<unk>  may result from any cause of increased glucocorticoid levels, whether due to medication or internal processes. Some sources however do not consider the glucocorticoid medication-induced condition as<unk> " proper, instead using the term "Cushingoid" to describe the medication's side effects which mimic the endogenous condition. Cushing's disease is a specific type of<unk>  caused by a pituitary tumor leading to excessive production of ACTH (adrenocorticotropic hormone). Excessive ACTH stimulates the adrenal cortex to produce high levels of cortisol, producing the disease state. While all Cushing's disease gives<unk> , not all<unk>  is due to Cushing's disease. Several possible causes of<unk>  are known. Exogenous The most common cause of<unk>  is the use of prescribed glucocorticoids to treat other diseases (iatrogenic<unk> . Glucocorticoids are used in treatment of a variety of disorders, including asthma and rheumatoid arthritis, and also used for immunosuppression after organ transplants. Administration of synthetic ACTH is also possible, but ACTH is less often prescribed due to cost and lesser utility. Rarely,<unk>  can also be due to the use of medroxyprogesterone acetate. In exogenous Cushing's, the adrenal glands may often gradually atrophy due to lack of stimulation by ACTH, the production of which is suppressed by glucocorticoid medication. Abruptly stopping the medication can thus result in acute and potentially life-threatening adrenal insufficiency and the dose must hence be slowly and carefully tapered off to allow internal cortisol production to pick up. In some cases, patients never recover sufficient levels of internal production and must continue taking glucocorticoids at physiological doses for life.<unk>  in childhood is especially rare and usually results from use of glucocorticoid medication. Endogenous Endogenous<unk>  results from some derangement of the body's own system of cortisol secretion. Normally, ACTH is released from the pituitary gland when necessary to stimulate the release of cortisol from the adrenal glands. * In pituitary Cushing's, a benign pituitary adenoma secretes ACTH. This is also known as Cushing's disease and is responsible for 70% of endogenous<unk> . * In adrenal Cushing's, excess cortisol is produced by adrenal gland tumors, hyperplastic adrenal glands, or adrenal glands with nodular adrenal hyperplasia. * Tumors outside the normal pituitary-adrenal system can produce ACTH (occasionally with CRH) that affects the adrenal glands. This etiology is called ectopic or paraneoplastic Cushing's disease and is seen in diseases such as small cell lung cancer. * Finally, rare cases of CRH-secreting tumors (without ACTH secretion) have been reported, which stimulates pituitary ACTH production. Pseudo-Cushing's syndrome Elevated levels of total cortisol can also be due to estrogen found in oral contraceptive pills that contain a mixture of estrogen and progesterone, leading to pseudo-Cushing's syndrome. Estrogen can cause an increase of cortisol-binding globulin and thereby cause the total cortisol level to be elevated. However, the total free cortisol, which is the active hormone in the body, as measured by a 24-hour urine collection for urinary free cortisol, is normal.
Cushing's syndrome
Cushing's disease
complications of Acromegaly
complications of Graves' disease
Sneddon's syndrome
Addison's disease
Sheehan's syndrome
Haim–Munk syndrome