Pheochromocytoma

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Presentation :

Pathophysiology :

• Rare tumors arising in the chromaffin cells of the adrenal medulla that secrete biogenic amines (norepinephrine, epinephrine, or dopamine) or their metabolites
  • Rarely arises in the organ of Zuckercandl, a small mass of chromaffin cells derived from neural crest located along the aorta, beginning cranial to the superior mesenteric artery or renal arteries and extending to the level of the aortic bifurcation

Diagnostic Testing:

• Indications for testing:
  • adrenergic-type spells (headache, sweating, and tachycardia)
  • incidentally discovered adrenal mass
  • resistant hypertension (>140/90 mm Hg)
  • hypertension with onset <20 years of age
  • idiopathic cardiomyopathy
  • hypertensive episode induced by anesthesia, surgery, or angiography
  • familial syndromes that predispose to pheochromocytoma (see following)
  • family history of pheochromocytoma or paraganglioma
• Twenty-four–hour urine measurements of metanephrines and catecholamines OR measurement of plasma metanephrines is preferred
  • Positive biochemical tests are followed by abdominal and pelvic CT with contrast.

Treatment :

• Surgery is the treatment of choice.
  • Use phenoxybenzamine (a non-selective, irreversible alpha blocker) and then a BB like propranolol to control BP preoperatively.
    • AVOID β-blockade before adequate α-blockade, as it can result in severe paroxysmal hypertension
    • Blood pressure target is < 130/80 mmHg
  • Give IV normal saline to maintain intravascular volume
  • Nitroprusside or phentolamine is indicated for treating intraoperative hypertensive crisis.
  • Intraoperative tachyarrhythmias should be controlled with propranolol or esmolol

Prognosis:

References: