Smudge had exactly the same symptoms, but it wasn't an infection, it was struvite (magnesium) crystals. His food was switched to Hill's Feline C/D (comes in canned and dry). It was touch and go for a while, as that in turn made him constipated, and the petroleum-based treats I was giving him to ease the constipation cause a different kind of urinary blockage (mucus plugs). I hadn't put two and two together, and the vet was stumped. But Smudge just let me know he wasn't going to eat the petroleum stuff any more, so I tried psyllium instead (mixed into his canned food, and Cat Lube treats crumbled over his kibble) and we finally got a happy ending!

The most important thing is to get an accurate urinalysis diagnosis. Cats can have more than one kind of crystals, and a food that can make one kind go away can make the other kind worse! Precise diagnosis based on a fresh urine sample is of the utmost importance.

Love, Columbine