What might be wrong with her ?

I took in a stray cat on the 16th Oct.   One day she seemed to loose control of her back legs and was dragging them behind her.  Next day she couldnt walk at all or even stand.  Now its affected her front legs too.  Shes been like this since a week ago yesterday.  She still drinks but isnt eating much, maybe a few mouthful throughout the day.  She can still bend her legs when shes led down and isnt incontinent.  The vet is not sure whats wrong with her and I cant afford any tests.  Tried to get some financial assistance with that but have not had any luck.  A blood clot can be ruled out as her legs are warm and there is a strong pulse in her back legs.  Bear in mind shes been like this over a week now and is still alive.   Vet thinks she is in her teens but says she has a nice strong heartbeat for a cat her age.

Shes been given anti flams/painkillers & antibiotics just in case some sort  of infection but vet thinks if no improvement very soon she should be put to sleep.  Whilst I would be ok with this if I had some idea what was wrong and there was little hope but when I dont know whats wrong I dont feel I want to put her to sleep when there is a chance she could recover.  I just dont know what to do and only got a couple days til vet wants to put her to sleep.

What do other people please think 'might' be wrong with her ?.  I understand no one can be sure but I would just like to hear what people think to help me decide.  Whilst there is lots of info online about possible causes of lost use of back legs I cant find anything much that is of any use where all 4 legs are affected so that could be a clue.

Also, does anyone think I should tell the vet Id like to wait a little bit longer before we resort to Enthuansia  ? For some reason this just doesnt feel right to me just yet

Thank you

I really don't know what that could be, but there is also a chance for recovery and I hope thats what she does. However if you see her getting worse and worse each day i could consider what the vet says.. Cats can be very unpredictable at times. Best of luck to you and I would say just show her love

If the Vet doesn't have any idea (other than a possible infection), based on a physical exam, then it would be really hard for anyone on the internet to try to make a diagnosis.  We did have ONE cat here on TCS that lost the use of all four legs, and they were never able to figure out the issue.  From what the owner said, that cat was miserable.  I guess she was able to determine this because she had been with the cat for his entire life, rather than rescuing it later in life

You said your little one is NOT incontinent. How does she use the litterbox?  Do you physically lift her in and out?  How do you know when she needs to go?  Or to you simply have her resting on puppy pads all the time? 

Bless you for trying to help this little one out   Have you tried all of these resources?  http://www.thecatsite.com/a/no-money-for-vet-care-how-to-find-help-and-save-your-cats-life