Consider in all patients presenting with headache greater than 60 years of age.

• Most common systemic vasculitis affecting large and medium sized arteries.
• Very rare in those <50 years old. Peak incidence in seventh decade.
• Can present with cranial and extracranial manifestations, complicating diagnosis.
• Often co-occurs with polymyalgia rheumatica.
• Visual loss or is the blindness most serious complication if left untreated.
• Development of aneurysms, also a serious, less commonly seen complication.

• American College of Rheumatology (ACR) developed classification criteria most widely used.
• Includes clinical, laboratory, imaging, and biopsy data for scoring and risk stratification.
• ACR guidelines mainly used for identifying patients with large vessel disease, and not necessarily targeted at clinical diagnosis.
• Giant Cell Arteritis (GCA) should be suspected in those >50 with the following features:
  • Headache, especially unilateral.
  • Visual changes.
  • Jaw claudication.
  • Constitutional symptoms including fevers, fatigue, joint/muscle aches.
  • Elevated inflammatory markers (CRP, ESR).
• Suspected GCA should be confirmed by temporal artery biopsy >1 cm or temporal artery Doppler ultrasound.

Pitfalls

• Sensitivity of temporal artery biopsy ranges from 50-95%.
• High false negative rate with unilateral biopsy.
• Glucocorticoids initiated prior to biopsy could reduce sensitivity of biopsy.

• Those with no visual loss at diagnosis should be treated with high dose glucocorticoids.
  • Prednisone 40-60mg oral per day.
• Tocilizumab should be added in addition to glucocorticoids at a dose of 162 mg subcutaneous weekly injection. Treatment duration generally 12-18 months, but should be left up to rheumatology recommendation.
• Those with visual loss or cerebrovascular manifestations should be treated with intravenous glucocorticoids.
  • Methylprednisolone 500-1000 mg daily x 3 days followed by prednisone 40-60 mg oral daily.
• Select cases with critical stenosis of affected vessels including cerebral or carotid arteries should have low dose aspirin added to treatment.
• Typical tapering of glucocorticoids should be done after 2-4 weeks in most cases.

• Most patients are suitable for outpatient management.
• Patients with unstable vital signs or signs of vascular complication including aortic aneurysm or critical narrowing of cerebral or carotid arteries should be admitted.

Transport considerations

• Patients may require referral to another centre if services such as rheumatology and vascular surgery are not available.

• Patients should be referred to a vascular surgeon for temporal artery biopsy within one week.
• Rheumatology should be consulted for outpatient follow-up.

• Those that do not experience improvement in their symptoms within 72-96 hours should have close follow up.

1. Ameer MA, Peterfy RJ, Khazaeni B. Giant Cell Arteritis (Temporal Arteritis). In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Dec 13]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK459376/

   
   

2. Maz M, Chung SA, Abril A, Langford CA, Gorelik M, Guyatt G, et al. 2021 American College of Rheumatology/Vasculitis Foundation Guideline for the Management of Giant Cell Arteritis and Takayasu Arteritis. Arthritis & Rheumatology. 2021 Aug;73(8):1349–65.

   
   

3. Diagnosis of giant cell arteritis – UpToDate [Internet]. [cited 2023 Dec 13]. Available from: https://www.uptodate.com/contents/diagnosis-of-giant-cell-arteritis

   
   

4. Smith JH, Swanson JW. Giant Cell Arteritis. Headache: The Journal of Head and Face Pain. 2014;54(8):1273–89.