Vasculitis

Basics

Description

  • Injury/inflammation of the walls of blood vessels:
    • Ischemia and necrosis
    • Aneurysms and hemorrhage
    • Immunopathologic mechanisms:
      • Deposition of circulating antigen–antibody complex and complement fixation
      • Cell-mediated hypersensitivity
      • Granulomatous tissue reaction from persistent inflammation and formation of epithelioid giant cells
  • Vasculitides represent a wide group of disorders:
    • Multisystem disease with constitutional symptoms and inflammatory lab findings
    • Secondary to another disorder or trigger, or primary if vasculitis is the principal feature and no other causes
    • Multiple factors determine presentation:
      • The size of the affected blood vessels
      • The specific distribution, severity, and duration of the inflammation

Etiology

  • Largest arteries:
    • Giant cell arteritis (GCA):
      • Granulomatous arteritis of the aorta and its major branches often involving the temporal artery
      • Patients >50 yr, often associated with polymyalgia rheumatica
    • Takayasu arteritis:
      • Granulomatous inflammation of the aorta and its major branches
      • Usually occurs in patients <50 yr
  • Medium-sized arteries:
    • Polyarteritis nodosa (PAN):
      • Small- and medium-sized arteritis
      • Common distribution includes vessels supplying the muscles, joints, intestines, nerves, kidneys, and skin
      • Most common in middle age
      • Associated with Hep B virus
    • Kawasaki disease:
      • Coronary arteries often involved. Involves large-, medium-, and small-sized arteries
      • Usually occurs in children, most commonly <5
  • Antineutrophil cytoplasmic antibodies (ANCA) associated are primarily IgG mediated and can be small or medium sized:
    • Granulomatosis with polyangiitis (Wegener granulomatosis):
      • Necrotizing vasculitis affecting small- to medium-sized vessels
      • Granulomatous inflammation of the upper and lower respiratory tract and glomerulonephritis
    • Microscopic polyangiitis:
      • Necrotizing affecting small vessels
      • Glomerulonephritis common example
      • Pulmonary capillaritis often occurs
    • Eosinophilic granulomatosis with polyangiitis (Churg–Strauss):
      • Small- and medium-sized arteries
      • Mainly lungs, GI, and nerves
      • Can also involve heart, skin, and kidney
  • Non-ANCA are primarily linked to immune complex deposition:
    • IgA vasculitis (Henoch–Schönlein):
      • Most patients <20 yr
    • Buerger disease (thromboangiitis obliterans)
    • Cryoglobulinemic vasculitis
    • Anti-GBM disease (Goodpasture)
    • Vasculitis of lupus, rheumatoid arthritis, Sjögren
  • Arteries and veins of various size:
    • Behçet disease
    • Relapsing polychondritis
  • Secondary vasculitides:
    • Drug-induced vasculitis:
      • Immune-checkpoint inhibitors
    • Bacterial infections:
      • Streptococcal, tuberculous, staphylococcal, Lyme disease, leprosy
    • Viral infections:
      • Hepatitis B or C, CMV, HSV, HIV
      • COVID has been associated with Kawasaki, IgA vasculitis, and leukocytoclastic vasculitis
    • Rickettsial infections
    • Hairy cell leukemia
    • Lymphoma
    • Serum sickness

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