What Is Cushing's Syndrome?
Cushing's syndrome is a hormonal disorder that occurs when a person's tissues are exposed to an excess of the hormone cortisol. Cushing's syndrome is sometimes called "hypercortisolism."
How Common Is Cushing's Syndrome?
Cushing's syndrome is fairly rare. For every 1 million people, two to five new cases are diagnosed each year, with about 10 percent of these being children and teenagers.
Cushing's syndrome commonly affects adults between the ages of 20 and 50.
Normally, the production of cortisol follows a precise chain of events. First, the hypothalamus, a part of the brain that is about the size of a small sugar cube, sends corticotropin-releasing hormone (CRH) to the pituitary gland. CRH causes the pituitary to secrete ACTH (adrenocorticotropin), a hormone that stimulates the adrenal glands. When the adrenals, which are located just above the kidneys, receive the ACTH, they respond by releasing cortisol into the bloodstream.
Cortisol performs vital tasks in the body. Cortisol helps:
- Maintain blood pressure and cardiovascular function
- Reduce the immune system's inflammatory response
- Balance the effects of insulin in breaking down sugar for energy
- Regulate the metabolism of proteins, carbohydrates, and fats
- Assist the body as it responds to stress.
When the amount of cortisol in the blood is adequate, the hypothalamus and pituitary release less CRH and ACTH. This ensures that the amount of cortisol released by the adrenal glands is precisely balanced to meet the body's daily needs. However, if something goes wrong with the adrenals or with their regulating switches in the pituitary gland or the hypothalamus, cortisol production can be affected, resulting in the symptoms of Cushing's syndrome.