[NeuroLogic]

Neurologist Phillip A. Low, M.D., founded the autonomic nervous system testing laboratory at the Mayo Clinic about 30 years ago. He and his colleagues set standards for quantified evaluation of autonomic function, including the thermoregulatory sweat test (TST).

A 2006 study entitled "Thermoregulatory Sweat Testing in Patients With Erythromelalgia" (pdf) [WARNING: Graphic Medical Image] reached the conclusion that small-fiber neuropathy is prevalent in most patients with erythromelalgia; and Thermoregulatory Sweat Testing is a sensitive and useful marker of small-fiber neuropathy in these patients.

I believe I've had peripheral neuropathy for several years, and I've noticed in the last year especially that my skin would heat up in different places inexplicably but then never sweat, so I couldn't cool down easily. I still wake up every night feeling too hot. (The anomaly is that my core temp. is cold at 96.8F.)

It seems skin pressure triggers a nerve reaction. When I stand, my left foot feels hot. When I sit, the same type of thing. When I lie down on my side, it soon feels uncomfortably hot.

Sometimes my skin will feel hot (but it's actually cold; for example, if I touch it with my hand). Other times it is actually hot, but there's no sweat. It feels as if the heat gets trapped. My pillow (water) also gets extremely hot during sleep even when the RT is 18C, but there's never a drop of sweat.

Does anyone else have anything like this? Or have you ever got a Thermoregulatory Sweat Test?

[Don_S]

Huh! Interesting.

I sometimes wake in the night with my legs covered in sweat. This occurs even on nights when the room temperature is cool.

My neuropathy only causes numbness and slight burning on the soles of my feet, and some numbness on the tops of my feet.

I'm not entirely sure the PN is causallly linked to the sweating, but the study you link to is provocative! Thanks.

[NeuroLogic]

Originally Posted by Don_S

Huh! Interesting.

I sometimes wake in the night with my legs covered in sweat. This occurs even on nights when the room temperature is cool.

My neuropathy only causes numbness and slight burning on the soles of my feet, and some numbness on the tops of my feet.

I'm not entirely sure the PN is causallly linked to the sweating, but the study you link to is provocative! Thanks.

I thought I had sensory nerve damage.

"Smaller sensory fibers without myelin sheaths transmit pain and temperature sensations. Damage to these fibers can interfere with the ability to feel pain or changes in temperature."

http://www.ninds.nih.gov/disorders/p...neuropathy.htm

I was hoping I didn't also have autonomic nerve damage.

"Common symptoms of autonomic nerve damage include an inability to sweat normally..."

http://www.ninds.nih.gov/disorders/p...neuropathy.htm

Progression of sensory nerve damage can be annoying but it sounds as if worsening autonomic nerve damage can lead to much more serious health problems.

[mrsD]

The actions of the autonomic nervous system on blood vessels is called vasomotor.

http://en.wikipedia.org/wiki/Vasomotor



Drugs can affect vasomotor tone as well as endogenous biogenic amines like serotonin and bradykinin. Endogenous epinephrine and acetylcholine also control vascular tone.
And this article while complex does explain the role of serotonin in hot flashes:
http://docs.google.com/viewer?a=v&q=...D1BXON-YWJ7pqQ

And men also have hot flashes:
http://www.health.harvard.edu/newswe...-An-update.htm

It can be quite complicated. Women learn this during menopause, as vasomotor side effects manifest then. Called hot flashes.

Many people also discover as they age, that using a top sheet is not a good idea in bed. This prevents air circulation around the legs and feet. Using a light cotton woven blanket (not a soft pile type) may be helpful in winter. Also switching to jersey bottom sheet allows air to circulate around your body at night. Finding a fabric for jammies, that is waffle woven, is also helpful. Normally during the day we are upright most of the time, so we have 360 degree air circulation around us. At night part of us is blocked from the air, and that can create heat problems. If you use a tempurpedic mattress or top cover, it is worse as this traps heat.
We give off many organic gasses thru our skin, and this gets blocked when sleeping. I've read that about 100 compounds are excreted thru our skin daily. So having fabrics that allow air to move around us at night can be important.

