Polymyalgia Rheumatica

Related Subjects: |Relapsing Polychondritis |Reactive Arthritis |Raynaud's Phenomenon |Polymyositis |Osteoporosis |Osteogenesis Imperfecta |Osteopetrosis

⚠️ If there is an associated headache or visual changes, always consider Temporal Arteritis (Giant Cell Arteritis, GCA) due to the risk of irreversible blindness.

📘 About

• PMR is a systemic inflammatory vasculitis primarily affecting extracranial arteries and causing non-specific systemic symptoms.
• It is closely linked to Temporal Arteritis (GCA), which can cause sudden blindness if untreated.

🧬 Aetiology

• Exact cause remains unknown, but involves a Th1 cell–mediated immune response.
• Elevated IL-6 plays a key role in inflammation.
• Associated with HLA-DR4 gene.

🔑 Clinical Features Suggestive of PMR

• Age > 50 years, duration of symptoms > 2 weeks.
• Bilateral aching of shoulder and/or pelvic girdle.
• Morning stiffness > 45 minutes.
• Raised inflammatory markers (ESR/CRP).

🩺 Clinical Presentation

• Sudden onset of generalised aches, headaches, and fatigue.
• Symmetrical shoulder stiffness (classic feature), worse in the morning.
• Associated systemic features: weight loss, fever, depression, nocturnal sweats.
• May show proximal muscle weakness (functional, not true myopathy).
• Symptoms typically show a dramatic response to corticosteroids within days.

🚩 Conditions to Exclude

• Active infection, malignancy.
• Rheumatic diseases: RA, SLE, inflammatory arthropathies, connective tissue diseases.
• Drug-induced myalgia: e.g. statins.
• Pain syndromes: fibromyalgia.
• Endocrine: hypothyroidism, other thyroid disease.
• Neurological: Parkinson’s disease.

🔬 Investigations

• Bloods: FBC (normocytic anaemia), U&E, LFT, CK, TFT to exclude mimics.
• Inflammatory markers: ESR often 50–120 mm/hr, CRP elevated.
• ALP: may be elevated (30%).
• Rheumatoid factor: negative, helps differentiate from RA.
• CXR: if systemic features or respiratory symptoms.
• Urinalysis: to rule out renal pathology/infection.

💊 Management

• Corticosteroids:
  • Prednisolone 15 mg daily × 3 weeks → taper (12.5 mg for 3 weeks, 10 mg for 4–6 weeks, then ↓ by 1 mg every 4–8 weeks).
  • If inadequate response → ↑ to 20 mg daily.
• Treatment duration typically 1–2 years.
• Bone protection: calcium + vitamin D supplements; consider bisphosphonates.
• Monitoring: watch for steroid complications (weight gain, diabetes, osteoporosis, HTN, dyslipidaemia).

📖 References

• Guidelines for the Management of Polymyalgia Rheumatica (PMR)

Cases — Polymyalgia Rheumatica (PMR)

• Case 1 — Classic presentation 👵: A 72-year-old woman presents with 2 months of bilateral shoulder and hip girdle stiffness, worse in the mornings (>45 minutes). She struggles to get out of a chair and lift her arms. ESR 82 mm/hr, CRP elevated. Rapid improvement after low-dose prednisolone confirms the diagnosis of PMR.
• Case 2 — Associated GCA ⚠️: A 68-year-old man with known PMR develops new temporal headache, scalp tenderness, and jaw claudication. Exam: tender, thickened temporal artery. ESR 104 mm/hr. Diagnosis: giant cell arteritis (GCA) complicating PMR. Managed with high-dose steroids and urgent ophthalmology review.
• Case 3 — Mimic uncovered 🔍: A 70-year-old woman presents with proximal muscle stiffness and pain. ESR mildly raised at 28 mm/hr. However, she also has proximal weakness and CK is elevated. Further workup reveals polymyositis rather than PMR. This highlights the need to distinguish true PMR from mimics.

Teaching Point 🩺: PMR affects those >50 years, with proximal stiffness, raised ESR/CRP, and dramatic steroid response. Always consider GCA (headache, visual loss, jaw claudication) and exclude mimics such as polymyositis, thyroid disease, or malignancy.