GPA

MPA

EGPA

ANCA associated vasculitis

Anti-neutrophil cytoplasmic antibodies (ANCA) are important as they are associated with a number of small-vessel vasculitides, including:

1. granulomatosis with polyangiitis (Wegener’s)
2. eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)
3. microscopic polyangiitis

ANCA associated vasculitis is more common with increasing age. Whilst each condition has its own distinct features, there are a number of common findings:

• renal impairment
  • caused by immune complex glomerulonephritis → raised creatinine, haematuria and proteinuria
• respiratory symptoms
  • dyspnoea
  • haemoptysiis
• systemic symptoms
  • fatigue
  • weight loss
  • fever
• vasculitic rash: present only in a minority of patients
• ear, nose and throat symptoms
  • sinusitis

General approach to first-line investigations:

• urinalysis for haematuria and proteinuria
• bloods:
  • urea and creatinine for renal impairment
  • full blood count: normocytic anaemia and thrombocytosis may be seen
  • CRP: raised
  • ANCA testing (see below)
• chest x-ray: nodular, fibrotic or infiltrative lesions may be seen

ANCA types

There are two main types of ANCA - cytoplasmic (cANCA) and perinuclear (pANCA). There is considerable overlap between which antibodies are found in which condition, but as a rule of thumb: