How to Diagnose Pheochromocytoma

A pheochromocytoma is a usually benign tumor derived from chromaffin cells. These cells are primarily located in the adrenal medulla and sympathetic nervous system, but a pheochromocytoma can develop virtually anywhere in the body. A pheochromocytoma is functional and secretes catecholamines which cause hypertension. It may be an inherited trait and is frequently associated with genetic disorders such as neurofibromatosis, Sturge-Weber, tuberous sclerosis and von Hippel-Lindau disease.

Instructions

• 1

  Expect pheochromocytomas to cause various symptoms, but all patients will experience hypertension at some point and this is usually sustained at the time of diagnosis. Episodic paroxysms of hypertensions also may be precipitated by excitement or physical activity.

• 2

  Conduct a physical examination of the patient. Pheochromocytomas usually cause the patient to be thin with a rapid forceful heartbeat. They also may feel warm with perspiration but have pallor and cool moist hands. A mass in the neck or deep in the abdomen may be palpable.

• 3

  Confirm a diagnosis of pheochromocytoma by measuring urinary catecholamines at 24-hour intervals. These chemicals include dopamine, epinephrine, metanephrine and norepinephrine.

• 4

  Minimize the patient's level of catecholamines as much as possible during the sampling period. Medications such as labetalol, levodopa and methyldopa are the largest cause of false positive results for pheochromocytomas.

• 5

  Locate the pheochromocytoma once its existence has been established biochemically. Larger tumors usually can be found with ultrasound but smaller ones may require Computed Tomography (CT) or Magnetic Resonance Imaging (MRI), especially for extra-adrenal tumors.