Vasculitis

Basics

Description

Injury to the walls of blood vessels from inflammation:
- 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 indices
- Secondary to another disorder or trigger, or primary if vasculitis is the principal feature and the cause is unknown
- Multiple factors determine presentation:
  - The size of the affected blood vessels
  - The specific distribution, severity, and duration of the inflammation
1 out of 2,000 adults has some form of vasculitis

Etiology

Largest arteries:
- Giant cell arteritis:
  - Granulomatous arteritis of the aorta and its major branches often involving the temporal artery
  - Patients >50 yr
- 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
- Kawasaki disease (mucocutaneous lymph node syndrome):
  - Coronary arteries are often involved and involves large-, medium-, and small-sized arteries
  - Usually occurs in children
Small- and medium-sized arteries:
- 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 is very common
  - 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
Small arteries:
- IgA vasculitis (Henoch–Schönlein):
  - Most patients <20 yr
- Buerger disease (thromboangiitis obliterans)
- Cryoglobulinemic vasculitis
- Anti-GBM disease (Goodpasture)
- Vasculitis of lupus, rheumatoid arthritis, Sjögren
- Drug-induced vasculitis:
Arteries and veins of various size:
- Behçet disease
- Relapsing polychondritis
Secondary vasculitides:
- Bacterial infections:
  - Streptococcal, tuberculous, staphylococcal, Lyme disease, leprosy
- Viral infections:
  - Hepatitis B or C, CMV, HSV, HIV
- Rickettsial infections
- Hairy cell leukemia
- Lymphoma
- Serum sickness

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