What are the diagnostic criteria for Polymyalgia Rheumatica (PMR)?

From the Guidelines

Diagnosing polymyalgia rheumatica (PMR) involves a combination of clinical evaluation, laboratory tests, and ruling out other conditions, with a focus on recognizing characteristic symptoms and elevated inflammatory markers, as recommended by the 2015 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) collaborative initiative 1. The diagnosis begins with recognizing the characteristic symptoms: bilateral shoulder and hip pain and stiffness, particularly severe in the morning or after periods of inactivity, along with fatigue, low-grade fever, weight loss, and general malaise in patients typically over 50 years old.

Key Diagnostic Criteria

• Bilateral shoulder and hip pain and stiffness
• Elevated inflammatory markers, such as erythrocyte sedimentation rate (ESR) typically above 40 mm/hr and C-reactive protein (CRP) also elevated 1
• Age over 50 years old
• Response to low-dose corticosteroids (prednisolone 15-20 mg daily) within 24-72 hours

Laboratory Tests and Imaging

• Blood tests: complete blood count, ESR, CRP
• Imaging studies: ultrasound may show bursitis or tenosynovitis in affected areas

Differential Diagnosis

• Rheumatoid arthritis
• Giant cell arteritis
• Fibromyalgia
• Various infections or malignancies It's crucial to exclude other conditions with similar presentations.

Diagnostic Approach

1. Clinical evaluation: recognize characteristic symptoms and physical examination findings
2. Laboratory tests: elevated inflammatory markers and complete blood count
3. Imaging studies: ultrasound to rule out other conditions
4. Response to corticosteroids: dramatic response to low-dose corticosteroids within 24-72 hours No single test confirms PMR, making the diagnosis primarily clinical, based on the combination of typical symptoms, elevated inflammatory markers, age over 50, and response to corticosteroid therapy, as outlined in the 2015 EULAR/ACR recommendations 1.

From the Research

Diagnostic Criteria for PMR

To diagnose Polymyalgia Rheumatica (PMR), the following criteria should be considered:

• Age: PMR typically occurs in patients over 50 years old 2
• Symptoms: Inflammatory pain in the shoulder and/or pelvic girdles, proximal joint pain and stiffness, and decreased mobility 2, 3, 4
• Blood tests: Elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels, although normal values do not rule out PMR 5, 6
• Medical imaging: Ultrasonography, 18-fluorodeoxyglucose positron emission tomography associated with total body computed tomography (18-FDG PET/CT) may assist in diagnosis 5, 3

Differential Diagnosis

PMR may be simulated by other conditions, including:

• Giant cell arteritis 2
• Rheumatoid arthritis 2
• RS3PE syndrome 2
• Spondyloarthropathy 2
• Systemic lupus erythematosus (SLE) 2
• Myopathy 2
• Vasculitis 2
• Chondrocalcinosis 2
• Endocrine disorders 2
• Malignancies 2
• Infections 2

Diagnostic Approach

A thorough diagnostic approach should include:

• Clinical evaluation: Patient history, physical examination, and assessment of symptoms 2, 3, 4
• Laboratory tests: ESR, CRP, and other blood tests to evaluate inflammation and rule out other conditions 2, 6
• Medical imaging: Ultrasonography, 18-FDG PET/CT, and other imaging modalities to confirm diagnosis and assess disease activity 5, 3
• Monitoring: Regular follow-up to assess response to treatment and evaluate for relapses 3, 6