cannot find the cause? He is not diabetic. Does not react as if in pain. He can move the leg. He has lost all of the muscle mass in the leg in just a few weeks. If anyone has any answers I would sure appreciate it. Anything is worth looking into. He is 11 years old and is a survivor of Feline Idiopathic Chylothorax. He has been symptom free of that for 2 years. He is obese but his diabetes test was absolutely normal.