Medicine · Diabetes Mellitus and Endocrine Disorders (Thyroid, Adrenal, Pituitary, Parathyroid)

A 28-year-old man presents with episodic hypertension (200/110 mmHg), headache, palpitations, and diaphoresis. 24-hour urine metanephrines are elevated at 4.2 mg/24h (normal < 0.9). CT abdomen shows an 8 cm right adrenal mass. What is the correct sequence of preoperative management?

  • A Beta-blockade first to control heart rate, then alpha-blockade, then surgery
  • B Combined alpha-beta blockade (labetalol) immediately, surgery within 48 hours
  • C Calcium channel blocker (amlodipine) alone, surgery within 1 week
  • D Alpha-blockade first (phenoxybenzamine), then beta-blockade, then surgery after 10–14 days
Correct answer: D. Alpha-blockade first (phenoxybenzamine), then beta-blockade, then surgery after 10–14 days

Explanation

The cardinal rule in pheochromocytoma preoperative preparation is alpha-blockade BEFORE beta-blockade. Phenoxybenzamine (irreversible non-selective alpha-blocker) is started 10–14 days preoperatively, achieving adequate volume expansion and preventing hypertensive crisis during tumour manipulation. If beta-blockade is initiated first in an unblocked patient, the unopposed alpha-adrenergic effects from catecholamines can precipitate severe hypertensive crisis. Beta-blockers are added only after adequate alpha-blockade is established, to control reflex tachycardia. High-sodium diet and volume loading are also recommended during this period.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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