What is the treatment for Susac syndrome?

Treatment for Susac Syndrome

The treatment for Susac syndrome should begin with high-dose corticosteroids as the mainstay therapy, followed by additional immunosuppressive agents as needed based on response and disease severity. 1

First-Line Treatment

• High-dose corticosteroids are the cornerstone of initial treatment for Susac syndrome, typically administered as intravenous methylprednisolone 1000 mg/day for 5 days, followed by oral maintenance therapy 2
• Prompt initiation of immunosuppressive therapy is critical as delayed treatment can lead to irreversible sequelae including dementia, blindness, and hearing loss 1
• Early recognition and treatment of Susac syndrome is essential to prevent permanent cognitive, visual, and hearing impairment 3

Second-Line and Adjunctive Therapies

• Intravenous immunoglobulin (IVIG) is an important second-line or adjunctive therapy, with improvement or stabilization noted in approximately 73% of patients when used in the acute period 4
• Plasma exchange (PLEX) may be an effective alternative or adjunct for patients who do not respond adequately to steroid treatment, with improvement or stabilization reported in 89% of treated cases 4
• For maintenance therapy or steroid-sparing effects, the following agents should be considered:
  • Mycophenolate mofetil 1, 4
  • Cyclophosphamide for more severe or refractory cases 4
  • Rituximab for patients who fail conventional immunosuppressive treatments 3

Treatment Approach Based on Disease Severity

For Mild to Moderate Disease:

• Begin with oral prednisone (1 mg/kg/day) with a slow taper over several months 2
• Add mycophenolate mofetil as a steroid-sparing agent 1, 4
• Consider antiplatelet therapy (aspirin) as an adjunctive treatment 4

For Severe or Refractory Disease:

• Initiate pulse methylprednisolone (1000 mg/day for 3-5 days) followed by oral prednisone 2
• Add IVIG (2 g/kg divided over 2-5 days) 5, 4
• Consider cyclophosphamide for patients with severe encephalopathy or progressive disease despite initial treatment 4
• For cases refractory to conventional therapy, consider rituximab or even infliximab as demonstrated in case reports 3

Duration of Treatment and Monitoring

• Long-term immunosuppression is often necessary, with treatment typically continued for at least 12 months after disease stabilization 1
• Regular monitoring should include:
  • Brain MRI to assess for new lesions 1
  • Retinal fluorescein angiography and optical coherence tomography to monitor retinal involvement 1
  • Audiometry to evaluate hearing function 1, 2
• Subcutaneous immunoglobulin may be considered for maintenance therapy to reduce hospital visits and allow more flexible administration 5

Special Considerations

• The full clinical triad (encephalopathy, branch retinal artery occlusions, and sensorineural hearing loss) is present in only 13-30% of patients at initial presentation, making diagnosis challenging 1
• Treatment should not be delayed while awaiting confirmation of the full triad if Susac syndrome is strongly suspected 1
• There are currently no reliable objective immune markers to monitor disease activity during treatment, necessitating close clinical monitoring and regular imaging studies 1

Treatment Challenges

• Due to the rarity of the disease, treatment recommendations are based primarily on retrospective case series and expert opinion rather than randomized controlled trials 1
• The variable presentation and natural course of the disease may necessitate individualized treatment approaches and combinations of immunosuppressive agents 1, 3
• Early aggressive therapy may prevent irreversible organ damage, particularly in patients presenting with severe encephalopathy 1, 2