Ethambutol Induced Optic Neuropathy

A patient with a past medical history of chronic Mycobacterium avium infection, on anti-mycobacterial medication for 5 months, presented with bilateral, painless, progressive visual loss for 1 month. Previous medical history significant for B cell lymphoma and macular degeneration. BCVA was OD: 20/150 and OS: 20/200, though we did not have access to what her baseline acuity was due to ARMD. HVF was unreliable but suggested central visual loss. OCT RNFL showed mild elevation of both optic nerves. Labs and CSF studies excluded inflammatory, infectious, nutritional and lymphoma. On MRI abnormal hyperintense T2 signal in the optic chiasm without enhancement or expansion was seen. This pointed to ethambutol optic neuropathy. Ethambutol was stopped and patient noticed improvement in vision.

Presentation Date: 03/14/2024

Issue Date: 03/29/2024