Polymyalgia Rheumatica

Question 1

Define polymyalgia rheumatica.

Answer 1

Polymyalgia rheumatica (PMR) is an inflammatory rheumatological syndrome that manifests as pain and morning stiffness involving the neck, shoulder girdle, and/or pelvic girdle in individuals older than age 50 years

Peripheral musculoskeletal involvement may also be present.

Question 2

What condition is polymyalgia rheumatica sometimes found alongside?

Answer 2

PMR occurs either as an isolated condition or associated with giant cell arteritis.

Question 3

How common is polymyalgia rheumatica?

Answer 3

• Incidence increases with age
• Rare in young
• Most common in northern Europeans - decreases from north to south Europe
• More common in females

Question 4

What is the aetiology of polymyalgia rheumatica?

Answer 4

• Seasonal variation
• Infection - adenovirus, respiratory syncytial virus, parainfluenza virus type I, parvovirus B19, Mycoplasma pneumoniae, chlamydia pneumoniae.
• Genetic - ethnic and familial differences; HLA-DRB1*04 and DRB1*01; ICAM-1 polymorphisms
• Endocrine - hormonal role suggestes with adrenal gland hypofunction in untreated patients –> inappropriately normal cortisol levels and low dehydroepiandrosterone

Question 5

What is the pathogenesis of polymyalgia rheumatica?

Answer 5

• Unclear but mechanisms could be similar to those seen in GCA
• Increased Interleukin-6 in serum and temporal artery biopsy has been shown
• Increased inflammatory cells and decreased immunosuppressive cells
• Imbalances in immunological regulation
• Tissue ischaemia may not be the underlying cause of PMR muscle symptoms

Question 6

What are the risk factors for PMR?

Answer 6

• >50 years
• GCA - About 15% to 20% of patients with PMR have GCA, whereas 40% to 60% of those with GCA have PMR
• female

Question 7

What are the symptoms of PMR?

Answer 7

• Acute onset pain and stiffness in neck and shoulders +/- hip girdle that is worse in the morning
• Difficulty getting out of bed - stiffness improves throughout day
• Constitutional symptoms - low grade fever, weight loss, asthenia, malaise, anorexia, night sweats, depression

Other:

• Asymmetrical joint pain
• Carpal tunnel syndrome symptoms
• Swelling of hands and feet

Question 8

What are the signs of PMR on physical examination?

Answer 8

• Limited range of active movement of shoulders and hips due to pain and stiffness.
• Difficulty rising from chair - may be caused by:
  
  • muscle tenderness of shoulder and hip regions
  • subacromial bursitis of shoulders,
  • trochanteric bursitis of the hips
  • oligoarthritis of peripheral joints
• Tenosynovitis - swelling of dorsal surfacsed of hands and feet and swelling of fingers.

Negative findings of oral ulcers, rashes, cardio/abdo/neuro abnormalities should be noted.

Question 9

What investigations would you do for PMR?

Answer 9

• ESR/CRP - elevated
• FBC- variable
• TSH -normal or raised in hypothyroidism
• serum protein electrophoresis - some myeloproliferative diseases may also present similarly with fatigue, bony pain and elevated ESR, checking an FBC and serum protein electrophoresis is also recommended - normal in PMR
• US - bursitis (most commonly trochanteric), joint effusions

Question 10

How do you manage PMR?

Answer 10

Corticosteroid - prednisolone (response in 24 to 72 hours); continue until ESR/CRP normalises and symptoms resolve (2-4 weeks)

Calcium + vit D + bisphosphonate - corticosteroid induced osteoporosis prophylaxis

Then:

NSAID (+PPI) - naproxen for when corticosteroid is withdrawn but not primary treatment

Methotrexate + folic acid -used in the setting of frequent relapses/exacerbations during corticosteroid tapering. Folic acid is indicated to decrease the risk of methotrexate adverse effects, particularly the risk of oral ulcers and bone marrow suppression.

Tocilizumab

Question 11

What are the complications of PMR?

Answer 11

• Relapsing PMR
• Complications of corticosteroid use - infection risk, osteoporosis, T2DM, hypertension, muscle weakness, cataract development, glaucoma, skin changes
• GCA
• Vascular events - higher in patients with PMR that those without (x2.6 risk)
• Complications of methotrexate use - myelosuppression, oral ulcers, hepatotoxicity, interstitial lung disease

Question 12

What is the prognosis with PMR?

Answer 12

• Good overall
• Response to treatment in 24-72 hours
• But relapses common
• Treatment typically requires 3 years
• Increased risk of relapse or prolonged therapy has shown association with female sex, high ESR (>40 mm/hour), and peripheral arthritis