Giant Cell Arteritis - Temporal Arteritis


Indications for Testing

  • Patient >50 years with visual changes or new onset headache

Criteria for Diagnosis

  • American College of Rheumatology (1990); 3 of 5 required (may have limited clinical use dependent upon patient population)
    • Age – >50 years
    • New localized headache
    • Temporal artery tenderness or decreased pulsation
    • ESR – >50 mm/hr
    • Abnormal arterial artery biopsy

Laboratory Testing

  • Nonspecific testing – helpful in excluding other diagnoses
    • CBC –  thrombocytosis, normochromic normocytic anemia
    • C-reactive protein (CRP)
    • Liver function studies – often abnormal
  •  Vasculitis evaluation
    • ANCA – high percentage have pANCA with MPO+
      • PR3 rarely positive


  • Temporal artery biopsy – demonstrates medium- and large-vessel vasculitis with giant cell infiltration
    • May have skip lesions; therefore, 1.5-2 cm long biopsy is recommended
  • Biopsy should be performed before day 4 if steroid therapy initiated
  • If initial biopsy is negative, perform biopsy on other side

Imaging Studies

  • Duplex ultrasonography
    • Halo sign is often present – defined as hypoechoic region around the lumen of the artery
    • Sensitivity <70%

Differential Diagnosis 

Clinical Background

Giant cell arteritis (temporal arteritis) is a systemic vasculitis that can produce permanent blindness if not treated in a timely manner. It is categorized as a large vessel vasculitis (Chapel Hill 2012).


  • Incidence – ~20/million in U.S. (Weyand, 2014); most common primary vasculitis in older patients
  • Age – peak age 70-80 years
    • Rare – <50 years
  • Sex – M<F, 1:2-6
  • Ethnicity – more common in Caucasians than African or Asian Americans; rare in Hispanic population


  • Medium- and large-vessel vasculitis – tends to affect aorta and extracranial branches of the carotid artery
  • Vasculitis causes ischemic disease – most common in the optic nerve
    • Can lead to vision loss, caused primarily by occlusive vasculopathy
  • Granulomas form in arterial media
  • Often associated with polymyalgia rheumatica

Clinical Presentation

  • Constitutional – fever, fatigue, malaise, weight loss
  • Otorhinologic – jaw claudication
  • Ophthalmologic – transient visual changes, diplopia, visual field cuts, permanent vision loss
  • Cardiovascular – arm claudication, thoracic artery aneurysm
  • Neurologic – headache, temporal artery pain, mononeuropathy
  • Polymyalgia rheumatica – may occur in up to 50% of patients
    • Manifests with severe stiffness and pain in shoulders, thighs, and buttocks
  • Dermatologic, renal, pulmonary – rarely involved

Indications for Laboratory Testing

  • Tests generally appear in the order most useful for common clinical situations
  • Click on number for test-specific information in the ARUP Laboratory Test Directory
Test Name and Number Recommended Use Limitations Follow Up
C-Reactive Protein 0050180
Method: Quantitative Immunoturbidimetry

Preferred evaluation for suspected vasculitis

Anti-Neutrophil Cytoplasmic Antibody with Reflex to Titer and MPO/PR-3 Antibodies 2002068
Method: Semi-Quantitative Indirect Fluorescent Antibody/Semi-Quantitative Multiplex Bead Assay

Preferred panel for evaluating and managing individuals with a  known diagnosis of vasculitis

Preferred reflex panel for the workup of suspected vasculitis is ANCA-associated vasculitis profile (ANCA/MPO/PR-3) with reflex to ANCA titer

Reflex pattern – if screen is positive, titer and MPO/PR-3 antibodies testing will be added to aid in antibody determination

Additional Tests Available
Click the plus sign to expand the table of additional tests.
Test Name and NumberComments
CBC with Platelet Count and Automated Differential 0040003
Method: Automated Cell Count/Differential

May help in ruling out infectious process

Urinalysis, Complete 0020350
Method: Reflectance Spectrophotometry/Microscopy

Screens for various metabolic and kidney disorders

Sedimentation Rate, Westergren (ESR) 0040325
Method: Visual Identification

Initial evaluation for suspected vasculitis

Hepatic Function Panel 0020416
Method: Quantitative Enzymatic/Quantitative Spectrophotometry

Initial screening for hepatobiliary inflammation

Panel includes albumin; ALP; AST; ALT; bilirubin, direct; protein, total; and bilirubin, total