Structural consequences of status epilepticus demonstrated with serial magnetic resonance imaging.

Abstract

To investigate MRI changes during tonic-clonic and focal motor status epilepticus. Serial MRI-investigations with saggital, coronal and axial spin-echo (SE) T1-weighted 500/15 (repetition time [TR] msec/echo time [TE] msec) with and without application of gadolinium-DTPA, proton-density-SE 2100/30 and SE T2-weighted 2100/90 images. Correlation with seizure frequency and general clinical state and by using constant EEG recordings as well as video-EEG monitoring. Initially, images were normal but several days after onset of status epilepticus focal hyperintensive signal changes on T2-weighted images consistent with focal oedema were seen. The oedema produced a local mass effect as demonstrated with angiography. These changes occurred at a time when there were massive epileptic discharges registered by EEG monitoring in both cases. On subsequent images the oedema resolved but atrophy in combination with a high signal on T2-weighted images suggestive of gliosis were noted in identical regions. In the 1st case it could not completely be ruled out that the signal changes were caused by an encephalitis. However, the signal changes occurred in close time correlation with the epileptic seizure activity rendering the assumption less likely that the signal changes were caused by the encephalitis. In the 2nd case the signal changes could not be attributed to cortical dysplasia or any other condition than the epileptic activity itself. Prolonged epileptic seizure activity may cause neuronal damage associated with a typical pattern of MRI signal changes.