Re: Follow up on Tying Up

["Susan Garlinghouse" <suendavid@worldnet.att.net>]

> to be a nutrition and management problem as exercise has been very
> gradual and at Falon's pace. Any thoughts would be appreciated,
> particularly yours Susan G.

I'm flattered that you think I might have an answer for you, but your vet is
more qualified than I am to figure out clin path stuff.  But, here goes
anyway---

>
> CPK  3649                            CPK 2500             100-300
> SGOT (AST) 3239                      AST  559             180-380

I wonder if there could be some chronic/permanant muscle tissue damage
and/or renal damage from the first tying-up episode.  I don't think the ASTs
of 559 are too much to worry about, but the increased CPKs indicate a recent
or ongoing episode, since the half-life is just a few hours (your vet
already knows this, but the half-life just means the time for half of the
remaining amount to clear out).  So there's something still going on for the
CPKs to still be elevated.  That doesn't necessarily mean an ongoing tie-up,
it can also be caused by dehydration, by muscle damage (like a strain or
something like that), or even your horse lying down for awhile (that's alot
of weight to be supported by any muscle group and the decrease in bloodflow
to an area can cause some release of CPKs).

The high calcium is still within normal limits and may just be due to the
very high calcium content in alfalfa.  However, high serum calcium can also
indicate renal disease, as can low sodium, assuming the horse has good
access to a salt block, and doesn't have any other sodium-losing things
going on, like diarrhea.

I wouldn't want to be the bearer of bad tidings, but I guess my own next
step would be ruling out renal disease with a complete blood panel and
definitely a urinalysis.  Even pulling a green top for blood gases wouldn't
be out of line, as I'd be interested to see if there were some metabolic
acidosis going on.  Blood gases will be alot easier if your vet has access
to an i-Stat, as you have to analyze those pretty quickly.  Some permanant
muscle damage/necrosis and associated renal damage could explain all the
findings you're seeing.   Don't be surprised if a UA comes back with
crystals in the urine, that's fairly normal for a horse on alfalfa.  I know
you've just done one blood panel, but I'd repeat it again to make sure those
muscle enzymes weren't just caused by her taking a little nap on hard
ground.  I'd also be interested in making sure liver function is okay---AST
helps indicate that (AST can be either from muscles or liver), also glucose,
cholesterol, bilirubin, bile acids and so on.

The other thing I would suggest is to take her off the alfalfa and just put
her onto plain grass hay (don't do it overnight, but take maybe two weeks to
make the switch slowly).  It is possible you can get most of these changes
due to the high calcium and protein in alfalfa, although it wouldn't explain
the borderline low sodium (which may be perfectly normal for this mare).
Check to make sure she really does have adequate access to some loose, plain
white salt (that no one else is driving her away or the block is so hard she
won't expend the effort to bite off pieces).  And as silly as it sounds,
make sure she's drinking enough---alot of these changes could be simply due
to dehydration if her water source is frozen, tastes bad or whatever.  Once
you had her onto grass hay, I'd give it a few weeks and run another panel to
see what if any changes had taken place.  That will at least tell you
whether the problem is nutritionally-based or pathologic (ie, kidney, liver,
muscle damage ,etc).

I wouldn't panic yet, Joanne---the plasma values are still within normal
ranges and the increased CPKs could just indicate she slept funny the night
before.

Keep us updated.

Best regards,
Susan G