What is the diagnosis and treatment of Polymyalgia Rheumatica (PMR)?

From the Guidelines

Polymyalgia rheumatica (PMR) should be diagnosed and treated with a combination of clinical symptoms, laboratory findings, and exclusion of other conditions, using low-dose oral prednisone starting at 12.5-25 mg daily, with gradual tapering and monitoring of symptoms, inflammatory markers, and steroid-related side effects, as recommended by the 2015 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) collaborative initiative 1.

Diagnosis

Diagnosis of PMR typically requires:

• Age over 50
• Bilateral shoulder and/or hip pain and stiffness lasting at least 2 weeks
• Elevated inflammatory markers (ESR >40 mm/hr or CRP >10 mg/L)
• Rapid response to glucocorticoid therapy

Treatment

Treatment centers on low-dose oral prednisone, starting at 12.5-25 mg daily, which usually produces dramatic symptom improvement within 24-72 hours.

• The initial prednisone dose should be individualized, taking into account the patient's risk of relapse and adverse events, with a higher dose considered in patients with a high risk of relapse and low risk of adverse events, and a lower dose in patients with relevant comorbidities 1.
• After 2-4 weeks of symptom control, prednisone should be gradually tapered by 1-2.5 mg every 2-4 weeks to a maintenance dose of 5-7.5 mg daily, then more slowly reduced over 1-2 years to prevent relapse.
• Regular monitoring of symptoms, inflammatory markers, and steroid-related side effects is essential.
• Calcium (1000-1200 mg daily) and vitamin D (800-1000 IU daily) supplementation should be initiated with steroid therapy to prevent osteoporosis, and bisphosphonates may be needed for those at high fracture risk.
• Methotrexate (7.5-20 mg weekly) can be added as a steroid-sparing agent in patients with frequent relapses or significant steroid side effects, as supported by moderate to high quality evidence 1.

Monitoring and Follow-up

Patients should be monitored for:

• Temporal arteritis symptoms (headache, jaw claudication, visual changes) as 15-30% of PMR patients develop this complication requiring higher steroid doses.
• Follow-up every 4-8 weeks in the first year, every 8-12 weeks in the second year, and as indicated in case of relapse or as prednisone is tapered off, as recommended by the 2015 EULAR/ACR collaborative initiative 1.

From the Research

Diagnosis of Polymyalgia Rheumatica (PMR)

• The diagnosis of PMR is based on clinical features such as new-onset bilateral shoulder pain, including subdeltoid bursitis, muscle or joint stiffness, and functional impairment 2.
• Constitutional symptoms and elevated inflammatory markers (>90%) are common in both PMR and giant cell arteritis (GCA) 2.
• Ultrasound imaging enables detection of bilateral subdeltoid bursitis in 69% of PMR patients 2.
• Although there are no specific laboratory tests, C-reactive protein and erythrocye sedimentation rates are elevated in over 90% of patients 3.
• The diagnosis may be aided by imaging, especially ultrasonography and magnetic resonance imaging (MRI) 3.

Treatment of Polymyalgia Rheumatica (PMR)

• Treatment currently consists of glucocorticoids at an initial dose of 12.5-25 mg prednisone equivalent daily 3.
• The optimal initial dose and tapering treatment regimens are unknown, but consensus-based recommendations suggest initial therapy for PMR is prednisone, 12.5 to 25 mg/day or equivalent 2.
• Treatment duration is typically 2-3 years but may be longer 3.
• Adjunctive methotrexate may reduce cumulative glucocorticoid dosage by 20% to 44% and relapses by 36% to 54% in both PMR and GCA 2.
• Methotrexate may be considered as an adjunct to glucocorticoids in patients with PMR or GCA who are at high risk of relapse 4.

Special Considerations

• Elderly onset rheumatoid arthritis is frequently misdiagnosed as PMR 3.
• Giant cell arteritis (GCA) occurs in approximately 20% of cases and up to two thirds of patients with GCA have symptoms of PMR 3.
• Temporal artery biopsy remains the standard for definitive diagnosis of GCA, but ultrasound and magnetic resonance imaging (MRI) of large vessels revealing inflammation-induced wall thickening can support the diagnosis of GCA 2.
• Patients with suspected GCA should receive empiric high-dose glucocorticoids because the condition may lead to blindness if untreated 4.