CAN NORMAL ERYTHROCYTE SEDIMENTATION RATE AND C-REACTIVE PROTEIN LEVEL BE A REASON FOR DIAGNOSTIC DELAY IN POLYMYALGIA RHEUMATICA?
Authors: M. Kara et al.
Elevated ESR and CRP are generally considered prerequisite for the diagnosis of Polymyalgia Rheumatica (PMR). However, in every-day clinic there are patients with classical symptoms and findings but normal serological inflammation markers. According to the authors of this study “ESR and CRP can be observed as normal in 13% of PMR patients”.
Of 54 patients with PMR (63% female, mean age 65.39±7.39 years), ESR and CRP were normal in 8 patients (14%). In these, serum amyloid A (SAA) was high and all patients showed bursitis as demonstrated with ultrasound. Comparison of the groups with normal and high levels of ESR and CRP showed that age at diagnosis was lower in the normal ESR and CRP group (p=0.027), while the symptom duration was longer (p<0.001). Rheumatoid factor positivity, presence of anaemia, and platelet count at the time of diagnosis, disease relapse and development of giant cell arthritis were similar in both groups. Multiple regression analysis showed long symptom duration associated with PMR with ESR and CRP normal levels (OR=0.045, %95 CI 0.03-0.676, p=0.025).
Normal CRP and ESR should not discourage to diagnose PMR. Ultrasound or MRI may be very helpful in such situation to get to the diagnosis and initiate treatment.