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Loop diuretic metabolic alkalosis — USMLE Step 3 MCQ

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HardInternal Medicine (chronic management)Loop diuretic metabolic alkalosisUSMLE Step 3

A 54-year-old took prednisone 20 mg daily for 8 months for an inflammatory disorder that is now quiescent. The dose has been tapered to 5 mg daily. After withholding glucocorticoid for 24 hours, the 8-AM serum cortisol is 11.2 mcg/dL (309 nmol/L). He is clinically well and wants to stop prednisone. What is the most appropriate next step?

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Correct answer: B — Stop prednisone now without routine corticotropin stimulation testing

The best answer is “Stop prednisone now without routine corticotropin stimulation testing”. At a physiologic glucocorticoid dose, morning cortisol is the recommended first test if biochemical confirmation of hypothalamic-pituitary-adrenal recovery is desired. A value above 10 mcg/dL (300 nmol/L) indicates recovery and permits glucocorticoid cessation; routine dynamic testing is not recommended. Values of 5–10 mcg/dL prompt continuation and retesting in weeks to months, whereas values below 5 mcg/dL prompt continuation and retesting after a few months.

Reference: Endocrine Society Clinical Practice Guideline: Glucocorticoid-Induced Adrenal Insufficiency: https://www.endocrine.org/clinical-practice-guidelines/glucocorticoid-induced-adrenal-insufficiency