Microscopic Polyangitis

Question 1

What is Microscopic Polyangitis?

Answer 1

An ill-defined autoimmune disease characterized by a systemic, pauci-immune, necrotizing, small-vessel vasculitis without clinical or pathological evidence of necrotizing granulomatous inflammation.

Question 2

What is the pathophysiology of Microscopic Polyangitis?

Answer 2

• Necrotising vasculitis, with few or no immune deposits, predominantly affecting small vessels.
• Necrotising glomerulonephritis is very common
• Pulmonary capillaritis often occurs
• Granulomatous inflammation is absent

Question 3

What are the main features of microscopic polyangitis?

Answer 3

• Fever
• Loss of appetite
• Weight loss
• Fatigue
• Kidney failure - haematuria, proteinura, rapidly progressive glomerulonephritis
• Pulmonary haemorrhage

Question 4

What tests would you do if you suspected vasculitis?

Answer 4

• Bloods - CRP, ESR, FBC, U+E’s, LFTs, ANCA
• Urinalysis
• CXR
• Renal Biopsy

Question 5

What blood test is most commonly associated with Microscopic polyangitis?

Answer 5

p-ANCA for MPO