PMR and GCA

Question 1

What is PMR? Presentation?

Answer 1

• inflammatory MSK disorder in adults > 50; subacute onset of symmetrical proximal muscle pain, aching and severe morning stiffness in neck, shoulders and pelvic girdle
  
  • ## 2/3 female; higher in whitesPresentation
  • SEVERE morning stiffness (worse than RA)
    
    • Localized to shoulders and pelvic girdle
  • No muscle weakness, minimal joint swelling
  • Fatigue, malaise, anorexia, wt loss
  • Labs - CRP and ESR
  • US/MRI - show inflammation

Question 2

PMR Pathogenesis

Answer 2

• Multi-genic (HLD-DR4)
• INTENSE acute phase response
  
  • Innate immune system activated –> MANY cytokines –> systemic inflammation (fever, anorexia, MSK inflammation and potentially vascular attack)
• No known cause (infectious?)

Question 3

What is GCA? Presentation/Complications?

Answer 3

• Giant - inflammatory vasculitis affecting large and medium arteries
  
  • PMR occurs in 40% GCA pts (same epidemiology)
  • Can occur b/f or after onset of GCA
• Presentation
  
  • Constitutional symptoms + headache
  • Symptoms related to compromised flow in arteries (occipital, ophthalmic, temporal, etc)
    
    • Jaw claudication (ischemia to mastication muscles)
    • Temporal artery tenderness
    • Visual disturbances/loss
    • PMR
• Complications
  - Ophthalmic artery - blindness (most feared)
  - Aortic aneurysms and dissections of aorta (late complication)
  - Large artery stenosis
  - INTRAmural inflammation
  
  • Labs - CRP and ESR + IL-6 correlates w/ disease severity / flares
  • Temporal artery biopsy -

Question 4

GCA Pathogenesis

Answer 4

Activation of dendritic cells –> chemokine release –> T cells and macrophages stimulated –> mass inflammatory response –> injury to vessel wall and blockage of vessel lumen

Question 5

Tx in PMR v GCA

Answer 5

BOTH VERY RESPONSIVE TO GCs

PMR - rapid improvement in 1-2 days; then slowly taper while following CRP and ESR (flares expected)

GCA - must be started immediately and give higher initial dose but similar taper w/ monitoring of CRP/ESR

- Symptoms of impaired blood flow do no improve as quickly as w/ PMR
- anti-IL-6 therapy - new steroid sparing therapy; very effective