Cushing syndrome

Cushing's syndrome (CS) is a rare endocrinological disease characterized by chronically elevated levels of the adrenal cortex hormone cortisol in the body. A distinction is made between the endogenous and exogenous (drug-induced) forms. Endogenous CS is caused by excessive production of glucocorticoids, usually due to pituitary or adrenal tumors, while the exogenous form is caused by long-term use of glucocorticoids.

Subtypes

The main forms of Cushing's syndrome are

• Endogenous Cushing's syndrome:
  • Cushing's disease (central CS): caused by a pituitary adenoma producing adrenocorticotropic hormone (ACTH) and/or overproduction of corticotropin-releasing hormone (CRH) in the hypothalamus, which stimulates the adrenal glands to produce more cortisol.
  • Ectopic Cushing's syndrome: ACTH is produced by tumors outside the pituitary gland, e.g. by small cell lung cancer or neuroendocrine tumors.
  • Adrenal Cushing's syndrome: Direct cortisol overproduction by adrenal cortical tumors.
• Exogenous (iatrogenic) Cushing's syndrome: caused by long-term use of glucocorticoids (e.g. prednisolone, dexamethasone) for the treatment of autoimmune or chronic inflammatory diseases.