I swear that cleaning the cat box is like working with wet cement--I actually do use a metal trowel to break it into manageable pieces.
Lola, the culprit, has been with us since I found her as a tiny kitten all alone in an alfalfa field. She was so young that I had to bottle feed her for a time. She's had the problem since she was about a year old--she's probably about 10 now.
Are there any medications, or food, or management schemes to curtail this?
Can you clarify what you mean by polyuremic? I have never heard that term before. (uremic typically refers to failing kidneys) It sounds like you mean polyuria (polyuric) if I am understanding what you are describing correctly (excessive urine?).
You may consider bloodwork and a specific gravity on the urine. SInce she has been like this since a year old, it doesn't sound typical of diabetes or acute kidney disease.
If she is indeed healthy, maybe switching to a different litter may help at least with the daunting task of litter cleaning! You don't really want to recude urine output, especially in cats who are so prone to renal disease.
I would also consider seeing if diet plays a role (have you changed this up before?)
Assuming all checks out with the vet and she's healthy but just drinks and goes a lot, I second changing litters.
The new varieties in the Scoop Away line (that boast never having to dump the box ever again) works very well for hard clumping urine almost immediately. I have not had one problem with litter sticking to the plastic box or falling apart when trying to scoop it. One of my cats goes in the same spot every time she pees and the other cat drinks like a fish and has the output to prove it. Between the two of them there's always a block of litter to clean out every evening along the left side of the box.
Bonus is that it comes in a 42lb bag so I don't have to pick up boxes of litter at the store every week to keep up with the top offs.
I have a cat that is diabetic. Although his diabetes is well managed, he still pees A LOT! It is just like wet cement. I have tried just about every litter out there and recently switched to the Tidy Cat Lightweight litter and so far I am loving it. The clumps are so much easier to manage.