GCA and PMR

Question 1

GCA symptoms

Answer 1

Systemic inflammation and ischaemic symptoms
- symptoms depend on distribution of vasculopathy
- general symptoms of fatigue and fever common
- isolated cranial GCA (80%), large vessel vasculitis (9%), elevated inflammatory markers only (9%), PMR (2%)
- jaw claudication, diplopia, visual loss

Question 2

MRI in diagnosis of GCA
sensitivity
NPV

Answer 2

94% sensitivity
92% negative predictive value

Question 3

Temporal artery biopsy
sensitivity

Answer 3

70-90% in temporal disease but as low as 50% in extra-cranial disease

Question 4

GCA pathogenesis

Answer 4

Antigenic stimulation in adventitia where vessel-specific TLR on dendritic cells are activated
CD83+ vascular dendritic cells produce T-cell attracting chemokines CCL19 and CCL21 recruiting T-cells
Monocytes are also recruited and differentiate into vessel macrophages and produce IL6 and IL1b
IL-6 induces differentiation of T cells into Th17 cells

Tissue macrophages produce IFNy, VEGF, platelet derived growth factor
Vascular smooth muscle cells express NOTCH ligands, which interact with NOTCH receptors on T cells to amplify inflammatory response and switch to synthetic myofibroblasts and proliferate in the intima causing narrowing of the vessel lume

Question 5

What are the late risks associated with GCA

Answer 5

thoracic aneurysm, usually 5 years after diagnosis, more common in men who smoke

Question 6

GCA treatment

Answer 6

High dose steroids:
If vision under-threat
Methylprednisolone 1mg IV for 3 days then prednisolone slow taper
Weekly Tocilizumab (IL-6 inhibitor) effective in reducing treatment failure and recurrence
MTX reduces risk of relapse

Question 7

GiACTA trial

Answer 7

Toci + rapid steroid wean vs. steroid alone
- higher complete remission and lower relapse rate in toci group

Question 8

PMR symptoms

Answer 8

Onset age >50 (but usually older)
Early morning stiffness (key symptom, lasting >45 minutes)
Hip and girdle stiffness
associated with fatigue, depression, weight loss

Question 9

PMR treatment

Answer 9

Prednisolone 15-25mg daily for 4 weeks, then,
wean by 2.5mg per 2 weeks until at 10mg, then,
wean by 1mg per month until lowest tolerated dose

Consider adding MTX as steroid sparing agent
Tocilizumab is effective but not on PBS

Question 10

PMR other considerations

Answer 10

Exercise
Vaccinations
Bone health

Question 11

PMR:
What proportion of GCA patients get PMR
What proportion of PMR patients get GCA

Answer 11

50% get PMR
10% get GCA