A 38-year-old woman from rural Maharashtra presents with episodic severe headaches, profuse sweating, and palpitations for 3 months. Her blood pressure during an episode is 180/110 mmHg, dropping to 130/80 mmHg between episodes. She denies chest pain or dyspnea. Physical examination reveals no neurofibromatosis stigmata. Plasma free metanephrines are elevated at 4.2 nmol/L (normal <0.9). CT abdomen shows a 3.5 cm left adrenal mass with heterogeneous enhancement. 24-hour urine metanephrines are also elevated. What is the most appropriate next step in management?

Explanation

## Clinical Diagnosis & Management This patient has a **classic presentation of pheochromocytoma**: episodic hypertension, headache, sweating, palpitations, with biochemical confirmation (elevated plasma free metanephrines 4.2 nmol/L and elevated 24-hour urine metanephrines) and a 3.5 cm adrenal mass on CT. The diagnosis is already established — both biochemical and anatomical. **Key Point:** When biochemical diagnosis is confirmed AND a localized adrenal mass is identified on CT, the **most appropriate next step is immediate alpha-blockade**, not additional functional imaging. MIBG scintigraphy is reserved for specific indications (suspected extra-adrenal/metastatic disease, negative CT/MRI with biochemical evidence, or hereditary syndromes). ## Why Alpha-Blockade First? Per **Harrison's Principles of Internal Medicine (21st ed.)** and **Endocrine Society Clinical Practice Guidelines**, once pheochromocytoma is biochemically confirmed and localized: 1. **Alpha-adrenergic blockade must be initiated immediately** to prevent life-threatening hypertensive crises — especially during any procedure, anesthesia induction, or tumor manipulation. 2. **Phentolamine** (short-acting, non-selective alpha-blocker) or **phenoxybenzamine** (long-acting) is started first; **propranolol (beta-blocker) is added ONLY after adequate alpha-blockade** to prevent unopposed alpha-stimulation causing severe hypertension. 3. Surgical consultation follows after hemodynamic stabilization (typically 10–14 days of alpha-blockade). **Clinical Pearl:** Starting a beta-blocker BEFORE alpha-blockade is dangerous — it removes the vasodilatory beta-2 effect, leaving unopposed alpha-mediated vasoconstriction, potentially precipitating a hypertensive emergency. ## Why Not MIBG Scintigraphy (Option C)? MIBG scintigraphy is **not routinely required** when: - Biochemical diagnosis is confirmed (plasma metanephrines >4× upper limit of normal is virtually diagnostic) - CT clearly identifies a unilateral adrenal mass MIBG is indicated when CT/MRI is negative but biochemistry is positive, when extra-adrenal paraganglioma is suspected, or when metastatic disease needs staging. In this case, a 3.5 cm adrenal mass with classic biochemistry makes MIBG an unnecessary delay to definitive management. ## Why Not Option D (Direct Surgery)? Proceeding directly to adrenalectomy **without preoperative alpha-blockade** risks catastrophic intraoperative hypertensive crisis, arrhythmias, and myocardial infarction during tumor manipulation — this is absolutely contraindicated. ## Why Not Option B (Doxazosin Monotherapy + Recheck)? Doxazosin is an acceptable alpha-blocker, but "recheck metanephrines in 4 weeks" delays surgical referral unnecessarily. The goal of alpha-blockade is hemodynamic preparation for surgery, not biochemical normalization. ## Correct Management Sequence **Alpha-blockade (phentolamine/phenoxybenzamine) → Beta-blockade if needed → Surgical consultation → Laparoscopic adrenalectomy** **High-Yield Mnemonic:** **Alpha before Beta, Beta before Knife** — never reverse this sequence in pheochromocytoma management. *Reference: Harrison's Principles of Internal Medicine, 21st ed., Chapter on Pheochromocytoma; Endocrine Society Guidelines 2014.*