Churg-Strauss syndrome

Eosinophilic Granulomatosis with Polyangiitis

David Goldemund M.D.
Updated on 19/06/2024, published on 19/06/2024
  • Churg-Strauss Syndrome (CSS, now more commonly referred to as Eosinophilic Granulomatosis with Polyangiitis or EGPA) is a rare systemic vasculitis that primarily affects small-sized vessels
    • CSS accounts for only 20% of patients with the systemic necrotizing vasculitis of the polyarteritis nodosa group
  • CSS typically affects middle-aged individuals
  • peripheral nervous system involvement is common, but cerebral infarction or hemorrhage may also occur
    • involvement of the CNS is associated with an increased risk for mortality and requires aggressive treatment with steroids and immunosuppressants
    • neuroimaging of CSS-related stroke is nonspecific
  • the diagnostic evaluation involves a combination of clinical, laboratory, imaging, and histopathological criteria; the condition should be considered in any patient who has asthma and develops eosinophilia and peripheral and/or CNS signs

Pathology and pathophysiology

  • medium- to small-vessel vasculitis that preferentially affects capillaries, arterioles, and venules
  • in some patients, the larger vessels can be affected, but this is uncommon
  • pathologically, CSS consists of three classical features:
    • necrotizing vasculitis
      • the presence of ANCA is associated with a “vasculitic” clinical picture and more frequent CNS involvement than in ANCA-negative patients
    • eosinophilic inflammation
      • eosinophils are linked to the release of their cytotoxic enzymes, which can lead to tissue damage
    • extravascular granulomas
  • the triggering events and cause of CSS remain unclear

Clinical presentation

  • characterized by a wide range of symptoms due to its systemic involvement
  • systemic symptoms – fever, malaise, weight loss
  • asthma, typically severe and adult-onset
  • allergic rhinitis and nasal polyps, chronic sinusitis with nasal obstruction, pulmonary infiltrates (nonfixed)
  • palpable skin purpura and subcutaneous nodules
  • mononeuritis multiplex – common, causing asymmetric pain, weakness, and sensory loss
  • cardiovascular symptoms – myocarditis (heart failure, arrhythmias), pericarditis (chest pain)
  • gastrointestinal symptoms – abdominal pain, diarrhea, and gastrointestinal bleeding
  • glomerulonephritis

Cerebrovascular complications of CSS

  • CNS is less often involved (< 10%) compared with peripheral lesions
  • cerebrovascular disease related to CSS has no specific pattern that could be used for diagnostic purposes
  • infarcts are typically small and multiple, and patients often present with diffuse encephalopathy; large cerebral infarcts are rare
  • occlusions of the dural sinuses, cerebral veins, and ophthalmic arteries have also been reported
  • there have been several reports of CSS presenting with intracranial hemorrhage
    • ICH probably due to uncontrolled hypertension
    • intraventricular hemorrhage from a necrotizing vasculitis of the choroid plexus

Diagnostic evaluation

Clinical evaluation

  • presence of adult-onset asthma and chronic sinusitis
  • mononeuritis multiplex or polyneuropathy
  • palpable skin purpura and nodules

Laboratory tests

  • Complete Blood Count (CBC):
    • eosinophilia – elevated eosinophil count (usually >10% or count >1.5 x 10^9/L)
  • elevated ESR and CRP
  • ↑ serum IgE levels
  • Antineutrophil Cytoplasmic Antibodies (ANCA) positivity
    • positive p-ANCA/MPO-ANCA in 40-60% of cases
  • tissue biopsy (skin, lung, nerve, or other affected tissues)
    • eosinophilic infiltration, granulomatous inflammation, and vasculitis of small to medium-sized vessels

Imaging studies

  • chest X-ray and high-resolution CT (HRCT) – pulmonary infiltrates, nodules, or ground-glass opacities
  • echocardiogram – assess for cardiac involvement such as myocarditis or pericarditis
  • standard stroke imaging (CT+CTA/MRI+MRA, ultrasound, etc.)

Other methods

  • EMG – detection of mononeuritis multiplex, etc.

Diagnostic criteria of the American College of Rheumatology
Diagnosis is established if ≥ 4 of the following six criteria are present:

  • asthma
  • eosinophilia >10%
  • mononeuritis multiplex or polyneuropathy
  • nonfixed pulmonary infiltrates
  • paranasal sinus abnormality
  • biopsy containing a blood vessel with extravascular eosinophils


  • glucocorticoids are the mainstay of therapy (pulse prednisolone 15 mg/kg for 1-3 days, followed by prednisone 1 mg/kg per day)
  • in some patients, other immunosuppressive drugs are added to the steroid regimen (steroid-sparing effect)
    • cyclophosphamide bolus should be considered in severe cases
    • rituximab has proven useful in the treatment of steroid-resistant cases, as well as in the prevention and treatment of relapse (however, efficacy is greatly reduced in ANCA-negative patients)
  • interleukin-5 (IL-5) antagonist monoclonal antibody
    • mepolizumab – approved by the FDA for use in adult patients with EGPA
    • benralizumab
  • plasma exchange has been studied in EGPA and other ANCA-positive vasculitides without a clear benefit


  • negative prognostic factors include:
    • renal insufficiency with serum Cr >1.58 mg/dL
    • CNS involvement
    • cardiomyopathy
    • presence of proteinuria (>1 g/d)
    • gastrointestinal tract involvement
  • the more factors, the higher the mortality

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Churg-Strauss syndrome