In stage 4 - a case SO severe (she is actually the rarest case any of the five doctors and two specialists have seen) - we have to choose the lesser of two evils. Gumdrop was experiencing pain and lameness due to it - pain killers (Tramadol) is the only option for us right now. Yes, there are risks with all medications, there are risks for people and medications as well, but the benefits far outweight the risks at this point. Gummy doesn't have many options and they will only operate as "salvage". In other words - as a absolute last resort because of her age and size.
The only thing we can do for Grumdrop is manage her pain. This is heartbreaking, but we can't force her to live with pain. She is just a baby.
I will look into Cartrophen and ask our vet. But when it all comes down to it - Gumdrop's comfort and happiness is THE most important thing in her life. If her life has to be shortened because of her disease or because of the only way to treat it ... at least it was a comfortable and happy life.
Thank you though. I do worry about her liver and kidneys - but I worry far more about her pain level and her ability to enjoy a bit of play and happiness in her life.