OK I lost it...heat stroke and heat exhaustion.

[mycrofft]

I am morally certain I read in an article or a manual that heat stroke and heat exhaustion are two different maladies (although you can have both), and that you do not have to progress through exhaustion to stroke.
Second, once a pt experiences heat stroke, despite prior hx, she/he is much more prone to heat exhaustion later . However, and despite personal observation supporting these, I cannot for the life of me find a citation. Anyone have one off the top of their heads?

 

[RustyShackleford]

It's not a great medical citation but in this article from the New York Times it insists that people that have suffered heat stroke in the past through MRI's and autopsies don't have damage to their hypothalamus therefore I am not sure if they are more susceptible to it in the future when it comes to a neuro response but maybe there is a thermo/metabolic tendency to be susceptible to it in the future.....I'm sure someone will chyme in with more experience on the subject.


http://www.nytimes.com/2010/06/15/health/nutrition/15best.html?_r=1&ref=health

 

[Sandog]

It is my understanding that heatstroke is a progression from heat exhaustion. Much like a overheating car due to lack of radiator fluid.

http://www.mayoclinic.com/health/heat-stroke/DS01025

 

[johnrsemt]

As a medic for multiple years at a Scout camp (both all summer and just for a week or 2) we had multiple patients with Heat Stroke that never had symptoms of Heat Exhaustion. Some had both one after the other; others had Heat Stroke with some of the symptoms of Heat Exhaustion at the same time just to be different.

As far as everything I have learned they are 2 seperate illnesses, and you do not have to have exhaustion to have Heat Stroke.

 

[johnrsemt]

Oh and we found out the hard way that you can get either or both while you are drinking alot of fluids (and I mean ALOT); had a staff member that had one of each about 4 weeks apart and he drank on average 5 gallons of water per day. And was witnessed drinking alot the 2 times he went down.

 

[mycrofft]

THanks so far!
My experience was with Nat Guard troops in the field including wearing MOPP gear (chemical warfare suits and masks). I saw exhaustion, stroke without exhaustion, a guy who sweated white (I am not exaggerating) who went on to heat exhaustion. Also saw a number of heat victims during a heat wave in Nebraska (1981), mostly older people without air conditioning.

BTW, NONE of the exhaustion victims were eating their meals, either. One wonders about protein, electrolytes and energy resources without these.

 

[mycrofft]

Good reference from the Mayo Clinic layperson article!!

http://www.merckmanuals.com/profess...illness/heatstroke.html?qt=heat stroke&alt=sh

Two types of heat stroke!

BTW for the "ice their groin and axilla" folks (ibid):

"Ice packs applied to the axillae and groin can be used but not as the sole cooling method. In life-threatening cases, packing a patient in ice, with close monitoring, has been advocated to rapidly reduce core temperature".


EDIT: OK, after digging, I do not find recent professional citations that heat illness/exhaustion is the necessary precursor to heat stroke. It is in the popular literature. I don't see why someone who is going into heat stroke cannot also experience heat exhaustion especially if there is an exercise component, but not as an absolute every-time thing.

 

[Sandog]

THanks so far!
My experience was with Nat Guard troops in the field including wearing MOPP gear (chemical warfare suits and masks). I saw exhaustion, stroke without exhaustion, a guy who sweated white (I am not exaggerating) who went on to heat exhaustion. Also saw a number of heat victims during a heat wave in Nebraska (1981), mostly older people without air conditioning.

BTW, NONE of the exhaustion victims were eating their meals, either. One wonders about protein, electrolytes and energy resources without these.

Perhaps the progression was so rapid as to not recognize the earlier signs.

 

[mycrofft]

Maybe. The signs are almost diametrically opposite, though.

I do NOT know how folks in SW Asia get used to wearing body armor and battle gear during the summer...then run around and maybe have to fight? Special physiology.

 

[Sandog]

Maybe. The signs are almost diametrically opposite, though.

I do NOT know how folks in SW Asia get used to wearing body armor and battle gear during the summer...then run around and maybe have to fight? Special physiology.

I am sure there are evolutionary physiological adaptations amongst races. Take the Inuit in Alaska for example.

 

[hippocratical]

You guys are way more senior/experienced than me, but my understanding was that:

Heat exhaustion: Symptoms caused primarily by dehydration and hypovolemia due to excessive sweating

Heat Stroke: If your body is unable to cool you below an internal temp of 41C then your enzymes start denaturing which'll kill ya quick

Please feel to correct me!

Oh, and regards to:
"I do NOT know how folks in SW Asia get used to wearing body armor and battle gear during the summer...then run around and maybe have to fight? Special physiology."
I traveled to SW Asia overground slowly (like 8 months from England to there) and when I was there I was fine in long pants and a shirt. Sweaty sure, but fine. The tourists who flew in were melting! Very amusing!

 

[Steam Engine]

THanks so far!
My experience was with Nat Guard troops in the field including wearing MOPP gear (chemical warfare suits and masks). I saw exhaustion, stroke without exhaustion, a guy who sweated white (I am not exaggerating) who went on to heat exhaustion. Also saw a number of heat victims during a heat wave in Nebraska (1981), mostly older people without air conditioning.

BTW, NONE of the exhaustion victims were eating their meals, either. One wonders about protein, electrolytes and energy resources without these.

Oh and we found out the hard way that you can get either or both while you are drinking alot of fluids (and I mean ALOT); had a staff member that had one of each about 4 weeks apart and he drank on average 5 gallons of water per day. And was witnessed drinking alot the 2 times he went down.

