Cat's back legs not functioning

Hi, my cat Leo is a 16 year old diabetic.  As of about an hour ago he seems to have lost use of his his back legs.  One seems to be working better than the other but after limping a few steps he just stops and cries.  We live in a single story home and he does not jump on things, so I don't think he has injured himself.  We're having a blizzard and there is no 24 hour vet anywhere near me, but I will of course take him first thing in the morning.  Any ideas what this could be?  I'm very, very concerned and don't know what to do for him.

I don't know much about feline diabetes or how it's treated, but apparently leg problems are fairly common:

http://www.felinediabetes.com/weak-back-rear-legs.htm
http://fiascofarm.com/herbs/diabetes.htm

Is there any way you could call an emergency vet and beg for a little advice over the phone? Sometimes that works. I hope all works out for you and your cat.
 

He has had the degenerative hind leg issues associated with diabetes for as long as I have been caring for him (about 8 months) but this is a sudden change.  Calling a clinic is a good idea, thanks.  I will see if I can get them to give me some advice.  

Any updates? 

I have heard saddle thrombosis can cause sudden horrific pain and paralysis.  If so, get to an emergency vet ASAP.  Immediate attention is the only hope if it is something this serious.

Unfortunately it turned out to be a blood clot blocking the artery in his leg blocking the blood flow and causing the paralysis.  Given his advanced age, other medical issues and the unpredictable outcome of treatment we ended up letting him go.  My vet supported the decision, she said the treatment could potentially takes months of hospitalization and he may not regain use of his legs.  The clot could also get worse or reoccur so it just didn't seem fair to keep him in that state.  I'm very sad but he was obviously in pain and just wouldn't have a had a good quality of life.  Thank you for checking up.

I'm very sorry to hear of the loss of Leo. You cared for him and made the best decision you knew of. May he rest with the angels.
 

I am sorry to hear the news.  I am sure you did everything possible for your Leo and this was the best choice given your options.

A saddle thrombosis is a blood clot and, unfortunately, a blood clot of this type is nearly impossible to treat.  I have only heard of one success story in a very young cat when he received medical attention immediately.

{{{Hugs}}} to you at this very sad time.  RIP Leo.

We are so sorry for your loss of Leo. When you feel like it, you might consider posting a tribute to him in our Crossing the Bridge Forum. I am going to lock this thread now.