Polymyalgia rheumatica

Overview

•Bilateral proximal pain - shoulders and/or pelvic girdle (hips); may begin unilaterally but quickly becomes bilateral

•Morning stiffness - lasting at least 45 minutes; patients struggle to get out of bed, lift arms above head, or rise from a chair

•No true muscle weakness - power preserved (5/5) on formal testing; apparent weakness is pain-limited, not myopathy

•Constitutional symptoms - fatigue, low-grade fever, anorexia, weight loss, depression

•Age >50, female predominance (2:1), rare under 50

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Pain in PMR arises from inflamed periarticular tissue (synovitis/bursitis), NOT the muscle itself - this is why passive shoulder movement is less painful than active, and why true weakness is absent.

Investigations

•ESR - typically >40-50 mm/hr (markedly elevated)

•CRP - elevated

•Creatine kinase (CK) - NORMAL in PMR; key differentiator from polymyositis

•FBC - normochromic normocytic anaemia; reactive thrombocytosis

•Rheumatoid factor / anti-CCP - negative (excludes RA)

•TFTs - exclude hypothyroidism (can mimic PMR)

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PMR is a clinical diagnosis - no single confirmatory test. Normal CK + elevated ESR/CRP in a patient >50 with proximal stiffness = PMR until proven otherwise.

Differential diagnosis

Management

🥇 First-line

•prednisolone 15 mg/day orally - dramatic response within 24-72 hours strongly supports diagnosis

•Taper gradually once symptoms controlled; most patients require steroids for 1-2 years; relapse in up to 50% during taper

•Bone protection: alendronate + calcium/vitamin D - start with steroids to prevent glucocorticoid-induced osteoporosis

•Monitor: blood glucose/HbA1c (steroid-induced diabetes), blood pressure, weight

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GCA red flags during PMR follow-up - act immediately: new headache, jaw claudication, visual disturbance/amaurosis fugax, scalp tenderness, tender/pulseless temporal artery. Start prednisolone 40-60 mg/day immediately and refer urgently to rheumatology - vision loss from GCA is irreversible.

PMR and GCA relationship

•15-30% of PMR patients develop GCA - the two conditions exist along a disease spectrum

•A patient presenting with GCA features (Q1: unilateral headache, jaw claudication, visual blurring, myalgia, night sweats) often has a background of PMR