Neurophysiologic evaluation of cyclosporine toxicity associated with bone marrow transplantation.

INTRODUCTION: Cortical blindness, a rare form of cyclosporine (CSA) neurotoxicity, has previously been described in only nine bone marrow transplant (BMT) recipients. METHODS: Our institution averages 35 allogeneic BMT's per year. In the past year we have seen two women with reversible cortical blindness secondary to CSA toxicity. RESULTS: Age (years) (Case 1; Case 2): 32; 22. Day post-BMT: 41; 50. Peak CSA level (ng/ml): 1159; 632. Both had a history of renal toxicity requiring adjustment of CSA dosage. MRI - both with diffuse while matter changes. EEG - both with moderate to severe generalized slowing. Visual evoked potentials were markedly prolonged in both. Auditory evoked potentials: minimally abnormal; normal. Somatosensory evoked potentials - both normal. Prompt improvement occurred with discontinuation of CSA. Followup neurophysiologic evaluations were normal, however structural changes remained on MRI. CONCLUSION: As neurophysiologic studies closely follow the clinical status they should be included in the evaluation and followup of CSA neurotoxicity.