To find out if it a patient has Hyperadrenergic POTS, specialized doctors typically order an endocrine test called a Catecholamine Blood Test. I had my test performed at Mayo Clinic’s Autonomic Clinic in Rochester, Minnesota. Want proof? Here is a glamor shot taken just prior to the test:
Okay, time to get serious! The Catecholamine Blood Test measures the patient’s dopamine, epinephrine, and norepinephrine levels. It is important for doctors performing the test to be aware of the importance of inserting an IV line then having the patient resting supine in a quiet, dark room prior to the supine blood draw for the most accurate results. Here’s an explanation of the proper procedure:
1) An IV line is put in place in the patient’s arm.
This is to draw blood later without triggering the release of catecholamines in reaction to the poke. Even if someone doesn’t mind needles, the body will release a bit of stress hormone in reaction to having a needle stuck into it.
2) The patient is left in quiet, dark room for 30 minutes. The patient should be supine, should be alone, and should not look at cell phone, magazines, or be listening to music.
This is to let the patient relax and let catecholamine levels come down to what will be used as the supine baseline level.
3) The technician will quietly come in the room and takes a blood sample through the IV line without speaking.
4) The patient is instructed to stand up and/or walk around for 10 minutes. Some centers have the patient remain upright for as long as 15 minutes.
5) Another blood sample is taken from the patient through the IV line, the IV line is removed, and the patient is free to go.
The doctor will compare the patient’s supine catecholamine levels versus the upright results to see how much the norepinephrine levels increased. My doctor at Mayo said it is normal for it to double and there are also lab reference levels available for what is “normal”. The increase in norepinephrine is not all the doctor will look at. High starting levels of certain catecholamines can indicate other problems such as the body not reuptaking norepinephrine correctly, however I’m no expert in that area.
Different doctors have different definitions of what qualifies as Hyperadrenergic POTS. Some say you need, POTS, hypertension, and high upright norepinephrine levels in order to meet criteria. Others say the only necessary symptom, aside from a POTS diagnosis, is abnormally high norepinephrine levels upright compared to supine. My opinion is the only qualification should be high upright norepinephrine levels. I don’t understand how it makes sense to look at an abnormal lab result, indicating excessive norepinephrine release during upright, but not supine posture, and conclude it indicates nothing simply because the patient doesn’t have high blood pressure. I think better labels would be Hyperadrenergic POTS with Hypertension/Hypotension/whatever. If you break down the word hyperadrenergic, my theory makes sense as it breaks down to mean quite literally, abnormal excess release of an epinephrinelike substance.
1. above, over, or in excess hypercritical
2. (in medicine) denoting an abnormal excess hyperacidity
Adrenergic: - adj.
1. Activated by or capable of releasing epinephrine or an epinephrinelike substance, especially in the sympathetic nervous system.
2. Having physiological effects similar to those of epinephrine.
If you don’t know much about norepineprhine and epinephrine (AKA noradrenalin and adrenalin), here are some resources that will quickly inform you without you needing to read pages and pages. For very easy, simple reads, click here (eHow) or here (Livestrong). If you like some technicality but still want a quick read, here is a short blog post on it. If you want a technical read with medical terminology, here you go (CV Physiology). I know eHow and Livestrong aren’t held in high regard, but the articles I linked are accurate from what I can see and are much easier to read and understand than a journal article!
Now, back to POTS subtypes! This article from Vanderbilt’s Autonomic Center asserts POTS subtype isn’t as important as previously thought in pointing to the underlying cause of a patient’s POTS. Rather than being thought of as pointing to a subtype, Vanderbilt believes testing should be thought of as pointing to a characterization which can be used to guide initial treatment. Part of the authors’ support for this approach is the fact different doctors use different criteria to diagnose Hyperadrenergic POTS which may be counterproductive for a patient going between different doctors who do not define a subtype the same. Several examples of how various doctors conclude a patient has Hyperadrenergic POTS are given. Some are way out there (to me anyway) such as just because a patient does not show any neuropathy or nerve damage (negative QSART), s/he has Hyperadrenergic POTS. I promise you, no reliable autonomic center would identify Hyperadrenergic POTS in this manner.
My concluding thoughts… I don’t really care if the doctor I am seeing thinks of my abnormal catecholamine test results as indicating a POTS subtype or simply as a characterization of my POTS. With how little is known about POTS, it was nice to have had QSART and Thermoregulatory sweat tests confirm I do not have any nerve damage or neuropathy going on, and catecholamine testing performed to confirm I do have adrenergic involvement. It also comforting to know my testing was performed with the highest standards in mind. I may not know much about what is going on in my body, but least I know one thing; my body’s norepineprhine levels increase 5 times when I go from supine to upright. I also know I do not have nerve damage which means this may be reversible. So, I actually know 2 things.
Mayo Clinic’s serum catecholamine reference levels for both supine and standing
Scroll down to “How to Prepare for the Test” for a list of foods and drugs to avoid prior to testing
Catecholamine testing for POTS in scientific literature (one article of many out there) — scroll down to Table 3 “Routine Evaluation of POTS” (Thought I’d throw it in here in case someone is trying to convince a local doctor to perform testing and needs empirical support)
My experience with catecholamine testing at Mayo — scroll down to “Endocrine Testing”