[A teenager with acute bilateral visual loss].

BACKGROUND

The diagnosis of acute optic neuropathy is made clinically. In young patients demyelinating optic neuritis is the most common cause. However, other autoimmune diseases, infections and other non-inflammatory conditions may also cause inflammation. Careful clinical workup is necessary to establish the correct diagnosis and treatment. We describe the clinical approach to a case of acute optic neuropathy with several atypical features. The same case was published in the Journal of Neuro-Ophthalmology.

CASE PRESENTATION: A male teenager developed acute and painless bilateral visual loss. Fundoscopy revealed optic disc hypaeremia with telangiectasia. Magnetic resonance imaging demonstrated contrast enhancement of the optic nerves and chiasm without evidence of demyelinating disease. There was no visual improvement after methylprednisolone treatment. Genetic analysis for the 3 common Leber hereditary optic neuropathy (LHON) mutations was negative. However, idebenone treatment was followed by a marked improvement in visual function. Whole mitochondrial genome sequencing eventually detected a rare LHON mutation.

INTERPRETATION: There are many different causes of acute optic neuropathy. Making the correct diagnosis is important, as clinical management differs. Idebenone is now a treatment option for LHON. Whole mitochondrial genome sequencing is sometimes necessary to confirm the diagnosis.