I worked with a client a while back who had autoimmune hepatitis which caused liver inflamaiton and other issues, but was pretty much not an issue for them when it came to exercise. This client was directed to me by their physician who wanted the client to lose weight to help them deal with the condition. There were no restrictions. But it is very important to get clearance for all clients with such a condition or any medical condition. I approached this client as I do all clients. I start off conservatively and train range of motion and stability along with improving aerobic conditioning first and then we progressed to resistance training. This client did very well. I believe they eventually had a liver transplant, but I was only involve long enough to give them the skills to exercise well on their own. Which they did, as I often saw them working out after our sessions had ended and checked up with them for some time before losing touch.