Giant Cell Arteritis

Question 1

Define Giant Cell Arteritis

Answer 1

Granulomatous vasculitis of large and medium-sized arteries. Typically affects branches of external carotid artery.

Question 2

Pathophysiology of GCA

Answer 2

1. Dendritic cells present antigen
2. CD4 T cells enter via vasa vasorum
3. T cells activate, proliferate and undergo clonal expansion in the cell wall
4. T cell release ifn gamma- stimulates macrophages causing formation of multi nucleated giant cell

Question 3

Risk factors of GCA

Answer 3

Gender (2 to 4 times greater incidence in females)
Age>50

Weak link to:
Smoking
Atherosclerosis

Question 4

Signs and symptoms

Answer 4

Headaches located over the temporal and occipital regions
Aching and stiffness in neck, shoulder hips, proximal extremities. Worse after inactivity.
Extremity claudication

Uncommon:
Loss of vision
Jaw claudication
Absent temporal artery pulse

Question 5

Investigation for GCA

Answer 5

ESR: Raised >50mm/hr
CRP: elevated
Temporal artery biopsy: histopathology typically shows granulomatous inflammation; in about 50% of cases, multinucleated giant cells are present
Temporal artery ultrasound: thickening (halo sign), stenosis or occlusion

Question 6

Treatment for GCA

Answer 6

Prednisolone 1mg/1kg/day for 4 weeks. Taper dose over 6-12 months
Aspirin 75 mg OD
Bisphosphonates (Calcium carbonate, ergocalciferol, alendronic acid)

If recurrent or steroids not working:
Methotrexate: 7.5 mg PO once weekly. Slowly increased to max. of 20 mg