Transient lesion in the splenium related to antiepileptic drug: case report and new pathophysiological insights

Transient focal lesions in the splenium of the corpus callosum (SCC) have been associated with antiepileptic drug (AED) treatment. However, the aetiology is widely unknown. We describe a transient SCC lesion in an epilepsy patient after abrupt AED reduction. Whole head high-field diffusion tensor imaging (DTI) including fully automated quantitative fractional anisotropy (FA) analysis was used to get insight into the pathophysiology of transient SCC lesions. Our results demonstrate that a reversible loss of directional fibre organisation in the splenium, likely due to intramyelinic oedema, is the morphological correlate of transient SCC lesions. We conclude that DTI provides a highly sensitive and quantitative tool to detect subtle and transient loss of fibre integrity associated with AED treatment.