I recently read your column concerning a cat that died after having crystals in its bladder. I want to share a possible way to prevent this.
One of my male cats developed the same condition, which was probably aggravated by being neutered too soon. I had to rush him to the emergency animal hospital in the middle of the night on three occasions because of his discomfort.
The hospital always has different vets on call, and the last time I brought my cat there, the doctor told me that her cat had the same tendency to produce crystals. She said that she gives her cat one-fourth cup of liquid every day, something he really likes so he laps it up immediately (it could be chicken broth, diluted juice from a can of tuna fish, etc.). This seemed to cure him, she said.
I tried the same thing, but my cat wouldn't drink anything I put in front of him, so I used a syringe (without the needle) and force-fed him the equivalent of one-fourth cup of water every night. It was a nuisance, because it was a total of 10 syringes full. Although he hated it at first, he became used to it and was fairly cooperative.
It did the trick, believe it or not. That was eight years ago; I religiously gave the water to him every day. He never had another episode, and he's 15 now. I stopped this routine a little more than a year ago, and he is still absolutely fine.