Eosinophilic granulomatosis with polyangiitis (EGPA), also known as Churg–Strauss syndrome (CSS) or allergic granulomatosis, is an extremely rare autoimmune condition that causes inflammation of small and medium-sized blood vessels (vasculitis) in persons with a history of airway allergic hypersensitivity (atopy).

• Type of systemic necrotizing vasculitis

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History

The disease was known as “Churg–Strauss syndrome“, named after Drs. Jacob Churg and Lotte Strauss who, in 1951, first published about the syndrome using the term “allergic granulomatosis” to describe it.

This condition is now called “eosinophilic granulomatosis with polyangiitis” to remove all eponyms from the vasculitides.

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Clinical features

Prodromal (allergic) stage:

• Airway inflammation: Asthma (>90% cases) and/or allergic rhinitis
  • Allergic rhinitis may cause rhinorrhea and nasal obstruction, and the formation of nasal polyps

Second (eosinophilic) stage:

• Hypereosinophilia: Causes tissue damage, most commonly to the lungs and the digestive tract
  • Weight loss, night sweats, asthma, cough, abdominal pain, and gastrointestinal bleeding. Fever and malaise may also be present

Third (vasculitic) stage:

• Hallmark of EGPA
• Can eventually lead to cell death and can be life-threatening

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Complications

Mainly due to 3rd stage:

• Abdominal complaints:
  • Peritonitis and/or ulcerations and perforations of the gastrointestinal tract
  • Acalculous cholecystitis
  • Granulomatous appendicitis
• Heart disease (M/serious, ½ of all deaths)
  • Myocarditis (due to eosinophilia/hypereosinophilia) (M/C)
  • Arteritis of coronary vessels
  • Pericardial tamponade
• Kidney complications (less common)

Diagnosis

Diagnostic criteria

American College of Rheumatology (1990) criteria:

1. Asthma
2. Eosinophilia (> 500/microliter), or hypereosinophilia (> 1,500/microliter)
3. Mononeuropathy/polyneuropathy
4. Unfixed pulmonary infiltrates
5. Paranasal sinus abnormalities
6. Histological evidence of extravascular eosinophils (biopsy)

For classification purposes, a patient shall be said to have Churg–Strauss syndrome (CSS) if at least 4 of these 6 criteria are positive.

Histopathology

Risk stratification

French Vasculitis Study Group “five-factor score”

Predicts the risk of death in Churg–Strauss syndrome using clinical presentations.

• Reduced renal function (creatinine >1.58 mg/dl or 140 µmol/l)
• Proteinuria (>1 g/24h)
• Gastrointestinal haemorrhage, infarction, or pancreatitis
• Involvement of the CNS
• Cardiomyopathy

The lack of any of these factors indicates milder case, with a five-year mortality rate of 11.9%.
The presence of one factor indicates severe disease, with a five-year mortality rate of 26%, and two or more indicate very severe disease: 46% five-year mortality rate.

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Management

• Glucocorticoids (prednisolone)
• Other immunosuppressive drugs:
  • Azathioprine
  • Cyclophosphamide