Polymyalgia rheumatica

Polymyalgia rheumatic (PMR) is a chronic inflammatory disease of unknown aetiology which presnts with pain and stiffness that is worst in the morning and particularly affects the shoulders and hips (1,2).

• PMR is the most common inflammatory musculoskeletal disease in older people and represents one of the frequent indications for long-term corticosteroid treatment in the community (2,3)
• features of PMR overlaps with those of giant cell arteritis suggesting that they might represent different types of the same disease process (1)

Although it is managed exclusively in general practice, it has been shown that there is a wide variation in practice and established diagnostic criteria are used infrequently (3).

British Society for Rheumatology (BSR) and British Health Professionals in Rheumatology (BHPR) guidelines for the management of polymyalgia rheumatica (PMR) recommends that corticosteroids therpay in PMR should commence only after a full assessment of the underlying cause has been made (4).

A step wise diagnostic approach has been proposed for the evaluation of polymyalgia rheumatica:

• assessment for core inclusion
  • bilateral shoulder and/or pelvic girdle aching
  • morning stiffness lasting more than 45 minutes.
  • abrupt onset
  • age over 50 years
  • duration more than 2 weeks
  • evidence of an acute phase response (increased ESR/CRP)
    
    
• assessment of core exclusion features and mimicking conditions
  • active infection
  • active cancer
  • evidence of active giant cell arteritis
    • abrupt-onset headache (usually temporal) and temporal tenderness
    • visual disturbance, including diplopia
    • jaw or tongue claudication etc
  • other inflammatory conditions
  • non inflammatory
  • endocrine
  • drug induced e.g. - statins
    
    
• assessment of the response to a standardised dose of 15 mg prednisolone
  • a patient-reported global improvement of 70% within a week of commencing steroids is consistent with PMR,with normalization of inflammatory markers in 4 weeks
  • a lesser response should point towards an alternative condition
    
    
• confirmation of diagnosis at early follow up
  • during follow up (4-6 weeks) PMR should be confirmed (and should be vigilant for mimicking conditions)

A review notes that glucocorticoids at 12.5-25 mg prednisone per day are effective in inducing remission in most individuals but, when tapered, relapses occur in 40-60% of those affected and side-effects are common (5).

Reference;

• (1) Kermani TA, Warrington KJ.Polymyalgia rheumatica. Lancet. 2013;381(9860):63-72.
• (2) Mackie SL, Mallen CD. Polymyalgia rheumatica. BMJ. 2013;347:f6937.
• (3) Helliwell T, Hider SL, Mallen CD. Polymyalgia rheumatica: diagnosis, prescribing, and monitoring in general practice. Br J Gen Pract. 2013;63(610):e361-6.
• (4) Dasgupta B et al. BSR and BHPR guidelines for the management of polymyalgia rheumatica. Rheumatology (Oxford). 2010;49(1):186-90.
• (5) Espigol-Frigole G et al. Polymyalgia rheumatica Lancet (October 10th 2023).