Dr. Podolin's Endocrine Exam Essay # 5

Differentiate among the causes of Cushing's Syndrome (i.e., Cushing's Disease, ectopic tumor, glucocorticoid excess, adrenal tumor)

Cushing's Syndrome - Hyper-secretion of cortisol by the adrenal cortex.  Caused by one of 4 things...Cushing's Disease, ectopic tumor, glucocorticoid excess, or adrenal tumor

• Cushing's Disease - Tumor on the anterior pituitary
  • Causes an increase release of Adrenocorticotropic Hormone (ACTH)
    • Causes an increase release of cortisol at the adrenal cortex
      • CRH is inhibited r/t increase of cortisol
        • ACTH does not react to decrease in CRH since it is independant of CRH due to the tumor.
• Ectopic Tumor - 
  • Some ectopic tumors release ACTH on there own in large amounts
    • Stimulates adrenal cortex to make too much cortisol
      • Hypothalmic CRH and ant. pituitary ACTH release are decreased in an attempt to decrease the cortisol levels...to no avail.
  • Rarely some ectopic tumors produce CRH
    • Increases ACTH release
      • Increases cortisol release
• Glucocorticoid excess - Glucocorticoids often injected for organ transplant patients to immunosuppress them to avoid rejection.
  • Cortisol levels abnormally high r/t exogenous administration
    • CRH and ACTH release is decreased but it doesn't affect cortisol levels since it is being injected
• Adrenal Tumor
  • _{Causes adrenal cortex to release too much cortisol}
    • _{CRH and ACTH release is decreased with no effect on cortisol levels r/t tumor continues to have the adrenal cortex to release cortisol}

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