Polymyalgia Rheumatica (PMR) and Giant Cell Arteritis (GCA)

Definition

• PMR: Inflammatory condition causing proximal muscle pain/stiffness, especially in the shoulders and hips.

• GCA (Giant Cell Arteritis): Vasculitis of large/medium arteries (commonly temporal arteries) with a risk of ischaemic complications such as vision loss.

Presentation

PMR-Specific

• Bilateral shoulder/hip pain and stiffness, worse in the morning

• Gradual onset, difficulty with daily activities (e.g. dressing, combing hair)

GCA-Specific

• Temporal headache (often unilateral), scalp tenderness

• Jaw claudication

• Visual changes: Blurred vision, amaurosis fugax, risk of permanent vision loss

• Systemic: Fever, weight loss, malaise

Shared Features

• Typically age >50 (peak 70–79), female predominance

• Morning stiffness >1 hour, improved with low-dose steroids

Investigations

Blood Tests

• ESR/CRP: Elevated in both PMR and GCA

• FBC: Normocytic anaemia common

• LFTs: ALP elevation (~20%)

Imaging

• Ultrasound for GCA: May show “halo sign” or arterial stenosis

• PET-CT: Can detect large-vessel involvement (subclavian, aorta) in GCA

Definitive GCA Diagnosis

• Temporal Artery Biopsy: Shows granulomatous inflammation ± multinucleated giant cells

Management

PMR

• Prednisolone 15 mg daily initially

  • Taper slowly based on symptom control and ESR/CRP

• Monitor ESR/CRP monthly for first 3 months, then 3-monthly

GCA

• High-Dose Steroids:

  • Prednisolone 60 mg daily, taper after ~4 weeks if stable

  • If vision-threatening: IV methylprednisolone (500–1000 mg daily x3 days), then high-dose oral

• Low-dose Aspirin (100 mg daily) for thrombotic risk reduction

• PPI for gastric protection with long-term steroids

• Urgent Temporal Artery Biopsy ideally within 1 week of starting steroids

General

• Monitor Steroid Side Effects: Osteoporosis, hypertension, hyperglycaemia

• Lifestyle: Weight-bearing exercise, calcium + vitamin D supplementation for bone health

Complications

PMR

• Chronic pain, risk of depression from prolonged disability or steroids

GCA

• Vision loss (irreversible if untreated)

• Stroke from large-vessel involvement

• Aortic aneurysm/dissection (long-term complication)

Prognosis

• PMR: Generally good with treatment, though relapses during steroid taper are common

• GCA: Good outcome if treated early; untreated can lead to severe ischaemic complications

Patient Education

• Timely treatment prevents complications (e.g. vision loss in GCA)

• Adherence to long-term steroid regimens and proper tapering is vital

• Bone health: Emphasise exercise, adequate calcium/vitamin D

• Recognise relapse or complications: Renewed headache, vision changes, or systemic symptoms