Giant cell arteritis: Difference between revisions

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==Background==
Also known as temporal arteritis


*[[Large-vessel vasculitis]] that occurs in older age and is associated with polymyalgia rheumatica
== Definition ==
*Also known as '''temporal arteritis'''


=== Epidemiology ===
* Large-vessel vasculitis that occurs in older age and is associated with polymyalgia rheumatica
*Most common systemic vasculitis in North America


== Epidemiology ==
=== Pathophysiology ===
*Granulomatous inflammation of the aortic arch and extracranial carotid artery


==Clinical Manifestations==
* Most common systemic vasculitis in North America


*After 50 years
== Pathophysiology ==
*[[Headache]], usually unilateral with tenderness
*[[Polymyalgia rheumatica]] (PMR)
*Jaw claudication
*Visual loss


=== Prognosis ===
* Granulomatous inflammation of the aortic arch and extracranial carotid artery
*Cycles of flares and remissions requiring adjustment in prednisone
*Very few can safely taper off of steroids altogether


==Investigations==
== ACR Classification Criteria ==


*Temporal artery biopsy
* Requires 3 of 5 criteria
**Shows mononuclear cell infiltrate with granulomatous inflammation, and usually multinucleated giant cells
** Age ≥50 years
**Findings are still visible 6-12mo after starting therapy
** New localized headache
*Ultrasound of temporal arteries
** Temporal artery tenderness or decreased temporal artery pulse
**Looking for "halo sign" of hypoechoic ring around Doppler flow
** ESR ≥ 50 mm/h: 10-20% false negative, though
**Sn 55-100%, Sp 78-100% (more specific than sensitive)
** Artery biopsy consistent with GCA: Up to 40% false negative, related to skip lesions, small biopsies, or lack of temporal artery involvement
**Disappears quickly with treatment
* ''Not'' diagnostic criteria
*MRI scalp arteries


===McMaster Workup===
== Clinical Presentation ==


*Initial investigation with ultrasound; if positive halo sign, can skip the rest
* After 50 years
*Low or moderate
* Headache, usually unilateral with tenderness
**Scalp artery MRI
* Polymyalgia rheumatica (PMR)
***Normal: treat based on MD diagnosis
* Jaw claudication
***Abnormal
* Visual loss
****Temporal artery biopsy
*****Negative: treat based on MD diagnosis (biopsy-negative GCA or other)
*****Positive: treat as GCA
*High
**Temporal artery biopsy
***Negative: treat based on MD diagnosis (biopsy-negative GCA or other)
***Positive: treat as GCA


== ACR Classification Criteria ==
== Investigations ==
*Requires 3 of 5 criteria

**Age ≥50 years
* Temporal artery biopsy
**New localized headache
** Shows mononuclear cell infiltrate with granulomatous inflammation, and usually multinucleated giant cells
**Temporal artery tenderness or decreased temporal artery pulse
** Findings are still visible 6-12mo after starting therapy
**[[ESR]] ≥ 50 mm/h: 10-20% false negative, though
* Ultrasound of temporal arteries
**Artery biopsy consistent with GCA: Up to 40% false negative, related to skip lesions, small biopsies, or lack of temporal artery involvement
** Looking for "halo sign" of hypoechoic ring around Doppler flow
*''Not'' diagnostic criteria
** Sn 55-100%, Sp 78-100% (more specific than sensitive)
** Disappears quickly with treatment
* MRI scalp arteries

=== McMaster Workup ===

* Initial investigation with ultrasound; if positive halo sign, can skip the rest
* Low or moderate
** Scalp artery MRI
*** Normal: treat based on MD diagnosis
*** Abnormal
**** Temporal artery biopsy
***** Negative: treat based on MD diagnosis (biopsy-negative GCA or other)
***** Positive: treat as GCA
* High
** Temporal artery biopsy
*** Negative: treat based on MD diagnosis (biopsy-negative GCA or other)
*** Positive: treat as GCA

== Management ==

* Prednisone 0.2-0.3mg/kg/day (and appropriate screening)
** Taper over 2 years, dropping by 5mg/d over a few weeks then slowing down
** Often aren't able to taper off altogether
* Low-dose ASA for cardiovascular and cerebrovascular protection
* Can consider adding steroid-sparing agent
** Tocilizumab (IL-6 receptor)
** Maybe methotrexate
** Not MMF or other DMARDs
* Follow ESR for response
* Annual chest x-rays for the first ten years, to monitor for thoracic aortic aneurysm


== Prognosis ==
==Management==


*[[Prednisone]] 0.2-0.3mg/kg/day (and appropriate screening)
* Cycles of flares and remissions requiring adjustment in prednisone
**Taper over 2 years, dropping by 5mg/d over a few weeks then slowing down
* Very few can safely taper off of steroids altogether
**Often aren't able to taper off altogether
*Low-dose [[ASA]] for cardiovascular and cerebrovascular protection
*Can consider adding steroid-sparing agent
**[[Tocilizumab]] (IL-6 receptor)
**Maybe [[methotrexate]]
**Not [[MMF]] or other DMARDs
*Follow [[ESR]] for response
*Annual chest x-rays for the first ten years, to monitor for thoracic aortic aneurysm


[[Category:Rheumatology]]
[[Category:Rheumatology]]

Latest revision as of 18:32, 4 July 2025

Background

  • Large-vessel vasculitis that occurs in older age and is associated with polymyalgia rheumatica
  • Also known as temporal arteritis

Epidemiology

  • Most common systemic vasculitis in North America

Pathophysiology

  • Granulomatous inflammation of the aortic arch and extracranial carotid artery

Clinical Manifestations

Prognosis

  • Cycles of flares and remissions requiring adjustment in prednisone
  • Very few can safely taper off of steroids altogether

Investigations

  • Temporal artery biopsy
    • Shows mononuclear cell infiltrate with granulomatous inflammation, and usually multinucleated giant cells
    • Findings are still visible 6-12mo after starting therapy
  • Ultrasound of temporal arteries
    • Looking for "halo sign" of hypoechoic ring around Doppler flow
    • Sn 55-100%, Sp 78-100% (more specific than sensitive)
    • Disappears quickly with treatment
  • MRI scalp arteries

McMaster Workup

  • Initial investigation with ultrasound; if positive halo sign, can skip the rest
  • Low or moderate
    • Scalp artery MRI
      • Normal: treat based on MD diagnosis
      • Abnormal
        • Temporal artery biopsy
          • Negative: treat based on MD diagnosis (biopsy-negative GCA or other)
          • Positive: treat as GCA
  • High
    • Temporal artery biopsy
      • Negative: treat based on MD diagnosis (biopsy-negative GCA or other)
      • Positive: treat as GCA

ACR Classification Criteria

  • Requires 3 of 5 criteria
    • Age ≥50 years
    • New localized headache
    • Temporal artery tenderness or decreased temporal artery pulse
    • ESR ≥ 50 mm/h: 10-20% false negative, though
    • Artery biopsy consistent with GCA: Up to 40% false negative, related to skip lesions, small biopsies, or lack of temporal artery involvement
  • Not diagnostic criteria

Management

  • Prednisone 0.2-0.3mg/kg/day (and appropriate screening)
    • Taper over 2 years, dropping by 5mg/d over a few weeks then slowing down
    • Often aren't able to taper off altogether
  • Low-dose ASA for cardiovascular and cerebrovascular protection
  • Can consider adding steroid-sparing agent
  • Follow ESR for response
  • Annual chest x-rays for the first ten years, to monitor for thoracic aortic aneurysm