Two cases of bilateral amiodarone-associated optic neuropathy

Introduction: The widespread use of amiodarone is limited by its toxicity, notably to the optic nerve. We report two cases of bilateral optic nerve neuropathy due to amiodarone, and provide a detailed description of the disease.

Observations: The first case was a 59-year-old man complaining from insidious monocular loss of vision within ten months of initiating amiodarone. Funduscopy and optical coherence tomography showed bilateral optic disc edema. The second case was a 72-year-old man presenting with a decrease in visual acuity in his left eye for a month. Funduscopy showed a left optic nerve edema, and fluorescein angiography showed bilateral papillitis. In both cases, the clinical presentation was not suggestive of ischemic neuropathy, because of the preservation of visual acuity and the insidious onset. In addition, both cardiovascular and inflammatory work-up were normal. An amiodarone-associated neuropathy was suspected, and amiodarone was discontinued with the approval of the cardiologist, with complete regression of the papilledema and a stabilization of visual symptoms.

Discussion: Differentiating between amiodarone-associated optic neuropathy and anterior ischemic optic neuropathy may be complicated by the cardiovascular background of such patients. The major criterion is the absence of a severe decrease in visual acuity; other criteria are the normality of cardiovascular and inflammatory work-up, and the improvement or the absence of worsening of symptoms after discontinuation of amiodarone.

Conclusion: Amiodarone-associated neuropathy remains a diagnosis of exclusion, and requires amiodarone discontinuation, which can only be done with the approval of a cardiologist, and sometimes requires replacement therapy.