Or the possibility of subclinical RA prior to PMR.

My reactive arthritis wasn't exactly subclinical but I would go for long periods of time without any symptoms. The arthritic damage became apparent after PMR was diagnosed. I believe PMR exacerbated my preexisting condition. The arthritic damage did seem to appear practically overnight. The way prednisone masks the pain of inflammatory arthritis and osteoarthritis made it seem like it happened overnight.

One of the hardest concepts I had to grasp was how I could have both reactive arthritis and PMR. It was very clear to my rheumatologist but I had it all muddled together into a single problem responsive to prednisone.