Polymyalgia rheumatica

Definition and Epidemiology

• Polymyalgia rheumatica (PMR) is an inflammatory disorder causing muscle pain and stiffness, primarily in the shoulders and hips.
• Typically affects people over 50 years old, with a higher prevalence in women and individuals of Northern European descent.
• Often associated with giant cell arteritis (GCA).

Pathophysiology

• The exact cause is unknown, but it is believed to involve an abnormal immune response.
• Genetic predisposition and environmental factors (possibly viral infections) are thought to contribute.
• Inflammation primarily affects the synovial membrane, bursae, and tendons around joints.

Clinical Features

• Sudden onset of pain and stiffness in the shoulders and hips.
• Symptoms are worse in the morning and after periods of inactivity.
• Associated fatigue, malaise, and mild fever.
• In patients with concurrent GCA: headaches, visual disturbances, jaw claudication.

Diagnosis

• Clinical diagnosis based on symptomatology and age.
• Elevated inflammatory markers: Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).
• No specific diagnostic tests, but imaging may be used to rule out other conditions.
• Response to low-dose corticosteroids is often considered diagnostic.

Management

• Corticosteroids (prednisolone) are the mainstay of treatment, with rapid improvement in symptoms.
• Gradual tapering of steroids based on symptoms and ESR/CRP levels.
• Long-term management may require low-dose corticosteroid therapy for 1-2 years or longer.
• Calcium and vitamin D supplementation to prevent steroid-induced osteoporosis.

Complications

• Potential side effects of long-term corticosteroid use: osteoporosis, diabetes, hypertension, weight gain.
• Increased risk of giant cell arteritis in patients with PMR.
• Chronic pain and stiffness can lead to functional impairment.