ABSTRACT
Primary adrenal insufficiency (PAI) or Addison disease is due to lack of production of cortisol and mineralocorticoids. PAI can be caused by infections (tuberculosis) or autoimmunity. Secondary adrenal insufficiency is due to hypothalamic/pituitary failure. Hyperpigmentation of the skin in PAI is due to subsequent increased pituitary secretion of proopiomelanocortin (POMC). A cleaved peptide of POMC is melanocyte-stimulating hormone, which stimulates production of melanin by melanocytes. Cushing syndrome is due to excess cortisol from a cortisol-producing adrenal tumor, excess adrenocorticotropichormone (ACTH)-producing pituitary tumor, ectopic ACTH-producing tumor, or due to iatrogenic glucocorticoids.
