Which statement best describes the pathophysiology of Cushing disease?

• A. Cushing disease is characterized by an oversecretion of insulin.
• B. Cushing disease is characterized by an oversecretion of glucocorticoid hormones.
• C. Cushing disease is characterized by an undersecretion of corticotropic hormones.
• D. Cushing disease is characterized by an undersecretion of glucocorticoid hormones.

Answer: (B)

In Cushing disease, the problem is excess cortisol caused by a pituitary adenoma that secretes ACTH. This ACTH stimulates the adrenal cortex to produce glucocorticoids, leading to sustained high levels of cortisol in the body. That’s why the statement describing oversecretion of glucocorticoid hormones best fits the pathophysiology. Cortisol is the primary glucocorticoid involved, and its excess drives the characteristic metabolic and systemic effects seen in Cushing disease. The other options don’t fit: insulin isn’t overproduced in this condition, and ACTH and cortisol are not undersecreted.