Giant Cell Arteritis - Temporal Arteritis

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).

Quick Answers for Clinicians

Which testing algorithms are related to this topic?

Diagnosis

Indications for Testing

  • Patient >50 years with
    • Visual changes or new onset localized headache
    • Elevated inflammatory marker(s)

Criteria for Diagnosis

Histologic diagnosis – temporal artery biopsy showing segmental inflammation

Laboratory Testing

  • Nonspecific testing – helpful in excluding other diagnoses
    • CBC –  thrombocytosis, normochromic normocytic anemia
    • C-reactive protein (CRP)
    • Erythrocyte sedimentation rate (ESR) – has been used traditionally with threshold of >50 mm/hr
    • Liver function studies – often abnormal
  •  Vasculitis evaluation
    • Antineutrophil cytoplasmic antibodies (ANCA) – high percentage have perinuclear ANCA (pANCA) with MPO+
      • Proteinase 3 (PR3) rarely positive

Histology

  • Temporal artery biopsy – demonstrates medium- and large-vessel vasculitis with giant cell infiltration
    • 1.5-2 cm long biopsy is recommended due to possibility of skip lesions
  • 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

Background

Epidemiology

  • Prevalence – ~20/million in U.S.; 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 (Weyand, 2014)

Pathophysiology

  • 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

ARUP Laboratory Tests

Preferred reflex panel for managing patients with a known diagnosis of vasculitis

May be assistive in evaluating suspected vasculitis

For the workup of suspected vasculitis, the preferred reflex panel is ANCA-associated vasculitis profile (ANCA/MPO/PR3) with reflex to ANCA titer

Panel includes ANCA, IgG; myeloperoxidase antibody; and serine proteinase 3 antibody

Preferred test to detect acute phase inflammation (eg, autoimmune diseases, connective tissue disease, rheumatoid arthritis, infection, or sepsis)

Nonspecific test used to detect inflammation associated with infections, cancers, and autoimmune diseases

Related Tests

May help in ruling out infectious process

Initial screening for hepatobiliary inflammation

Panel includes albumin; alkaline phosphatase (ALP); aspartate aminotransferase (AST); alanine aminotransferase (ALT); bilirubin, direct; protein, total; and bilirubin, total

Screens for various metabolic and kidney disorders

Medical Experts

Contributor

References

Additional Resources