In secondary adrenal insufficiency, what would you expect the ACTH level to be?

In secondary adrenal insufficiency, the ACTH (adrenocorticotropic hormone) level is typically low. This condition occurs due to a lack of stimulation from the pituitary gland, which produces ACTH. When the hypothalamus or pituitary does not produce adequate amounts of ACTH, the adrenal glands receive insufficient signals to produce cortisol. As a result, cortisol levels drop.

In contrast to primary adrenal insufficiency, where the adrenal glands themselves are damaged and cannot produce cortisol, leading to high levels of ACTH as a compensatory response, secondary adrenal insufficiency's mechanism revolves around insufficient ACTH production. This distinction is crucial when diagnosing and managing adrenal disorders. Thus, the expected level of ACTH in secondary adrenal insufficiency is low, reflecting the underlying pituitary or hypothalamic pathology rather than adrenal gland failure.