[Changes in cerebral perfusion induced by etomidate in patients with temporal lobe epilepsy]

Epilepsy is one of the major neurological disorders, affecting roughly 0.5-2% of the world's population and approximately 20-25% of patients are resistant to medication.

To analyze the response of cerebral perfusion (assessed by SPECT) and bioelectrical activity (measured in scalp and mesial temporal region) to etomidate.

We studied 10 patients presurgically evaluated and studied by video-EEG with foramen ovale electrodes (EFO) and SPECT. Etomidate was administered (0.1 mg/kg), followed by (99)mTc-HmPAO during the study in the video-EEG + EFO.

The side-effects consisted of myoclonus (n = 7) and moderate pain (n = 2). There had been no significant respiratory or cardiovascular effects. The bioelectrical activity in the scalp consisted in a brief initial rapid activity, followed by a generalized and hypervoltaged delta pattern for several minutes. In the epileptogenic zone, there was a marked increase of interictal activity. Increased cerebral perfusion was observed in all areas studied, especially in temporal region (mesial and lateral) areas and thalamus. In the tail of the non-epileptic hippocampus, we observed the second largest increase in cerebral perfusion, the only region that is different from contralateral area.

Activation by etomidate induces a specific and repetitive response in the bioelectrical activity. In addition, cerebral perfusion changes directly related to the epileptogenic region may serve therefore as a diagnostic tool in the near future.