Wegener Granulomatosis

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Wegener Granulomatosis

  • ANCA-associated vasculitides
    • Wegener granulomatosis
    • microscopicpolyangiitis
    • Churg-Strauss syndrome
  • Wegener granulomatosis is characterized in its full expression by
    • vasculitis of small arteries, arterioles, and capillaries
    • necrotizing granulomatous lesions of both upper and lower respiratory tract
    • glomerulonephritis
  • occurs most commonly in the fourth and fifth decades of life
  • affectsmen and women with equal frequency.
  • Clinical Findings
    • 90% of patients presenting with upper or lower respiratory tract symptoms or both.
      • Upper respiratory tract symptoms can include nasal congestion, sinusitis, otitis media, mastoiditis, inflammation of the gums, or stridor due to subglottic stenosis.
    • The lungs are affected –cough, dyspnea, and hemoptysis.
    • Other early symptoms can include
      • migratoryoligoarthritis with a predilection for large joints
      • symptoms related to ocular disease
        • unilateralproptosis from orbital pseudotumor
        • red eye from scleritis
        • episcleritis
        • anterior uveitis
        • peripheralulcerative keratitis
      • purpura or other skin lesions
      • dysesthesia due to neuropathy
    • Renal involvement
      • develops in three-fourths of the cases
    • Fever, malaise, and weight loss are common
    • congestion, crusting, ulceration, bleeding, and even perforation of the nasal septum.
    • Destruction of the nasal cartilage with “saddle nose” deformity occurs late.
    • Newly acquired hypertension, a frequent feature of polyarteritisnodosa, is rare in Wegener granulomatosis.
    • Venous thrombotic events (eg, deep venous thrombosis and pulmonary embolism) are a common occurrence in Wegener granulomatosis, at least in part because of the tendency of the disease to involve veins as well as arteries.
    • limited forms of Wegener granulomatosis-  in which the kidney is spared
      • often confined to the respiratory tract
      • areANCA-negative.
      • ANCA
        • Serum tests for ANCA help in the diagnosis of Wegener granulomatosis ANCA
        • “PR3-ANCA”
          • directed against proteinase-3 (PR3)
          • cytoplasmic pattern of immunofluorescence (C-ANCA) is caused by PR3-ANCA
          • has a high specificity (> 90%) for either Wegener granulomatosis or a closely related disease, microscopic polyangiitis
          • In the setting of active disease, particularly cases in which the disease is severe and generalized to multiple organ systems, the sensitivity of PR3-ANCA is > 95%.
        • “MPO-ANCA,”
          • directed against myeloperoxidase (MPO)
          • causesperinuclear (P-ANCA) pattern
          • more likely to occur in microscopic polyangiitis or Churg-Strauss
      • ANCA levels correlate erratically with disease activity
      • changes in titer of ANCA should not dictate changes in therapy in the absence of supporting clinical data.
  • Histologic findings
      • Histologic features of Wegener granulomatosis include vasculitis, granulomatous inflammation, geographic necrosis, and acute and chronic inflammation.
      • The full range of pathologic changes is usually evident only on thoracoscopic lung biopsy.
      • Granulomas
        • observed only rarely in renal biopsy specimens
        • found much more commonly on lung biopsy specimens.
      • Renal biopsy
        • discloses a segmental necrotizing glomerulonephritis with multiple crescents
          • this is characteristic but not diagnostic.
        • renal lesion of Wegener granulomatosis (and other forms of “ANCA-associated vasculitis”) is a pauci-immune glomerulonephritis
          • because of the relative absence (compared with immune complex–mediated disorders) of immunoreactants—IgG, IgM, IgA, and complement proteins—within glomeruli.

 

  • Imaging
    • Chest CT
      • more sensitive than chest radiography
      • lesions include infiltrates, nodules, masses, and cavities.
      • Hilaradenopathy
        • unusual in Wegener granulomatosis
        • if present, sarcoidosis, tumor, or infection is more likely.

 

      • Differential Diagnosis
        • RA versus WG
          • rheumatoid arthritis typically involves small joints of the hand
          • Wegener granulomatosis favors large joints, such as the hip, knee, elbow, and shoulder.
        • Causes of an acute pulmonary-renal syndrome
          • Wegener granulomatosis
          • SLE
          • Goodpasture syndrome
          • microscopicpolyangiitis
      • Treatment
        • For patients with severe Wegener granulomatosis, cyclophosphamide and prednisone remain the standard of care for remission induction.
        • Azathioprine
          • aseffective as cyclophosphamide in maintaining disease
          • Before the institution of azathioprine, patients should be tested for deficiencies in the level of thiopurinemethyltransferase
      • Methotrexate
          • viewed as an appropriate substitute for cyclophosphamide in patients who do not have significant renal dysfunctionor immediately life-threatening disease.


Wegener’s granulomatosis and microscopic polyangiitis
Wegener’s granulomatosis (also known as granulomatosis with polyangiitis) is a type of vasculitis that affects small and medium blood vessels. Symptoms can include saddle nose deformity, chronic sinusitis, and collapsed trachea. Microscopic polyangiitis is similar to wegener’s granulomatosis except it only affects small blood vessels in the lungs or kidneys. Learn how the presence of granulomas and antibodies (cANCA and pANCA) differentiate these two conditions.
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