Pheochromocytoma - A Rare Condition Exposed by Neurotransmitter Testing

The New York Times did a remarkable story the other day that ended with the line "When you hear hoofbeats, the chances are good that it's a horse…but we must also remember that sometimes the circus is in town. [1]

ZRT is apparently hosting the circus this year. At the odds of 3-8 individuals per million – ZRT has been instrumental in discovering two cases of pheochromocytoma tumors in the last six months. A condition that my clinical physiology teacher, Dr. Bettenburg, said was so rare that we would never see one, and if we did, we should contact her – so I did, this week. 

What is Pheochromocytoma?

Pheochromocytomas are tumors occurring primarily in the adrenal gland (85%) and the abdomen (98%), while approximately 2% occur in other parts of the body (brain excluded). While they are extremely rare, they can run in families, have been associated with other syndromes and genetic abnormalities, and can sometimes be malignant (most likely in non-adrenal tumors). A pheochromocytoma secretes catecholamines that activate a cascade of "fight or flight symptoms" without a cause.


The catecholamines include epinephrine, norepinephrine, dopamine, and dopamine’s metabolite DOPAC (tested in ZRT's NeuroAdvanced profile). The catecholamines are so called because they consist of a chemical structure called a catechol, which is a benzene ring with two adjacent hydroxyl groups and an amine-containing side-chain. They are derived from the amino acid tyrosine which comes either from the diet or synthesized in the body from phenylalanine, and are produced by the adrenal medulla and the sympathetic nervous system.

Their job is to respond to acute stressors – a fear, a threat, intense sound or light, low blood sugar, or any other trauma. When the chromaffin cells of the adrenals or the postganglionic fibers of the nervous system respond to a trigger, they dump vast amounts of catecholamines into the system, acutely causing an increase in heart rate, blood pressure, blood sugar, alertness, and lung volume, changes to skin circulation, digestive slowing, dilation of the pupils, inhibition of erections, dilation of blood vessels to the muscle, and mobilization of glycogen and fat for energy production.

All of these effects happen within moments, and the entire brain system, from the amygdala – hypothalamus – pituitary – adrenal glands and the entire sympathetic nervous system are activated almost instantaneously. These catecholamines are then broken down, mostly by the enzyme monoamine oxidase (MAO), into their metabolites VMA, HVA, and normetanephrine (NMN). 

Consequences of Catecholamine Production in the Absence of Stressors

So, what happens when you are producing these catecholamines when you don't have reason to? You can have symptoms that look just like panic attacks, hypertension, irregular heart rates, and headaches; all conditions that are much, much more common than a pheochromocytoma. Like these more common conditions, the symptoms of pheochromocytoma happen in "spells" that can occur at varying frequencies from daily to monthly, and thus a rare tumor is not likely to be the cause that gets considered.

Symptoms of pheochromocytomas [2] which happen episodically include:

  • Hypertension
  • Headaches
  • Palpitations/Irregular heart beat
  • Tremors
  • Anxiety
  • Nausea
  • Epigastric pain
  • Flank/back pain
  • Constipation
  • Weight loss

However, in two instances, ZRT testing found that these common symptoms were in fact indicative of pheochromocytoma. Interestingly, only one patient had the classic severe hypertension that a differential diagnosis of pheochromocytoma requires. The other patient's main symptoms were anxiety, irregular heart rhythms, tremors, and anxiety; symptoms that never suggested a pheochromocytoma in the differential diagnosis. 

What is the Pheochromocytoma Test? Routine Neurotransmitter Testing.

It's extremely likely that as we do more neurotransmitter testing we will determine that these tumors are not that rare after all.

Pheochromocytomas are traditionally diagnosed by plasma metanephrine testing or by 24-hour catecholamine and metanephrine testing. It is clear that ZRT's 4-point urine testing is just as accurate. Urine testing is not as sensitive, but is very specific while plasma (blood) testing is very sensitive, but not as specific [3]. When pheochromocytoma is suspected, lab tests are followed up by abdominal CT or MRI and additional blood work to screen for genetic mutations that contribute to pheochromocytoma. Treatment is surgery with the best anesthesiologist you can find, because just touching these tumors can cause massive dumping of catecholamines and spikes of blood pressure that can be life threatening. Once removed, unless malignant, patients do extremely well.

We are so happy that the two people who were helped by ZRT in the discovery that they had pheochromocytoma will receive the care they need to finally feel better. It's extremely likely that as we do more and more neurotransmitter testing we will determine that these tumors are not that rare after all.

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