Epilepsia
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Review Comparative Study
Acute management of seizures in the syndromes of idiopathic generalized epilepsies.
Three of the seizure types (myoclonic, absence, and generalized tonic-clonic) and syndromes associated with idiopathic generalized or genetic epilepsies can present an acute status epilepticus picture that requires acute therapy. These are not the usual seizures observed in status epilepticus because most of these patients have secondary generalized or symptomatic generalized convulsive seizures. In this review, I discuss the unique presentation and treatment options for the acute management of seizures in the syndromes of idiopathic generalized epilepsy (IGE), with special emphasis on the seizures of status epilepticus, which persist over time or occur in a series without recovery of consciousness.
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Prevention of posttraumatic epilepsy (PTE) is of primary importance to reduce the degree of functional morbidity following traumatic brain injury (TBI). However, the effects of antiepileptic drugs (AEDs) in patients with TBI must be assessed separately in terms of prevention and control of provoked seizures (which include immediate and early posttraumatic seizures) and prevention of subsequent unprovoked seizures (late posttraumatic seizures or PTE). ⋯ The failure to influence the risk of PTE in studies of patients with TBI are similar to findings of meta-analysis of randomized clinical trials on seizure prevention in other conditions, such as febrile seizures, cerebral malaria, craniotomy, and excessive alcohol intake. For these reasons, the prophylactic use of AEDs should be short-lasting and limited to the prevention of immediate and early seizures. Chronic treatment should be considered only after a diagnosis of PTE.
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Traumatic brain injury (TBI) not only has considerable morbidity and mortality, but it is a major cause of epilepsy. We wish to determine the frequency of TBI, special groups at risk for TBI, and mortality from TBI. ⋯ TBI is a major public health problem as well as a major cause of epilepsy. If primary prevention is to be undertaken, we must understand the epidemiology of the condition. The primary causes of TBI vary by age, socioeconomic factors, and geographic region, so any planned interventions must be tailored accordingly.
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Annually in the U. S. about 500,000 head injuries are severe enough to require hospitalization. Past studies of severe head trauma estimate the risk of late seizures, which are synonymous with epilepsy, to be from 26 to 53%. ⋯ The data suggest that a limited time domain exists for VPA to intervene in the epileptogenic process, requiring the earliest possible intervention. We contend that protection from posttraumatic epileptogenesis can be conferred only if agents are given soon after trauma. A pilot study is proposed to begin to translate these findings to explore the feasibility of early VPA delivery to severe head trauma patients admitted to Kings County Hospital Center in Brooklyn, NY, a Level 1 trauma center.
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Generalized epilepsy involves abnormally synchronized activity in large-scale neuronal networks. Burst firing of action potentials is a potent mechanism for increasing neural synchrony and is thought to enhance cortical and thalamic rhythmic network activity. Absence seizures, a form of generalized epilepsy, occur in children as brief 5- to 10-s periods of behavioral arrest associated with massive 3- to 4-Hz spike-wave discharges in cortical and thalamic networks. ⋯ Can enhanced burst firing in one region of the nervous system, such as the cortex, transform the entire thalamocortical network from normal activity to spike-and-wave seizures? Enhanced burst firing in corticothalamic neurons may increase gamma-aminobutyric acid-B (GABAB) receptor activation in the thalamus, leading to the slower, more synchronous oscillations seen in spike-and-wave seizures. Does "generalized" spike-wave activity homogeneously involve the entire brain, or are there crucial nodes that are more important than others for the generation and behavioral manifestations of generalized seizures? Animal and human data suggest that so-called generalized seizures involve selective thalamocortical networks while sparing others. A greater understanding of these molecular and network mechanisms will ultimately lead to improved targeted therapies for generalized epilepsy.