People with symptoms of Cushing's disease are tested to see if a tumor in the pituitary gland is releasing a high amount of the adrenocorticotropic hormone, for this type of tumor causes the disease. The hormone stimulates the adrenal glands to release the hormone cortisol, which in turn stimulates the production of cholesterol. Those with Cushing's usually have high blood pressure as well, a disorder that's also associated with a high cholesterol level.
What is Cushing's Disease?
People with Cushing's disease have a benign tumor in the anterior pituitary gland of the brain. The tumor is called a pituitary adenoma and it is referred to as benign because it does not spread to other places or invade other structures. It can press on structures, however, and cause damage in that way. But most pituitary adenomas are very small -- less than 10 mm -- and 50 percent of them are smaller than 5 mm.
Symptoms
The symptoms of Cushing's disease are described in "Handbook of Pathophysiology" by Elizabeth Corwin, Ph.D. People with this disorder may have large areas of fat on their back, referred to as a "buffalo hump." They have a round, full "moon face," and their abdomens protrude from the fat; yet their arms and legs are thin. They have purple lines on their thighs, breasts and abdomen called purple striae, and may also have weak muscles, wounds that do not heal well, and high cholesterol.
Risk Factors for High Cholesterol
A sedentary lifestyle together with eating too much trans fats, saturated fats and cholesterol can lead to high cholesterol levels in the bloodstream. This can also result from smoking cigarettes, drinking too much alcohol or a secondary effect of diabetes mellitus. A high cholesterol level increases the risk of developing heart disease. People with Cushing's disease may have high blood pressure.
Cushing's Disease and Cholesterol
The pituitary adenoma secretes a high amount of the adrenocorticotropic hormone, or ACTH. Normally, the anterior pituitary obeys biofeedback telling it to stop releasing ACTH, but the adenoma ignores this and keeps releasing it into the bloodstream, causing the adrenal gland to secrete cortisol. Thus, people with Cushing's have a high amount of cortisol in their bloodstream and too much cortisol can result in excessive levels of triglycerides and cholesterol, per Daniel Rader, M.D., Professor of Medicine at the University of Pennsylvania School of Medicine in Harrison's Principles of Internal Medicine."
References
- "Handbook of Pathophysiology"; Elizabeth Corwin, MSN, Ph.D., FNP; 2000
- "Harrison's Principles of Internal Medicine"; Anthony Fauci, M.D., Dennis Kasper, M.D., Dan Longo, M.D. et al.; 2008
- The Merck Manual for Healthcare Professionals: Dyslipidemia
