Progressive weakness in hind legs 8 year old Jack Russell
About 2 months ago our female 8 year old JRT became lethargic, weak and unable to jump into car or run up steps. Multiple vet visits haven't identified cause of problem; negative blood work, ruled out Lyme disease, X-rays of spine and hips were normal ( no arthritis). This is progressively getting worse to the point now that she has difficulty just turning over on her back and it is a struggle for her to get up. Her hind legs tremor when on her back. Once outside, she walks very slowly until she gets warmed up so to speak, then she trots along fine. In the house she just sleeps. She doesn't seem to be in pain, but maybe she is a stoic little girl or we atre't picking up on the signs. She is slightly overweight and needs exercise, but hard to know how much to push or if we should. Advice please.