Researchers don't know exactly what causes cells within the adrenal gland to develop into a tumor. What they do know is that pheochromocytomas begin in special cells called chromaffin cells, which are found in the core of the adrenal gland. Your adrenal glands are part of your endocrine system, which produces hormones that regulate processes throughout your body.

The role of hormones

Your adrenal glands are located on top of your kidneys, and they produce hormones, including catecholamines. The most important of these are adrenaline (epinephrine) and noradrenaline (norepinephrine). Your body needs these hormones to maintain blood pressure and to help cope with stressful situations. Physical and emotional stresses usually trigger their release. When secreted into your bloodstream, catecholamines increase your heart rate and blood pressure and affect several other body functions.

Multiple tumors possible

Pheochromocytomas usually affect only one adrenal gland. However, you may have more than one tumor in an adrenal gland or you may develop tumors in both adrenal glands. Because chromaffin cells also are situated in nerve tissue throughout your body, pheochromocytomas occasionally arise outside of the adrenal glands (paraganglioma). Common locations for paraganglioma include the heart, neck, bladder, back wall of the abdomen and along the spine.

Causes of hypertensive crisis associated with pheochromocytoma

An attack of high blood pressure (hypertensive crisis) associated with pheochromocytoma typically lasts less than an hour. Blood pressure may be normal or elevated between the episodic symptoms.

Hypertensive crisis and other signs and symptoms may be brought on by emotional distress or anxiety, surgical anesthesia, or physical activities that press on the tumor, such as:

  • Changes in body position
  • Exercise
  • Pregnancy
  • Lifting
  • Having a bowel movement
  • Urination

Additionally, these factors can trigger a high blood pressure episode:

  • Using drugs or stimulants that raise your blood pressure, such as decongestants, amphetamines or cocaine.
  • Eating foods rich in tyramine — an amino acid normally found in your body that helps regulate blood pressure. Tyramine is found in imported beer, some wines, processed meats or fish, fermented cheeses, soy sauce, bananas, avocados, and overripe or spoiled food.
  • Taking a monoamine oxidase inhibitor (MAOI) to treat depression. Examples of MAOIs include phenelzine (Nardil), tranylcypromine (Parnate) and isocarboxazid (Marplan).
Apr. 05, 2011