Pheochromocytoma

Background

• Rare tumor arising from chromaffin cells in adrenal medulla or other paraganglia in the body
• Increased catecholamine production leading to its clinical manifestations

Clinical Features

• Paroxysms usually lasting <1 hour of the following symptoms:
  • Headache
  • Tremor
  • Alternating periods of normal and elevated blood pressure, and can cause resistant hypertension and hypertensive emergency
  • Tachycardia
  • Flushed skin
  • Palpitations
  • Diaphoresis
  • Anxiety
• Weight loss

Differential Diagnosis

Hypertension

• Hypertensive emergency
• Stroke
• Sympathetic crashing acute pulmonary edema
• Ischemic stroke
• Intracranial hemorrhage
• Preeclampsia/Eclampsia
• Autonomic dysreflexia
• Scleroderma renal crisis
• Acute glomerulonephritis
• Type- I myocardial infarction
• Volume overload
• Urinary obstruction
• Drug use or overdose (e.g stimulants, especially alcohol, cocaine, or Synthroid)
• Renal Artery Stenosis
• Nephritic and nephrotic syndrome
• Polycystic kidney disease
• Tyramine reaction
• Cushing's syndrome
• Obstructive sleep apnea
• Pheochromocytoma
• Hyperaldosteronism
• Hyperthyroidism
• Anxiety
• Pain
• Oral contraceptive use

Evaluation

• Plasma free metanephrines
• Urinary fractionated metanephrines
• Plasma and urine catecholamines
• CT with adrenal protocol imaging to localize tumor
• PET scan may eventually be required
• General lab features include hyperglycemia, hypercalcemia, and erythrocytosis

Management

• Hypertensive crisis:
  • α blockade with phenoxybenzamine or phentolamine acutely
    • Phentolamine: 5mg IM/IV q2-4h PRN
  • Nitroprusside
  • Nicardipine
• Beta blockade can be started 2 days later
  • If beta blockade started before alpha blockers, unopposed alpha activity can precipitate hypertensive emergency
• Eventual surgical resection of tumor

Disposition

• Admission to a monitored setting

See Also

• Hypertensive emergency