Do epileptic seizures damage the brain?:

The consequences of uncontrolled epilepsy

The consequences of epilepsy can be quite severe and include shortened lifespan, excessive bodily injury, neuropsychological and psychiatric impairment, and social disability. There is evidence that seizures cause brain injury, including neuronal death and physiological dysfunction. Mortality rates are 4-7 times higher in people with medically refractory seizures, and injury rates are substantial, ranging from one per 20 person-years to as much as one per 3 person-years. Quality of life is impaired in epilepsy, and relates to seizure control. Psychosocial disabilities, including lower social interaction with reduced marriage rates and reduced employment levels, are more common in people with refractory seizures. Complete seizure control is desirable, since seizures potentially constitute a serious threat to health and well-being. Therefore, satisfactory seizure control should be defined as having no seizures. Treatment should be directed to preventing seizures whenever possible and achieving control early in the course of illness. The risks of uncontrolled seizures outweigh the risks of aggressive medical or surgical therapy.

Drug treatment of epilepsy: when does it fail and how to optimize its use?

Although modern community-based studies have shown that a majority of people with newly diagnosed epilepsy will enter long-term remission, seizures remain refractory to treatment in a substantial proportion of this population--perhaps as much as 40%. A consensus is being reached that, for operational purposes, pharmacoresistance can be suspected when two appropriately chosen, well-tolerated, first-line antiepileptic drugs (AEDs) or one monotherapy and one combination regimen have failed due to lack of efficacy. Poor prognostic factors include lack of response to the first AED, specific syndromes, symptomatic etiology, family history of epilepsy, psychiatric comorbidity, and high frequency of seizures. These observations suggest that prognosis can often be determined early in the course of the disorder. We propose a management paradigm that aims to maximize the chance of successful AED therapy, including the early use of "rational polytherapy" for patients not responding to monotherapy, and to identify efficiently patients suitable for "curative" resective surgery, in particular those with mesial temporal lobe epilepsy. An orderly approach to each epilepsy syndrome will optimize the chance of perfect seizure control and help more patients achieve a fulfilling life.

Rapid and long-term alterations of hippocampal GABAB receptors in a mouse model of temporal lobe epilepsy

Alterations of gamma-aminobutyric acid (GABA)B receptor expression have been reported in human temporal lobe epilepsy (TLE). Here, changes in regional and cellular expression of the GABAB receptor subunits R1 (GBR1) and R2 (GBR2) were investigated in a mouse model that replicates major functional and histopathological features of TLE. Adult mice received a single, unilateral injection of kainic acid (KA) into the dorsal hippocampus, and GABAB receptor immunoreactivity was analysed between 1 day and 3 months thereafter. In control mice, GBR1 and GBR2 were distributed uniformly across the dendritic layers of CA1-CA3 and dentate gyrus. In addition, some interneurons were labelled selectively for GBR1. At 1 day post-KA, staining for both GBR1 and GBR2 was profoundly reduced in CA1, CA3c and the hilus, and no interneurons were visible anymore. At later stages, the loss of GABAB receptors persisted in CA1 and CA3, whereas staining increased gradually in dentate gyrus granule cells, which become dispersed in this model. Most strikingly, a subpopulation of strongly labelled interneurons reappeared, mainly in the hilus and CA3 starting at 1 week post-KA. In double-staining experiments, these cells were selectively labelled for neuropeptide Y. The number of GBR1-positive interneurons also increased contralaterally in the hilus. The rapid KA-induced loss of GABAB receptors might contribute to epileptogenesis because of a reduction in both presynaptic control of transmitter release and postsynaptic inhibition. In turn, the long-term increase in GABAB receptors in granule cells and specific subtypes of interneurons may represent a compensatory response to recurrent seizures.