A 38-year-old man with a 6-month history of episodic headaches, profuse sweating, and palpitations presents to the emergency department. Blood pressure is 168/104 mmHg. Plasma free metanephrines are elevated at 4.2 times the upper limit of normal. A CT abdomen shows a 3.5 cm left adrenal mass. What is the most appropriate next step in management?

Explanation

## Diagnosis & Confirmation **Key Point:** This patient has biochemically confirmed pheochromocytoma (elevated plasma free metanephrines) with imaging evidence of a left adrenal mass. The next step is not further diagnostic confirmation but **hemodynamic preparation and staging**. ## Pre-operative Management Algorithm ```mermaid flowchart TD A[Biochemically confirmed pheo + imaging]:::outcome --> B[Alpha-blockade first]:::action B --> C[Phenoxybenzamine or doxazosin]:::action C --> D[Target: BP control + orthostatic hypotension]:::action D --> E[Add beta-blocker after alpha control]:::action E --> F[Labetalol or atenolol]:::action F --> G[Staging: 131I-MIBG or PET-CT]:::action G --> H[Assess for metastases]:::decision H -->|No metastases| I[Surgical resection]:::action H -->|Metastases present| J[Multidisciplinary planning]:::action ``` ## Rationale for Correct Answer **High-Yield:** The classic pre-operative sequence for pheochromocytoma is: 1. **Alpha-blockade first** (phenoxybenzamine 10–40 mg/day, titrated over 7–10 days) 2. **Then beta-blockade** (only after alpha control achieved; prevents unopposed alpha effects) 3. **Staging imaging** (131I-MIBG scintigraphy or PET-CT to detect metastases) 4. **Surgical resection** (once hemodynamically stable and staging complete) **Clinical Pearl:** Initiating beta-blockers before adequate alpha-blockade can precipitate a hypertensive crisis due to unopposed alpha-adrenergic vasoconstriction. This is a classic trap in pheochromocytoma management. **Key Point:** Phenoxybenzamine (non-selective, irreversible alpha-blocker) is preferred over selective alpha-1 blockers (doxazosin, prazosin) because it provides more complete and sustained blockade of catecholamine effects, including alpha-2 mediated feedback inhibition. ## Pre-operative Goals - Systolic BP target: 140–160 mmHg (allows for intra-operative fluctuations) - Orthostatic hypotension acceptable (sign of adequate alpha-blockade) - Heart rate control: 60–80 bpm (after beta-blockade) - Volume expansion: IV fluids to restore depleted intravascular volume [cite:Harrison 21e Ch 405]