Polymyalgia Rheumatica

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Introduction

Polymyalgia rheumatica (PMR) is an inflammatory disorder characterised by pain and stiffness around the proximal muscles, specifically the shoulders, neck and hips.1

PMR can exist in isolation but often co-exists with other rheumatological disorders. PMR commonly affects Caucasian females over the age of 50 years with the peak age of onset being 70-80 years.2

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Aetiology

The exact aetiology of PMR is not fully understood. It is recognised as an immune-mediated inflammatory disorder with some autoimmune and familial associations, but the link is not well defined.

Additionally, because the age of onset is older adults, it is believed that those with a genetic predisposition may develop PMR as their immune system ages along with changes to neurohormonal regulation.3

While the term “polymyalgia” suggests PMR has a muscle-related aetiology, PMR tends to primarily affect the peri-articular structures such as tendons, bursa and synovium.4 There is often no pathology seen in a muscle biopsy.


Risk factors

Risk factors for polymyalgia rheumatica include:


Clinical features

History

PMR tends to present acutely or sub-acutely over days to weeks.

Patients describe pain, stiffness and weakness in the muscles of their neck, shoulders, buttocks and hips which affect their activities of daily living.

The distal muscles of the upper and lower limbs are rarely affected. Symptoms are worst first thing in the morning often lasting over an hour.5

Typical symptoms of PMR include:

  • Shoulders: patients describe a reduced range of motion and difficulty with reaching overhead
  • Hips: patients have difficulty getting up from a chair or climbing stairs without support
  • Constitutional symptoms: low-grade fevers, weight loss, night sweats, malaise, fatigue and anorexia

The symptoms of PMR overlap with many systemic infections or malignancies so red flag symptoms of unintentional weight loss, night sweats, fevers, and personal or family history of malignancy should prompt consideration for sinister pathologies. 

PMR has a strong association with giant cell arteritis (GCA) leading most clinicians to consider them as disorders on the same spectrum of disease.6 Patients who present with PMR should be screened for GCA symptoms.

Giant cell arteritis (GCA)

Giant cell arteritis (GCA) is a vasculitis that affects the large vessels. The most common presentation is temporal arteritis, where there is inflammation of the temporal artery and its branches.7

Typical symptoms of GCS include:

  • Painful and tender scalp: often while combing or rubbing shampoo into their hair
  • Headaches: new temporal headaches
  • Jaw claudication: pain in the jaw while eating/ chewing
  • Visual changes: blurring or loss of vision

For more information, see the Geeky Medics guide to GCA (temporal arteritis).

GCA needs to be treated as a medical emergency as it can result in permanent vision loss if left untreated.8

It is important to note that GCA can also affect other large vessels especially the aorta and its branches. In milder cases, this may present as arm pain, but in more severe cases it could result in an aortic aneurysm.9

Clinical examination

Typical findings of PMR on clinical examination include:10

  • Bilateral proximal muscles may be diffusely tender to touch. Tender points may indicate bursitis.
  • Active and passive range of motion is limited by pain
  • Muscle strength is normal or limited by pain in the proximal muscles
  • The scalp may be tender to touch suggestive of GCA
  • An examination of the temporal artery may demonstrate a thickened temporal artery with diminished or lack of palpable pulse

The neurological examination is usually normal.


Differential diagnoses

Differential diagnoses to consider in the context of PMR include:

  • Inflammatory conditions: rheumatoid arthritis, myositis, fibromyalgia
  • Infectious conditions: Lyme disease, infective endocarditis
  • Malignancy: multiple myeloma
  • Other: osteoarthritis, hypothyroidism

Investigations

Laboratory investigations

Relevant laboratory investigations include:

  • Full blood count (FBC): normocytic anaemia or thrombocytosis may be seen in ongoing inflammation
  • Inflammatory markers: erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are almost always elevated in PMR. CRP is sensitive for acute disease activity and is followed up to assess response to treatment.11

Because the symptoms of PMR can be generalised and non-specific, further blood tests should be considered to exclude other conditions. These tests include LFTs, renal function tests, immunoglobulins, rheumatoid factor (RF), anti-CCP, thyroid function tests, calcium and alkaline phosphatase.

