Bob wrote:
>In the last decade, there has been perhaps a dozen incidences of
>cystine stones, maybe up to two dozen
 
Replace "decade" with "year" and it is more accurate recently for what is
being seen in just one to two of the university urolith labs (depending
on the figure used).  So, it makes sense as a possible typo (?).  I can't
know what another meant, of course, and will not pretend that I do.
Also, remember that most stones don't get tested; instead there is a
tendency to assume that they are going to be the more common struvite
stones.  To top it off a number that get tested never wind up in urolith
labs -- just with one of the very many pathologists used by vets.  The
change in rates is why there is concern among researchers about possible
vulnerabilities been pushed; the figures changed suddenly and markedly.
Are cystine stones increasing?  Some researchers think the evidence
indicating that is possible is good enough that they are studying it.
Another urolith expert at a different university I have spoken with says
he thinks they are not increasing, but also that they have instead always
been more common than thought, but they simply aren't tested and when
they are pathologists and treating vets often skip the further step of
contacting urolith labs.  Is a third possibility possible and there is
just a statistical anomaly happening?  Sure.  What can't be done is to
draw conclusions before the data is in.
 
Of course, there is a useful, cheap, fast, and easy test which finds some
(all?) of the ferrets with vulnerability to cystine stones, so it's kind
of a no-brainer to do it periodically for any ferret on a high protein
diet.  The question is more at what stage it finds them since that it not
well enough known.  Just check the urine pH.  If it too acidic then the
ferret has a decent chance of being at risk for struvite stones so
protein will need to be reduced (BUT if it is too alkaline that ferret
is at risk for struvite stones and needs vegetable intake reduced).
 
You can find urine pH in
http://www.miamiferret.org/fhc/physiology.htm
Urine pH 6.5-7.5; mild to moderate protein urea is common and normal.
Neutral is 7.0 with pH, so notice that the range extends to 0.5 on
either side of that.
 
Again: testing urine pH is easy, cheap, and fast.  We've come to consider
it is logical inclusion in regular testing, and to top it off if you can
get just a tiny bit of urine you can even do it yourself at home with
color strips that you can buy from your vet or a pharmacy for almost
nothing.
 
Otherwise, don't draw conclusions until the study is done.  That is
always wise.
 
For your vets' files here is the study info:
Dr. Michelle Hawkins VMD DABVP(study coordinator),
2108 Tupper Hall, University of CA, Davis, CA 95616,
1-530-752-1363 (phone), <[log in to unmask]>.
 
Heck, just going from pers. coms. (including a few people who have
posted but more who are afraid of being jumped on) there are more FML
ferrets with cystine stones in their recent pasts than the lower figure
in the post to which I respond.  Is it a high figure?  No, of course,
not.  No one ever said it was.  Are cystine stones and cystine slush very
inclined to prove fatal when they occur?  Yes, uncomfortably so, and
those who are saved (especially males who are more inclined to block)
have a tendency toward kidney damage and often to needing a penile
amputation and urethra rerouting.  Our young Hilbert is just finally now
beginning to bounce back enough that he doesn't look gaunt after almost
dying a full year ago from related kidney damage.
 
It may be that centuries of milk and bread, and many decades of kibble
use on farms has had its impact of vulnerable individuals not dying off,
which increases rate of vulnerability once a higher protein diet is tried
again.  Remember how very many generations ferrets have in just the span
of one human generation.  Only rigorous study will tell, so don't jump
the gun in either direction by drawing conclusions prematurely, and do
use the easy, cheap, fast urine pH testing option just to be safest.
After all, why not?
 
-- Sukie (not a vet)
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[Posted in FML issue 4976]