Good Morning and welcome. I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
I am so sorry for what has happened to your precious Lucky. These signs that she was showing at first were typical neurologic signs and the fact that she had a seizure means that this has affected her Central Nervous system. This could be a benign brain tumor, more common than most people think, that has grown large enough to interfere with the function of nerves. With this condition, the prognosis is grave. There is also a possibility that Lucky may have been suffering from an Encephalitis, an infection in the Central Nervous system that could possibly be treated but often, too much damage has been done to the brain tissue that the prognosis is also grave.
I know this has haunted you to know if you have done the right thing for your precious Lucky...in most cases such as this, the symptoms will never get better and probably will get worse.
You have done the kindest thing possible for your precious Lucky bu easing his suffering. I know this is very difficult but seeing him getting worse even with treatment would have broken your heart even more.
You did all you could for your best friend and that is all you could do...if Lucky were mine, I would have had to make this decision....
My thoughts and prayers are with you and your precious Lucky!!
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please Reply so I can clarify for you
Sincerely, XXXXX XXXXX