What is the initial treatment for vasculitis (Vasculitis) affecting the Central Nervous System (CNS)?

Initial Treatment for Central Nervous System Vasculitis

The initial treatment for vasculitis affecting the central nervous system (CNS) should be high-dose glucocorticoids combined with cyclophosphamide or rituximab, depending on disease severity and specific vasculitis type. 1

Classification of CNS Vasculitis

CNS vasculitis can be categorized as:

1. Primary angiitis of the CNS (PACNS) - isolated to the CNS
2. Secondary CNS vasculitis - CNS involvement as part of systemic vasculitis or due to infections

Initial Treatment Algorithm

First-Line Therapy

• Induction therapy for severe CNS vasculitis:
  • High-dose glucocorticoids: IV methylprednisolone 500-1000 mg/day for 3-5 days 1
  • PLUS one of the following immunosuppressants:
    • Cyclophosphamide: Preferred for severe disease with rapidly declining neurological function 1, 2
      • IV: 15 mg/kg every 2-3 weeks (dose adjusted for renal function)
      • OR Oral: 2 mg/kg/day (maximum 200 mg/day)
    • Rituximab: 375 mg/m² weekly for 4 weeks or 1000 mg on days 1 and 15 1, 3

Choosing Between Cyclophosphamide and Rituximab

• Favor cyclophosphamide when:

  • Severe CNS involvement with rapid neurological deterioration 1
  • Markedly reduced neurological function 2

• Favor rituximab when:

  • Fertility preservation is important 4
  • Less severe disease 1
  • Contraindications to cyclophosphamide exist 4

• Consider combination therapy:

  • For extremely severe, rapidly progressive disease, a combination of rituximab and cyclophosphamide (limited course) may be used 1

Treatment Duration and Monitoring

• Induction phase: 3-6 months 1

• Maintenance phase: After remission is achieved, transition to less toxic agents:

  • Rituximab (for maintenance): 500 mg every 6 months 1
  • OR Azathioprine: 2 mg/kg/day 1
  • OR Methotrexate: up to 25 mg/week 1

• Glucocorticoid tapering: Follow a structured tapering schedule over 3-6 months 1

  • Week 1: 1 mg/kg/day (maximum 60-80 mg/day)
  • Gradual taper to 5-10 mg/day by 6 months

Special Considerations

• Infectious vasculitis: When CNS vasculitis is due to infections (e.g., VZV, neurosyphilis), treating the underlying infection is essential 1
• HIV-associated vasculopathy: Combine antiretroviral therapy with aspirin 1
• Prophylaxis during treatment:
  • Pneumocystis jirovecii prophylaxis with trimethoprim/sulfamethoxazole for patients on cyclophosphamide 4
  • Bone protection for patients on long-term glucocorticoids 4

Monitoring Response

• Regular neurological assessment
• MRI imaging to monitor disease activity
• Laboratory monitoring:
  • Complete blood count
  • Renal and liver function tests
  • ANCA levels (if initially positive) 1

Prognosis and Treatment Response

Studies show that approximately 80-85% of patients with CNS vasculitis respond favorably to treatment with either prednisone alone or prednisone with cyclophosphamide 2. However, relapses occur in about 25-27% of patients, with higher relapse rates observed in those treated with prednisone alone 2.

Poor prognostic factors include large vessel involvement, cerebral infarcts at diagnosis, and older age at diagnosis 2. Early aggressive treatment is crucial to prevent permanent neurological damage and improve long-term outcomes.