Epilepsia
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Temporal lobe epilepsy (TLE) affects brain areas beyond the temporal lobes due to connections of the hippocampi and other temporal lobe structures. Using functional connectivity magnetic resonance imaging (MRI), we determined the changes of hippocampal networks in TLE to assess for a more complete distribution of abnormality. ⋯ The observed connectivity changes in TLE indicate dysfunctional networks that underlie widespread brain involvement in TLE. There are identifiable differences in the connectivity of the hippocampi between left and right TLE.
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The contribution of glial cells, mainly astrocytes and microglia, to the pathophysiology of epilepsy is increasingly appreciated. Glia play a pivotal role in the initiation and maintenance of the central nervous system (CNS) immune response and neuronal metabolic and trophic supply. Recent clinical and experimental evidence suggests a direct relationship between epileptic activity and CNS inflammation, which is characterized by accumulation, activation, and proliferation of microglia and astrocytes. Concomitant glia-mediated mechanisms of action of several antiepileptic drugs (AEDs) have been proposed. However, their direct effects on glial cells have been rarely investigated. We aimed to investigate the effect of commonly used AEDs on glial viability, the gap junctional network, the microglial activation, and cytokine expression in an in vitro astroglia/microglia co-culture model. ⋯ CNS inflammation is characterized by a disturbance of glial cell functions. Strong microglial activation, a typical hallmark of inflammation, was induced by VPA in M5 and continued in M30 co-cultures. With regard to the direct relation between CNS inflammation and seizures, VPA seems to be unsuitable for reducing inflammatory conditions. The reverse effect was achieved after CBZ. We noticed significant microglial inactivation, after incubation of the M30 co-cultures. In conclusion, we suggest that AEDs with antiinflammatory glial features are beneficial for seizures caused by persistent brain inflammation.
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Review Practice Guideline
Cavernoma-related epilepsy: review and recommendations for management--report of the Surgical Task Force of the ILAE Commission on Therapeutic Strategies.
Cerebral cavernous malformations (CCMs) are well-defined, mostly singular lesions present in 0.4-0.9% of the population. Epileptic seizures are the most frequent symptom in patients with CCMs and have a great impact on social function and quality of life. However, patients with CCM-related epilepsy (CRE) who undergo surgical resection achieve postoperative seizure freedom in only about 75% of cases. ⋯ The Surgical Task Force of the Commission on Therapeutics of the International League Against Epilepsy (ILAE) and invited experts reviewed the pertinent literature on CRE. Definitions of definitive and probable CRE are suggested, and recommendations regarding the diagnostic evaluation and etiology-specific management of patients with CRE are made. Prospective trials are needed to determine when and how surgery should be done and to define the relations of the hemosiderin rim to the epileptogenic zone.
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Tumors, particularly low grade glioma and glioneuronal tumors, account for 25-35% of patients who are undergoing epilepsy surgery for intractable seizures. A comprehensive epilepsy evaluation including video-electroencephalography (EEG) monitoring is useful for most of these patients, to determine the optimal extent of resection for the achievement of seizure-free outcome without causing postoperative deficits. Video-EEG monitoring for patients with brain tumor should also be considered in specific situations, such as patients with new postoperative seizures or advanced tumors with unexplained mental status change.
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Review Case Reports
Depths and grids in brain tumors: implantation strategies, techniques, and complications.
Patients with intracranial mass lesions are at increased risk of intractable epilepsy even after tumor resection due to the potential epileptogenicity of lesional and perilesional tissue. Risk factors for tumoral epilepsy include tumor location, histology, and extent of tumor resection. In epilepsy that occurs after tumor resection, the epileptogenic zone often does not correspond precisely with the area of abnormality on imaging, and seizures often arise from a relatively restricted area despite widespread changes on imaging. ⋯ Subdural grids offer excellent contiguous coverage of superficial cortex and allow resection using the same craniotomy, facilitating understanding of anatomic relationships. Depth electrodes offer superior coverage of deep structures, are easier to use in cases where a previous craniotomy is present, are not associated with anatomic distortion due to brain shift, and may be associated with a lower complication rate. We review the biology of focal postoperative epilepsy and invasive diagnostic strategies for the surgical evaluation of medically refractory epilepsy in patients who have undergone resection of intracranial mass lesions.