Exertional hyponatremia?

 

[shfd739]

Exertional hyponatremia?

Seems like Ive heard of this but its been way too long.

I do remember my former vollie FD/EMS chief who was an occupational health nurse by trade and much smarter than me always pushed gatorade and salty snacks during rehab. We kept granola bars and peanut butter crackers on the rescue unit along with chilled water and gatorade. He also pushed us to drink a 20oz water or gatorade on the way to calls during hot weather.

Not sure how much it helped but we never had anyone go down.

 

[RocketMedic]

Maybe. The signs are almost diametrically opposite, though.

I do NOT know how folks in SW Asia get used to wearing body armor and battle gear during the summer...then run around and maybe have to fight? Special physiology.

Lots of conditionin, lots of food, intelligent and steady movement and load planning, and vehicle support. Food and water cannot be overstated. I was eating 8 -9000 calories a day and losing weight in summer 2010.

 

[Veneficus]

Mycrofft,

there is a PDF that an army scientist (doctor may be a strong word) where he researched and detailed heat related emergencies in the most detail I have ever seen. PM me your email (so I don't have to search for it ), and I will fire it off to you.

As for drinking water and dehydrating.

This is one of the biggest misconceptions I have ever seen. (Especially in a desert)

Your body does not absorb free water.

Your kidney reabsorbs water that is attached to NA, K, CL, and glucose.

So if you have lots of water but none of the above, you are just going to urinate it out at some point and be worse off because you think the water your drinking is helping when in fact you are experiencing net loss.

Either in the way of a snack or hydration formula that includes it, you must have these elements. (petroleum flavored water at KAF doesn't count)

The WHO has figured this out in drought populations decades ago and even have a cheap oral rehydration formula available on their website.

Before you give up your power or gatorade though, fair warning, the WHO formula may not cost but pennies, but it tastes like :censored::censored::censored::censored:.

 

[onrope]

Mycrofft,

there is a PDF that an army scientist (doctor may be a strong word) where he researched and detailed heat related emergencies in the most detail I have ever seen. PM me your email (so I don't have to search for it ), and I will fire it off to you.

As for drinking water and dehydrating.

This is one of the biggest misconceptions I have ever seen. (Especially in a desert)

Your body does not absorb free water.

Your kidney reabsorbs water that is attached to NA, K, CL, and glucose.

So if you have lots of water but none of the above, you are just going to urinate it out at some point and be worse off because you think the water your drinking is helping when in fact you are experiencing net loss.

Either in the way of a snack or hydration formula that includes it, you must have these elements. (petroleum flavored water at KAF doesn't count)

The WHO has figured this out in drought populations decades ago and even have a cheap oral rehydration formula available on their website.

Before you give up your power or gatorade though, fair warning, the WHO formula may not cost but pennies, but it tastes like :censored::censored::censored::censored:.

I would like to see the PDF to enlighten some people. Had a situation recently where someone went down during a strenuous hike. IV saline and d50 did wonders. No thyamine in protocols down here. Any better ALS interventions?

 

[mycrofft]

As I've mentioned before, when I was working in parallel but independently from my MD's at a big summer exercise, we found oral rehydration and meal discipline was as successful at returning troops to duty as was intravenous fluids. None of our patients on either side were so obtunded as to require parenteral (non-oral) measures. I was the goad, bugging people, stopping people in their chem suits who were looking overtired (poor balance, just sitting downing the middle of ops) and either making them drink or (more frequently) taking them back to the medical tent to de-suit and soak up some 1/2 strength Gatorade and 100% water.

Veneficus, isn't water absorbed form the large bowel but retained by the kidneys? (Sometimes I have wished the bladder could reabsorb water).

 

[Veneficus]

As I've mentioned before, when I was working in parallel but independently from my MD's at a big summer exercise, we found oral rehydration and meal discipline was as successful at returning troops to duty as was intravenous fluids. None of our patients on either side were so obtunded as to require parenteral (non-oral) measures. I was the goad, bugging people, stopping people in their chem suits who were looking overtired (poor balance, just sitting downing the middle of ops) and either making them drink or (more frequently) taking them back to the medical tent to de-suit and soak up some 1/2 strength Gatorade and 100% water.

Veneficus, isn't water absorbed form the large bowel but retained by the kidneys? (Sometimes I have wished the bladder could reabsorb water).

attaching your files now...

Most water is absorbed by the small bowel.

The kidney has the ability to retain or excrete water. But its ability to retain is based on what I listed above.

If you don't have any, the kidney cannot retain water. SIADH and diabetes insipidus demonstrate this really well.

But I am sure you remember urine is not the only way to lose water.

You are right on point about oral rehydration being not only the most common, but most effective method.

 

[mycrofft]

After following people exercising in chem gear for hours in 90 deg heat and seeing the sweat outlines they left after I had them lay down on cool concrete like lizards, I'm very cognizant of "insensible" water loss. Always a shock to remove your gas mask and seeing the sweat actually drain out.

Bowel absorption: OK, my old text was saying the large bowel was reclaiming much of the water REMAINING after passage through the small bowel.
Nice bit from univ of Colorado, cited without permission:

http://www.vivo.colostate.edu/hbooks/pathphys/digestion/smallgut/absorb_water.html

 

[FLdoc2011]

Little different, but SIADH and DI are more about free water balance then disturbances in electrolyte absorption/secretion, despite the abnormal sodium lab findings.

Different from what's being discussed above as far as sweating and exertional losses where you're losing electrolytes that need to be replaced.