My sister suffers from a rare disease which causes small fiber polyneuropathy, or the killing of nerves in her hands and feet. As it progresses she has trouble standing or using her hands. If that was the worst of it, then it might be liveable given the time between severe attacks is years or more. Unfortunately, it also causes intense and mostly constant pain and burning sensations, pain so bad that conventional narcotic painkillers have trouble controlling it. After some time working with the hospital I narrowed it down to autoimmune mediated. Her Doctors finally agreed, but only after first dismissing it as anything from she was faking it, all the way to lupus.