Vasculitis Flashcards
Vasculitis
General term for inflammation of blood vessel wall
Vasculitis Clinical Features
- Varied, depend on size and location of vessel targeted
- In addition to localized effects, vasculitis may frequently include systemic symptoms (fatigue, myalgias, arthralgias, malaise)
Vasculitis Classification Schemes
- Forms of vasculitis grouped according to:
1) size/diameter of vessel involved
2) role of immune complexes
3) presence of specific autoantibodies
4) presence/absence of granuloma formation
5) organ specificity
6) patient population most affected - Clinical and pathologic features of various entities can overlap
Vasculitis Main Pathological Mechanisms
- Immune-mediated inflammation (non-infectious)
- Direct invasion of blood vessel by infectious pathogens
Non Infectious Vasculitis
•Immunologic injury to blood vessels may be due to:
- Immune complex deposition
- Anti-neutrophil cytoplasmic antibodies (ANCA)
- Anti-endothelial cell antibodies
- Autoreactive T-cells
•Treatment generally involves various forms of immunosuppression: Corticosteroids, cyclophosphamide, anti-TNF agents, intravenous immunoglobulin (IVIg)
Non Infectious Vasculitis - Immune Complex-Associated Vasculitis
- Usually seen in systemic disorders, associated with autoantibody formation
a. SLE
b. Serum sickness
c. Arthus reaction - Also seen in:
a. Drug hypersensitivity vasculitis
i. Antibodies form against drug-modified self-proteins or against foreign molecules from drug
b. Immunologic vasculitis secondary to infection (not direct invasion of organism into vessel)
i. Antibodies form to circulating antigens related to microbes and subsequent complexes form and deposit in vessels, causing vasculitis
Non Infectious Vasculitis - Immune Complex-Associated Vasculitis Morphologc Features
a. Acute inflammation of vessels with associated immune complexes
i. If due to SLE – will have “full house” staining on immunofluorescence
b. Affected vessels may have fibrinoid necrosis
c. Renal manifestations of SLE vary by class
Non Infectious Vasculitis - Anti-Neutrophilic Cytoplasmic Antibody (ANCA) Associated Vasculitis
- ANCA = group of antibodies that react with neutrophil cytoplasmic antigens
a. Detection of ANCA very useful for diagnosis
b. Titer of ANCA usually correlates with disease severity, recurrence - Two types a. Anti-proteinase 3 (PR3) – i.e. c-ANCA (c = cytoplasmic staining pattern on immunofluorescence)
b. Anti-myeloperoxidase (MPO) – i.e. p-ANCA (p = perinuclear staining pattern on immunofluorescence) - ANCA’s thought to be implicated directly in pathogenesis of the vasculitis
a. ANCA can activate PMN’s, stimulate release of reactive oxygen species and proteolytic enzymes, and induce inflammation - ANCA’s are directed against cellular antigens and cause local injury (type II hypersensitivity) but do not form circulating immune complexes to any significant degree
a. Vascular lesions do not contain discrete immune complexes when visualized under immunofluorescence, therefore they are “pauci-immune” - ANCA-associated vasculitis tends to predominantly affect lung and kidney (“pulmonary renal syndrome”), although other organs can be involved
Non Infectious Vasculitis - Anti-Neutrophilic Cytoplasmic Antibody (ANCA) Associated Vasculitis - Granulomatosis with Polyangiitis
- Previously called “Wegener granulomatosis”
- Associated with cANCA (PR3)
- Males > Females affected, average age 40 yrs
- Rapidly fatal if untreated (80% mortality in 1 year)
Non Infectious Vasculitis - Anti-Neutrophilic Cytoplasmic Antibody (ANCA) Associated Vasculitis - Granulomatosis with Polyangiitis Classic Triad
• Necrotizing and/or granulomatous inflammation of upper respiratory tract, lung and kidney
Non Infectious Vasculitis - Anti-Neutrophilic Cytoplasmic Antibody (ANCA) Associated Vasculitis - Granulomatosis with Polyangiitis Morphologic Features
- Morphologic features
- Lung: Granulomas with necrosis, acute inflammation of alveolar capillaries with hemorrhage
- Renal: Pauci-immune necrotizing and crescentic glomerulonephritis
- General: No immune complexes (pauci-immune)