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Endocrine · Topic 11 of 13

Pheochromocytoma

Endocrine · adrenal medulla

Pheochromocytoma

A catecholamine-secreting tumor: confirm with plasma free metanephrines, then alpha-block first — never a beta-blocker alone — before adrenalectomy.

Key numbers
Screen with plasma free metanephrinesUp to 99% sensitive
Alpha-blockade first, 7–14 days before surgeryα-block 7–14 days
01 · Look forHeadache, sweating, palpitations with hypertension

Suspect pheochromocytoma with the classic triad of headache, diaphoresis and palpitations plus hypertension — sustained or paroxysmal (paroxysmal in about 45%) — especially in younger or resistant hypertension.

02 · Defined byScreen with plasma free metanephrines

First test: plasma free metanephrines (up to 99% sensitive) or 24-hour urinary fractionated metanephrines; metanephrines are produced continuously, unlike catecholamines, which are released intermittently.

03 · GiveAlpha-blockade first, 7–14 days before surgery

Every functional tumor gets preoperative alpha-blockade (phenoxybenzamine or doxazosin) for about 7–14 days before surgery, titrated toward BP < 130/80 mmHg.

01

Causes & risk factors

Why it happens
Paroxysm triggers: anesthesia, palpation, unopposed beta-blockadeParoxysms can be provoked by induction of anesthesia, tumor palpation or abdominal pressure, postural change, emotional stress, unopposed beta-blockade, or micturition when the tumor is in the bladder.
02

Do right now

In this order
First moves
1
Screen with plasma free metanephrinesUp to 99% sensitive
→
2
Image only after positive metanephrines: CT first
→
3
Alpha-blockade first, 7–14 days before surgeryα-block 7–14 days
→
4
Add a beta-blocker only after alpha-blockade
→
5
Laparoscopic adrenalectomy is definitive treatment
Why each step
Screen with plasma free metanephrinesFirst test: plasma free metanephrines (up to 99% sensitive) or 24-hour urinary fractionated metanephrines; metanephrines are produced continuously, unlike catecholamines, which are released intermittently.
Image only after positive metanephrines: CT firstLocalize the tumor only after metanephrines are positive: CT first, MRI when radiation must be limited or disease is metastatic; gallium-68 DOTATATE PET is more sensitive than MIBG or FDG-PET for functional imaging.
Alpha-blockade first, 7–14 days before surgeryEvery functional tumor gets preoperative alpha-blockade (phenoxybenzamine or doxazosin) for about 7–14 days before surgery, titrated toward BP < 130/80 mmHg.
Add a beta-blocker only after alpha-blockadeAdd a beta-blocker (eg, propranolol) only after adequate alpha-blockade — typically 3–4 days in — to control reflex tachycardia; a calcium channel blocker can be added for residual hypertension.
Laparoscopic adrenalectomy is definitive treatmentSurgical removal is the treatment of choice once BP is controlled: minimally invasive adrenalectomy for most pheochromocytomas, open resection for most paragangliomas.
03

Management

Orders
High-sodium diet and fluids before surgeryOrder a high-sodium diet and liberal fluid intake during preoperative alpha-blockade to re-expand the contracted blood volume and prevent postoperative hypotension.
Crisis: IV phentolamine or nitroprussideTreat a hypertensive paroxysm or crisis with phentolamine 1–5 mg IV or a nitroprusside infusion (preoperative or intraoperative); control tachyarrhythmias with esmolol or propranolol.
04

Red flags & don'ts

Avoid harm
Never start a beta-blocker before alpha-blockade avoidDo not give a beta-blocker until alpha-blockade is adequate: blocking beta-mediated vasodilation leaves catecholamine vasoconstriction unopposed and can paradoxically raise blood pressure into crisis.
Watch for post-op hypotension and hypoglycemia complicationAfter tumor removal, expect hypotension (give volume; norepinephrine if needed) and hypoglycemia as catecholamine suppression of insulin lifts — check glucose closely, especially in patients on antihyperglycemics.
05

The rules

Know these
Offer genetic testing to every patientNearly 50% are germline: offer genetic testing to all (MEN 2A/2B, von Hippel-Lindau, NF1, SDHx); check calcitonin for MEN 2 and test paraganglioma patients for SDHx mutations.
06

Commonly confused

Tell apart
False-positive metanephrines: drugs, stress, upright drawDraw plasma metanephrines supine after ≥ 30 minutes recumbent; tricyclics, MAO inhibitors, SNRIs/SSRIs, sympathomimetics, stimulants and acute stress can falsely raise results, and every positive needs follow-up.
07

More detail

Reference
Show 6 reference facts
About 90% arise in the adrenal medulla; adrenal tumors are bilateral in about 10% and malignant in about 10%, whereas about 30% of extra-adrenal paragangliomas are malignant. Peak age is 20–40 years.
Other clues: hyperglycemia with inappropriately low insulin, hemoconcentration from a contracted plasma volume, orthostatic hypotension, weight loss in older adults, and a catecholamine cardiomyopathy.
For known or suspected bilateral tumors (eg, MEN), give hydrocortisone 100 mg IV twice daily before and during surgery to prevent acute adrenal insufficiency after bilateral adrenalectomy.
Provocative tests (histamine, tyramine, glucagon) are hazardous and unnecessary; a clonidine suppression test is rarely needed. Keep phentolamine at hand during any testing.
Intraoperatively: continuous arterial-line monitoring, avoid histamine-releasing relaxants and preoperative atropine; 1–2 units of blood may be transfused before resection in anticipation of blood loss.
Metastatic disease: continue alpha- and beta-blockade; metyrosine lowers catecholamine synthesis; I-131 MIBG or lutetium-177 DOTATATE, chemotherapy, sunitinib or belzutifan are options. Follow all patients lifelong for recurrence.
Pearl

Alpha before beta: block the vasoconstriction first, then slow the heart — a beta-blocker alone can trigger a hypertensive crisis.

Sources · Merck Manual Professional — Pheochromocytoma (full review Jan 2026) · Lenders JW et al. Pheochromocytoma and paraganglioma: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2014;99:1915–42 · Pheochromocytoma: an updated scoping review from clinical presentation to management and treatment. Front Endocrinol 2024 (PMC11671257) · Zhu W et al. The use of doxazosin before adrenalectomy for pheochromocytoma: is the duration related to intraoperative hemodynamics and postoperative complications? (cites the Endocrine Society 7–14 days; PMC7575471) · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).