<prompt> Answer this question truthfullyCould you explain the pathophysiology of secondary adrenal insufficiency?  <response>: <reason> Hypothalamus produces corticotropin releasing hormone CRH that stimulates pituitary glands corticotrophs to release adrenocorticotrophic hormone ACTH. Anterior pituitary glands corticotroph cells produce ACTH that in turn stimulates adrenal cortexs zona glomerulosa to produce cortisol. Cortisol is produced by zona glomerulosa of the adrenal gland and provides feedback to pituitary and hypothalamus.Secondary adrenal insufficiency is caused by the processes occurring outside adrenal glands: pituitary causes, drugs, and genetic causes. These disease processes causes the decreased production of adrenocorticotrophic hormone ACTH. Chronic steroid therapy causes suppression of hypothalamic pituitary adrenal axis HPA axis. In some cases of adrenal insufficiency, hyponatremia is seen due to an abnormal increase in antidiuretic hormone ADH which in turn caused due to deficiency of cortisol due to decreased excretion of free water. The feedback loop causes secretion of corticotropin-releasing hormone CRH, again an ADH secretagogue. There is a negative feedback on CRH and ACTH by cortisol. In adrenal insufficiency, this effect is removed and cortisol inhibits ADH excretion directly showing the reciprocal relation of ADH increase when cortisol is low. ADH inappropriate secretion leads to more water absorption leading to hyponatremia. 