Pheochromocytoma is a catecholamine-secreting tumor of the adrenal medulla (chromaffin cells) causing episodic hypertensive crises. The board triad: headache + diaphoresis + palpitations in paroxysmal episodes. Blood pressure spikes to 200–250/150 mmHg during a surge; between episodes, BP may be normal or chronically elevated. Triggers include tumor palpation, emotional stress, increased intra-abdominal pressure, contrast dye, tricyclic antidepressants, and dopamine-blocking medications. Pre-surgical alpha-then-beta rule: alpha-blockade FIRST (phenoxybenzamine or doxazosin — blocks vasoconstriction, allows volume expansion), then beta-blockade ONLY AFTER adequate alpha blockade is established. Beta-blockade alone is CONTRAINDICATED — removing beta-mediated vasodilation while alpha-constriction is unopposed causes a catastrophic hypertensive crisis. Nursing responsibilities: never palpate the abdomen; minimize stimulation; monitor for episodic hypertensive crisis and document BP/HR/symptoms during episodes; post-operatively monitor for profound hypotension (catecholamine source removed — adrenergic tone drops dramatically); watch for glucose normalization (GH/epinephrine excess had been driving hyperglycemia).