About Giant Cell Arteritis

Giant cell arteritis (GCA) is a chronic systemic vasculitis of medium and large sized arteritis (includes aorta and its branches).

  • Most common vasculitis in people >50 yo
  • Incidence increases with age
    • 10x more common in pts in their 80s than those in their 50s-60s
  • Temporal arteritis is often a manifestation, but can also be due to an ANCA-associated vasculitis
  • Medical emergency due to risk of blindness
  • 40-60% of pts with GCA have polymyalgia rheumatica (PMR) symptoms, while 15-20% of patients with PMR will develop GCA
    • Screening PMR patients is important!
  • 17x increased risk of abdominal aortic aneurysm (AAA), thoracic aortic aneurysm (TAA)
(view references)

Clinical Presentation & Diagnostic Workup

  • Most common vasculitis in adults >50 yo
  • Gold standard for diagnosis: temporal artery biopsy
    • Ultrasound has utility, but it is operator dependent
  • Evaluation includes new-onset temporal headaches, jaw claudication, scalp tenderness, vision loss, PMR symptoms (pain and morning stiffness affecting neck, shoulders, pelvic girdle)
  • Elevated inflammatory markers without other explanation
    • Do not always have to be present but can be a clue

Treatment

  • Treatment should not be delayed for diagnostic purposes if vision loss is threatened
  • Mainstay treatment: steroids
    • New emerging therapies are available, such as IL-6 inhibition with tocilizumab

Monitoring

  • Common to have PMR symptoms with GCA
  • Need to monitor PMR patients for GCA

Incidence

  • 2-3x more common in women
  • Commonly reported in whites of Northern European descent

Temporal Artery Abnormalities & Scalp Tenderness

  • Superficial temporal artery
  • Tenderness
  • Beading
  • Thickening
  • Can be pulsatile (view image)

Constitutional Symptoms

  • Weight loss
  • Low grade fever
  • Fatigue
  • Night sweats

Visual Symptoms

  • Amaurosis fugax (transient vision loss)
  • Acute visual loss
    • Visual loss occurs in 15% of patients (MC due to ischemic neuritis)
    • Blindness is abrupt and painless
  • Diplopia

PMR Symptoms

  • Pain and morning stiffness
  • Affecting the neck, shoulders, and pelvic girdle

Other

  • Bruits in axilla, reduced BP in upper limbs
  • Jaw and/or tongue claudication, limb claudication
  • Elevated CRP and ESR without other reasons such as infection, malignancy

Biopsy

  • Temporal artery biopsy is gold standard
    • Biopsy often shows findings of arteritis even after more than 14 days of steroid therapy
    • Ideally obtained within 7 days of starting steroids

Imaging

  • U/s of temporal artery, however dependent on skill of ultrasonographer
  • Can consider CT, PET, or MRI for aorta and extracranial arteries 
    • Steroids should not alter imaging if done within 1-2 weeks of treatment

Lab Workup

  • ESR, CRP, or other nonspecific markers of inflammation
  • Other vasculitides
    • Takayasu arteritis
      • Also affects aorta and primary branches, but typically under 40 yo and F
    • Granulomatosis with polyangiitis (GPA)
    • Polyarteritis nodosa (PAN)
    • Microscopic polyangiitis (MPA)
  • Intracranial pathology, lesions
  • Other causes of headache
  • Other causes of vision loss
  • Malignancies (especially with elevated inflammatory markers)

Glucocorticoid Therapy

  • Initial dosing 1 mg/kg daily in divided doses
  • Do not delay by waiting to confirm by biopsy or imaging if clinical suspicion is high, especially in the setting of threatened or acute vision loss 
  • If threat of acute visual loss at diagnosis, should be treated with pulse IV glucocorticoids (methylprednisolone 1 g daily X3 days)
  • High dose therapy is usually continued for 1 month or until ESR/CRP normalize and then is tapered slowly
    • Taper can last 6 months-2 years

Aspirin

  • Low dose aspirin (81 mg/day) should be used in all GCA pts to reduce cardiovascular risk and blindness 

Adjunctive Immunosuppressive Therapy

  • Adjunctive immunosuppressive therapy with tocilizumab (IL-6 inhibitor)
    • Give tocilizumab to pts with refractory or relapsing disease with difficulty tapering off glucocorticoids or to those with increased risk of glucocorticoid-related adverse effects
    • Need to consider bone protection due to long-term steroid use (bisphosphonate)
  • Regular follow-up every 3 months
  • Monitor based on symptoms:
    • Worsening headaches
    • Increased temporal artery tenderness
    • Scalp tenderness
    • Jaw/tongue claudication
    • PMR symptoms
  • Monitor for signs of AAA or TAA
    • Needs to be urgently evaluated in a GCA patient
    • Yearly abdominal ultrasound should be considered
  • Monitor with ESR and CRP (which should decrease and normalize with treatment)