I found this forum after hours of Googling the same symptoms others have discussed. My then-7 mo. old rescue cat, Ponchik, developed weak hindquarters -- first just sort of clumsy, then losing all muscle tone. He'd jump down from a sofa and his hind end would just collapse. He began sleeping more, lost his appetite, and instead of raising his rump when pet, he would seem to "melt" under the slightest touch. He'd had a severe ear mite case leading to infection, so we originally thought it might be neurological damage. (Switched vets during the course of the issue, and turned out he was also allergic to that antibiotic ... new vet was *far* better & cat specialist.) Nothing helped him improve -- not antibiotics, not prednisolone, not anti-inflammatories, nothing. He continued to grow weaker. His hind legs just weren't working.
Our vet ran tests after tests. Nothing showed up. Then I found this thread, read the posts by Ryebread, and I looked more closely at my cat. After some research into traits and characteristics, and looking at pictures, I realized Ponchik was obviously part-Burmese. I went back to my vet with some of this information, but he said that my cat didn't look Burmese (except for his coat), that his potassium and CK serum levels were normal, and that he had no cervical ventroflexion (dropping his head/neck, which is supposedly the classic symptom of hypokalemia). So I kept researching, while my cat kept declining -- and by now, he had a major eye inflammation that wasn't responding to treatment, & it was getting redder and more closed. He also started peeing outside the litter box around the house because he'd wake from sleep & be too weak to get himself to the box in time.
I found another link to an article on vet site that discussed how hypokalemia could occur with or *without* the cervical ventroflexion (http://www.thecatclinic.com.au/category/info-for-vets/
). At the end of my rope, I took that to my vet, who said we could try a low dose of potassium as a last ditch effort. (My cat was now 10 mo. old, and she thought he was declining too rapidly and we might have to discuss "other options," i.e., euthanasia.)
It's now been less than two weeks, and like Ryebread's posts, my cat is improving drastically. He gets 1/2 tablet of potassium 2x/day. His back legs are gaining strength fast, and while he's still a touch clumsy, he climbed up into my child's top bunk yesterday, and he's been playing again (chasing a string down the hall). His appetite is back & he's gaining weight. He'd stopped talking, and now won't shut up -- and his voice is stronger (talkiness is also a main Burmese trait). He follows us everywhere and simply seems SO much happier. Our other two cats, who had started ignoring him, are now interacting with him again. His recovery is absolutely amazing. Ryebread talked about the major improvement of her Burmese kitten in 3 and 6 weeks. I feel as though if mine has improved this much in less than 2 weeks, I have real hope that he's going to be "normal" again.
I am so thankful that I pursued this course of treatment, and that I found these resources through Google and kept searching. If not, my cat would probably be dead by now. I don't know if this will help anyone else. But if you suspect your cat is even part Burmese, and he/she shows any weakening, weight loss, etc. (do a search on Ryebread's posts for a great description of symptoms), talk to your vet about potassium supplements -- EVEN if your cat isn't dropping its head/neck, and EVEN if the potassium level, white blood count, CK level are all normal. The bottom line is that a low dose won't hurt, and it's meant the difference between life and death for my kitty. We are so, so happy!