Epilepsy

Brain maturation and epilepsy

Authors: Dulac O, Milh M.

Eventually, glutamate and gamma-aminobutyric acid (GABA) are both excitatory; the first cortical synapses start to appear, some myelin is found in the cerebral hemispheres, and the long tracts are barely visible. The premature activation of N-methyl-D-aspartate (NMDA) transmission seems to generate neonatal myoclonic encephalopathy. Benign neonatal seizures and migrating partial seizures of infancy may result from an excessive or premature excitability in the deep layers. Benign rolandic epilepsy and continuous spikes and waves during slow sleep are associated with an excess of excitatory and inhibitory cortical synapses. West and Lennox-Gastaut syndromes are related to an age-dependent, diffuse cortical hyperexcitability; the clinical presentation depends on the age at onset, and spike synchronization is achieved by myelination. Idiopathic generalized epilepsy is driven by brain maturation, which induces a frontal hyperexcitability responsible for myoclonic-astatic seizures at an age comprised between that of infantile and juvenile myoclonic epilepsies. The extensive physiological time frame preceding the maturation of the hippocampal-neocortical system could explain the scarcity of cortical injuries resulting from a lesion in infants.

Pediatric Intracerebral Hemorrhage: Acute Symptomatic Seizures and Epilepsy

Authors: Beslow LA, Abend NS, Gindville MC, Bastian RA, Licht DJ, Smith SE, Hillis AE, Ichord RN, Jordan LC.

IMPORTANCE Seizures are believed to be common presenting symptoms in neonates and children with spontaneous intracerebral hemorrhage (ICH). However, few data are available on the epidemiology of acute symptomatic seizures or the risk for later epilepsy. OBJECTIVE To define the incidence of and explore risk factors for seizures and epilepsy in children with spontaneous ICH. Our a priori hypotheses were that younger age at presentation, cortical involvement of ICH, acute symptomatic seizures after presentation, ICH due to vascular malformation, and elevated intracranial pressure requiring urgent intervention would predict remote symptomatic seizures and epilepsy. DESIGN Prospective cohort study conducted between March 1, 2007, and January 1, 2012. SETTING Three tertiary care pediatric hospitals. PARTICIPANTS Seventy-three pediatric subjects with spontaneous ICH including 20 perinatal (≥37 weeks' gestation to 28 days) and 53 childhood subjects (>28 days to <18 years at presentation). MAIN OUTCOME MEASURES Acute symptomatic seizures (clinically evident and electrographic-only seizures within 7 days), remote symptomatic seizures, and epilepsy. RESULTS Acute symptomatic seizures occurred in 35 subjects (48%). Acute symptomatic seizures as a presenting symptom of ICH occurred in 12 perinatal (60%) and 19 childhood (36%) subjects (P = .07). Acute symptomatic seizures after presentation occurred in 7 children. Electrographic-only seizures were present in 9 of 32 subjects (28%) with continuous electroencephalogram monitoring. One-year and 2-year remote symptomatic seizure-free survival rates were 82% (95% CI, 68-90) and 67% (95% CI, 46-82), respectively. One-year and 2-year epilepsy-free survival rates were 96% (95% CI, 83-99) and 87% (95% CI, 65-95), respectively. Elevated intracranial pressure requiring acute intervention was a risk factor for seizures after presentation (P = .01; Fisher exact test), remote symptomatic seizures, and epilepsy (P = .03, and P = .04, respectively; log-rank test). CONCLUSIONS AND RELEVANCE Presenting seizures are common in perinatal and childhood ICH. Continuous electroencephalography may detect electrographic seizures in some subjects. Single remote symptomatic seizures occur in many, and development of epilepsy is estimated to occur in 13% of patients at 2 years. Elevated intracranial pressure requiring acute intervention is a risk factor for acute seizures after presentation, remote symptomatic seizures, and epilepsy.

Traumatic brain injury: Risks of epilepsy and implications for medicolegal assessment

Authors: Christensen J.

Traumatic brain injury (TBI) is a potentially preventable cause of epilepsy. Increasing incidence among army personnel and the high incidence among children and young people raise concern. This article presents a review of selected studies dealing with the risks of TBI and the risk of posttraumatic epilepsy in humans. The incidence of persons admitted to hospital with TBI has decreased in developed countries in recent years. However, there is little change in TBI-associated deaths, and the decrease in hospitalization may merely reflect that more people with head injury are cared for on an outpatient basis. It is clear that epilepsy is a frequent consequence of brain injury, even many years after the injury. However, several well-controlled studies have been unable to identify therapies that prevent the development of epilepsy after TBI. Posttraumatic epilepsy has significant implications for the affected individuals, family, and society. Despite several interventions used to prevent posttraumatic epilepsy, the only proven "intervention" to date is to prevent TBI from occurring.

