Autoimmune

Question 1

How do you diagnose microscopic polyangiitis?

Answer 1

Diagnosis of exclusion:
1. pANCA or cANCA found in serum (in 10% they have neither)

2. No ENT involvement, no Granuloma formation in lungs - exclude granulomatosis with polyangiitis
3. No eosinophilic granulomatosis with polyangitis
   - by exclusion, it is MPA

Question 2

How do you diagnose ANCA vasculitis?

Answer 2

1. History: respiratory, GI, skin rashes, joint pains, peripheral neuropathy
2. ANCA present in serum - present in 85% of people
3. Kidney biopsy
4. Lung haemorrhage proof
   - CT-thorax or CXR
   - Carbon monoxide transfer factor (distinguishes pulmonary oedema and blood in the alveoli)
5. Nerve conduction velocity studies - peripheral neuropathy
6. ENT assessment - check for internal injuries in nasal tract