[glenntaj]

--with documented small fiber neruopathy, especially from metabolic (i.e., diabets, thyroid) or autoimmune causes (which would likely include a lot of "idiopathic" people) have some degree of autonomic dysfunction.

For many people, fortunately, this is fairly limited, even subclinical, and only revealed through specialized testing, such as the sweat test. This occurs as the autonomic fibers are also unmyelinated and fall into the category of "small fiber" (as mentioned, the other "small fiber" nerves subsume the sensation of pain and temperature; some neurologists will refer to these fibers as "free nerve endings").

The most common manifestation of this small scale dysautonomia is blood pressure changes, but sweat disruptions and digestive/eliminative disruptions are also fairly frequent.

http://neuromuscular.wustl.edu/senso...ml#sfpnchronic

http://neuromuscular.wustl.edu/autonomic.html

[cyclelops]

I came out of my test completely orange....I was supposed to be purple. I was the orangiest that they had seen. That said, if I get nervous, I can sweat buckets.

[NeuroLogic]

"Of the 2 methods for testing the sweating mechanism, TST is more sensitive than QSART."

"Some patients with erythromelalgia (perhaps 5%-10%) cannot tolerate the test..."

I don't know if I have erythromelalgia, but I doubt I would survive the TST.

"The patient is enclosed in a cabinet with 45°C-50°C air temperature and 35%-40% relative humidity... Maximal sweating is generally achieved in 30 to 65 minutes."

I feel extreme stress when the room temp hits 25C. Today I was in a room that was 26C and my chin nerves got very agitated, too. My body reacts within seconds of the temp rising.

I'm starting to suspect the failure to sweat allows the heat to rise so high it virtually burns and actually damages nerves.

Recently I'd wake up with cold feet. I can't raise the RT and still get to sleep so I wore socks. Now my ankles are sensitive and feel burning instead of just my feet.

A few years ago, I was reading a book while lying on my back. My back felt a little hot, but I ignored it and kept reading. Shortly afterwards I felt a muscle spasm, and not long afterwards, and to this day, I cannot lie on my back comfortably without a cooling pad. Otherwise the twitches or spasms return and I feel very stressed out.

I used to think the problem was with my hypothalamus, because it regulates temperature, but now I'm not so sure.

"Erythromelalgia is a rare neurovascular peripheral pain disorder in which blood vessels, usually in the lower extremities (or hands), are episodically blocked (frequently on and off daily), then become hyperemic and inflamed. There is severe burning pain (in the small fiber sensory nerves) and skin redness. The attacks are periodic and are commonly triggered by heat, pressure, mild activity, exertion, insomnia or stress."

My attacks have been triggered by heat, pressure, insomnia and stress, and they have affected my feet and hands, but there hasn't been any skin redness I've noticed, so I don't know if I've got Erythromelalgia.

There were times in the last year, but not so much lately, where I'd feel too hot and then five seconds later too cold. This oscillation would happen repeatedly in a short period of time, like 5-10 minutes.

As I mentioned in another thread, one time when I do sweat, but only a little, is just after coming out of a nap. My hands and feet tingle without pain for about 30 seconds, and both get slightly moist/almost sweat.

I've suspected an endocrine issue that could be affecting nerves and sweat glands. I've had some kind of chronic fatigue for decades. The current chronic heat sensitivity typically caused insomnia which worsens the fatigue/prevents full recovery after rest.

I made a breakthrough of some kind recently when I read about how the body cycles during sleep.

[Couponmom2003]

My 2 year old has some form of anhidrosis, and we are trying to find out more. Is the mayo clinic the only place you can get a therm irregularity sweat test done?