Giant cell arteritis

Giant cell arteritis (GCA) is a common granulomatous vasculitis affecting medium- to large-sized arteries. It may also be known as temporal arteritis or cranial arteritis, given its propensity to involve the extracranial carotid artery branches such as the temporal artery

Giant cell arteritis is the most common primary systemic vasculitis. It has an incidence of 200 per million persons per year 6. Typically affects older individuals with patients usually being older than 50, with a peak incidence between the ages of 70 and 80 3. There is a recognised female predilection.

There are many possible clinical features that present in a subacute fashion 10:

It is histologically similar to other large vessel vasculitides (such as Takayasu arteritis) showing granulomatous inflammation of arteries with infiltration predominantly by histiocytes, lymphocytes, and multinucleated giant cells. The characteristic multinucleated giant cells are only found in ~50% of cases 1.

Can potentially affect any medium to large-sized vessels, affecting the aorta (~20% of cases 7) and its major branches, particularly the extracranial branches of the carotid artery 6.

  • increased diameter of the temporal artery and hypoechoic wall thickening (halo sign)
    • with duplex ultrasound, sensitivity is 87% and specificity is 96% 9
    • more specific for giant cell arteritis if bilateral 8
    • reversible under corticosteroid treatment; this is reflected in the normalization of the sonographic features
  • stenosis may be present but is not a specific sign for giant cell arteritis 8

Findings on CT include:

  • wall thickening of affected segments
  • calcification
  • mural thrombi

Arterial phase CT (angiography) is useful for assessing luminal abnormalities:

  • stenoses
  • occlusions
  • dilatations
  • aneurysm formation
  • T1 C+ (Gd)
    • the best sequence for assessment
    • shows mural inflammation very well 2,4
    • mean wall thickness increased in the affected region
    • luminal diameter correspondingly decreased in the affected region
    • reported approximate sensitivity and specificity is 80% and 97%, respectively 2 

Treatment is with corticosteroid therapy and aspirin 11.

Imaging differential considerations include:

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Article information

rID: 10936
System: Vascular
Synonyms or Alternate Spellings:
  • Temporal arteritis
  • Giant cell arteritis (GCA)
  • Maladie de Horton
  • Horton disease
  • Cranial arteritis

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Cases and figures

  • Case 1: temporal arteritis
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  • Case 2: halo sign
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  • Good evidence of ...
    Case 3: baseline study
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  • Case 3 :changes after therapy
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  • Case 4: on right
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  • Case 5: on left
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  • Case 6: aortitis
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