A patient on long-term high-dose glucocorticoid therapy for rheumatoid arthritis is planned for elective surgery. The concern for adrenal suppression is related to which mechanism?

• A Sustained supraphysiological glucocorticoid levels provide negative feedback on the hypothalamic-pituitary axis, suppressing CRH and ACTH secretion and causing adrenal cortical atrophy from disuse ✓
• B Exogenous corticosteroids cause direct destruction of adrenal cortical cells over time
• C Glucocorticoids upregulate cortisol-binding globulin, reducing free cortisol and causing secondary adrenal hypertrophy
• D Exogenous corticosteroids competitively inhibit endogenous cortisol binding to mineralocorticoid receptors

Explanation

Prolonged exposure to supraphysiological exogenous glucocorticoids suppresses the hypothalamic-pituitary-adrenal (HPA) axis through sustained negative feedback — CRH and ACTH secretion are suppressed. Without ACTH trophic support, the adrenal cortex (zona fasciculata and reticularis) undergoes atrophy. After cessation of exogenous steroids, the atrophic adrenal glands cannot mount adequate cortisol responses to surgical/physiological stress for weeks to months, creating risk of addisonian crisis. 'Stress dosing' of hydrocortisone perioperatively is required.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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