Polymyalgia Rheumatica
Common inflammatory condition in older adults characterised by bilateral shoulder and hip girdle pain and stiffness with raised inflammatory markers. Responds dramatically to low-dose corticosteroids. Closely associated with giant cell arteritis (15-20% have coexistent GCA).
Key Facts
PMR affects ~1 in 1,000 of the UK population over 50; most common inflammatory rheumatic condition in older adults Characterised by bilateral shoulder and hip girdle pain and stiffness, worse in the morning (>45 minutes), with raised ESR/CRP Dramatic response to prednisolone 15mg OD within 24-72 hours is virtually diagnostic (if no response, reconsider diagnosis) 15-20% of PMR patients develop GCA; ask about headache, visual symptoms, jaw claudication at every visit Treatment: prednisolone 15mg OD tapering over 1-2 years; relapse rate 30-50% during taper No specific diagnostic test; diagnosis is clinical + raised inflammatory markers + steroid response USS shoulders: bilateral subacromial/subdeltoid bursitis and/or biceps tenosynovitis supports diagnosis Differential: late-onset RA, malignancy, hypothyroidism, PMR-like presentation of GCA, infection
Overview
Key Facts
PMR is the most common inflammatory rheumatic disease in the elderly. Its hallmark is the dramatic response to low-dose steroids. Always screen for GCA.
Epidemiology
- Incidence: ~50-80 per 100,000 in >50 age group
- Peak age: 70-80; almost never <50
- F:M 2-3:1
- More common in Northern European populations
Pathophysiology
- Synovitis and bursitis in proximal joints (shoulders, hips) and periarticular structures
- IL-6-driven inflammatory response (same pathway as GCA)
- Biopsy of synovium shows macrophage and T-cell infiltration
- Not a myopathy: CK is normal; muscle power is normal (limited by pain)
Clinical Presentation
Core Features
- Bilateral shoulder pain and stiffness (most common; 70-95%)
- Bilateral hip girdle pain and stiffness (50-70%)
- Morning stiffness >45 minutes (often >1 hour)
- Difficulty: raising arms above head, getting out of bed/chair, turning in bed
- Systemic: fatigue, malaise, low-grade fever, weight loss, depression
Important Negatives
- No true muscle weakness (limited by pain, not weakness)
- CK normal (distinguishes from polymyositis)
- No joint swelling (though some peripheral oedema may occur)
Red Flags (May Indicate GCA or Alternative Diagnosis)
- New headache, jaw claudication, visual symptoms → GCA; escalate treatment
- Peripheral arthritis → consider late-onset RA
- Night sweats, weight loss → malignancy screen
- Failure to respond to 15mg prednisolone → reconsider diagnosis
Differential Diagnosis
| Diagnosis | Key Features | Investigation |
|---|---|---|
| Late-onset RA | Symmetrical small joint arthritis, RF/CCP positive | RF, anti-CCP, X-ray |
| GCA | Headache, jaw claudication, visual symptoms | Temporal artery USS/biopsy |
| Polymyositis | True weakness, elevated CK | CK, EMG, biopsy |
| Hypothyroidism | Fatigue, weight gain, constipation | TFTs |
| Malignancy | Weight loss, night sweats, new symptoms | CT, myeloma screen |
| OA | Mechanical pain, no morning stiffness, normal ESR | X-ray |
| Statin myalgia | Statin use, mild CK elevation | Drug history |
Diagnosis / Investigation
Bloods
- ESR: characteristically elevated (usually >40, often >50-100)
- CRP: elevated (more responsive than ESR)
- FBC: normocytic anaemia, thrombocytosis possible
- LFTs: raised ALP (20-30%)
- CK: NORMAL (essential to exclude myositis)
- TFTs: exclude hypothyroidism
- RF, anti-CCP: negative (excludes RA)
- Myeloma screen: serum protein electrophoresis (elderly with raised ESR)
- Calcium: exclude hyperparathyroidism
Imaging
- USS shoulders: bilateral subacromial/subdeltoid bursitis, biceps tenosynovitis (supports diagnosis)
- USS hips: trochanteric bursitis, hip joint synovitis
- PET-CT: may show bursitis/synovitis; also useful for large-vessel GCA screening
Clinical Assessment
- Use BSR/BHPR guidelines or ACR/EULAR 2012 classification criteria (score ≥4/6 suggests PMR)
Management
Pharmacological
BSR Guidelines:
- Prednisolone 15mg OD: starting dose
- Expect dramatic improvement within 24-72 hours (if not, reconsider diagnosis)
- Taper: reduce to 12.5mg at 3 weeks → 10mg at 6 weeks → reduce by 1mg every 4-8 weeks
- Typical treatment duration: 1-2 years; many patients need longer (median ~2 years)
- Guided by symptoms + CRP/ESR (not CRP alone)
Relapse:
- 30-50% relapse during taper
- Increase prednisolone to last effective dose → retaper more slowly
Steroid-Sparing:
- Methotrexate 7.5-10mg weekly: consider early if high relapse risk, steroid side effects, or comorbidities (diabetes, osteoporosis)
- Limited evidence but some benefit in reducing steroid dose and relapse
Tocilizumab:
- Emerging evidence for PMR (PMR-SPARE trial); not yet standard of care
Supportive
- Bone protection: calcium/vitamin D + bisphosphonate (DEXA scan)
- PPI: if risk factors for GI complications
- Cardiovascular risk: manage diabetes, hypertension
- Exercise: maintain mobility; physiotherapy referral
Monitoring
- CRP/ESR: every 2-4 weeks initially, then 3-monthly
- Screen for GCA symptoms at every visit
- Glucose: steroid-induced diabetes screening
- DEXA scan: at baseline if starting prolonged steroids
Referral Criteria
- Typical PMR responding to steroids → GP management appropriate
- Atypical features or diagnostic uncertainty → rheumatology
- GCA symptoms → urgent/emergency treatment
- High relapse rate or steroid dependence → rheumatology for steroid-sparing therapy
Prognosis
- Excellent prognosis with corticosteroid treatment
- Most patients achieve remission and discontinue steroids within 1-3 years
- 15-20% require treatment for >3 years
- Relapse rate: 30-50% during taper; more common with rapid taper
- GCA development: 15-20% of PMR patients; ongoing vigilance required
- Steroid complications (osteoporosis, diabetes, cataracts, weight gain) are the main source of morbidity
- Mortality: near-normal life expectancy with appropriate treatment
Other Relevant Information
ACR/EULAR 2012 PMR Classification Criteria
| Criterion | Score (without USS) | Score (with USS) |
|---|---|---|
| Morning stiffness >45 min | 2 | 2 |
| Hip pain/limited ROM | 1 | 1 |
| Absence of RF and CCP | 2 | 2 |
| Absence of other joint involvement | 1 | 1 |
| ≥1 shoulder with USS changes | N/A | 1 |
| Both shoulders with USS changes | N/A | 1 |
Score ≥4 (without USS) or ≥5 (with USS) classifies as PMR
PMR Steroid Taper (BSR)
| Time | Dose |
|---|---|
| Week 0 | 15mg |
| Week 3 | 12.5mg |
| Week 6 | 10mg |
| Then | ↓ by 1mg every 4-8 weeks |
| Target | Off steroids by 1-2 years |