Eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA), previously known as the Churg-Strauss syndrome (CSS), refers to a small to medium vessel necrotizing pulmonary vasculitis. It is also classified under the spectrum of eosinophilic lung disease and as a type of pulmonary angiitis and granulomatosis.

Epidemiology

The incidence typically peaks around the 3 to 4 decade with an annual incidence rate of around 0.24-1.78 per 100,000 .

Clinical presentation

Almost all patients have asthma and eosinophilia. Patients also have extrapulmonary signs and symptoms such as sinusitis, diarrhea, skin purpura, and/or arthralgias.

Diagnostic criteria

The 1990 American College of Rheumatology criteria requires a positive biopsy for vasculitis and at least four of the six criteria listed below (sensitivity 85% and specificity 99.7%) :

• asthma: present in almost all patients
• blood eosinophilia ( >10% of the total white blood cell count): present in almost all patients
• mono/polyneuropathy
• transient pulmonary infiltrates
• paranasal sinus abnormalities: pain or radiographic abnormality
• presence of extravascular eosinophils on a biopsy specimen

Pathology

Can be histologically identical to classic polyarteritis nodosa or microscopic polyangiitis. Around 25% of patients will have renal disease .

Biopsy of parenchymal opacities may show a mixture of necrotizing granulomas, eosinophilic pneumonia, and granulomatous vasculitis .

Markers

• pANCA: ~75%

Radiographic features

Plain radiograph

Chest radiographs are nonspecific but may show:

• peripheral consolidation, which may be transient/migratory
• small pleural effusions - up to 50% of cases

CT

Imaging features include:

• peripheral or random parenchymal opacification (consolidation or ground glass)
  • this tends to be the most frequent feature ; can be transient
  • often bilateral and can sometimes be symmetrical
  • parenchymal opacification is predominantly peripheral or random in distribution
• less common features include
  • features related to eosinophilic infiltration of the bronchial wall and asthma
    • centrilobular nodules and
    • bronchial wall thickening and/or dilatation
    • bronchiectasis
• regular and smooth interlobular septal thickening: may reflect the presence of edema secondary to cardiac involvement or eosinophilic septal infiltration
• cavitation: rare and if present other co-existing pathology should be considered, e.g. granulomatosis with polyangiitis, infection
• mediastinal lymphadenopathy is seen in less than 25% of cases

MRI

Cardiac MRI

Cardiac involvement clinically manifests in about 66% of patients and can be found in up to 92% of autopsies , they include:

• delayed myocardial enhancement is a commonly described finding; can be intramyocardial, subepicardial, or subendocardial
  • not confined to one vascular territory (cf. myocardial infarction)
• myocardial edema: high T2 signal 
• reduced left ventricular ejection fraction 

Treatment and prognosis

Corticosteroids (most commonly prednisone) are the mainstay of treatment. Patients with cardiac, renal, gastrointestinal, or CNS involvement, require additional immunosuppression (e.g. cyclosporine, azathioprine).

The condition generally has a low mortality rate compared with other systemic vasculitides . Cardiac involvement may, however, be a significant contributor to disease-related death and may occur in up to 60% of cases .

History and etymology

It was first described in 1951 by Jacob Churg and Lotte Strauss, American physicians based in New York .

Differential diagnosis

• eosinophilic pneumonia
• granulomatosis with polyangiitis
  • usually has cavitating nodules 
• pulmonary infection 

Siehe auch:

• Polyarteriitis nodosa
• Vaskulitis
• Milchglasverschattungen
• chronic eosinophilic pneumonia
• idiopathic hypereosinophilic syndrome
• pulmonale Eosinophilie
• Mikroskopische Polyangiitis
• consolidation

und weiter:

• Granulomatose mit Polyangiitis
• Ileitis terminalis
• verdickte interlobuläre Septen
• pulmonale Vaskulitis
• zentrilobuläre Lungennoduli
• chronic bilateral airspace opacification
• Carrington's disease
• Kutane leukozytoklastische Angiitis
• diffuse Alveolarblutung
• Amiodaronlunge
• segmentale arterielle Mediolyse (SAM)
• Vaskulitis des Zentralen Nervensystems
• Vaskulitis im Gastrointestinaltrakt