Definition of vasculitis
Vessel wall inflammation, may be infectious or non-infectious
Types of vasculitis
- Non-infectious vasculitis:
a. Small vessel vasculitis
i. ANCA-positive
- Wegner granulomatosis
- Microscopic polyangiitis
- Churg-Strauss syndrome
ii. ANCA-negative
- Henoch-Schonlein Purpur
- Cryoglobulinemic vasculitis
b. Medium vessel vasculitis
- Polyarteritis nodosa
- Kawasaki disease
c. Large vessel vasculitis
- Takayasu disease
- Giant cell (temporal) arteritis
- Infectious vasculitis
What are the main initiating immunological mechanisms in non-infectious vasculitis
- Immune complex deposition: type III hypersensitivity
- Systemic immunological diseases (SLE, polyarteritis nodosa)
- Drug hypersensitivity (penicillin, streptokinase)
- Viral infection (HBV) - Anti-neutrophilic cytoplasmic antibodies (ANCA):
ANCA-activated neutrophils degranulate, releasing ROS
- Anti-myeloperoxidase (MPO-ANCA/p-ANCA)
- Anti-proteinase-3 (PR3-ANCA/c-ANCA) - Anti-endothelial cell antibodies: type II hypersensitivity
- Seen in Kawaksaki disease
Wegener granulomatosis
- Triad of acute necrotizing granulomas of upper &/or
lower respiratory tract, necrotizing granulomatous
vasculitis (especially in lungs) & glomerulonephritis - Associated with c-ANCA
Microscopic polyangiitis
- Necrotizing vasculitis (commonly in glomeruli or
pulmonary capillaries) - Associated with p-ANCA
Churg-Strauss syndrome
- Very rare necrotizing vasculitis
- Associated with asthma, lung infiltrates, eosinophilia & allergic rhinitis
- Associated with p-ANCA
Henoch-Schonlein purpura
- IgA immune complexes
2. Also causes IgA nephropathy
Polyarteritis nodosa
- Necrotizing vasculitis (typically affects renal & visceral arteries but spares the lungs)
- Associated with chronic HBV infection
Kawasaki disease
- Acute, febrile, self-limiting disease of infancy & childhood
- Predilection for coronary artery, can cause acute myocardial infarction
Takayasu disease
- Granulomatous vasculitis amongst those under 50
- Associated with ocular disturbances & weakening of
pulse in upper extremities
Giant (temporal) arteritis
- Granulomatous vasculitis amongst elderly (>50)
- Affects arteries of head (temporal, ophthalmic, vertebral)
- Associated with polymyalgia rheumatica
Causes of infectious vasculitis
- Bacterial pneumonia, septicaemia, embolization of
infective endocarditis - Fungal infections (especially Mucor & Aspergillus spp.)
Pathological effects & consequences of infectious vasculitis
- Mycotic aneurysms (due to weakened vessel wall)
- Thrombosis & subsequent infarction of tissues supplied by affected vessels
- Hemorrhage
