Vasculitis

Overview
  • Vasculitis refers to inflammation of the blood vessels and can manifest as a primary disease of the vasculature or can occur secondarily to other pathogenic processes. Vasculitis syndromes can affect nearly any segment of the vasculature throughout the body and the clinical consequences usually depend on which blood vessels are involved. Clinical consequences are usually due to luminal narrowing and thus ischemia to downstream tissues or occasionally from thrombosis of the affected vessel or hemorrhage from it. Because of their inflammatory nature, many vasculitis syndromes are accompanied by constitutional symptoms.
Pathogenesis
  • Overview
    • The pathogenesis of most vasculitis syndromes is poorly understood, although in most cases immune processes appear to be at work. Several basic pathogenic themes can be abstracted from the various syndromes as discussed below.
  • Immune Complex Deposition
    • In many vasculitis syndromes a pathogenic role for vascular deposition of immune complexes is suspected. Consequently, many vasculitis syndromes may be related to the prototypical immune complex disease, Serum Sickness, and thus a form of Type III Hypersensitivity. In some cases the complexed antigen is thought to be of exogenous or microbial origin whereas in others it is suspected to be derived from endogenous antigens.
  • Anti-neutrophil Cytoplasmic Antibodies (ANCAs)
    • ANCAs are auto-antibodies which react with antigens in the cytoplasmic region of neutrophils. Their presence is associated with several vasculitis syndromes although their precise role in pathogenesis is poorly understood. Furthermore, titers of ANCAs tend to rise and fall with disease activity and so are useful as diagnostic tools for management of these conditions. ANCAs are classified according to their differential specificity to neutrophilic antigens.
    • c-ANCAs stain neutrophils in a cytoplasmic pattern and are observed in Wegener Granulomatosis
    • p-ANCAs stain neutrophils in a perinuclear pattern and are observed in Microscopic Polyangiitis and Churg-Strauss Syndrome
Member Diseases
Subtopics