PMR - Ten Top Tips for Diagnosis and Management

The diagnosis and management of polymyalgia rheumatica (PMR) is a challenge. We see lots of people with aches and pains, notably in the age group in whom PMR presents (peak age 70-80 years), the range of potential diagnoses is high, yet getting the diagnosis right is so important given most people with PMR will need 1-2 years of steroid therapy. 

A BJGP study from 2018 (BJGP 2018; 68 (676)) discussed some of the challenges we face in primary care, and highlighted two issues which are often poorly considered, notably an awareness of other conditions that can mimic PMR (including malignancies), and the starting dose of prednisolone. The British Society of Rheumatology guideline dates back to 2009/10, so a recent pair of articles in the Lancet (Vol 402, Iss 10411 Oct 21, 2023) and NEJM (N Engl J Med 2023; 389:1328-1329) give a welcome update, with positive news about potential future therapeutics for this difficult to treat condition. 

We summarise the diagnosis and management in the attached KISS, but here are 10 Top Tips which highlight some of the key learning points for us in primary care:

1. Typical features: PMR is characterised by aching and stiffness in the neck, torso, shoulders and pelvic girdle which typically come on over days. Early morning stiffness (usually >45 minutes) is a key feature, but can be prolonged throughout the day, and can affect sleep. Bilateral shoulder pain radiating to the elbows is the most common symptom (70-95%), with pelvic girdle pain (often in groins, lateral aspects of hips radiating to thighs/knees) being less common (50-70%). Low grade systemic features including low-grade fever, depression, fatigue, weight loss and anorexia are common (up to 40%). PMR is rare in those aged <60.
2. Always consider/rule out other diagnoses that can mimic PMR and investigate before starting steroids. Important alternative diagnoses include: 
   • Malignancy especially lung cancer (consider CXR) and myeloma. 
   • Giant cell arteritis (GCA) or other large vessel vasculitis. 
   • Non-inflammatory MSK conditions esp. OA and bilateral shoulder tendinopathies.
3. Clinical features that might point to alternative diagnoses:
   • If pain is more widespread (rather than predominantly proximal) consider malignancy e.g. myeloma. 
   • If pain is more mechanical rather than inflammatory (i.e. worsens with activity rather than improving with activity) consider non-inflammatory conditions e.g. OA, bilateral shoulder tendinopathies. 
   • If more prominent systemic features, cranial symptoms (e.g. scalp sensitivity/headache), thickening/hardness or reduced pulsation of temporal artery consider GCA/other large vessel vasculitis. 
4. Consider inflammatory marker levels. Although low/normal ESR/CRP can be seen in PMR, this is unusual - if so consider non-inflammatory MSK conditions. If ESR/CRP are very high e.g. ESR >100 alternative diagnoses need to be considered e.g. myeloma, GCA/other large vessel vasculitis. 
5. Initial steroid dose. When giving a trial of treatment start at 15mg of prednisolone - the vast majority of patients will get a dramatic improvement in symptoms after 24-72 hours (and will think you’re the greatest clinician ever!). 
6. Be very wary of using prednisolone doses >20mg. International guidance universally agrees that doses in excess of 25mg are inappropriate - higher doses can ‘treat’ or mask more serious conditions e.g. vasculitis, malignancy, and give you a false positive response. If only partial response to 20mg prednisolone refer to rheumatology. 
7. Be patient and realistic. Warn patients at the outset that most people with PMR need treatment for 1-2 years and tapering steroids needs to be done slowly.
8. Relapse in PMR is common (>40%) but consider other non-PMR diagnoses if symptoms worsen when steroids tapered e.g. non-inflammatory MSK conditions, but also GCA; alongside re-assessing clinically repeating ESR/CRP can be helpful - if no rise the symptoms may not be due to PMR relapse and if significant rise consider if this is a vasculitic picture developing e.g. GCA.
9. Bone loss can occur early in people starting steroids, so assess osteoporosis risk early with FRAX, and consider starting empirical bone protection with bisphosphonates whilst awaiting DEXA scan if high risk (e.g. women aged >70, previous fragility fracture, FRAX score exceeding intervention threshold).
10. Refer for specialist input if unable to taper steroids at reasonable intervals, if patients relapse 2 or more times, or if on steroids for >2 years; steroid-sparing agents including methotrexate may be considered, and there is emerging evidence supporting IL6 blocking DMARDS as a way of reducing the steroid burden.