ANCA vasculitis

Question 1

What is ANCA?

Answer 1

Anti-neutrophil cytoplasmic antibodies

Question 2

Name 2 important small vessel vasculitis associated with ANCA?

Answer 2

Granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)

Microscopic polyangiitis

Question 3

What are the two may types of ANCA

Answer 3

cytoplasmic ANCA (cANCA)

perinuclear ANCA (pANCA)

Question 4

List symptoms that should push you to consider an ANCA associated vasculitis

Answer 4

Renal impairment (~65%)
- caused by immune complex glomerulonephritis → raised creatinine, haematuria and proteinuria

Respiratory symptoms (~45%)
- dyspnoea
- haemoptysis

Systemic symptoms
- fatigue
- weight loss
- fever

Vasculitic rash (+ systemic symptoms < 20%)
- present in only a minority of patients

ENT symptoms (~45%)
- sinusitis

Eye symptoms (<20%)
- painful, red eye (scleritis)
- diplopia with proptosis (caused by retro-orbital granulomatous mass)

Nerve symptoms (~30%)
- paraesthesia/weakness in keeping with mononeuritis multiplex or other peripheral neuropathy
- consider ANCA associated vasculitis in the absence of an alternative explanation (e.g., diabetes, B12 deficiency) and esp. in wrist drop or foot drop

Question 5

What Ix would you do 1st line for ANCA associated vasculitis?

Answer 5

Urinalysis for haematuria and proteinuria

Bloods
- urea and creatinine for renal impairment
- FBC : normocytic anaemia and thrombocytosis may be seen
- CRP : raised
- ANCA testing (cANCA, pANCA)

Imaging
- CXR: nodular, fibrotic or infiltrative lesions may be seen

Question 6

What is the target of cANCA?

Answer 6

Serine proteinase 3 (PR3)

Question 7

What is the target of pANCA?

Answer 7

Myeloperoxidase (MPO)

Question 8

What % of cANCA vs pANCA is associated with granulomatosis with polyangiitis?

Answer 8

cANCA = 90%

pANCA = 25%

Question 9

What % of cANCA vs pANCA is associated eosinophilic granulomatosis with polyangiitis?

Answer 9

cANCA = low

pANCA = 50%

Question 10

What % of cANCA vs pANCA is associated microscopic polyangiitis polyangiitis?

Answer 10

cANCA = 40%

pANCA = 75%

Question 11

What other conditions are associated with pANCA?

Answer 11

UC : 70%

Primary sclerosing cholangitis : 70%

Anti-GBM disease : 25%

Crohn’s disease : 20%

Question 12

Can cANCA be used for monitoring?

Answer 12

Yes

There is some correlation between cANCA levels and disease activity

Question 13

Can pANCA be used for monitoring?

Answer 13

No

pANCA cannot be used to monitor disease activity

Question 14

What are the risk factors for ANCA associated vasculitis?

Answer 14

Increasing age : incidence increases progressively with age until the mid-late 80s
- however ANCA associated vasculitis can present at any age

Affects all ethnicities

M = F

Environmental - e.g., exposure to cocaine, hydralazine and propylthiouracil

Question 15

Sources

Answer 15

https://www.bmj.com/content/369/bmj.m1070

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