Blood-brain barrier dysfunction, TGFβ signaling, and astrocyte dysfunction in epilepsy

Authors: Heinemann U, Kaufer D, Friedman A.

Brain insults, including traumatic and ischemic injuries, are frequently followed by acute seizures and delayed development of epilepsy. Dysfunction of the blood-brain barrier (BBB) is a hallmark of brain insults and is usually surrounding the core lesion. Recent studies from several laboratories confirmed that vascular pathology is involved in the development of epilepsy and demonstrate a key role for astroglia in this process. In this review, we focus on glia-related mechanisms linking vascular pathology, and specifically BBB dysfunction, to seizures and epilepsy. We summarize molecular and physiological experimental data demonstrating that the function of astrocytes is altered due to direct exposure to serum albumin, mediated by transforming growth factor beta signaling. We discuss the reported changes and their potential role in the observed hyperexcitability as well as potential implications of these findings for the future development of new diagnostic modalities and treatments to allow a full implementation of the gained knowledge for the benefit of patients with epilepsy. © 2012 Wiley Periodicals, Inc.

Neurosurgical treatment of tuberous sclerosis complex lesions

Author: Pascual-Castroviejo I.

BACKGROUND: Tuberous sclerosis complex (TSC) is an autosomal dominantly inherited syndrome. Renal disease is the main cause of death. Brain disorders are the origin of more frequent and severe problems, such as tumors, epilepsy, and mental retardation. Participation of neurosurgeons in the study and especially in the treatment of TSC patients is often required.

MATERIALS AND METHODS: Two types of pathological conditions mainly require neurosurgical interventions in TSC: subependymal giant cell astrocytomas (SGCA) and cortical tubers. SGCA are located in the cerebral region close to the foramina of Monroe, uni- or bilaterally, and originate in hamartomas that can grow slowly as well as rapidly, even suddenly, especially in cases with intratumoral cyst, causing increased intracranial pressure (ICP) with severe risk for visual loss and life. Neurosurgeons have to participate in the follow-up of the patients as soon as the risk of ICP exists to remove the tumor when the criteria of SGCA growth are present. The other intracranial lesions that require neurosurgical intervention by are the cortical tubers.

CONCLUSION: These dysplastic lesions are associated with TSC in almost the 100% of affected persons and are the cause of epilepsy in most patients. The seizures can be resistant to antiepileptic medication in many cases in which a tuber is identified as the origin of the focal seizures after functional studies, such as EEG, MR, PET, etc. In these cases, only surgical removal of the tuber and the perituberal epileptogenic foci can cure the epilepsy. Large tubers are more epileptogenic than smaller ones.

Etiologic features of newly diagnosed epilepsy: Hospital-based study of 892 consecutive patients in West China

Authors: Si Y, Liu L, Hu J, Mu J, Fang JJ, An DM, Zhao LL, Tian LY, Zhou D.

PURPOSE: We evaluated data from a large cohort of newly diagnosed epilepsy patients from the biggest epilepsy center in West China. The aim was to determine the most prevalent etiologic factors in this region.

METHODS: From May 2008 to May 2010, the clinical data of patients with newly diagnosed epilepsy were consecutively, systematically and prospectively recorded in a database. The data were analyzed according to sex, age, seizure type, etiology, and other factors.

RESULTS: The present study examined 892 patients with newly diagnosed epilepsy. Among these patients, 346 (38.8%) were confirmed as symptomatic, with the largest constituent ratio among the elderly (63.2%). In this symptomatic group, central nervous system (CNS) infections and traumatic brain injuries (TBI) were the two most common etiologies. When analyzed according to age bracket, cortical dysplasia, mesial temporal sclerosis, and CNS infection were the most frequent causes among young patients (<18 years). On the other hand, CNS infection and TBI were the two most common causes in patients between 18 and 60 years. Stroke was the most common cause of newly diagnosed symptomatic epilepsy in the elderly (>60 years).

CONCLUSIONS: More than 30% of newly diagnosed epilepsy cases were shown to be symptomatic by medical history as well as careful clinical and laboratory examination. Detailed epilepsy assessments are essential to formulate a therapeutic plan and to improve prognosis. The etiology spectrum found in this large cohort forms a comparative baseline for future studies.

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