Why are patients with Cushing's syndrome more prone to infections?

• A. Increased insulin production
• B. Immunosuppression from excess cortisol
• C. Decreased ACTH production
• D. Enhanced neutrophil function

Answer: (B)

Excess cortisol from Cushing's syndrome suppresses the immune system. Glucocorticoids blunt the inflammatory response by lowering cytokine production, decreasing lymphocyte proliferation, and impairing macrophage and neutrophil function, including chemotaxis. They also raise blood glucose, and hyperglycemia further impairs leukocyte activity and wound healing. Altogether, this immunosuppression makes infections more likely. You may see a higher neutrophil count, but these cells don’t migrate well to infection sites or kill pathogens effectively, so defense is weakened rather than strengthened.