What is the treatment for Churg-Strauss syndrome?

Treatment of Churg-Strauss Syndrome (Eosinophilic Granulomatosis with Polyangiitis)

High-dose corticosteroids are the cornerstone of treatment for Churg-Strauss syndrome (EGPA), with additional immunosuppressive therapy required for patients with poor prognostic factors or organ-threatening disease. 1

Initial Assessment and Risk Stratification

Before initiating treatment, patients should be assessed for:

• ANCA status (positive in ~40% of cases)
• Organ involvement (particularly cardiac, renal, gastrointestinal, and neurological)
• Five-Factor Score (FFS) to determine prognosis:
  • Poor prognostic factors include: cardiac involvement, gastrointestinal involvement, renal insufficiency, proteinuria, and central nervous system involvement

Treatment Algorithm

First-Line Therapy

1. For all patients with EGPA:

   • Systemic corticosteroids: Prednisolone 1 mg/kg/day (or equivalent) initially 1, 2
   • For severe/rapidly progressive disease: IV pulse methylprednisolone (500-1000 mg daily for 3 days) followed by oral corticosteroids 1

2. For patients with FFS=0 (no poor prognostic factors):

   • Corticosteroids alone as initial therapy (93% achieve remission with this approach) 2
   • Gradual tapering over 12-18 months 1

3. For patients with FFS≥1 (poor prognostic factors) or organ/life-threatening disease:

   • Corticosteroids PLUS cyclophosphamide:
     • IV pulse cyclophosphamide (preferred over oral route) 1
     • Typically 6 pulses at 2-4 week intervals 2

Maintenance Therapy

After achieving remission (typically 3-6 months):

• For patients initially treated with cyclophosphamide:

  • Switch to azathioprine or methotrexate for 12-18 months 1
  • Continue low-dose corticosteroids (often needed long-term for asthma control) 2

• For patients initially treated with corticosteroids alone:

  • Gradual tapering of corticosteroids
  • Many patients (79%) require continued low-dose corticosteroids to control respiratory symptoms 2

Treatment of Relapses or Refractory Disease

1. For minor relapses:

   • Increase corticosteroid dose temporarily

2. For major relapses or refractory disease:

   • Add or switch immunosuppressive agent:
     • Azathioprine (2 mg/kg/day) 2, 3
     • Cyclophosphamide (if not previously used) 2
     • Rituximab (particularly for ANCA-positive patients) 1
     • Intravenous immunoglobulin (IVIG) for patients with cardiac or neural involvement unresponsive to conventional therapy (400 mg/kg daily for 5 days) 4

Special Considerations

1. Cardiac involvement:

   • Requires aggressive immunosuppression with corticosteroids plus cyclophosphamide
   • Consider IVIG for refractory cardiac disease 4
   • Regular cardiac monitoring with echocardiography

2. Neurological involvement:

   • Peripheral neuropathy may respond slowly to treatment
   • IVIG may be beneficial for refractory neuropathy 4

3. Respiratory management:

   • Continue asthma treatments (inhaled corticosteroids, bronchodilators)
   • Most patients require long-term low-dose corticosteroids for asthma control 2

4. Prophylaxis:

   • Pneumocystis jirovecii pneumonia prophylaxis with trimethoprim-sulfamethoxazole for patients on cyclophosphamide or high-dose corticosteroids
   • Bone protection for patients on long-term corticosteroids

Monitoring and Follow-up

• Regular clinical assessment for disease activity and treatment-related complications
• Blood tests: Complete blood count, renal function, liver function, inflammatory markers
• Urinalysis for proteinuria/hematuria
• Pulmonary function tests for respiratory involvement
• Cardiac evaluation if symptoms develop

Prognosis

With appropriate treatment, survival rates at 1 and 5 years are excellent (100% and 97%, respectively) 2. However, relapses are common (approximately 35% of patients), particularly during the first year of treatment 2. Long-term corticosteroid therapy is often required, which can lead to significant side effects in about 31% of patients 2.