MS and Heat, Why?

[CureOrBust]

Hi,

This seems like such a "known", yet I cant find any distinctive medically accepted reason for it. ie MS'ers heat intolerance.

What are the current thoughts on this by the medical profession?

I understand the Prokarin / histamine train of thought, but i am guessing this is not the general practice / accepted reason. or is it?

I am guessing there must be some "accepted" rationale behind it considering Ive herd it was the old way to diagnose MS.

[HarryZ]

I understand the Prokarin / histamine train of thought, but i am guessing this is not the general practice / accepted reason. or is it?

I am guessing there must be some "accepted" rationale behind it considering Ive herd it was the old way to diagnose MS.

The big problem with MS is that most theories that try to explain the disease are just that ...."theories". After decades of research, the scientists still don't know what causes the disease. They can't prove it's an auto-immune disease. In fact, they can't prove much if anything about MS!

The Prokarin theory about heat is as good as any of them. For years I had read that the heat problem was caused by the nerves not operating properly. Then a couple of years ago at a fatigue seminar, the neuro told the audience that there had been new thoughts that a lack of a certain metabolism in the brain was the culprit. To me that leaned more toward the Prokarin theory than what was previously thought for years.

My wife used to be totally intolerant of any heat. Sitting in the sun for just a few minutes would turn her into a "noodle"! After being on Prokarin for 6 years, she is far more tolerable to the heat and humidity.

So you use what works for you when it comes to MS and let the experts fight among their theories!

Harry

[Melody]

John could not tolerate summers for several years until last summer. Prior to copaxone by the way. It was either the flax seed or the turmeric or maybe the vitamin D.

[NHE]

This seems like such a "known", yet I cant find any distinctive medically accepted reason for it. ie MS'ers heat intolerance.

If I remember correctly, heat acts to slow nerve conduction velocity potentially through an inhibitory effect of potassium channels. A small change in conduction velocity can cause a worsening of symptoms especially with nerves which are already damaged due to demyelination.

A few years ago I attended a seminar by a researcher who was studying mutant potassium channels in fruit flies. This mutation caused the flies to be particularly sensitive to heat. The speaker put a glass vial of flies on an overhead projector and within a few minutes the flies stopped moving. They began to slowly move around again after cooling off for a few minutes.

A PubMed search on 'potassium AND channel AND heat' brings up a few articles which may be of interest.

NHE

[NHE]

OK, this is a bit of an older paper but it does provide evidence supporting the role of heat induced nerve conduction velocity deficit in MS.

• Effect of raising body temperature on visual and somatosensory evoked potentials in patients with multiple sclerosis.
  J Neurol Neurosurg Psychiatry. 1979 Mar;42(3):250-5.
  
  The effects of raising body temperature on the visual (VEP) and somatosensory (SEP) evoked potentials were observed in normal subjects and in patients with multiple sclerosis. The amplitude of the VEP was significantly reduced to the same degree after heating in normal subjects and in patients with multiple sclerosis but there was no effect on the latency of the potential. Changes in amplitude could not be related to reduction in acuity. In contrast, the cervical SEP was greatly disorganised after heating in many patients with multiple sclerosis while the only effect in normal subjects was to reduce the latency by increasing peripheral conduction velocity. These results suggest that heat caused conduction block in demyelinated axons in the sensory pathways of the cervical spinal cord.

NHE

[Brainteaser]

I can't help with the 'why' regarding the effect of heat on MS. However, it is something which affects me, also. It is noticeable when I sleep on my back rather than my side, for any period of time. I have greater difficulty getting out of bed. This suggests that it is not the raising of the body temperature, per se but the raising of the temperature of just the spinal column. Perhaps someone needs to invent a spinal column temperature stabilising device?
Regards,
Phil.

[jimmylegs]

oh sleeping on my back messes me up too. stupid walls keep getting in my way when i get up.

as far as gimpy handedness goes, i think my nerve conduction gets just as messed up when i'm out in the cold as it does when i sleep on my back.

couple of abstracts re normal nerves, demyelinated nerves:

Muscle Nerve. 1994 Mar;17(3):336-44.

Nerve conduction and temperature: necessary warming time.

Franssen H, Wieneke GH.

Rudolf Magnus Research School in the Neurosciences, Department of Clinical Neurophysiology, Utrecht, The Netherlands.

The purpose of this study was to estimate the time needed to warm an extremity prior to measuring nerve conduction. In 8 normal subjects tibial and sural nerve conduction variables were measured during cooling and warming of the leg in water of 18 degrees C and 36 degrees C, respectively. During cooling, nerve conduction velocity (NCV) decreased and distal motor latency (DML), duration, and area of the compound muscle action potentials (CMAP), and compound nerve action potentials (CNAP) increased. The reverse occurred during warming. During cooling or warming the change in these variables became progressively smaller with time. The time course could therefore be described by an exponential relation, the parameters of which were determined. On the basis of these data, correlations were calculated between the skin temperature at the start of the investigation and the warming time needed to obtain a good estimate of nerve conduction variables at 36 degrees C. The use of correction factors, instead of actual warming, yielded acceptable errors only for NCV and not for the other variables.

