Status epilepticus, a continuous seizure or multiple seizures in rapid succession, is especially strongly correlated with the development of PTE; status seizures occur in 6% of all TBIs but are associated with PTE 42% of the time, and quickly halting a status seizure reduces chances of PTE development. Pathophysiology
For unknown reasons, trauma can cause changes in the brain that lead to epilepsy. There are a number of proposed mechanisms by which TBI causes PTE, more than one of which may be present in a given person. In the period between a brain injury and onset of epilepsy, brain cells may form new synapses and axons, undergo apoptosis or necrosis, and experience altered gene expression. In addition, damage to particularly vulnerable areas of the cortex such as the hippocampus may give rise to PTE.Blood that gathers in the brain after an injury may damage brain tissue and thereby cause epilepsy. Products that result from the breakdown of hemoglobin from blood may be toxic to brain tissue. The "iron hypothesis" holds that PTE is due to damage by oxygen free radicals, the formation of which is catalyzed by iron from blood. Animal experiments using rats have shown that epileptic seizures can be produced by injecting iron into the brain. Iron catalyzes the formation of hydroxyl radicals by the Haber-Weiss reaction; such free radicals damage brain cells by peroxidizing lipids in their membranes.
Post-traumatic epilepsy (PTE) is a form of acquired epilepsy that results from brain damage caused by physical trauma to the brain (traumatic brain injury, abbreviated TBI). A person with PTE experiences 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 acquired epilepsy (in which seizures are caused by an identifiable organic brain condition).It is not known 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 post-traumatic 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.