Support or help sudden leg weakness

Hello,
It's been awhile since I've posted here. My cat Dax has suddenly lost mobility. He's 12 and has been taking 2.5mg of felimazole twice per day for 16 days to treat hyperthyroid.
He seemed to be responding well to meds. He started to seem less food obsessed but still eating. He put on 7 oz in weight. The last 2 days he seemed more lethargic. Last night barely moving. This morninghe couldn't even stand on his hind legs at all.
We went to the vet this morning. They said his hind limbs are warm, receiving blood, and it's unlikely to be a blood clot. They took xray and said everything looks normal, healthy spaces between discs, etc.
Vet said it's likely a fibroid that may be on the spinal cord. To rest him, help him express his bladderfor the next few days. He was given corticosteroids and sent home. They said it may works itself out or it may not.
Vet insists it's not related to felimazole.
I just want to know if anyone has any advice or seen this?
My cat is like a ragdoll. I'm devastated.

Just learned the name for this is fibrocartilaginous embolism. If anyone has experienced this please respond. Thank you.

So they took xrays and didn't find anything, so your Vet is simply speculating that it's the fibroidcartilaginous embolism, correct? (It's extremely RARE in cats)    Is there some way to actually diagnose it?  What about bloodwork?  Did they do any?  sometimes if a cat is low on Potassium they will get weak hind legs, and potassium pills will solve the problem post haste. 

Is your Vet familiar with how to treat this, IF he has been absolutely diagnosed with it?  If not, I would call around to see if any other Vets in your area have ever treated it in cats, since it is so rare.  If so, I would take him to be seen by them, just to make sure he is getting the best treatment possible.

Hi,
My vet has seen this in many dogs. His back legs are currently paralyzed or were not responding at the vets office. He can hold his head up today and Dax did push his right back leg against my hand today. They diagnosed it by process of elimination. My vet I trust and have been going to for years. They did do blood work. His thyroid is responding to meds. Kidneys and heart are healthy.
I'm taking him back next week to see if he shows improvement. I do see some encouraging signs but I do understand progress will be slow. I'm planning to see if the vet will do an mri. Dax doesn't seem to be feeling pain.He is eating food by hand enthusiastically.
My biggest problem at the moment is learning to express his bladder. He does seem to be emptying it but not being able to get around its just free flowing. Not dribbling. I did it successfully once but when I got up this morning he was soaked and I had to bathe him.

I apologize for typos I'm on my phone.I truly appreciate your response.

Update: this morning Dax sat up on his own. He however does not have any interest in food so far today.

I will be talking to the vet tomorrow morning

Yay that he's getting the use of his legs back.  Boo that his appetite is waning, although that could be just because he's confused about what's going on, or could be he need a change in his thyroid meds.   Keep trying, try different foods, try warming them up so they smell more, try sprinkling with toppers, even parmesan cheese from the green can.   Then definitely speak to your Vet about that as soon as you can.  Hopefully his appetite will return soon.

Kitties...they are SUCH a worry    

Update: Dax stood up on all 4 legs when I got home from work. Still trying to tempt him with various foods. He ate 2 treats. However with such improvement his appetite will hopefully return tonight.
Based on everything I've read about FCE it seems to be a fair diagnosis. Prognosis is looking better but we will see what the vet says tomorrow.
Thanks again.

Update: I know this thread is not popular but someone else may deal with a rare FCE in the future. After a week Dax has regained most of his mobility. He is not jumping but can walk and climb stairs while under supervision. His blood work is good and thyroid is stabilizing.
I am currently looking into acupunctureand trying to find someone in my area.
Dax's appetite is still low but he is eating some. The vet was not seriously concerned and we are pushing forward. His prognosis looks better each day.
Edit: I forgot to mention he is using the litter box on his own and is in control of his bladder function

That's wonderful news   Still a little worrisome about his appetite though.  Wonder if it's the thyroid meds?  (am I repeating myself ?) 

Anyway, a happy update is always appreciated!

Update: It's been nearly 4 months since Dax's FCE. He has regained 95% of his reflexes and mobility. The only lasting effects I've noticed is he walks with his back legs slightly bent compared to before. He jumps leaps and gets into everything, no nook is too high to reach---such as the top of the fridge.

Although an FCE is rare in cats we've seen first hand it does happen. It could have resulted from his thyroid issues being resolved or an injury that was not witnessed. Dax has responded amazingly well to felimazole and now weighs 10.2 lbs. This will be my final update for this post.
My only wish for others is that they please keep this in mind if a cat experiences sudden paralysis and no injuries show up on an xray. There is little in the way of literature about FCE in cats and they provided a grim prognosis, as it can only be verified post-mortem. Remember Dax and his amazing progress. My vets were awesome in encouraging us to wait and see how he responded even though neither of them had seen this condition in a cat.

Have a great holiday season.

What a handsome boy he is   I"m SO glad he's doing  well.  Thank you so much for the update.

SO happy to read this!!!! Wishing you and Dax a Merry Christmas!!!

Thank you for this uplifting story. My cat most likely has FCE as well, MRI this morning is scheduled to validate.