A 38-year-old woman presents with progressive painless visual loss in the right eye over 3 weeks with a central scotoma. MRI shows a gadolinium-enhancing lesion of the right optic nerve without chiasmal involvement. VEP shows prolonged P100 latency in the right eye. The MOST likely diagnosis is:
- A Optic neuritis (demyelinating) ✓
- B Anterior ischemic optic neuropathy (AION)
- C Leber hereditary optic neuropathy
- D Optic nerve sheath meningioma
Explanation
Demyelinating optic neuritis in the context of multiple sclerosis presents in a young adult with subacute, painful (pain on eye movement) visual loss, central scotoma, RAPD, and color desaturation. MRI shows gadolinium enhancement of the involved optic nerve, reflecting breakdown of the blood-nerve barrier at the site of active demyelination. VEP shows prolonged but preserved P100 latency. AION presents acutely in older patients (often >50 years) without gadolinium enhancement, with altitudinal field loss and optic disc swelling. LHON is a mitochondrial disorder presenting in young males. Optic nerve sheath meningioma shows optociliary shunt vessels and a tram-track sign on CT.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.