What is the treatment for optic neuritis?

Treatment of Optic Neuritis

High-dose intravenous methylprednisolone at 1000 mg/day for 3 days is the first-line treatment for optic neuritis and should be initiated promptly. 1, 2

Immediate Treatment Protocol

Standard First-Line Therapy

• Administer IV methylprednisolone 1000 mg/day for 3 days, which represents the evidence-based standard according to the American Academy of Neurology 1
• This can be followed by oral prednisone taper (1 mg/kg for 11 days), though the IV component is the critical element 3
• Never use oral prednisone alone as monotherapy - this increases the risk of recurrent episodes and is contraindicated 4
• Treatment duration of 3 days is sufficient; extending to 5 or 7 days shows no additional benefit in visual recovery 5

Critical Timing Considerations

• Initiate treatment within 2 weeks of symptom onset - delays beyond this timeframe are associated with significantly poorer visual outcomes 1, 2
• Earlier treatment is more effective at preventing retinal ganglion cell death, though this is based on experimental models 6
• The landmark Optic Neuritis Treatment Trial established that IV methylprednisolone accelerates visual recovery and reduces the 2-year risk of developing multiple sclerosis (7.5% vs 16.7% with placebo) 3

Alternative Route of Administration

• Bioequivalent high-dose oral prednisone (1250 mg/day) may be considered as an alternative to IV methylprednisolone if IV access is problematic 7
• A 2018 randomized trial demonstrated non-inferiority of oral prednisone 1250 mg compared to IV methylprednisolone 1000 mg for visual recovery at 6 months 7
• This option reduces hospitalization costs and may be more convenient, though IV remains the established standard 7

Disease-Specific Treatment Modifications

Neuromyelitis Optica Spectrum Disorder (NMOSD)

• Initial treatment remains IV methylprednisolone 1000 mg/day for 3-5 days 1
• Add plasma exchange (PLEX) early if inadequate response to steroids, as NMOSD-associated optic neuritis tends to be more severe 1, 2
• Long-term immunosuppression is mandatory to prevent relapses - rituximab is preferred over azathioprine for maintenance therapy 1, 2
• Test for MOG-IgG antibodies after first recurrence, as standard MS treatments may worsen outcomes in MOG-antibody disease 1

Systemic Lupus Erythematosus (SLE)

• Use combination therapy: pulse IV methylprednisolone plus IV cyclophosphamide for SLE-associated optic neuritis 1, 2
• Visual prognosis is poorer in SLE-related cases, with only 30% maintaining visual acuity >20/25 2
• Consider anticoagulation if antiphospholipid antibodies are present and patient fails immunosuppressive therapy 1, 2

Second-Line Treatments for Refractory Cases

When to Escalate Therapy

• Plasma exchange should be initiated for severe cases with no response to IV steroids within 5-7 days 1, 2
• Rituximab is the preferred agent for refractory NMOSD-associated optic neuritis 1, 2
• Mycophenolate mofetil or azathioprine serve as alternative steroid-sparing maintenance agents 1, 2

Essential Diagnostic Workup

• Obtain MRI of brain and orbits with contrast to assess for demyelinating lesions and rule out alternative diagnoses 1, 2
• Brain MRI findings are the strongest predictor of MS risk - patients with ≥3 white matter lesions have a 5.53-fold increased risk of developing MS 3
• Visual evoked potentials can detect subclinical bilateral optic nerve involvement 1, 2

Monitoring Strategy

• Perform ophthalmological evaluations including visual acuity, visual fields, and funduscopy every 4-6 weeks initially 8
• Repeat MRI at 3-6 months to assess for new demyelinating lesions 8
• Watch for relapses during steroid taper - they occur in 50-60% of cases and require prompt re-treatment 1, 2, 8

Critical Pitfalls to Avoid

• Do not delay treatment beyond 2 weeks - this significantly worsens visual outcomes 1, 2, 8
• Never use oral prednisone as monotherapy - it increases recurrence risk compared to placebo 4, 3
• Do not assume complete recovery means no MS risk - approximately 50% will develop MS within 15 years, with highest risk in those with abnormal brain MRI 8
• Instruct patients to return immediately for new vision loss in either eye - this warrants repeat MRI and re-treatment 8

Pediatric Considerations

• Adjust methylprednisolone dosing to 30 mg/kg/day (maximum 1000 mg/day) in children 1