I currently have a cat that was walking/running around and the next thing I knew, he had absolutely no use of his back legs. I took him to the vet where he currently is, and they ran X-rays and blood work. His blood work came back normal, and he has a pulse in both of his back legs and feet, therefore, she does not seem to be thinking that this is due to a blood clot. The X-rays showed a spot that looked somewhat dense and the vet doesn't know if it was just the X-ray or a lesion. She did however, state that even if it were a lesion, she could not imagine him instantly losing all mobility without having any prior symptoms. She mentioned that it could be an injury to his spinal cord, etc. they put him on some anti-inflammatory meds, etc. and said that there was absolutely no improvement with him today. The crazy part, is that he seems to be in no pain just stressed because he cannot move his back end. He still seems lovable, purrs, etc. she said that usually there would be some improvement by now. The problem is, that in order for them to diagnose further, they would recommend taking him to a specialist, have an MRI performed and then surgery if necessary. The MRI alone, would cost a couple thousand dollars she said. I absolutely do not have that kind of money! What do I do? I do not want to have him euthanized, but I also do not want him to suffer either. If he is not in pain, would it be considered suffering because of the quality of life that he will have?

Do you know if he can urinate or defecate on his own?
If he doesn't appear to be in pain, I have seen a few paralyzed cats - owners usually get those wheelchairs for them. But whether your cat can urinate or defecate is a big factor - you may have to learn to deal with that and express his bladder.

You could ask your vet to send the x-rays to a specialist first, to see if they can determine what it is. A specialist will be able to 'see' more in the rad than a regular vet who is not specifically trained in radiography. It's worth a shot at this point.