J Neuroophthalmol. 1995 Jun;15(2):70-8.

Comment in:
J Neuroophthalmol. 1995 Jun;15(2):63-9.

Visual evoked potentials during hyperthermia.

Saul RF, Hayat G, Selhorst JB.

Department of Neurology, Geisinger Medical Center, Danville, Pennsylvania, USA.

OBJECTIVES: We sought to evaluate the effect of hyperthermia (HT) on central conduction pathways by alterations in pattern visual evoked potentials (PVEPs) in normal and demyelinated optic nerves. MATERIALS AND METHODS: We studied PVEP peak latency and amplitudes in 10 normal subjects and six patients with demyelinating optic neuropathy before and during HT. RESULTS: In normal subjects, a mean rise in temperature of 2.5 degrees C resulted in a decrease in the second positive peak (P2) latency of 6.1 ms (p < 0.0001) and a slight decline in P2 amplitude of 1.16 muV (p < 0.009). These results were compared to those obtained from six patients with multiple sclerosis. These patients had a history of monocular optic neuritis; two patients had had bilateral optic neuritis, and one patient had not had involvement of the optic nerve. Average temperature elevations during PVEPs were 1.60 degrees C. PVEPs among these patients showed decrease in mean P2 latencies, except in patients with multiple sclerosis, who showed an increase in latency with 60 min check size in the left eyes. There was a consistent decline in P2 amplitudes. Loss of amplitude was greater among the six optic nerves of those patients having transient, mild losses in visual acuity during HT. Reductions in P2 amplitude were best explained by partial or complete conduction block. CONCLUSIONS: These changes in conduction time and amplitude during HT provide a neurophysiologic correlation to the well-known sensitivity of demyelinated optic nerves to elevated temperatures. They are also relevant to the monitoring of central pathways in the operative or intensive care setting. The demonstrated reversible loss of amplitudes also gives promise to therapeutic manipulation of impaired pathways by impeding the loss of current from denuded nerve fibers.

[CureOrBust]

thanks all, I have been off-line a couple of days, and so have come back to a wealth of info to read.

The reason I was interested in the heat / MS thing is that I dont think i personally am heat intolerant. I was also not personally reactive to prokarin (ie it didnt work any wonders for me) AND I am definitely MORE affected by being cold. Its as if when i am cold my muscles go stiff, and it becomes harder to control them.

Further on the heat thing, I also have a well below average body temperature. "normal" is suppose to be around 37C (98.6F) but I hover around the low 36's (96.8F).

[HarryZ]

The reason I was interested in the heat / MS thing is that I dont think i personally am heat intolerant. I was also not personally reactive to prokarin (ie it didnt work any wonders for me) AND I am definitely MORE affected by being cold. Its as if when i am cold my muscles go stiff, and it becomes harder to control them.

If you are not susceptible to the heat and more effected by the cold, the general rule is that Prokarin won't likely help you all that much, if any. Just curious to ask if you suffer from fatigue or not because usually if MS patients are bothered by the heat, they suffer from a lot of fatigue as well.

Harry

[jimmylegs]

Its as if when i am cold my muscles go stiff, and it becomes harder to control them.

i think that happens to everyone at low temps, per the abstract i posted. certainly always happened to me when working outdoors in winter, since long before ms.

likely it happens more easily when the nerves are compromised. my hands went dead outside today and it was 13 degrees or so, not really that cold. we nervetards probly have a steeper slope on our conduction-temp curves, what say?

[Brainteaser]

I don't want to alarm people but heat intolerance may be linked to the length of time one has had MS. I am reminded that my intolerance to heat commenced after about Year 15 of MS and has got progressively worse over the past 9 years. I recall vividly it first occuring whilst holidaying in Mauritius......So, I'm not sure it (heat intolerance) is a 'black' or 'white' phenomenon, but rather something that develops over time - at least that's what happened for me, anyway.
Regards,
Phil.

[mrhodes40]

Phil,
I agree with you. For years I said heat did not bother me, so this seems to be my experience as well. it sure does now!
marie

[lyndacarol]

Phil, Marie...I echo your statements exactly! Heat did not bother me in the past; today I soon become a "noodle" with just a bit of heat!

[CureOrBust]

If you are not susceptible to the heat and more effected by the cold, the general rule is that Prokarin won't likely help you all that much

Yeah, i read that, but hoped for the best.

if any. Just curious to ask if you suffer from fatigue or not because usually if MS patients are bothered by the heat, they suffer from a lot of fatigue as well.

fatigue is a definite for me, but not heat.

I have had MS for about 10years (but only diagnosed just over a year ago), which got significantly worse about a year ago.

[Niko]

I rarely chime into the conversations here. But I am an avid reader.

On this topic, I will add to. My fatigue greatly increases when heat *and* humidity are involved.

If it's a nice day out and 80 degrees(F) and very low humidity I am just fine.
But, if it's the same temp with high humidity, I'm huddling near an A/C drinking ice water.

In any event, keep yourselves cool and comfortable

- Niko