Vasculitis

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Vasculitis Basics - Vessel Villains

  • Inflammation & necrosis of blood vessel walls, leading to impaired blood flow & organ damage.
  • Classification (Chapel Hill Consensus Conference - CHCC):
    • Large-vessel vasculitis (LVV): Giant cell arteritis (GCA), Takayasu arteritis (TAK).
    • Medium-vessel vasculitis (MVV): Polyarteritis nodosa (PAN), Kawasaki disease (KD).
    • Small-vessel vasculitis (SVV):
      • ANCA-associated vasculitis (AAV): Microscopic polyangiitis (MPA), Granulomatosis with polyangiitis (GPA), Eosinophilic granulomatosis with polyangiitis (EGPA).
      • Immune complex SVV: IgA vasculitis (Henoch-Schönlein purpura), Cryoglobulinemic vasculitis.

⭐ The Chapel Hill Consensus Conference (CHCC) nomenclature is widely used for classifying vasculitides based on vessel size and etiology.

Histopathology of Leukocytoclastic Vasculitis

  • Pathogenesis: Immune complex deposition, anti-neutrophil cytoplasmic antibodies (ANCAs), direct T-cell mediated injury. 📌 Mnemonic (ANCA): Anti-Neutrophil Cytoplasmic Antibodies target enzymes in neutrophils (MPO, PR3).

Clinical Clues - Skin Deep & More

  • Cutaneous Manifestations:

    • Palpable purpura: Non-blanching, raised lesions; hallmark, often on lower extremities & dependent areas.

    ⭐ Palpable purpura, especially on lower extremities, is the most common cutaneous manifestation of small vessel vasculitis.

    • Livedo reticularis/racemosa: Net-like, violaceous pattern.
    • Nodules, papules, vesicles, bullae, ulcers, digital gangrene.
    • Urticarial vasculitis: Persistent wheals (>24h), often painful/burning, may leave pigmentation.
  • Systemic Clues (Variable):

    • Constitutional: Fever, malaise, weight loss, arthralgia, myalgia.
    • Renal: Hematuria, proteinuria (e.g., IgA vasculitis, ANCA-associated vasculitis).
    • GI: Abdominal pain, melena (e.g., IgA vasculitis).
    • Pulmonary: Cough, hemoptysis, dyspnea (e.g., ANCA-associated vasculitis).
    • Neurological: Mononeuritis multiplex, peripheral neuropathy, headache, stroke.
    • Ocular: Episcleritis, uveitis, retinal vasculitis.
  • 📌 Mnemonic (HSP features): "Henoch's Shönlein Purpura" - Hematuria, Stomach ache (abdominal pain), Palpable purpura, Arthritis (often Ankles/knees).

Diagnostic Drilldown - Finding the Fire

  • Essential Labs:
    • CBC (anemia, thrombocytosis), ↑↑ESR/CRP.
    • Urinalysis (RBCs, casts, proteinuria).
    • Renal function (Creatinine), LFTs.
    • Hepatitis B/C serology, Cryoglobulins (check with purpura, arthralgia, weakness).
  • ANCA (Key for Small Vessel Vasculitis):

    ⭐ A positive ANCA test is highly suggestive of certain small vessel vasculitides: c-ANCA/PR3 for GPA and p-ANCA/MPO for MPA and EGPA.

  • Biopsy (Gold Standard):
    • Site: Skin (newest purpuric lesion for LCV), Kidney (pauci-immune GN in ANCA+), Nerve, Lung.
    • DIF: IgA deposition (IgA Vasculitis), C3.
  • Targeted Imaging:
    • CXR/HRCT Chest (nodules, infiltrates, hemorrhage - GPA, EGPA, MPA).
    • Angiography (medium/large vessels: aneurysms, stenosis - PAN, Takayasu).
    • Doppler US (GCA: temporal artery 'halo sign'). Leukocytoclastic vasculitis skin biopsy
  • Kawasaki Disease
    • Fever >5d + 📌 CRASH & Burn (Conjunctivitis, Rash, Adenopathy, Strawberry tongue, Hand/foot edema).
    • Risk: Coronary aneurysms.
    • Rx: IVIG 2g/kg + Aspirin (80-100mg/kg/d3-5mg/kg/d).

    ⭐ Kawasaki disease requires prompt treatment with IVIG and high-dose aspirin to prevent coronary artery aneurysms.

  • Henoch-Schönlein Purpura (HSP) / IgA Vasculitis
    • Tetrad: Palpable purpura (buttocks/legs), Arthritis, Abd pain, Renal (IgA nephropathy).
    • Post-URI. Palpable purpura in vasculitis
  • Behçet's Disease
    • Recurrent oral & genital ulcers, uveitis.
    • Pathergy test (+). HLA-B51.
  • Polyarteritis Nodosa (PAN)
    • Medium-vessel; spares lungs. Hep B assoc.
    • Livedo reticularis, nodules, renal (no GN), neuropathy. "Rosary bead" angiography.

High‑Yield Points - ⚡ Biggest Takeaways

  • Palpable purpura: Hallmark of Leukocytoclastic Vasculitis (LCV).
  • Henoch-Schönlein Purpura (HSP): IgA deposition, classic triad (purpura, arthritis, abdominal pain), often post-URI.
  • Polyarteritis Nodosa (PAN): Associated with Hepatitis B, affects medium vessels; presents with nodules, livedo reticularis.
  • GPA (Wegener’s): c-ANCA positive; involves upper/lower respiratory tract and kidneys.
  • EGPA (Churg-Strauss): Asthma, eosinophilia, p-ANCA positive.
  • Microscopic Polyangiitis (MPA): p-ANCA positive; causes pauci-immune glomerulonephritis and pulmonary capillaritis.

Practice Questions: Vasculitis

Test your understanding with these related questions

A 24-year-old woman presents with abdominal pain, joint discomfort, and lower limb rash. She was well until 1 week before presentation. On examination, she has a palpable purpuric rash on her legs, nonspecific abdominal discomfort, and no active joints. She has 3+ proteinuria, normal WBC, no eosinophils, and elevated creatinine of 1.6 mg/dL. Biopsy of the rash confirms vasculitis with immunoglobulin A (IgA) 3+and C3 (complement 3) deposition on immunofluorescence.For the above patient with vasculitis syndrome, select the most likely diagnosis.

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Flashcards: Vasculitis

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_____ disease is associated with dermatitis herpetiformis, which are small, herpes-like vesicles on the skin

TAP TO REVEAL ANSWER

_____ disease is associated with dermatitis herpetiformis, which are small, herpes-like vesicles on the skin

Celiac

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