Now I have access to a real computer I will go into more detail than in my brief post yesterday.
Seizures and strokes are obviously not the same. While nothing can be said as an absolute let me say the following: A stroke can result in damage to the brain that could result in seizures occurring in the future but a seizure is not likely (but possible) to cause a stroke. Your dog may have developed idiopathic epilepsy causing a seizure but the severe ataxia you describe does not sound like it is just a seizure side effect.
Severe ataxia in the rear of an animal/dog can be caused by many things. Since you got your dog to a specialty care hospital I am certain that you are getting great care and should listen to the specialists.
My story/experience with a dog that suffered a stroke follows.
I had a 9+ year old female that was a very active and a nationally ranked performance dog. She was also a chow hound and would eat just about anything. Unfortunately she ingested a wad of dry grass that blocked her GI track. Nothing conclusively showed on X-ray so exploratory surgery was performed. In a multi-hour surgery her entire GI track was gone through by the surgeon feeling his way until he found the blockage. End result the blockage was removed but when the dog came out from anesthesia she was totally ataxic in her rear. Initially it was thought to be the result of the pain meds (side effect) but was determined after 48 hours to be the result of a vascular stroke that occurred under/during the surgery.
We had a difficult decision and nearly put her down as she was unable to stand, walk or anything. We were convinced to give her a chance and to watch her for the next week or so. We brought her home and using a belly sling helped her get up to eat and go out to urinate and defecate.
That is where we started to see a very interesting phenomenon. This dog was a very active dog and in addition to her daily workouts for competition she got a mile walk every morning and also evening. When we took her out for the bathroom breaks, she wanted to go for her walk. She would try to drag us and her self using the front legs to drive her body, out the drive as though she wanted to go on her beloved walk. This went on and we started to see slow improvements in her ability to stand upright She could not stand without weaving unsteadily for months. She slowly regained the ability to walk in a very unsteady fashion. Months went by and she showed slow improvements. Eventually she regained almost full normal movement and gait. For the rest of her life she did exhibit severe unsteadiness when ever she lost visual stimuli. I discovered it by accident and confirmed it by blindfolding her and found she could barely stand/move in a straight line.
I wrote an article on this case years ago and have given you just the bare minimums of the story in this posting.
Bottom line her desire to go on her beloved bi-daily one mile walks somehow gave her the will, motivation, whatever to do what was thought to be basically impossible. Her brain somehow rewired the neurological pathways such that she was able to regain near full functionality with almost no deficits. There are so many factors that can be involved in any injury and the subsequent recovery that nothing is a given.
Don't give up hope. Give your buddy a good quality life and give him a chance to see if the wonder of the dog's brain can do anything.
I wish you and your dog the best and hope that things turn around and you see improvement.