Imaging

Relevant imaging investigations include:12,15

  • Ultrasound (US): commonly shows joint effusion, synovitis or bursitis which can be useful in assessing the degree of inflammation and monitoring response to therapy
  • Magnetic resonance imaging (MRI): MRI is a more sensitive test to assess for synovitis and bursitis (not routinely performed)
  • Fluorodeoxyglucose F18- positron emission tomography (FDU PET): new imaging modality used to see increased uptake in the bursa and synovium of the shoulders, ischial tuberosity and greater trochanters consistent with the pain of PMR. FDU PET is also useful for assessing vasculitis (not routinely performed).
Investigations for giant cell arteritis (GCA)

Patients with symptoms of GCA will require further investigation. The current gold standard confirmatory test for GCA is a temporal artery biopsy (TAB).13

GCA is known to have skip lesions, so a negative result on a biopsy doesn’t exclude GCA. Prompt treatment with steroids may also give false-negative results on TAB.

Ongoing research supports minimally invasive diagnostic modalities including ultrasound and magnetic resonance angiogram (MRA) to better assess the entire length of the affected arteries. These non-invasive modalities also allow the assessment of other large vessels like the aorta and its branches implicated in GCA.


Diagnosis

There is no single test for the diagnosis of PMR. It is a clinical diagnosis based on the following features:

  • Age of onset over 50 years
  • The classical presentation of symptoms with proximal muscle stiffness and pain that is worse in the mornings
  • A blood test showing elevated inflammatory markers (ESR and CRP)
  • Improvement of symptoms with the initiation of steroid therapy

Management

Medical management

Glucocorticoids (e.g. prednisolone) are the mainstay of treatment for PMR.

Glucocorticoids should be tapered (a reducing course) over a period of weeks to months as symptoms resolve and inflammatory markers improve. 

Glucocorticoid tapering

NICE suggest the following regime for tapering the dose of prednisolone when treating PMR:14

  • Continue prednisolone 15 mg each day until symptoms are fully controlled (usually 3 weeks)
  • Reduce the dose to 12.5 mg each day for 3 weeks
  • Reduce the dose to 10 mg each day for 4–6 weeks
  • Reduce the dose by 1 mg every 4–8 weeks until treatment is stopped

Glucocorticoids tapers are important, as a rapid withdrawal of steroids after long-term use can result in an Addisonian crisis. The rate of taper differs based on the duration of steroid therapy and the clinical response of PMR symptoms. 

Steroid side effects

Glucocorticoids have numerous side effects, both with short term and long-term use:

  • Diabetes: glucocorticoids cause hyperglycaemia and can precipitate a hyperglycaemic hyperosmolar state (HHS) in patients with co-morbid diabetes
  • Gastro-oesophageal reflux disease (GORD)/peptic ulcer disease: glucocorticoids can worsen acid reflux, so the addition of a proton-pump inhibitor (PPI) may be indicated
  • Osteoporosis: given that elderly women have lower bone density and are the main demographic of PMR, glucocorticoids can further increase fracture risk. This group may benefit from bone prophylaxis like denosumab (RANKL antagonist), calcium and vitamin D supplements.

Glucocorticoid sparing therapy

Glucocorticoid sparing drugs are used in PMR and GCA to limit the adverse effects of extended glucocorticoid use. These may include disease-modifying anti-rheumatic agents (DMARDs) or biologics.

Methotrexate is an anti-folate DMARD that can be used to manage PMR symptoms as part of a glucocorticoid taper. Tocilizumab is a licensed IL-6 inhibitor that reduces the acute inflammatory response.  


Complications

PMR can have a relapsing and remitting course, with asymptomatic periods and acute flares.

Most long-term complications of PMR are linked to glucocorticoid therapy. There has been a concern regarding increased cardiovascular mortality, but a recent (2015) meta-analysis suggests that with control of systemic inflammation, the risk of cardiovascular mortality is equivalent to the general population.15

Patients presenting with PMR or GCA should be counselled about GCA symptoms and advised to seek advice immediately if symptoms arise. GCA can present at any time in the disease progression. Active inflammation in GCA is linked with the following potentially significant complications:

  • Blindness
  • Stroke
  • Aortitis leading to aortic aneurysm

Key points

  • PMR is the second most common rheumatological condition which primarily affects the proximal muscles of the neck, shoulders, and hips. Patients describe difficulty reaching overhead and getting up from a chair
  • PMR and GCA frequently occur together and are believed to be disorders on the same spectrum of disease
  • GCA is a large vessel vasculitis that most commonly affects the temporal artery causing symptoms of scalp tenderness, jaw claudication and visual disturbances. It is treated as a medical emergency because untreated it causes blindness.
  • Blood tests typically reveal elevated inflammatory markers (CRP and ESR), which can be used to assess response to treatment and relapse respectively
  • The current gold standard test for GCA is a temporal artery biopsy, but new research is demonstrating superior outcomes with minimally invasive imaging modalities like ultrasound and MRA
  • Both PMR and GCA respond well to steroid therapy. Steroids should be tapered and replaced with steroid-sparing drugs where possible to minimise the adverse effects of steroid use
  • Long term prognosis is good with good control of vascular inflammation, and the ability to recognise a flare and to seek appropriate medical care

