Long-term corticosteroid use is the most likely cause of Cushing syndrome in a patient with a history of asthma. Which statement best supports this?

• A. Abruptly Withdrawing Cortisone Therapy
• B. Lack of ACTH Related to the Pituitary Gland
• C. Taking Corticosteroids for Many Years
• D. Poorly Functioning Adrenal Glands

Answer: (C)

Long-term systemic corticosteroid use introduces excess glucocorticoids into the body, producing the characteristic features of Cushing syndrome. Exogenous steroids provide glucocorticoid activity that drives fat redistribution, glucose intolerance, hypertension, and muscle weakness, even as the body's own cortisol production is suppressed. This suppression lowers ACTH due to negative feedback, and the adrenal glands may atrophy, but the external steroids keep the high glucocorticoid effect. That’s why taking corticosteroids for many years is the best explanation. Abruptly stopping therapy would cause adrenal failure rather than Cushingoid features, lack of ACTH describes a pituitary-related deficiency leading to low cortisol, and poorly functioning adrenal glands would cause cortisol deficiency rather than excess.