Secondary Adrenal Insufficiency

Secondary Adrenal Insufficiency is a condition where the body does not produce enough of the hormone cortisol because the brain's signal to the adrenal glands is disrupted. This happens when the pituitary gland, which controls hormone release, fails to send enough adrenocorticotropic hormone (ACTH). The adrenal glands themselves are usually healthy but become underactive due to this lack of stimulation. This condition affects the endocrine system and can cause symptoms like fatigue, weakness, and low blood pressure. It differs from primary adrenal insufficiency because the problem starts in the brain, not the adrenal glands. Without enough cortisol, the body struggles to respond to stress and maintain normal metabolism.

Secondary Adrenal Insufficiency is defined as inadequate cortisol production due to deficient secretion of ACTH by the pituitary gland, leading to adrenal cortex hypofunction. It is most commonly caused by pituitary disorders such as pituitary tumors, surgery, radiation, or abrupt withdrawal of exogenous glucocorticoids suppressing the hypothalamic-pituitary-adrenal (HPA) axis. Unlike primary adrenal insufficiency, aldosterone production is typically preserved because it is regulated by the renin-angiotensin system. Clinically, it presents with hypocortisolism symptoms including fatigue, hypotension, and hypoglycemia, but without hyperpigmentation or significant electrolyte abnormalities. The condition is significant because cortisol deficiency impairs stress response and metabolism, potentially leading to adrenal crisis if untreated.