Diagnosis and evaluation

• Laboratory testing
  
  
  
  • Fractionated plasma and/or 24-hour urine levels of metanephrines, catecholamine metabolites (normetanephrine and metanephrine), have superior diagnostic sensitivity over testing for parent catecholamines.
    
  • 24-hour urine catecholamine levels may also be useful.
  
  
• Imaging
  
  
  
  • Computed tomography (CT):
    
    
    
    • Recommended for initial anatomical imaging.
    
    
  • Magnetic resonance imaging (MRI):
    
    
    
    • Recommended for initial anatomical imaging.
    
    
  • ¹²³I-labeled metaiodobenzylguanidine (MIBG) scintigraphy:
    
    
    
    • Functional imaging – localizes adrenergic tissue.

Critical management

• Management of emergencies in patients with pheochromocytoma depends on symptoms. It should always include pharmacological treatment to block the effects of high levels of circulating catecholamines and prevent complications.
  
• Hypertensive crisis due to pheochromocytoma should be treated with repeated doses of phentolamine, a continuous infusion of phentolamine, or a continuous infusion of sodium nitroprusside.
  
• Definitive treatment for pheochromocytoma is surgery, which should be delayed until the patient is medically stable in order to improve survival.
  
• Recommended preoperative pharmacological treatment options:
  
  
  
  • First initiate phenoxybenzamine, a noncompetitive alpha-1 and alpha-2 adrenergic receptor antagonist, to reduce blood pressure fluctuation and ease vasoconstriction; side effects include orthostatic hypotension and reflex tachycardia.
    
  • Metyrosine, an inhibitor of catecholamine synthesis, may be added.
    
  • Selective alpha-1 receptor antagonists such as terazosin, prazosin, and doxazosin do not cause reflex tachycardia.
    
  • Calcium channel blockers such as diltiazem effectively control blood pressure and prevent catecholamine-induced coronary vasospasm.
    
  • Beta-blockade may be added to prevent reflex tachycardia or treat arrhythmia or angina but should only be used in conjunction with alpha-blockade to avoid dangerous unopposed alpha effects.
  
  
• After adequate control and stabilization of blood pressure, the tumor should be surgically removed.
  
• Patients should be followed indefinitely, particularly if they have familial or extra-adrenal disease.
  
• Inoperative disease or disease in which resection is not curative may be treated with adrenergic antagonists, chemotherapy, radiotherapy, and/or debulking.

Sudden deterioration

• Emergency surgical removal of the tumor is indicated if the patient deteriorates despite aggressive medical treatment appropriate for pheochromocytoma, even if the patient is critically ill, to increase chances of survival.

Vasopressor of choice: Vasopressors are not often indicated as patients are usually hypertensive and tachycardic, but if a patient becomes hypotensive from either over-medication or hemodynamic lability, consider norepinephrine or phenylephrine.

References

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