From the Guidelines
Yes, it is possible to have polymyalgia rheumatica (PMR) without elevated C-reactive protein (CRP) levels, as stated in the 2022 study 1, which notes that CRP may be normal in some cases of PMR.
Key Points to Consider
- The diagnosis of PMR relies heavily on clinical presentation, including characteristic symptoms such as bilateral shoulder and hip girdle pain and stiffness, particularly in the morning, difficulty raising arms above shoulder level, and significant improvement with low-dose corticosteroid therapy.
- According to the 2024 study 1, relapses may also be present despite normal erythrocyte sedimentation rate (ESR) and C reactive protein (CRP), particularly, but not only, in people who are treated with interleukin-6 receptor (IL-6R) blocking agents.
- Treatment typically begins with prednisone at 10-20mg daily, as recommended in the 2022 study 1, with gradual tapering over time based on symptom response.
- For patients with normal inflammatory markers but typical symptoms, a diagnostic trial of prednisone may be used - a dramatic improvement within 24-72 hours supports the PMR diagnosis.
- Regular monitoring is essential regardless of initial CRP levels, as disease activity can fluctuate over time, and patients should be educated about possible adverse consequences of therapy and taught to recognise them, as emphasized in the 2024 study 1.
Important Considerations for Management
- Early referral to a rheumatologist should be considered, especially in cases of insufficient response to acceptable doses of corticosteroids and in cases requiring corticosteroid-sparing regimens.
- Patients should receive information about comorbidities, such as osteoporosis, diabetes mellitus, or cardiovascular disease, which are relevant to the disease and/or its treatment.
From the Research
Polymyalgia Rheumatica without Elevated CRP
- Polymyalgia rheumatica (PMR) is an inflammatory rheumatic disorder characterized by elevated inflammation markers, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) values 2.
- However, a non-abnormal ESR or CRP value does not preclude the diagnosis of PMR, as stated in a 2017 study published in the Nederlands tijdschrift voor geneeskunde 2.
- A case report of a 100-year-old man with PMR and normal ESR and CRP values at the time of diagnosis highlights the possibility of PMR with normal inflammatory indices 3.
Diagnostic Challenges
- The absence of an elevated ESR does not exclude the diagnosis of PMR, as reported in a 1997 study published in the Journal of clinical rheumatology 4.
- A 2023 study published in Medicine found that among 54 PMR patients, 8 (14%) had normal ESR and CRP values, and serum amyloid A (SAA) was elevated in all these patients 5.
- The study suggests that PMR patients can have normal ESR and CRP values at the time of diagnosis, and alternative diagnostic approaches, such as ultrasonography and SAA measurement, can be useful 5.
Alternative Diagnostic Approaches
- A 2018 study published in Rheumatology (Oxford, England) developed alternatives to the PMR activity score (PMR-AS) that do not require CRP, including the clin-PMR-AS and CRP-imputed (CRP-imp) PMR-AS 6.
- The study found that these alternative scores can be used to monitor PMR activity in everyday practice, especially in patients without available CRP values or those receiving IL-6 antagonist therapy 6.