Microscopic polyangiitis

Question 1

What size of vessels are affected by microscopic polyangiitis?

Answer 1

small-vessel ANCA vasculitis.

Question 2

Clinical features of MPA

Answer 2

Renal impairment:
- raised creatinine
- haematuria
- proteinuria

systemic symptoms:
- fever
- lethargy
- myalgia
- weight loss

rash:
- palpable purpura

respiratory:
cough
dyspnoea
haemoptysis

mononeuritis multiplex

Question 3

Is p-ANCA or c-ANCA associated with MPA?

Answer 3

pANCA (against MPO) - positive in 50-75%

cANCA (against PR3) - positive in 40%

(both associated but p-ANCA more likely to be positive)