Makindo Medical Notes

A systemic disease with asthma and pulmonary infiltrates preceding eosinophilia, sinusitis, vasculitis, peripheral neuropathy, and a restrictive cardiomyopathy.

About

• Eosinophilic Granulomatosis with Polyangiitis (EGPA), formerly known as Churg-Strauss Syndrome, is a systemic vasculitis characterized by eosinophil-rich necrotizing granulomatous inflammation affecting small to medium-sized vessels.
• Commonly involves the respiratory system and other organs, often starting with asthma and allergic rhinitis, before progressing to systemic manifestations.

Clinical Features

• Respiratory symptoms such as asthma and allergic rhinitis, which may precede systemic symptoms by years.
• Pulmonary manifestations include transient infiltrates, often with associated dyspnea and cough.
• Skin involvement presents as palpable purpura, nodules, or ulcers due to vasculitis.
• Neurological manifestations include peripheral neuropathy, particularly mononeuritis multiplex.
• Cardiac involvement, such as restrictive cardiomyopathy and heart failure, can be a serious complication.
• Renal involvement may manifest as glomerulonephritis with proteinuria and haematuria.
• Systemic symptoms include fever, weight loss, and general malaise.

Churg-Strauss Syndrome Diagnostic Criteria

• Requires four of the following six criteria for diagnosis:
• Presence of asthma.
• Eosinophilia greater than 10% in the peripheral blood.
• Evidence of neuropathy in a vasculitis pattern (e.g., mononeuritis multiplex).
• Transient pulmonary infiltrates on imaging.
• A history of sinus disease, including chronic rhinitis or sinusitis.
• Evidence of extravascular eosinophilia on biopsy (e.g., eosinophil-rich infiltrates in tissues).

Associations

• May be seen in patients on Montelukast, a leukotriene receptor antagonist used for asthma management.
• Overlap with other eosinophilic conditions, such as eosinophilic pneumonia or chronic eosinophilic bronchitis.

Investigations

• Blood Tests:
  • FBC: Eosinophilia > 10% (1.5 × 10⁹/L).
  • U&E: Assess renal function for possible glomerulonephritis.
  • CRP/ESR: Elevated inflammatory markers.
• Autoimmune Markers:
  • ANCA (MPO) positive: Present in approximately 50% of cases.
  • ANCA (PR3) positive: Present in around 40% of cases.
• Imaging:
  • CXR: Transient pulmonary infiltrates.
  • CT Chest: May show ground-glass opacities, nodules, or bronchial wall thickening.
• Lung Function Tests:
  • PEFR: Shows reduced values consistent with worsening asthma control.
  • Spirometry: May reveal obstructive or restrictive patterns.
• Nerve Conduction Studies: Useful in assessing peripheral neuropathy, especially mononeuritis multiplex.
• Biopsy: Confirms the diagnosis with findings of necrotizing granulomas and eosinophilic infiltration.

Management

• Referral to a specialist in rheumatology or immunology for definitive diagnosis and management.
• Corticosteroids: High-dose prednisone or equivalent should be started to control inflammation and eosinophilia.
• Immunosuppressive Agents:
  • Cyclophosphamide: Used for severe disease, especially with cardiac or renal involvement.
  • Azathioprine or Methotrexate: Considered as steroid-sparing agents for maintenance therapy.
• Biologic Therapy: Mepolizumab (anti-IL5) may be considered for refractory cases with high eosinophil counts.
• Monitor for adverse effects of long-term steroid use, including osteoporosis, hyperglycemia, and immunosuppression.
• Management of comorbid asthma and allergic rhinitis with inhalers and nasal corticosteroids as needed.
• Management of cardiac complications such as restrictive cardiomyopathy with heart failure medications.

Prognosis

• Prognosis depends on the extent of organ involvement and response to treatment.
• Cardiac involvement is a significant predictor of poor prognosis and requires aggressive management.
• Early diagnosis and appropriate immunosuppressive therapy can improve outcomes and prevent irreversible damage.

References

• Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss) - NCBI Bookshelf
• Rheumatology.org - EGPA Fact Sheet
• UpToDate: Eosinophilic Granulomatosis with Polyangiitis