Polymyalgia Rheumatica

General Overview

💡PMR is the most common inflammatory rheumatologic condition in the elderly (peak incidence at 70-80yo) and typically affects women (3 female:1 male).

• Manifests with:

  • Age >50 yo

  • Musculoskeletal symptoms (lasting > 2 weeks):

    • Symmetric pain/aching and morning stiffness > 45 mins affecting shoulders/neck/hip

    • Stiffness relieved with activity

  • Systemic symptoms (fatigue, malaise, night sweats, depressed mood)

    • Fever should prompt to rule out inflammatory (GCA) or infectious pathology

  • Elevated ESR (more prognostic) and/or CRP (more sensitive)

  • Rapid improvement with low-dose systemic steroids (eg. 15-25mg/day prednisone)

• Exclude non-inflammatory, inflammatory (such as giant cell arteritis or rheumatoid arthritis), drug, endocrine, infectious and malignancy

Red Flags (Features of Giant Cell Arteritis)

~20% associated with giant cell (temporal) arteritis

• New sudden-onset headache

• New sudden-onset visual changes

• Upper cranial nerve palsies

• Jaw/tongue claudication

• Limb claudication or suggestion of large vessel involvement

• Prominence, beading or diminished pulse of temporal artery

• Temporal tenderness

• Fever, anemia, constitutional symptoms/signs

Physical examination

• Cardio

  • Assess bilateral BP discrepancy, temporal arteries swelling/tenderness/bruits (to detect GCA)

• MSK

  • Decreased ROM of shoulders, neck, hips but preserved muscle strength

  • Muscle tenderness surrounding affected joints

• Neuro

  • Normal muscle strength in PMR (despite subjective weakness or pain)

Investigations

• ↑ ESR, ↑ CRP

  • ESR elevation better correlated to severity but CRP more sensitive (99% Sn)

• Rule out mimics:

  • ANA, RF, anti-CCP (SLE, rheumatoid arthritis)

  • CK (polymyositis/dermatomyositis)

  • CBC, SPEP/FLC, Calcium, ALP, Vitamin D (bony disease, eg. multiple myeloma)

  • TSH (hypothyroidism)

• Other: LFT, UA

Treatment

💡 Given risks of long-term corticosteroid use, consider baseline BMD and consider osteoporosis prophylaxis

• Prednisone 15mg PO daily (can also be divided BID)

  • Response usually observed within three days

    • If no response after one week, consider increase to 20mg PO daily

      • If still no response, consider alternative diagnosis (most commonly RA)

  • Maintain effective steroid dose for 2-4 weeks until after symptoms resolve, then gradually taper every 2-4 weeks (example regimen:15mg x 2-4w → 12.5mg x 2-4w → 10mg x 2-4w → 9mg x 4-8w → 8mg x 4-8w → 7mg x 4-8w → etc.)

    • Can often take 1-2 years to fully taper off steroids!

• Relapse is common (treat with previously effective dose), monitor for giant cell arteritis (temporal arteritis)

• Refer to Rheumatology if atypical (e.g., age < 50, systemic symptoms, peripheral or asymmetric joint involvement, systemic symptoms, low ESR/CR, relapse or prolonged therapy)

Last edited 2021-08-04
B. Paul, K. Chan