Secondary adrenal insufficiency is characterized by a deficiency in adrenal cortical hormones due to dysfunction of the hypothalamus or pituitary gland rather than dysfunction of the adrenal gland itself. Corticotropin-releasing hormone (CRH) from the hypothalamus stimulates the release of adrenocorticotropic hormone (ACTH) from the anterior pituitary gland. ACTH stimulates the production of glucocorticoids in the adrenal cortex. In secondary adrenal insufficiency, there is a deficiency of ACTH that disrupts the hypothalamic-pituitary-adrenal axis and causes a decrease in corticosteroid production.

Tumors of the pituitary or surrounding structures are the most common cause of secondary adrenal insufficiency. This includes adenomas, cysts, craniopharyngiomas, and other tumors. Traumatic brain injuries, especially those that result in trauma to the pituitary stalk, should also be considered.

Secondary adrenal insufficiency can cause hypotension, hypoglycemia, fatigue, and weight loss. Due to pituitary or hypothalamic dysfunction, other endocrine systems may also manifest deficiency. Visual impairment can occur if a tumor compresses the nearby optic chiasm.

Adrenal crisis is a potentially life-threatening complication. It is characterized by severe hypotension, vomiting, dehydration, abnormal electrolytes, and hypoglycemia. This requires immediate evaluation and treatment with intravenous (IV) fluid boluses and hormone replacement.