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> This was sent to me from a
> old friend (veterinarian) Tom Dombroski.
Since this topic is being addressed on both Ridecamp and the AERC list,
pardon me if I reply to both places in the sake of saving myself some time
this morning.

First off, my condolences to Darolyn, and I also commend you, Darolyn, for
being willing to freely share your observations regarding both Adios and
Albanet. What the rider observed (both short term and long term) is an
important part of understanding what is going on here.

I think Drs. Dombroski and Henneman are on the right track here, and I'd
like to add a few more thoughts/observations of my own--some concurring,
some not.  And I'll also address some questions/comments that have been
added by other posters as well.

First, yes, I'm sure that travel and change in climate were a factor in both
horses.  These are factors in virtually ALL horses in major events such as
WECs and Pan-Ams.  They are unavoidable if we are going to have such
events--and the bottom line is to recognize that they are stressors and ride
accordingly.  With regard to altitude--I think it is far less of a factor
than the other two.  Horses tend to function far better with an increase in
altitude than people do.  Still, it is one more small straw on the
proverbial camel.

Second, Dr. Dombroski has HIT THE NAIL ON THE HEAD with regard to ileus--but
add to the ileus (shut-down of the gut motility) the fact that these horses
also have an imbalance going on at the cellular level that interferes with
how water and electrolytes are transported across the cell membranes and
incorporated into the cells.  (I don't have Dr. Henneman's post in front of
me, but I think she was alluding to this as well.)  Basically, what you have
left is a bag (the stomach) that holds at most about 2 gallons (and will be
uncomfortable at that) from which there is no longer any outlet and which is
no longer permeable to fluids.  So--you pump it full of fluids, and it
stretches to capacity--and beyond capacity it breaks.  I've NEVER liked the
practice of administering fluids to metabolically compromised horses via
stomach tube, and I honestly thought the practice had gone out the window.
Guess not.  I concur with Dr. Dombroski that this is NOT an acceptable
veterinary procedure in metabolically compromised horses and will go so far
as to say that Adios might have been salvageable right up to the point that
inappropriate veterinary intervention effectively ended his life.  To give
the benefit of the doubt--there is also always the possibility that the
horse drank himself to this point before the fluids were administered--but
given Darolyn's description from the time of treatment, I doubt it.

I'd also share an episode here from my own experience treating one
particular compromised horse with regard to hypocalcemia and ileus--I had
one horse several years ago that presented with a post-ride colic and
dehydration with which we intervened with intravenous fluids.  We were just
beginning to realize the importance of calcium then, and I didn't just
automatically add a bit (which I likely would now).  We had roughly 15-20
liters of fluid on board and some pain meds, and the horse suddenly started
to get REALLY uncomfortable.  I suspected an ileus, and I had a milk fever
product in my kit (high calcium), so I started carefully adding that,
monitoring the heart to make sure we weren't running the calcium in too
fast.  In about 10 minutes, the horse gratefully humped up and started to
urinate--and peed, and peed, and peed, and PEED!  His problem was that his
BLADDER couldn't contract, either, given the lack of calcium!  Thank heavens
we gave it in time, and didn't rupture THAT!  His pulse dropped to
near-normal levels, we continued to rehydrate for a bit, but he went on to
an uneventful recovery.

To back up a step, and to try to understand how Adios GOT to the point of
needing intervention...  Travel and climate have been considered, and are
factors.  I agree with Darolyn that the stress of the separation from the
traveling buddy is a likely contributor, and with Dr. Henneman that there
are physiological responses to such stressors that impact the horse
metabolically.  Where I part company with the conclusions drawn is with
regard to handling the problem by iatrogenically adding MORE concentrated
electrolytes!   One has to understand that the horse is NOT just a big
mixing vat where one has to dump in the right ingredients to keep the
mixture in some sort of homeostasis.  One poster on ridecamp has already
alluded to human literature with regard to hyponatremia about how one does
not effectively absorb the sodium in sports drinks once one has gotten
borderline, but rather has to consume the sodium in FOOD.  Consider how the
gut normally processes things.  Sodium and other e-lytes normally come along
in the presence of food and/or water.  The gut is designed also to handle
water that does not have e-lytes in it, and to absorb it across cell
membranes.  Adding concentrated e-lytes causes the water gradient to be just
the opposite of what one desires--it tends to draw fluid INTO the gut,
unless the gut is in sufficiently good shape to actively transport those
ions across cell membranes and into the cells and the circulation.  We are
talking here about horses that are ALREADY compromised, and Darolyn herself
has stated that both Adios and Albanet exhibited a reluctance to drink the
less-than-pure water on the trail but tanked up on the really clear stuff in
camp.  They were trying to tell you something, and that is that it is WATER
they crave, NOT more e-lytes!  I submit that MORE e-lytes (at least
administered orally) in such a situation would be apt to make the metabolic
problem worse, NOT better.  Yep, bloodwork might still indicate that they
need them IN THE CIRCULATORY SYSTEM.  That is NOT the same thing as needing
to dump more of them into the gut, where they may actually AGGRAVATE the
need in circulation!  What this horse is telling you is that it is time to
STOP and to intervene--but by getting the fluids and e-lytes directly into
the circulation where there is some hope of them doing some good.

I would add here that it is precisely this sort of scenario which makes me
question the levels of e-lytes that we orally shove down some of these
horses.  If the horse truly "needs" this much e-lyting to continue, perhaps
we are flirting with the envelope a little too much and should consider
managing the horse instead by slowing down, taking a longer break, and
eating more.

I'm going to throw another factor into the equation here as well, which I
don't think anyone has pointed out yet--and that is the family lines of
these two horses.  They share considerable family elements with other horses
that I've had to treat for ileus and for anterior enteritis--both of which
could lead to the set of symptoms Darolyn described.  I would submit that
heredity is an issue here as well--that some families have GI tracts which
become deranged more readily from stress and from fluid and e-lyte
imbalances than do others.  Slight differences in enzymes, cell membranes,
etc. are as heritable as correct or incorrect conformation, the shape of
one's face, or one's coat color.  That doesn't mean I'd throw out otherwise
talented horses just because they come from such families--but it DOES mean
that I'd be watchful of certain systems and particularly tuned to certain
clues if I were riding a horse from that family.  I've likewise seen family
lines (different ones than this one) that tend to thump and family lines
that seem more prone to tie-ups.  I think this sort of knowledge of the
metabolic strengths and weaknesses of family lines should be more actively
pursued so that one can watch out for specific problems in specific
individuals and be prepared to manage them accordingly.

Again, my apologies for "shotgunning" this reply to both lists, and again,
my condolences to Darolyn.

Heidi


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