Vasculitis

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Vasculitis: Classification & Pathogenesis - Vessel Vandals Intro

  • Definition: "Vessel Vandals" - inflammation & damage to blood vessel walls (arteries, veins, capillaries), leading to tissue ischemia, organ damage, necrosis, or hemorrhage.
  • Pathogenesis: Primarily immune-mediated mechanisms:
    • Immune complex deposition (Type III Hypersensitivity).
    • ANCA (Anti-Neutrophil Cytoplasmic Antibodies) targeting PR3 (c-ANCA) or MPO (p-ANCA).
    • Anti-Endothelial Cell Antibodies (AECA).
    • Autoreactive T-cells (granulomatous inflammation).
    • Less commonly: direct pathogen invasion.
  • Classification (Dominant vessel size - CHCC 2012):

Vasculitis: Healthy vs. Inflamed Blood Vessel

⭐ Systemic symptoms (fever, myalgia, arthralgia, malaise, weight loss) are common across many vasculitides.

Large Vessel Vasculitis: GCA & Takayasu - Aorta's Agony

  • Giant Cell Arteritis (GCA)

    • Age >50 yrs. Affects temporal, ophthalmic arteries.
    • Sx: Headache, jaw claudication, visual loss, Polymyalgia Rheumatica (PMR).
    • Dx: ↑ ESR (>50 mm/hr), temporal artery biopsy (granulomas, giant cells).
    • Rx: Urgent high-dose steroids (prednisone 40-60 mg).
    • Giant Cell Arteritis: Temporal Artery Biopsy Histology
  • Takayasu Arteritis

    • Age <40-50 yrs (young Asian women). "Pulseless disease".
    • Sx: ↓Pulses (BP diff >10 mmHg btw arms), claudication, bruits. Aortic arch syndrome.
    • Dx: ↑ ESR, angiography (CT/MR) shows stenosis/thickening.
    • Rx: Corticosteroids.
    • 📌 TakaYAsu: Young Asian.

⭐ GCA: Risk of irreversible blindness mandates immediate high-dose steroid therapy if suspected (e.g., new headache, visual sx, jaw claudication in elderly).

Medium Vessel Vasculitis: PAN & Kawasaki - Artery Afflictions

  • Polyarteritis Nodosa (PAN)

    • Necrotizing vasculitis of medium-sized arteries; spares pulmonary circulation.
    • Associated with Hepatitis B (HBsAg) in ~30% cases.
    • Clinical: Fever, weight loss, myalgia, abdominal pain (mesenteric ischemia), hypertension (renal artery involvement), mononeuritis multiplex.
    • Pathology: Transmural inflammation, fibrinoid necrosis, "beads-on-a-string" appearance on angiography.
    • 📌 Mnemonic: Pulmonary Artery Not involved.
  • Kawasaki Disease (Mucocutaneous Lymph Node Syndrome)

    • Typically affects children < 5 years.
    • Clinical: Fever >5 days, conjunctivitis, rash, adenopathy, strawberry tongue, hand-foot changes (edema, erythema, desquamation).
    • Major complication: Coronary artery aneurysms.
    • Treatment: IVIG and Aspirin.

Renal angiogram: Polyarteritis nodosa (PAN)

⭐ Kawasaki Disease is the leading cause of acquired heart disease in children in developed countries; coronary artery aneurysms are a feared complication, treat with IVIG and high-dose aspirin initially, then low-dose aspirin for thromboprophylaxis.

Small Vessel Vasculitis: ANCA & Immune Complex - Capillary Crisis

Affects capillaries, venules, arterioles. Two types: ANCA-associated (AAV) & Immune Complex-mediated (ICV).

  • ANCA-Associated Vasculitis (AAV): Pauci-immune (scant/no immune deposits).
    • Microscopic Polyangiitis (MPA): p-ANCA (MPO). Necrotizing GN, pulmonary capillaritis. No granulomas.
    • Granulomatosis with Polyangiitis (GPA): c-ANCA (PR3). Triad: URT, LRT (nodules, cavities), renal (RPGN). Necrotizing granulomas. 📌 C-ANCA, Cavities.
    • Eosinophilic GPA (EGPA): p-ANCA (MPO) in ~50%. Asthma, ↑eosinophils (>10% or >1500/μL), neuropathy. Eosinophilic granulomas.
  • Immune Complex Vasculitis: Immune complex deposition.
    • IgA Vasculitis (HSP): Children. Palpable purpura (buttocks, lower limbs), arthralgia, abdominal pain, IgA nephropathy. Post-URI.
    • Cryoglobulinemic Vasculitis: HCV-linked. Meltzer's triad: purpura, arthralgia, weakness. Type II/III cryoglobulins.
    • Anti-GBM Disease (Goodpasture's): Abs to Type IV collagen (α3). Pulmonary hemorrhage, RPGN. Linear IgG IF.

Capillary Crisis (Pulmonary-Renal Syndrome):

  • Diffuse Alveolar Hemorrhage (DAH) + Rapidly Progressive Glomerulonephritis (RPGN). Life-threatening.
  • Seen in AAV (MPA, GPA), Anti-GBM disease.
  • Rx: High-dose steroids, cyclophosphamide/rituximab, plasmapheresis.

Causes of Diffuse Alveolar Hemorrhage Syndromes

⭐ GPA (Wegener's) is characterized by the triad of upper respiratory tract, lower respiratory tract, and renal involvement, often with c-ANCA (PR3-ANCA) positivity.

High‑Yield Points - ⚡ Biggest Takeaways

  • Giant Cell Arteritis: Elderly, temporal artery, polymyalgia rheumatica, risk of blindness; prompt steroids.
  • Takayasu Arteritis: "Pulseless disease", young females, granulomatous inflammation of aortic arch & branches.
  • Kawasaki Disease: Children <5 yrs, coronary artery aneurysms risk; mucocutaneous signs, IVIG + aspirin.
  • Polyarteritis Nodosa (PAN): Medium-vessel vasculitis, Hepatitis B link, renal/visceral arteries, spares lungs.
  • ANCA-associated: GPA (c-ANCA): URT/LRT/Kidney granulomas; MPA (p-ANCA): Lung/Kidney, no granulomas; EGPA (p-ANCA): Asthma, eosinophilia.

Practice Questions: Vasculitis

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All of the following conditions are associated with raised ANCA, except:

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Flashcards: Vasculitis

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Vasculitides often present with symptoms of organ ischemia due to _____ of inflamed vessels or luminal narrowing from fibrosis

TAP TO REVEAL ANSWER

Vasculitides often present with symptoms of organ ischemia due to _____ of inflamed vessels or luminal narrowing from fibrosis

thrombosis

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