Management of Acute Optic Neuritis
The most appropriate initial management is B) IV methylprednisolone 1000 mg daily for 3 days, which is the established first-line treatment for acute optic neuritis based on landmark trial data and current guidelines. 1, 2
Rationale for IV Methylprednisolone
High-dose intravenous methylprednisolone (1000 mg/day for 3 days) is the recommended first-line treatment because it accelerates visual recovery and provides slightly better visual outcomes at 6 months compared to placebo or oral corticosteroids. 1, 2, 3
The landmark Optic Neuritis Treatment Trial (ONTT) definitively established that:
- IV methylprednisolone speeds recovery of visual function, particularly for visual field defects (P = 0.0001) 3
- At 6 months, patients treated with IV methylprednisolone had better visual fields (P = 0.054), contrast sensitivity (P = 0.026), and color vision (P = 0.033) 3
- Treatment should be initiated promptly, as delays beyond 2 weeks are associated with poorer outcomes 1, 2
Why NOT Oral Prednisone
Oral prednisone alone is contraindicated and should never be used as monotherapy for optic neuritis. 4, 3
Critical evidence against oral prednisone:
- The ONTT showed oral prednisone (1 mg/kg/day) provided no benefit over placebo 3
- Oral prednisone actually increased the risk of recurrent optic neuritis episodes (relative risk 1.79; 95% CI 1.08-2.95) 3
- Visual outcomes with oral prednisone did not differ from placebo at any time point 3
Clinical Context of This Case
This patient's presentation is highly suggestive of demyelinating optic neuritis, likely related to multiple sclerosis given:
- CSF oligoclonal bands (indicating intrathecal inflammation) 2
- CT hyperdensity in the optic nerve region 2
- Classic triad: visual loss, relative afferent pupillary defect, and the typical demographic (young woman) 4
Treatment Protocol
Administer IV methylprednisolone 1000 mg daily for 3 days, which may be followed by a short oral prednisone taper (1 mg/kg/day for 11 days), though the taper is optional. 1, 2, 3
Higher doses up to 30 mg/kg (not exceeding 1000 mg/day) may be considered in severe cases, though 1000 mg/day is the standard dose. 1, 2
Important Caveats
MRI of the brain with contrast should be obtained urgently (if not already done with adequate sequences) to assess for white matter lesions, as their presence is the strongest predictor for developing multiple sclerosis—75% risk with lesions versus 25% without lesions at 15 years. 5, 2
Monitor for disease-modifying therapy needs: Patients with brain MRI lesions should be considered for early disease-modifying therapy to prevent progression to clinically definite MS, as there is evidence of early axonal damage in acute optic neuritis. 5
Consider plasma exchange for refractory cases: If visual function does not improve after 3-5 days of IV methylprednisolone, plasma exchange should be considered as second-line therapy. 1, 2
Test for MOG-IgG antibodies after first recurrence, as patients with MOG antibody disease may worsen with standard MS treatments and require different management strategies. 2