I ordered an ESR,  Rheumatoid Factor, CBC, and complete metabolic panel.  His exam and history strongly suggested PMR but also RA.  I ordered hand films also.

At that time we did not have Anti-CCP and were not using CRP.

I empirically started him on 20 mg prednisone for presumptive PMR.  My rheumatology colleagues had taught me that a quick response was a empiric diagnostic test.

I called him the next day and he told me that he had taken the pill, gone to sleep and awoke asymptomatic.  Diagnosis likely confirmed.

ESR came back greater than 80.  CBC was normal as was CMP.  RF was negative.  Hand films showed no destruction.

Over the next two years we would taper his prednisone.  He periodically ran out of meds and symptoms returned, resolved once we restarted the prednisone.

Researching his problem I found (in the Primer of rheumatic diseases) a description of overlap between seronegative RA and PMR.  Given his response and elevated sed rate (and no progression to deforming RA) I have always assumed that he did have the overlap syndromes.

This article  Polymyalgia rheumatica vs late-onset rheumatoid arthritis   adds some confusion to my previous conclusions.

This abstract continues my confusion – Presenting features of polymyalgia rheumatica (PMR) and rheumatoid arthritis with PMR-like onset: a prospective study

So I am not sure about the final diagnosis because he definitely had characteristics of both.  The good news is that both respond to low dose prednisone.