Cyclosporine A neurotoxicity among bone marrow transplant recipients.

Cyclosporine A (CsA) neurotoxicity is an iatrogenic disease with significant morbidity and occasional mortality. We retrospectively reviewed the cases of CsA neurotoxicity among bone marrow transplant recipients at our institution, and summarized the current literature on the subject. The neurologic presentation is varied and the neurologic manifestations are reversible, even after prolonged toxicity, in most instances. Serum CsA level is useful in evaluation, as the level is high in most instances. However, in a case of suspected neurotoxicity, withdrawal of the drug is the only way of determining presence or absence of such toxicity. The electrophysiologic studies, especially electroencephalogram (EEG), is very sensitive in identifying the problem, but lacks specificity. On the other hand, the neuroimaging studies are helpful in making a diagnosis if they show characteristic findings of hyperintense lesions affecting posterior cerebral regions on T2 weighted magnetic resonance images (MRI) or white matter hypodensities on computed tomographic (CT) scan. These lesions are probably due to breakdown of blood-brain barrier resulting in leakage of fluid in interstitial space. The breakdown could be serious enough to cause microhemorrhages that may coalesce to produce macrohemorrhages.