Vasculitis can be approached according to the size of the vessel that is affected and/or the mechanism of inflammation.
LARGE VESSEL VASCULITIS
Takayasu Arteritis
Giant cell arteritis
MEDIUM-SIZED VESSEL VASCULITIS
PolyArteritis Nodosa (PAN)
Kawasaki Disease
SMALL VESSEL VASCULITIS
To approach the etiology of vasculitis within small vessels, we further subdivide it into whether the inflammation is secondary to an antibody directed against some component of the vessel (ANCA-associated or the Anti-GBM antibody), or whether there is indirect destruction due to the deposition of immune complexes within the vessel wall (an antibody bound to some antigen)
ANCA-ASSOCIATED SMALL VESSEL VASCULITIS
ANCA-associated destruction affects multiple vessels all over (hence the term POLYangiitis). It can be further subdivided whether it demonstrates cytoplasmic or nuclear staining pattern on fluorescence
C-ANCA= CYTOPLASMIC + against Protease 3
(Wegner's) Granulomatosis with polyangitis
P-ANCA= PERINUCLEAR + against MyeloPerOxidase (MPO)
(Churg-Strauss) Eosinophilic granulomatosis with polyangitis
(PAN) Microscopic PolyANgitis
ANTI-GLOMERULAR BASEMENT MEMBRANE (ANTI-GBM)
SMALL VESSEL VASCULITIS
Goodpasture Syndrome
IMMUNE COMPLEX SMALL VESSEL VASCULITIS
Cryoglobulinemic Vasculitis
IgA Vasculitis (Henoch-Schonlein purpura)
Hypocomplementemic Urticarial vasculitis (Anti-C1q vasculitis)
There will be separate posts demonstrating histologic examples and further details of each of the above diseases.
POP QUIZ
Let's see if you can still remember a few of the high yield associations you learned about these diseases back in the good ol' med school days...
1. How can you DDx Wegner's from Churg Strauss?
Both have granulomatous inflammation with geographic necrosis
Wegner's does NOT have inc eosinophils
Churg Strauss has inc eosinophils + often a history of asthma or allergies
2. How can you DDx Wegners from Goodpasture syndrome?
Both cause problems in the lung & kidney
Wegners is cANCA + and also involves the UPPER respiratory tract (nose bleeds etc)
Goodpasture's (anti-GBM) does NOT affect the URT
3. What is the antibody against in c-ANCA?
Which disease(s) does it cause?
Proteinase 3; cytoplasmic +; c-Anti-Neutrophil Cytoplasmic Ab
Wegner's (aka weCners) Granulomatosis
4. What is the antibody against in p-ANCA?
Which disease(s) does it cause?
Myeloperoxidase (MPO); perinuclear +; p-Anti-Neutrophil Cytoplasmic Ab
Churg Strauss/Eosinophilic Granulomatosis & microscopic polyangiitis