Endocrine · Year 2 · from Endocrine

Case 1: Pheochromocytoma Presenting with Paroxysmal Hypertension

Patient Demographics

  • Age: 42 years
  • Sex: Male
  • Occupation: Construction foreman

Chief Complaint

"I get these terrible episodes with headaches, sweating, and my heart racing."

History of Present Illness

A 42-year-old man presents with a 6-month history of episodic symptoms occurring 2-3 times per week. During episodes, he experiences severe pounding headaches, profuse sweating, palpitations, and an overwhelming sense of anxiety or "impending doom." Episodes last 15-30 minutes and resolve spontaneously. He becomes pale rather than flushed during attacks. Between episodes, he feels generally well. His blood pressure at home ranges from 120-135/80 during asymptomatic periods but spikes to 200-220/110-120 during episodes. He notes that episodes can be triggered by bending over, lifting heavy objects at work, or straining during bowel movements. He has lost 10 pounds over 6 months despite normal appetite.

Physical Examination (Between Episodes)

  • Vital Signs: BP 142/88 mmHg (seated), 118/76 mmHg (standing - orthostatic drop), HR 78 bpm
  • General: Appears anxious but well-nourished
  • Skin: No hyperpigmentation, mild diaphoresis
  • HEENT: Fundoscopic exam shows mild hypertensive changes
  • Cardiovascular: Regular rhythm, no murmurs, normal heart sounds
  • Abdomen: Soft, no palpable masses
  • Neurologic: Normal

Workup

  • Biochemical Testing:
  • Plasma free metanephrines:
  • Metanephrine: 1.8 nmol/L (elevated, normal <0.5)
  • Normetanephrine: 4.2 nmol/L (markedly elevated, normal <0.9)
  • 24-hour urine fractionated metanephrines:
  • Metanephrine: 890 μg/24hr (elevated, normal <400)
  • Normetanephrine: 1,650 μg/24hr (elevated, normal <900)
  • 24-hour urine catecholamines:
  • Epinephrine: 45 μg/24hr (elevated)
  • Norepinephrine: 520 μg/24hr (elevated)
  • Chromogranin A: 380 ng/mL (elevated, normal <100)
  • Imaging:
  • CT adrenal glands: 4.5 cm right adrenal mass, heterogeneous enhancement, 35 HU (not lipid-rich)
  • MRI: T2 hyperintense ("light bulb sign"), heterogeneous enhancement
  • I-123 MIBG scan: Intense uptake in right adrenal mass, no extra-adrenal uptake
  • Genetic Testing: No pathogenic variant identified (sporadic case)
  • Additional Studies:
  • Glucose: 142 mg/dL (elevated)
  • Calcium: Normal (rules out MEN2-associated hyperparathyroidism)

Diagnosis

Pheochromocytoma (catecholamine-secreting adrenal tumor)

Treatment

PREOPERATIVE PREPARATION (Critical - 10-14 days before surgery):

  1. Alpha-blockade FIRST:
  • Phenoxybenzamine 10 mg BID, titrate up every 2-3 days
  • Target: BP <130/80 sitting, systolic >90 standing (adequate blockade without excessive orthostasis)
  1. Liberal salt and fluid intake: To expand intravascular volume (counters chronic vasoconstriction-induced volume depletion)
  2. Beta-blockade ONLY AFTER adequate alpha-blockade:
  • Propranolol 20 mg TID or metoprolol (for reflex tachycardia)
  • NEVER start beta-blocker before alpha-blocker (risk of unopposed alpha-mediated hypertensive crisis)
  1. Monitor for orthostatic symptoms (indicates adequate alpha-blockade)
  2. Avoid triggers: Certain medications (metoclopramide, opioids), abdominal palpation

SURGICAL:

  1. Laparoscopic right adrenalectomy
  2. Intraoperative arterial line monitoring
  3. IV phentolamine and nitroprusside available for hypertensive surges during tumor manipulation
  4. Expect hypotension after tumor removal (prepare volume and vasopressor support)

POST-OPERATIVE:

  1. Monitor blood pressure (hypertension should resolve)
  2. Monitor glucose (often normalizes)
  3. Repeat plasma metanephrines at 2-4 weeks (confirm biochemical cure)
  4. Annual biochemical surveillance (lifetime - recurrence possible)
  5. Genetic counseling and testing (recommended for all patients)

Clinical Pearl

Pheochromocytoma classically presents with the triad of episodic headache, sweating, and palpitations, often with paroxysmal hypertension. Plasma free metanephrines have >96% sensitivity, making a negative result essentially rule out the diagnosis. The "rule of 10s" has been updated: 30-40% of cases are now known to be hereditary (not 10%), mandating genetic testing for all patients. The principle of "alpha before beta" is critical in preoperative preparation - beta-blockade alone eliminates beta-2 vasodilation, leaving alpha-1 vasoconstriction unopposed, which can precipitate life-threatening hypertensive crisis. Phenoxybenzamine provides irreversible, long-acting alpha-blockade ideal for preoperative preparation. Surgical cure is possible in >90% of patients with benign tumors.

Clinical Image

High-power microscopic image of pheochromocytoma showing characteristic nests of chromaffin cells (Zellballen pattern) with granular cytoplasm containing catecholamine-rich secretory granules.

Image Source: Wikimedia Commons - "Pheochromocytoma histology" License: CC BY-SA 3.0 URL: https://commons.wikimedia.org/wiki/File:Pheochromocytoma_-_very_high_mag_-_cropped.jpg

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