Cushing's disease is a rare condition, affecting about 10 people out of one million, caused by excess cortisol in the body. Cortisol is most commonly known as the stress hormone, as it is produced during the body's natural "fight or flight" reflex. It also reduces inflammation, assists the liver in the removal of toxins, and helps the body to use salt properly. Too much cortisol in the body, however, can be dangerous to a person's health, causing problems like reduced immunity and decreased bone mass. If left untreated, Cushing's disease can lead to heart disease and possibly death.
Cushing's syndrome refers to the increase of cortisol levels due to one of two reasons. The first is as a side effect of taking glucocorticoid medications, such as asthma medications or other drugs that contain steroids. The second cause is the over-production of cortisol in the adrenal glands. This second type of Cushing's is called Cushing's disease. Although it is also seen in dogs and horses, it is most common in humans.
The over-production of cortisol in the adrenal glands is the result of a small non-cancerous tumor, called an adenoma, in the pituitary glands, which are located near the bottom of the brain. Pituitary glands control the adrenocorticotropic hormone (ACTH). ACTH is then carried to the adrenal glands, found near the kidneys. Based on the amounts of ACTH sent out, the adrenal glands produce the cortisol that the body needs.
The most common symptom of Cushing's disease is weight gain, predominantly in the trunk and around the face. Excess deposits of fat around the back of the neck, collar bone and in the face are frequently seen. An increased amount of sweating, insomnia, hypertension, and dry, thin skin are also common symptoms. Women may see an increase in hair growth and may suffer from irregular periods. High blood pressure, diabetes and longer healing times may also be symptoms of Cushing's disease.
Cushing's disease is diagnosed by comparing the levels of cortisol in a person's urine over a 24-hour period. Magnetic resonance imaging (MRI) and computated axial tomography (CAT) scans may also be used, in addition to the urine test. Once Cushing's disease has been confirmed, surgery will be scheduled. During the surgery, the tumors in the pituitary gland will be removed. Radiation treatments may be used for a short while after the surgery, to assure that the tumor will not reform. Steroid replacement medications will also be used until the pituitary glands begin functioning normally again.