A 35-year-old woman presents with episodic headaches, palpitations, and excessive sweating. She has a history of resistant hypertension requiring multiple medications. Her blood pressure is currently 170/100 mmHg. Physical examination reveals a thin woman with mild tachycardia. Complete blood count, electrolytes, and renal function are normal. Which of the following is the most appropriate initial diagnostic test?

The correct answer to the question "A 35-year-old woman presents with episodic headaches, palpitations, and excessive sweating. She has a history of resistant hypertension requiring multiple medications. Her blood pressure is currently 170/100 mmHg. Physical examination reveals a thin woman with mild tachycardia. Complete blood count, electrolytes, and renal function are normal. Which of the following is the most appropriate initial diagnostic test?" is Option B: Plasma metanephrines or 24-hour urine metanephrines.

The other options — A) Renal artery duplex ultrasound, C) Thyroid stimulating hormone (TSH), D) Serum aldosterone-to-renin ratio — are incorrect for this USMLE Exam Prep question. As explained above: The constellation of paroxysmal hypertension, headaches, palpitations, and sweating is highly suggestive of pheochromocytoma, a catecholamine-secreting tumor. The most appropriate initial diagnostic …