Transient splenium lesions in presurgical epilepsy patients: incidence and pathogenesis

Transient splenium corporis callosi (SCC) lesions are related to rapid reduction of antiepileptic drugs (AEDs). The range of substances with predilection for SCC changes, their pathophysiology and their occurrence are still unknown.

In a prospective 2-year study an epilepsy-dedicated MRI protocol supplemented by DWI and ADC maps was performed after AED withdrawal for diagnostic seizure provocation in all patients with pharmacoresistant seizures locally admitted to the Department of Epileptology.

Of 891 presurgical epilepsy patients, 6 (0.7%) had SCC lesions with cytotoxic edema on DWI. Carbamazepine combined with other AEDs was administered in five of those patients. In the study period we observed identical lesions in a schizophrenic patient treated with olanzapine and citalopram, in a patient with oropharyngeal carcinoma treated with alkylating agents, and in a hypernatremic patient following neurohypophyseal granular cell tumor surgery.

Transient SCC lesions are related to rapid AED reduction but may occur in similar conditions with fluid balance alterations. We contribute further clinical data in this field to better classify the pharmaceuticals that are prone to the described cerebral cytotoxic side effects in the SCC and to clarify their incidence among presurgical epilepsy patients.