How to Interpret Endocrine Tests

In Episode 68 of Med School Question of the Week for USMLE, Alisa Khomutova, MedSchoolCoach expert tutor, answers this medical school question: A 45-year-old woman comes to the physician for a health maintenance examination. She has had generalized fatigue and muscle aches for the last 6 months. She has a PMH of hypertension and migraines. Current medications include amlodipine and sumatriptan. Vitals shows a temperature of 37C, pulse of 92/min and blood pressure of 152/105 mm Hg. Physical examination is wnl. Serum studies show a Na of 144, K of 2.3, Cl of 99, Ca of 8.9, BUN of 16 and Crt of 1.1 Her blood pressure medication is discontinued and 5 days later her plasma aldosterone concentration is 45 ng/dL (N=3.6 – 24.0 ng/dL) and plasma renin activity is 0.39 ng/mL/h (N=0.3 to 4.2 ng/mL/h). An oral sodium loading test over 3 days fails to reduce aldosterone. A contrast-enhanced CT scan of the abdomen and pelvis shows a 3-cm, homogenous, right-sided adrenal mass with rapid contrast washout. She is counseled about her treatment options and chooses to pursue surgery. Which of the following is the most appropriate next step in management?

• Full body CT scan (pan CT)
• MRI of abdomen and pelvis
• Spironolactone therapy
• Triamterene therapy
• Fludricortisone suppression test
• Adrenal Vein Sampling
• Unilateral adrenalectomy
• Bilateral adrenalectomy