In a client with Cushing syndrome, why is there concern for developing diabetes mellitus?

In a client with Cushing syndrome, why is there concern for developing diabetes mellitus?

• A. Cortical hormones stimulate rapid weight loss.
• B. Tissue catabolism results in a negative nitrogen balance.
• C. Glucocorticoids accelerate gluconeogenesis.
• D. Excessive ACTH damages pancreatic tissue.

Answer: (C)

In Cushing syndrome, the excess glucocorticoids raise blood glucose primarily by speeding up glucose production in the liver and by making body tissues less sensitive to insulin. Cortisol stimulates gluconeogenesis, increasing the production of glucose from amino acids and glycerol in the liver. At the same time, it counteracts insulin’s effects in peripheral tissues, so glucose uptake by muscle and fat cells is reduced. This combination leads to higher blood glucose levels and places stress on pancreatic beta cells, which over time can result in diabetes mellitus.

That’s why the statement about glucocorticoids accelerating gluconeogenesis is the best explanation for the diabetes risk in Cushing syndrome. Other features, like weight changes or tissue breakdown, occur with cortisol excess but don’t directly account for the development of diabetes. Excess ACTH raises cortisol but doesn’t by itself damage pancreatic tissue.