What is the initial treatment for multiple sclerosis (MS) presenting with unilateral optic neuritis (single eye blindness)?

Initial Treatment for Multiple Sclerosis Presenting with Single Eye Blindness (Optic Neuritis)

The initial treatment for multiple sclerosis presenting with optic neuritis should be high-dose intravenous methylprednisolone at 1000 mg daily for 3 days, followed by an oral prednisone taper. 1

Diagnostic Approach

Before initiating treatment, confirm the diagnosis with:

• MRI of both orbits and brain with and without contrast
  • Look for T2 hyperintensity and enhancement of the optic nerve
  • Evaluate for brain demyelinating lesions that may predict MS development 2, 1
• Clinical features supporting optic neuritis:
  • Painful visual loss (pain with eye movement)
  • Reduced visual acuity
  • Afferent pupillary defect
  • Dyschromatopsia (color vision defects)
  • Central visual field defect 3

Treatment Algorithm

First-Line Treatment

1. Intravenous methylprednisolone 1000 mg daily for 3 days 1
2. Follow with oral prednisone taper (typically 1 mg/kg/day with gradual taper)
3. Initiate treatment as early as possible, ideally within the first few hours of symptom onset 1

Important Cautions

• Avoid oral prednisone alone (without prior IV methylprednisolone) at 1 mg/kg/day as it may increase the risk of recurrent optic neuritis 1, 4
• Screen for contraindications to steroid therapy:
  • Active ocular herpes simplex
  • Systemic fungal infections
  • Hepatitis B infection 1

Evidence Supporting This Approach

The Optic Neuritis Treatment Trial (ONTT) demonstrated that IV methylprednisolone followed by oral prednisone:

• Accelerates visual recovery (though final visual outcome is similar to placebo in most cases)
• May reduce the short-term risk of developing clinically definite MS within the first two years 4

The treatment effect was most pronounced in patients with abnormal brain MRI at presentation 4. High-dose corticosteroids speed recovery from relapses but don't significantly impact long-term disability 5.

For Steroid-Refractory Cases

If there is inadequate response to corticosteroids:

• Consider plasmapheresis (plasma exchange), which shows improvement in approximately 79% of steroid-refractory cases 1
• For severe cases, additional immunosuppressive options include:
  • Cyclophosphamide (particularly effective when combined with IV methylprednisolone)
  • Rituximab (especially for cases with features of neuromyelitis optica) 1

Monitoring and Follow-Up

• Assess visual acuity improvement at 8 days, 30 days, and longer-term 6
• Schedule follow-up MRI to monitor for new demyelinating lesions
• Consider disease-modifying therapy for MS if:
  • Brain MRI shows multiple demyelinating lesions
  • Patient has high risk of MS conversion 1

Prognosis

• Approximately 95% of patients with typical optic neuritis will have significant visual recovery 3
• Poor prognostic factors include:
  • Extensive MRI lesions
  • Delay in treatment initiation (>2 weeks)
  • Younger age at disease onset 1

Visual recovery typically begins within 2-3 weeks after symptom onset, even without treatment, but corticosteroids accelerate this recovery process 6, 3.