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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