A 45-year-old man presents with episodic severe hypertension, palpitations, diaphoresis, and pallor. Plasma metanephrines are 4-fold elevated. 24-hour urine catecholamines are elevated. After alpha-blockade with phenoxybenzamine is established, what is the correct sequence for additional preoperative preparation?
- A Add beta-blocker first, then calcium channel blocker
- B Calcium channel blocker simultaneously with alpha-blocker
- C Beta-blocker only, after adequate alpha-blockade ✓
- D High-sodium diet and fluid loading only
Correct answer: C. Beta-blocker only, after adequate alpha-blockade
Explanation
In pheochromocytoma, alpha-adrenergic blockade (phenoxybenzamine) must be established first to prevent unopposed alpha stimulation causing hypertensive crisis. Beta-blockers are added ONLY after adequate alpha-blockade to control reflex tachycardia; initiating beta-blocker before alpha-blockade can precipitate hypertensive crisis by blocking beta2-mediated vasodilation while leaving alpha1 receptors unopposed. High-sodium diet and fluid loading help expand the contracted plasma volume after vasodilation from alpha-blockade.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.