What are the diagnosis and management guidelines for polymyalgia rheumatica (PMR)?

Polymyalgia Rheumatica: Diagnosis and Management

Diagnosis

Diagnose PMR clinically in patients over 50 years with bilateral shoulder and hip girdle pain plus morning stiffness, elevated inflammatory markers, and systematic exclusion of mimicking conditions, then confirm with rapid response to 12.5-25 mg prednisone daily. 1

Clinical Presentation to Identify

• Bilateral shoulder and/or pelvic girdle pain with pronounced morning stiffness 2, 3
• Onset may be acute or develop over days to weeks 3
• Systemic symptoms including fatigue, fever, and weight loss may occur 3
• Age >60 years is typical; age <60 requires specialist referral 4, 5

Mandatory Pre-Treatment Laboratory Workup

Before prescribing any therapy, obtain the following baseline investigations: 1

• Inflammatory markers: ESR and/or CRP (typically elevated) 4, 5
• Autoantibodies: Rheumatoid factor and/or anti-CCP to exclude rheumatoid arthritis 4, 5
• Complete blood count 5
• Metabolic panel: Glucose, creatinine, liver function tests 1
• Bone profile: Calcium, alkaline phosphatase 1
• Urinalysis (dipstick) 1
• Consider additionally: Protein electrophoresis, TSH, creatine kinase, vitamin D 1

Additional Testing Based on Clinical Suspicion

• If atypical features present: ANA, ANCA, or tuberculosis testing to exclude mimicking conditions 1
• Chest radiograph at physician discretion to exclude malignancy or infection 1
• Ultrasound may show bilateral subdeltoid bursitis, assisting diagnosis 6, 7

Conditions That Must Be Excluded

The diagnosis requires systematic exclusion of: 5

• Inflammatory mimics: Giant cell arteritis (mandatory search), rheumatoid arthritis, spondyloarthropathy, vasculitis, RS3PE syndrome 6
• Non-inflammatory conditions: Bilateral rotator cuff disease, shoulder capsulitis 4
• Malignancy (especially if poor glucocorticoid response) 6
• Infections 6
• Endocrine disorders 1
• Drug-induced syndromes (including immune checkpoint inhibitor therapy) 4
• Inflammatory myositis (presents with true weakness, not just pain) 4

When to Refer to Specialist

Refer immediately for: 1, 5

• Peripheral inflammatory arthritis beyond oligoarticular pattern 5
• Systemic symptoms beyond typical PMR 5
• Low or normal inflammatory markers despite typical symptoms 5
• Age <60 years 4, 5
• High risk of or existing glucocorticoid-related side effects 8
• PMR refractory to glucocorticoid therapy 8
• Relapses or anticipated prolonged therapy 8

Management

Initial Glucocorticoid Therapy

Start prednisone 12.5-25 mg daily as first-line therapy, not NSAIDs. 8, 9

Dose selection within this range: 8

• Higher doses (closer to 25 mg): For patients with high relapse risk (female sex, ESR >40 mm/hr, peripheral arthritis) AND low adverse event risk 5, 8
• Lower doses (closer to 12.5 mg): For patients with relevant comorbidities (diabetes, osteoporosis, hypertension, cardiovascular disease, peptic ulcer, glaucoma) 8

Expected response: Rapid improvement within less than one week; failure to respond suggests alternative diagnosis (giant cell arteritis, malignancy, infection) 6, 9

Glucocorticoid Tapering Protocol

Follow this structured tapering schedule: 8

1. Weeks 0-4 to 8: Reduce from initial dose to 10 mg/day prednisone 8
2. After achieving remission: Taper by 1 mg every 4 weeks until discontinuation 8
3. Alternative: Use alternate-day tapering schedules 8

Methotrexate as Glucocorticoid-Sparing Agent

Add methotrexate 7.5-10 mg/week early in treatment for: 5

• Patients at high risk of relapse 5
• Anticipated prolonged therapy requirement 5
• Comorbidities where glucocorticoid adverse events are more likely 5

Note: Methotrexate yields only modest effect but is the most commonly used steroid-sparing agent 9, 7

Biologic Therapy Considerations

• Anti-TNF agents are NOT effective in PMR and should not be used 6, 9
• Tocilizumab (anti-IL-6 receptor): Case series suggest efficacy in refractory PMR, but controlled trials are needed 9

Comorbidity Assessment and Management

Before initiating therapy, assess and address: 1, 8

• Hypertension, diabetes, glucose intolerance, cardiovascular disease 8
• Dyslipidemia, peptic ulcer disease 8
• Osteoporosis (particularly recent fractures) - implement bone protection 8
• Cataract or glaucoma risk factors 1
• Chronic or recurrent infections 1
• Current NSAID use 1

Monitoring Schedule

Structure follow-up visits as follows: 5, 8

• First year: Every 4-8 weeks 5, 8
• Second year: Every 8-12 weeks 5, 8
• During flares or tapering: Increase frequency as indicated 8

At each visit, monitor: 8

• Disease activity and inflammatory markers (ESR, CRP) 8
• Glucocorticoid-related side effects 8
• Comorbidities and risk factors for relapse 8

During flares, repeat: 5

• ESR and/or CRP, complete blood count 5
• Glucose, creatinine, liver function tests 5
• Bone profile 5
• Rheumatoid factor and/or anti-CCP 5
• Creatine kinase 5

Risk Factors for Relapse and Prolonged Therapy

The strongest predictors are: 5, 8

• Female sex 5, 8
• High baseline ESR (>40 mm/hour) 5, 8
• Peripheral inflammatory arthritis at presentation 5, 8

Note: Female sex is also associated with higher risk of glucocorticoid side effects 4

Non-Pharmacological Management

Implement individualized exercise program to: 5

• Maintain muscle mass and function 5
• Reduce fall risk, particularly important in older adults on long-term glucocorticoids 5

Provide patient education on: 8

• PMR impact and treatment effects 8
• Comorbidities and disease predictors 8
• Importance of adherence to tapering schedule 8

Shared Decision-Making

Create an individualized PMR management plan through shared decision-making between patient and physician, considering: 1, 8

• Patient preferences regarding initial glucocorticoid dose 1
• Individual tolerance for glucocorticoid side effects versus relapse risk 8
• Comorbidity burden and life expectancy 8

Common Pitfalls to Avoid

• Do not use response to steroids as a defining diagnostic feature of PMR, though rapid response is expected 2
• Do not miss giant cell arteritis: Perform painstaking search for temporal artery symptoms, jaw claudication, visual symptoms 6
• Do not start with doses >25 mg prednisone unless giant cell arteritis is suspected 8
• Do not use anti-TNF biologics as they are ineffective 6, 9
• Do not overlook checkpoint inhibitor-induced PMR in cancer patients, which may present atypically 4