Inflammation of blood vessels, clinical manifestation depends on which part of the body (often widespread) and what size vessel affected.
Classic presentations are:
- rash esp purpuric, pernio (swelling of subcutaneous tissue),
- ischaemia eg infarction (brain, gut, digits),
The Chapel Hill system provides definitions for 10 different forms of adult vasculitis but is of debatable utility. EULAR consensus criteria look pretty good [Annals of the Rheumatic Diseases. 65(7):936-41, 2006. PMID 16322081].
Differential: hyperlipidaemia esp severe familial, coagulopathy, fibromuscular dysplasia (familial).
Classified by size of vessel affected (although a degree of overlap often exists):
- Large vessel ie aorta- Takayasu. May be preceding inflammatory-type illness. ?headache/dizziness, ?inflamm eg Raynauds, episcleritis etc. Claudication, absent pulses, subclavian bruit.
- Medium vessel – Kawasaki disease, Wegener’s (C-ANCA pos, nasal/oral lesions, pulmonary lesions, GN, granulomata), Polyarteritis Nodosa (PAN: livedo, neuropathy, aneurysms), Churg Strauss (ANCA pos, asthma, eosiniophilia, neuropathy)
- Small vessel vasculitis – Henoch Schonlein Purpura (HSP) is the classic one, but also cryoglobulinaemia (?hyperviscosity, assoc with malignancy and chronic viral infection)
eg SLE, mixed CT, infective esp streptococcus.
Characterized by one or more anti-neutrophil cytoplasm auto-antibodies. These are screened for by immunofluorescence (IF) that can reveal specific patterns of staining, viz pANCA (peripheral staining), cANCA (cytosol staining). cANCA is predominantly due to Peroxidase 3 antibodies, and is seen in Granulomatosis with polyangiitis (previously Wegener’s granulomatosis, so should be Wanca?!), pANCA is mainly due to Myeloperoxidase antibodies and bacterial permeability increasing factor (BPI), and is seen in 50% of microscopic polyangiitis.
These patterns and antibodies are also associated with rheumatoid arthritis, CF, IBD, drug induced vasculitis, Churg Strauss syndrome, autoimmune liver disease etc.
But in children these are not very sensitive and in any case no evidence that distinction influences treatment or prognosis. The type of ANCA seems to be related to the population rather than the disease! Probably has direct toxic effect.
Imaging is the second modality of investigation, esp MR angiography.
Untreated, these diseases have 90% 2 yr mortality…