| Cushing's syndrome is a condition caused by excess corticosteroids in an individual's body. These steroids can be produced by the body itself or can result from high doses of medical steroids being administered to the individual. Cushing's syndrome is characterized by a large, round face and a thick torso with comparatively thin arms and legs. Muscle weakness, depression, hallucinations, thin skin that bruises easily and heals slowly, and purple streaks on the abdomen are also common signs and symptoms of this condition.
The adrenal glands located on top of the kidneys produce cortisol. Under normal conditions, the release of cortisol is controlled by the pituitary gland and the hypothalamus in the brain. The hypothalamus sends a hormone (corticotropin-releasing hormone or CRH) to the pituitary gland. CRH causes the pituitary gland to secrete a hormone called ACTH (adrenocorticotropic hormone). ACTH is the signal for the adrenal gland to produce cortisol.
A common cause of Cushing's syndrome is the administration of glucocorticoid drugs (such as prednisone) or ACTH for various medical reasons. This is called exogenous Cushing's syndrome. Individuals with any disease requiring prolonged use of corticosteroid medications are at increased risk of developing Cushing's syndrome. Examples of some medical conditions that are often treated with glucocorticoids or ACTH and may increase one's risk of developing Cushing's syndrome include rheumatoid arthritis, lupus, asthma, or other chronic inflammatory diseases.
When a tumor (adenoma) of the pituitary gland produces excessive amounts of ACTH, there is a subsequent release of excess cortisol by the adrenal glands. This condition is called Cushing's disease (hypercortisolism), and it accounts for about 70% of the naturally occurring (endogenous) cases of Cushing's syndrome. Another 15% of the naturally occurring cases of Cushing's syndrome are caused by release of cortisol from noncancerous (benign) or cancerous (malignant) tumors of the adrenal gland (adrenal adenoma and adrenal carcinoma). The remaining 15% of cases are caused by the production of ACTH by a tumor (either benign or malignant) located elsewhere in the body (ectopic ACTH syndrome) (Adler).Risk: Cushing's syndrome most commonly affects adults between the ages of 20 and 50, although it can strike at any age. Although Cushing's syndrome is not inherited, some people have an inherited predisposition to tumors of the hormone-secreting glands. This predisposition places these individuals at a higher risk for Cushing's syndrome than the general population.
Cushing's disease more commonly affects women of reproductive age, but it can occur in men and women at any age (Kirk). Women are five times more likely than men to have Cushing's syndrome caused by a pituitary or an adrenal tumor (Adler).
Ectopic ACTH syndrome is caused by lung tumors (usually carcinoid) in 50% of cases. Other ACTH-producing tumors include thymomas, pancreatic islet cell carcinomas, and medullary carcinomas of the thyroid. Ectopic ACTH syndrome affects men more often than women because lung cancer occurs more frequently among men (Adler). Incidence and Prevalence: Cushing's syndrome is relatively rare, affecting about 13 of every million individuals each year (Adler). |
Source: Medical Disability Advisor