout the body.

The high level of cortisol builds up over time to cause the signs and symptoms of Cushing’s syndrome (physical, emotional, cognitive).

If a person has Cushing’s disease, it means that a group of abnormal cells has built up in the pituitary gland to form an ACTH-producing pituitary tumor. These abnormal cells produce ACTH, just as normal pituitary gland cells do—only far too much.7 The excess ACTH travels to adrenal glands. The adrenal glands are then bombarded with signals to produce more and more cortisol. As a result, the adrenal glands continuously secrete too much cortisol.2

Next, read about signs and symptoms of hypercortisolism

References: 1. Newell-Price J, Bertagna X, Grossman AB, Nieman LK. Cushing’s syndrome. Lancet. 2006;367:1605-1617. 2. Nieman LK, Ilias I. Evaluation and treatment of Cushing’s syndrome. Am J Med. 2005;118:1340-1346. 3. Lin DD, Loughlin KR. Diagnosis and management of surgical adrenal diseases. J Urol. 2005;66:476-483. 4. Dorland’s Online Dictionary Web site. Accessed October 2, 2009. 5. Arnaldi G, Angeli A, Atkinson AB, et al. Diagnosis and complications of Cushing’s syndrome: a consensus statement. J Clin Endocrinol Metab. 2003;88:5593-5602. 6. Pathophysiology of disease: disorders of the hypothalamus & pituitary gland. Access Medicine Web site. Accessed July 30, 2009. 7. Else T, Hammer GD, Lingappa VR. Disorders of the hypothalamus & pituitary gland. Accessed July 14, 2009.