What can cause secondary adrenal insufficiency?

Secondary adrenal insufficiency occurs when there is inadequate stimulation of the adrenal cortex from the pituitary gland, often due to a deficiency in adrenocorticotropic hormone (ACTH). Corticosteroid therapy is a common cause of this condition. When patients are administered corticosteroids, especially over a long-term period, the negative feedback mechanism inhibits the release of ACTH from the pituitary gland. Consequently, the adrenal glands may atrophy due to disuse, leading to insufficient hormone production when the corticosteroids are withdrawn or diminished, manifesting as secondary adrenal insufficiency.

The other options, while relevant to adrenal function, do not primarily lead to secondary adrenal insufficiency. Genetic mutations might cause primary adrenal insufficiencies, an autoimmune response is typically associated with primary adrenal insufficiency (Addison's disease), and adrenal tumors usually lead to primary adrenal insufficiency or hypersecretion rather than affecting the pituitary's regulation of adrenal hormones. Thus, corticosteroid therapy is the definitive and most common external trigger for secondary adrenal insufficiency.