Reviewer

Dr Grainne Murphy

Consultant Rheumatologist


Editor

Dr Chris Jefferies


References

  1. Mackie, S. L., & Mallen, C. D. (2013). Polymyalgia rheumatica. BMJ, 347(Dec, 031).
  2. Salvarani, C., Gabriel, S. E., Michael O’Fallon, W., & Hunder, G. G. (1995). Epidemiology of polymyalgia rheumatica in Olmsted county, Minnesota, 1970–1991. Arthritis & Rheumatism, 38(3), 369–373. 
  3. Weyand, C. M., & Goronzy, J. J. (2003). Giant-Cell Arteritis and Polymyalgia Rheumatica. Annals of Internal Medicine, 139(6), 505. 
  4. Ochi, J., Nozaki, T., Okada, M., Suyama, Y., Kishimoto, M., Akaike, G., Tasaki, A., Ohde, S., Saida, Y., & Yoshioka, H. (2015). MRI findings of the shoulder and hip joint in patients with polymyalgia rheumatica. Modern Rheumatology, 25(5), 761767. 
  5. Soubrier, M., Dubost, J.-J., & Ristori, J.-M. (2006). Polymyalgia rheumatica: diagnosis and treatment. Joint Bone Spine, 73(6), 599–605.
  6. Dejaco, C., Duftner, C., Buttgereit, F., Matteson, E. L., & Dasgupta, B. (2017). The spectrum of giant cell arteritis and polymyalgia rheumatica: revisiting the concept of the disease. Rheumatology, 56(4), 506–515. 
  7. Barros, S., Lopez-Diaz, M. J., Garcia-Porrua, C., Sanchez-Andrade, A., & Llorca, J. (2005). Giant Cell Arteritis. Medicine, 84(5), 269–276.
  8. Chen, J. J., Leavitt, J. A., Fang, C., Crowson, C. S., Matteson, E. L., & Warrington, K. J. (2016). Evaluating the Incidence of Arteritic Ischemic Optic Neuropathy and Other Causes of Vision Loss from Giant Cell Arteritis. Ophthalmology, 123(9), 19992003. 
  9. Janssen, S. P., Comans, E. H., Voskuyl, A. E., Wisselink, W., & Smulders, Y. M. (2008). Giant cell arteritis: Heterogeneity in clinical presentation and imaging results. Journal of Vascular Surgery, 48(4), 1025–1031.
  10. van der Geest, K. S., Sandovici, M., Brouwer, E., & Mackie, S. L. (2020). Diagnostic Accuracy of Symptoms, Physical Signs, and Laboratory Tests for Giant Cell Arteritis. JAMA Internal Medicine, 180(10), 1295–1304.
  11. Cantini, F., Salvarani, C., Olivieri, I., Macchioni, L., Ranzi, A., Niccoli, L., Padula, A., & Boiardi, L. (2000). Erythrocyte sedimentation rate and C-reactive protein in the evaluation of disease activity and severity in polymyalgia rheumatica: A prospective follow-up study. Seminars in Arthritis and Rheumatism, 30(1), 17–24.
  12. Huwart, A., Garrigues, F., Jousse-Joulin, S., Marhadour, T., Guellec, D., Cornec, D., Gouillou, M., Saraux, A., & Devauchelle-Pensec, V. (2018). Ultrasonography and magnetic resonance imaging changes in patients with polymyalgia rheumatica treated by tocilizumab. Arthritis Research & Therapy, 20(1). 
  13. Sait, M. R., Lepore, M., Kwasnicki, R., Allington, J., Balasubramanian, R., Somasundaram, S. K., Vashisht, R., & Barkeji, M. (2017). The 2016 revised ACR criteria for diagnosis of giant cell arteritis – Our case series: Can this avoid unnecessary temporal artery biopsies? International Journal of Surgery Open, 9, 19-23. 
  14. NICE Clinical Knowledge Summary. Polymyalgia rheumatica. Available from: [LINK]
  15. Ungprasert, P., Koster, M. J., & Warrington, K. J. (2015). Coronary artery disease in giant cell arteritis: A systematic review and meta-analysis. Seminars in Arthritis and Rheumatism, 44(5), 586–591. 

 

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