urinary trouble

my 5 year old persian, neutered male is having some kind of problem..he has haematuria which is that he has blood in his urine..the thing is he's had UTI before & he always had trouble urinating & he was cranky & aggressive, with no appetite..but now he jst urinates blood..but his appetite is normal, & he URINATES..the last times he didn't except when the vet catheterized him??? any body out there know ne thing abt what i'm saying?? i already started a uti treatment..but i'm very anxious & worried..HELP

What diagnostics has the veterinarian been able to run?

While I don't have an answer, I do have a question with a similar problem. My 3 yr old female sometimes shows a faint pink colour in her urine, but not always. She is very active, eats & drinks normally (that is eats alot , remains the most affectionate of our 3 cats and aside from this 'pink urine' problem seems healthy. We noticed this about a week ago, and wasn't sure it was her until yesterday. I called our vet who didn't seem concerned, and gave me an appointment for next week. Her stool looks ok (although I will bring a sample of it with me to the vet). One other thing, she seems to 'like' just sitting in the litter box, sometimes it seems like she is 'squatting', other times she just lays around in it. So I can't tell if she is 'straining to go' or just relaxing. She is an indoor cat, and has all her shots etc.

...sounds like a possible UTI or maybe even something more involved. A UTI can cause the cat to feel that she needs to urinate all the time despite the fact there may be no urine to expell. Cats with UTIs will commonly stand or squat in their litterboxes and not urinate. The pinkish colored urine is likely pink because it's tinted with blood.

I wish the vet could see her sooner. The poor thing is probably misrable.