Polymyalgia Rheumatica (PMR): Comprehensive Guide for Healthcare Professionals and Patients
1. Introduction
Definition: Polymyalgia rheumatica (PMR) is an inflammatory condition characterized by pain and stiffness in the shoulders, neck, and hips, primarily affecting individuals over 50 years old.
Epidemiology: PMR predominantly affects women and is more common in individuals of Northern European descent, with a peak incidence between 70–80 years of age.
Significance: PMR can significantly impair daily activities and is closely associated with giant cell arteritis (GCA), a more serious inflammatory condition requiring immediate attention.
2. Causes and Risk Factors
Causes:
The exact cause is unknown, but immune system dysfunction and genetic predisposition are suspected.
Possible triggers include infections or environmental factors.
Risk Factors:
Age >50 years.
Female gender (2–3 times more common in women).
Genetic predisposition (e.g., HLA-DR4).
3. Pathophysiology
Chronic inflammation involving cytokines (IL-6, IL-1, TNF-alpha) leads to synovitis and bursitis in proximal joints, resulting in pain and stiffness.
4. Symptoms and Features
Common Symptoms:
Bilateral shoulder and hip pain, often worse in the morning.
Morning stiffness lasting >30 minutes.
Fatigue, low-grade fever, and unintentional weight loss.
Associated Features:
Difficulty with activities like dressing or rising from a chair.
5. Complications
Functional disability due to persistent pain and stiffness.
Risk of developing giant cell arteritis (15–20% of cases).
Corticosteroid-related side effects from long-term treatment.
6. Diagnosis
Clinical Features: Symmetrical pain and stiffness in proximal muscles, with symptom onset lasting at least 2 weeks.