[Transient high-intensity T2 signal in the splenium of the corpus callosum in a non-epileptic patient]

Transient splenial lesions of the corpus callosum have been mainly reported in epileptic patients. We report the case of a non-epileptic woman with bipolar affective disorder treated by oxcarbazepine which was withdrawn because of a mild hyponatremia (128 mmol/l). A confusional state followed withdrawal and the electroencephalogram was free of spike or sharp waves. Brain MRI showed a single splenial lesion of the corpus callosum revealed by a high intensity T2 signal on FLAIR and diffusion sequences. Because of a major depressive episode, twelve sessions of electroconvulsive therapy were performed and yielded clinical improvement. A second brain MRI performed 5 weeks later was normal. The relevances of this cases are the non-epileptic status of the patient, the drug incriminated (oxcarbazepine), and the normalisation of brain MRI despite electroconvulsive therapy. Different mechanisms of this brain MRI abnormality are discussed including the sudden withdraw of oxcarbazepine. Prognosis of transient splenial lesions of the corpus callosum is good. Clinicians should search for recent metabolic disorders and therapeutic modifications.