Polymyalgia Rheumatica / Temporal Arteritis

What is Polymyalgia Rheumatica (PMR)

PMR is an inflammatory disorder that causes muscle pain and stiffness, particularly in the shoulders, neck, and hips. It does not cause muscle weakness-only pain and stiffness.

Common Symptoms:

• Sudden onset of bilateral shoulder pain and stiffness, often worse in the morning.
• May also involve hips, thighs, and neck.
• Systemic symptoms: fatigue, mild fever, weight loss, depression.
• Elevated inflammatory markers: ESR (erythrocyte sedimentation rate) and CRP (C-reactive protein).
• Rapid improvement with low-dose corticosteroids (e.g., prednisone).

What is Temporal Arteritis (GCA)

GCA is a vasculitis (inflammation of blood vessels) that affects medium to large arteries, especially the temporal arteries (located on the side of the head) and other arteries in the head and neck.

Common Symptoms:

• New headache, often on one side of the head.
• Scalp tenderness (e.g., pain when combing hair).
• Jaw claudication (pain in the jaw when chewing).
• Visual symptoms: blurred vision, double vision, or sudden vision loss (a medical emergency).
• Systemic symptoms similar to PMR.
• Diagnosis is supported by elevated ESR/CRP and confirmed by temporal artery biopsy or ultrasound.
• Requires high-dose corticosteroids immediately to prevent blindness.

Treatment

• Corticosteroids are the mainstay for both conditions.
• PMR: Low dose (e.g., 10-20 mg/day prednisone).
• GCA: High dose (e.g., 40-60 mg/day prednisone) plus urgent referral if vision symptoms are present.
• Gradual tapering is needed over months to years.
• Monitoring for relapse and corticosteroid side effects is important.
• Some cases require steroid-sparing agents like methotrexate or tocilizumab (Actemra).

Relationship Between PMR and GCA

• About 15-20% of patients with PMR develop GCA.
• About 40-60% of patients with GCA have PMR symptoms.
• They share similar pathophysiology and often respond to steroids.