"Mike S." wrote in message
oups.com...

How (or at what point) do I know if and when he needs surgery to remove
the stone?

I don't want to alarm you- but a ureterolith can cause an obstruction of
urine flow that can result in anuric acute renal failure and death if the
obstruction isn't removed in ~24 hours. A partial obstruction of a ureter
results in decreased renal blood flow, reduced glomerular filtration rate-
and eventually irreversible damage to the kidney. Usually, the time between
diagnosis and surgery is 2-4 days.

The sign that it needs to be removed would be the inability to urinate due
to an obstruction- which is a true urologic emergency. However, the physical
condition that he'd be in would make him a poor anesthetic and surgical
candidate.

Some vets recommend placing the cat on a calcium oxalate diet (Hill's
Prescription Diet x/d) to hopefully prevent the ureterolith from become any
larger- but this is very risky because the stone can cause an obstruction at
any time- e.g., late at night, on a weekend or while you're at work.



I was under the impression that all calcium oxalate stones
have to be surgically removed. Will the stone move from the ureter and
into the bladder?

Yes- but only in about 1 out of 3 cats. CalOx ureteroliths are usually
embedded in the wall of the ureter- that's why they usually must be removed
surgically. There is some anecdotal evidence that glucagon (0.1 mg/cat bid
S/C) might relax ureteral smooth muscle which might help the stone pass into
the bladder. There are no controlled studies and we've haven't tried it,
so, I can't make any recommendations.



The vet acted like it wouldn't move and would stay in
the ureter.

I didn't see the x-ray or sonogram so I don't know how big it is or its
exact location- but most ureteroliths are embedded in the ureter and don't
budge. Your cat obviously isn't obstructed (yet) so, a CalOx diet might
prevent the stone from getting any larger- but there's no guarantee and its
a very high risk and dangerous strategy because the cat can block at any
time.


He thoroughly confused me because he gave me the runaround
when I asked about how to remove it.

That's probably because he not well informed and/or he doesn't have any
experience in ureteral surgery. When a vet knows what he's talking about
they usually explain each option very clearly and make sure you understand.

I've been very hesitant to mention shock-wave lithotripsy (actually
""extracorporeal shock-wave lithotripsy" (ESWL) because its only successful
in about 50% of the cases in small animals. The procedure is noninvasive
but still carries anesthetic and post-procedure risks- albeit less than
surgery. The cost is about the same as surgery. The problem is- if ESWL is
unsuccessful, can you or would you afford surgery? If you can afford both-
then, I would try ESWL first- you might get lucky. But if you can't afford
both, then, I would opt for surgery because it has better odds of being
successful-- ~91%.

Lithotripsy isn't available everywhere- usually only in veterinary
university hospitals or top shelf vet hospitals such as the Animal Medical
Center in NYC. If you would like more information on feline ureteral
surgery, let me know.

Best of luck,

Phil