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This is a clinician-written, evidence-based summary aligned to the USMLE Step 2 CK Content Outline. It is intended for medical students preparing for USMLE Step 2 CK. Management reflects current ACC/AHA, USPSTF, and APA guidelines. Always cross-reference with UpToDate, institutional protocols, and clinical judgment.
The Bottom Line
- Classic triad: episodic headache, diaphoresis, palpitations with paroxysmal hypertension
- Best screening test: plasma free metanephrines or 24-hour urinary fractionated metanephrines
- Image only after biochemical confirmation unless emergent circumstances require otherwise
- Preoperative treatment: alpha-blockade first, then beta-blockade only after adequate alpha blockade
- Beta-blocker before alpha-blocker can cause unopposed alpha vasoconstriction and hypertensive crisis
Overview
Pheochromocytomas are catecholamine-producing tumors arising from adrenal medulla chromaffin cells. Related extra-adrenal tumors are paragangliomas. Catecholamine secretion may be episodic or sustained, producing paroxysmal hypertension, tachyarrhythmias, headaches, sweating, and anxiety-like attacks. The disease is high-yield because correct preoperative pharmacologic preparation prevents lethal hypertensive crisis during surgery.
Epidemiology
Pheochromocytoma is rare but important in resistant hypertension, adrenal incidentaloma, hypertensive crisis during anesthesia, and hereditary endocrine syndromes. It may occur sporadically or with MEN2, von Hippel-Lindau disease, neurofibromatosis type 1, and succinate dehydrogenase mutations. In MEN2, pheochromocytoma must be excluded before thyroidectomy for medullary thyroid cancer to prevent perioperative crisis.
Clinical Features
Symptoms
Episodic severe headache, palpitations, diaphoresis
Paroxysmal anxiety, tremor, pallor, or panic-like attacks
Chest pain, dyspnea, or syncope during hypertensive episodes
Abdominal pain, nausea, weight loss
Symptoms triggered by surgery, anesthesia, exercise, urination, certain foods, or medications
Signs
Paroxysmal or sustained hypertension, sometimes resistant
Tachycardia, orthostatic hypotension from volume contraction
Pallor and diaphoresis during attacks
Hypertensive emergency: encephalopathy, pulmonary edema, aortic dissection, MI, stroke
MEN2 clues: medullary thyroid cancer, hyperparathyroidism, mucosal neuromas
Investigations
First-line
Plasma free metanephrinesHighly sensitive; best when patient is supine/rested and interfering medications considered
24-hour urinary fractionated metanephrines and catecholaminesAlternative screening test; useful when plasma test equivocal
BMP and glucoseHyperglycemia may occur due to catecholamine effects; assess renal function before imaging
Second-line
CT or MRI abdomen/pelvisLocalize tumor after biochemical confirmation. MRI preferred in pregnancy, children, or hereditary syndromes to reduce radiation
Genetic testingRecommended for many patients because hereditary disease is common enough to affect management and family screening
ECG/echocardiogramIf cardiomyopathy, arrhythmia, or prolonged catecholamine exposure suspected
Specialist
Functional imagingMIBG, PET, or other nuclear imaging for metastatic, extra-adrenal, multifocal, or recurrent disease
Preoperative endocrine and surgical planningVolume expansion and blockade must be optimized before adrenalectomy
1
Confirm and localize
- Biochemical confirmation with plasma free or urinary fractionated metanephrines
- Then CT/MRI for localization; do not rely on imaging alone because incidentalomas are common
2
Preoperative preparation
- Alpha-blockade for 7-14 days: phenoxybenzamine or selective alpha-1 blocker such as doxazosin
- High-sodium diet and fluids after alpha-blockade to expand contracted intravascular volume
- Add beta-blocker only after adequate alpha-blockade if persistent tachycardia
- Calcium channel blockers may be adjuncts when BP remains elevated or alpha-blockade limited
3
Definitive therapy
- Laparoscopic adrenalectomy for most adrenal pheochromocytomas
- Open surgery for large, invasive, or malignant-appearing tumors
- Lifelong biochemical follow-up because recurrence can occur
4
Hypertensive crisis
- ICU management with IV alpha blockade or vasodilators such as phentolamine, nicardipine, or nitroprusside
- Avoid isolated beta-blockade
Complications
- Hypertensive emergency: Stroke, MI, pulmonary edema, aortic dissection, renal failure
- Catecholamine cardiomyopathy: Reversible or severe stress cardiomyopathy can occur
- Perioperative hypertensive crisis: Especially if tumor is manipulated without adequate alpha blockade
- Malignant/metastatic paraganglioma: Risk varies by genotype and tumor location
- Postoperative hypotension or hypoglycemia: Sudden catecholamine withdrawal can cause vasodilation and increased insulin secretion
USMLE Step 2 CK Exam Tips
- 1Triad of headache + sweating + palpitations with episodic hypertension = pheochromocytoma
- 2Screen with plasma free metanephrines, not abdominal CT first
- 3Alpha before beta. Beta-blocker first is dangerous due to unopposed alpha vasoconstriction
- 4MEN2 patient needs pheochromocytoma ruled out before thyroid surgery
- 5Adrenal incidentaloma + hypertension spells = test metanephrines
- 6Orthostatic hypotension can occur despite hypertension because chronic catecholamines contract plasma volume
- 7Post-op hypoglycemia is a classic complication after catecholamine-secreting tumor removal
practicetest your knowledge on pheochromocytomaApply what you've learnt with USMLE Step 2 CK-style questions from the iatroX Q-Bank — endocrine and beyond.
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