What causes Cushings?
Cushing’s syndrome occurs when the body’s tissues are exposed to excessive levels of cortisol for long periods of time. Many people suffer the symptoms of Cushing’s syndrome because they take glucocorticoid hormones such as prednisone for asthma, rheumatoid arthritis, lupus or other inflammatory diseases. Others develop Cushing’s syndrome because of overproduction of cortisol by the body. Normally, the production of cortisol follows a precise chain of events. First, the hypothalamus, a part of the brain which 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. It helps maintain blood pressure and cardiovascular function, reduces the immune system
When cortisol or other glucocorticoid hormones (such as hydrocortisone, prednisone, methyl-prednisolone or dexamethasone) are taken in excess of the normal daily requirement for a prolonged period of time, it causes Cushing’s syndrome. This “iatrogenic” (caused by the treatment) form is unfortunately a necessary side effect when high doses of these steroid hormones must be used to treat certain life-threatening illnesses, such as asthma, rheumatoid arthritis, systemic lupus, inflammatory bowel disease, some allergies, and others. Spontaneous overproduction of cortisol in the adrenals is divided into two groups – those due to an excess of ACTH and those that are independent of ACTH. A pituitary tumor producing too much ACTH, stimulating the adrenals to grow (hyperplasia) and to produce to much cortisol, is the most common type, and this is called Cushing’s disease. It is the cause of 70% of spontaneous Cushing’s syndrome. ACTH can also be produced outside the pituitary in a benign or ma
