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Post-traumatic epilepsy (PTE) is a form of epilepsy that results from brain damage caused by physical trauma to the brain (traumatic brain injury, abbreviated TBI). A person with PTE suffers repeated post-traumatic seizures (PTS, seizures that result from TBI) more than a week after the initial injury.〔 〕 PTE is estimated to constitute 5% of all cases of epilepsy and over 20% of cases of symptomatic epilepsy〔〔 (in which seizures are caused by an identifiable organic brain condition).〔 〕 It is not known how to predict who will develop epilepsy after TBI and who will not.〔 〕 However, the likelihood that a person will develop PTE is influenced by the severity and type of injury; for example penetrating injuries and those that involve bleeding within the brain confer a higher risk. The onset of PTE can occur within a short time of the physical trauma that causes it, or months or years after.〔 〕 People with head trauma may remain at a higher risk for seizures than the general population even decades after the injury.〔 PTE may be caused by several biochemical processes that occur in the brain after trauma, including overexcitation of brain cells and damage to brain tissues by free radicals.〔 〕 Diagnostic measures include electroencephalography (EEG) and brain imaging techniques such as magnetic resonance imaging, but these are not totally reliable. Antiepileptic drugs do not prevent the development of PTE after head injury, but may be used to treat the condition if it does occur. When medication does not work to control the seizures, surgery may be needed.〔 Modern surgical techniques for PTE have their roots in the 19th century, but trepanation (cutting a hole in the skull) may have been used for the condition in ancient cultures.〔 ==Classification== Seizures may occur after traumatic brain injury; these are known as post-traumatic seizures (PTS). However, not everyone who has post-traumatic seizures will continue to have post-traumatic epilepsy, because the latter is a chronic condition. However, the terms PTS and PTE are used interchangeably in medical literature.〔〔 〕 Seizures due to post-traumatic epilepsy are differentiated from non-epileptic post-traumatic seizures based on their cause and timing after the trauma. A person with PTE suffers late seizures, those occurring more than a week after the initial trauma.〔 Late seizures are considered to be unprovoked, while early seizures (those occurring within a week of trauma) are thought to result from direct effects of the injury. A provoked seizure is one that results from an exceptional, nonrecurring cause such as the immediate effects of trauma rather than a defect in the brain; it is not an indication of epilepsy.〔 〕 Thus for a diagnosis of PTE, seizures must be unprovoked. Disagreement exists about whether to define PTE as the occurrence of one or more late, unprovoked seizures, or whether the condition should only be diagnosed in people with two or more.〔 〕 Medical sources usually consider PTE to be present if even one unprovoked seizure occurs, but more recently it has become accepted to restrict the definition of all types of epilepsy to include only conditions in which more than one occur.〔 〕 Requiring more than one seizure for a diagnosis of PTE is more in line with the modern definition of epilepsy, but it eliminates people for whom seizures are controlled by medication after the first seizure.〔 As with other forms of epilepsy, seizure types in PTE may be partial (affecting only part of one hemisphere of the brain) or generalized (affecting both hemispheres and associated with loss of consciousness).〔 〕 In about a third of cases, people with PTE have partial seizures; these may be simple or complex.〔 In simple partial seizures, level of consciousness is not altered, while in complex partial seizures consciousness is impaired.〔 When generalized seizures occur, they may start out as partial seizures and then spread to become generalized.〔 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Post-traumatic epilepsy」の詳細全文を読む スポンサード リンク
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