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Vasculitis for the Physician Assistant Licensing Exam

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Overview of Vasculitis
    • Definition: Vasculitis is inflammation of blood vessels, leading to vessel wall damage, narrowing, or occlusion, which can compromise blood flow and result in organ damage.
    • Classification:
  • Large vessel vasculitis: Affects large arteries (e.g., giant cell arteritis, Takayasu arteritis).
  • Medium vessel vasculitis: Affects medium-sized arteries (e.g., polyarteritis nodosa, Kawasaki disease).
  • Small vessel vasculitis: Affects small arteries, capillaries, and venules (e.g., granulomatosis with polyangiitis, microscopic polyangiitis, Henoch-Schönlein purpura).
    • Etiology:
    • Idiopathic in most cases, but may be secondary to infections, autoimmune disorders, medications, or malignancies.
Clinical Features
    • General Symptoms:
  • Systemic symptoms like fever, fatigue, weight loss, and muscle pain.
  • Organ-specific symptoms depend on the type of vasculitis and affected vessels.
    • Large Vessel Vasculitis:
    • Giant cell arteritis: Headache, jaw claudication, scalp tenderness, visual impairment.
    • Takayasu arteritis: Limb claudication, diminished pulses, blood pressure discrepancies between limbs.
    • Medium Vessel Vasculitis:
    • Polyarteritis nodosa (PAN): Abdominal pain, hypertension, kidney involvement, mononeuritis multiplex.
    • Kawasaki disease: Fever, mucocutaneous inflammation, conjunctivitis, coronary artery aneurysms.
    • Small Vessel Vasculitis:
    • Granulomatosis with polyangiitis (GPA): Sinusitis, lung nodules, renal involvement (glomerulonephritis).
    • Microscopic polyangiitis (MPA): Pulmonary hemorrhage, glomerulonephritis.
    • Henoch-Schönlein purpura (HSP): Palpable purpura, abdominal pain, arthritis, renal involvement.
Diagnosis
    • Laboratory Tests:
  • Elevated inflammatory markers (ESR, CRP).
  • Autoantibodies: ANCA (for GPA and MPA), elevated IgA (for HSP).
  • Basic labs may show anemia of chronic disease, leukocytosis, and elevated creatinine in renal involvement.
    • Imaging:
    • Angiography: Useful for detecting vessel stenosis or aneurysms in medium and large vessel vasculitis.
    • CT or MRI: To evaluate structural abnormalities in vessels.
    • Biopsy:
  • The gold standard for diagnosing vasculitis, particularly small vessel vasculitis.
Treatment
    • Corticosteroids:
  • High-dose corticosteroids are first-line treatment for most vasculitis cases.
  • Tapering regimen required to prevent relapse after symptom control.
    • Immunosuppressive Agents:
  • Cyclophosphamide, methotrexate, or azathioprine for severe or refractory cases.
  • Rituximab: Used in ANCA-associated vasculitis (GPA, MPA).
    • Biologics and Special Therapies:
    • Tocilizumab: Used for giant cell arteritis.
    • IVIG: Administered in Kawasaki disease to prevent coronary artery aneurysms.
Essential Points
    • Vasculitis is classified based on the size of the affected vessels: large, medium, or small.
    • Diagnosis involves clinical features, laboratory testing (e.g., ANCA, ESR), imaging, and biopsy when needed.
    • Early treatment with corticosteroids and immunosuppressants is essential to prevent irreversible organ damage.
    • Prompt recognition and management of conditions like giant cell arteritis and Kawasaki disease are critical to avoid severe complications such as blindness or coronary aneurysms.