I have just been told that I was very likely misdiagnosed 14 months ago by my original rheumatologist. I am seeing a new one who thinks I have late-onset rheumatoid arthritis, which is somewhat different than the early onset type. It has a sudden onset, like PMR, and affects larger joints, such as shoulders and knees, also like PMR. I was sero-negative for RA originally, but now a much more sensitive set of blood markers has become available. It is called “anti-CAR-P” and one of my values (anti CAR-Pab) is high, indicating early stage RA. Also, I had an ultrasound of my shoulders, which revealed areas of bone erosion, which is not usually found in PMR but is indicative of RA. All this info was provided by my pcp, but I see my regular rheumatologist on Monday.