Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR)

 

Definitions of giant cell arteritis (GCA) and polymyalgia rheumatica (PMR)

  • Giant cell arteritis is an inflammatory vasculitis affecting large vessels.
    • Commonest vasculitis & among the commonest causes of acute vision loss
    • Unknown aetiology, but is associated with polymyalgia rheumatica,
  • Polymyalgia rheumatica (PMR) an inflammatory condition affecting the muscles and joints of the pelvic and shoulder girdles

 

Epidemiology of GCA and PMR

  • 29 per 100,000 (in Europe)
    • 50% of GCA have PMR
    • 15% of PMR have CGA
  • Increases with age
    • Very rare in under-50s, with mean age of onset at 70 years
  • Women > men  3:1
  • Caucasian > Afro-Caribbean

 

Aetiology of GCA and PMR

  • Aetiology unknown, except that it is an inflammatory vasculitis of large arteries.
  • May be a genetic component as familial clusters sometimes occur

 

Pathology of giant cell arteritis (GCA)

  • Abnormal, sometimes pulseless temporal arteries
  • Histology on biopsy
    • Inflammatory infiltrates
    • Fragmentation & distortion of internal elastic lamina
    • Multinucleated giant cells in <50%

 

Presentation of giant cell arteritis (GCA)

  • Headache (usually temporal)
  • Jaw claudication
  • Scalp tenderness
  • Tenderness and/or thickening of one of the temporal arteries
  • Visual impairment (involvement of ophthalmic artery)
  • Systemic features
    • Anorexia, weight loss, fever, sweats, malaise
  • Other systems
    • Aortic root involvement in 15%, which can cause aneurysms years later.
      • Can cause asymmetric pulses and BP, and bruits
    • Strokes can occur due to ischaemia and narrowing of aortic or intracerebral vessels

 

Differential diagnosis of giant cell arteritis (GCA)

  • Headaches
    • Migraine, tension headache, trigeminal neuralgia, cluster headache
  • Intracranial pathology (tumour, vascular malformation)
  • TIA (vision loss)
  • Cervical spine disease
  • Sinus disease
  • TMJ pain
  • Systemic vasculitides/connective tissue disorders (all rare) e.g.
    • Takayasus (young women, absent arm pulses, visual loss, carotid bruits)
    • Polyarteritis nodosa (muscle pains, “abdominal angina”, livedo reticularis, anaemia, raised WCC, raised ESR, proteinuria)
    • Polymyositis (proximal muscle weakness, raised CK)

 

Diagnosis of giant cell arteritis (GCA)

  • The American College of Rheumatology’s criteria for diagnosing giant cell arteritis is:
    • Age >50 years
    • New onset headache
    • Abnormalities of the temporal arteries on palpation
    • ESR >50 mm/hour
    • Abnormal temporal artery biopsy.
  • The presence of three or more criteria has a sensitivity of 97% and a specificity of 79% for a diagnosis of giant cell arteritis.

 

Presentation of polymyalgia rheumatica (PMR)

  • Age >50
  • Sudden onset, severe pain of shoulders, neck, hips and lumbar spine
    • For >2/52
    • Difficulty combing hair or reaching to shelves.
  • Symptoms are worse in the morning, and can last for several hours ( at least >45min)
  • Systemic features
    • Anorexia, weight loss, fever, sweats, malaise
  • Even PMR predisposes to vascular events so should be treated promptly

 

Video discussing about PMR

Investigations in giant cell arteritis (GCA) and polymyalgia rheumatica (PMR)

  • Bloods
    • Anaemia of chronic disease
      • Can have deranged LFTs
    • ESR and CRP usually very raised
      • 95% of GCA will have an ESR over 50
      • CK normal
    • Protein electrophoresis to exclude myeloma
  • CXR to look for aneurysm formation
  • Urinalysis (blood and protein for systemic vascular involvement)

 

  • PMR-specific investigations
    • Search for malignancy with a good history and full examination including skin breast exam and digital rectal exam (DRE).
  • GCA-specific investigations
    • Temporal artery biopsy
      • Can be done within 14 days of starting steroid treatment but loses sensitivity over time
      • May be negative due to skip lesions
      • Shouldn’t delay steroids for biopsy
    • PET scan if suspicion of large vessel involvement
      • E.g. Marked systemic features, high inflammatory markers despite steroid treatment
      • NB may be non-diagnostic if on >10mg/day prednisolone
    • Colour duplex of temporal arteries
      • Sensitivity (and negative predictive value) 95%

 

Treatment of giant cell arteritis (GCA) and polymyalgia rheumatica (PMR)

  • Treatment of both GCA and PMR is steroids.
    • The reducing regime must be tailored to the patient’s symptoms and inflammatory response. The dose depends on whether GCA is present
    • Both diseases tend to require 18-24 months of treatment
  • Giant cell arteritis (GCA)
    • If no visual involvement: 40-60mg prednisolone OD
      • Symptoms should improve in 7-14 days
      • Taper dose after 1-2 months gradually
        • By 10mg every 2/52 to 20mg, then by 2.5mg every 2-4/52 to 10mg, then by 1mg every 1-2 months
    • Vision loss/amaurosis fugax
      • IV methylprednisolone 500mg-1g od for 3 days
      • Consider 60mg prednisolone PO if established visual loss
    • 30-50% can stop taking steroids after 2 years.  Some patients will be unable to come off of steroids completely and may be on a low dose long-term; in these people a steroid-sparing immunosuppressant (usually methotrexate) may be considered.

 

  • Polymyalgia rheumatica (PMR)
    • Prednisolone PO 15mg for 3-4/52
      • Reduce by 2.5mg every month until 10mg, then by 1mg/month
    • Symptoms often improve quicker than GCA

 

  • Steroid protection (50% on long-term steroids will get a fracture)
    • Calcium and vitamin D supplements
    • Bisphosphonate
    • PPI
    • 75mg aspirin (reduces visual loss & CVAs) unless contraindications
    • Consider DEXA in under 70s

 

Prognosis of GCA and PMR

  • Visual symptoms are often irreversible
    • If one eye affected, 20-50% chance of bilateral vision loss without treatment
  • Most patients respond to steroid treatment, but on average need two years of treatment
    • There is therefore treatment-related morbidity: osteoporosis, mood changes, obesity, hypertension, hyperlipidaemia, myopathy, diabetes, cataracts, skin changes, bruising, fluid retention.
    • If poor or inadequate response to steroids, steroid sparing agents such as methotrexate can be used under rheumatological guidance

 

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