eMedicine Specialties > Neurology > Seizures and Epilepsy
Posttraumatic Epilepsy
Updated: Oct 11, 2006
Introduction
Background
Posttraumatic epilepsy (PTE) refers to a recurrent seizure disorder, the cause of which is believed to be injury to the brain. This injury can be a result of head trauma or a sequel to an operation on the brain. The term PTE must be differentiated from the term posttraumatic seizure (PTS), which signifies any seizure that occurs as a sequel to brain injury. If the seizures occur within 24 hours of the injury, they are called immediate PTSs. A PTS that occurs within 1 week of injury is termed early PTS, and a seizure that occurs more than 1 week after injury is termed late PTS. About 20% of people who have 1 late PTS never have any more, and these people should not be described as having PTE.
Pathophysiology
The mechanism by which trauma to the brain tissue leads to recurrent seizures is unknown. Cortical lesions seem important in the genesis of the epileptic activity. Early seizures are likely to have a different pathogenesis than late seizures; early PTS are thought to be a nonspecific response to the physical insult. In the pathophysiology of the PTE kindling model of epilepsy, damage by free radicals caused by iron deposition from extravasated blood and damage by excitotoxicity due to accumulation of glutamate have been postulated.
Some natural antioxidants, such as alpha-tocopherol and condensed tannins, have been demonstrated to be prophylactic for the occurrence of epileptic discharge in the iron-injected animal brain. These studies suggest that the natural antioxidants may be useful alternative medications for preventing PTE.
Frequency
United States
Although the incidence of epilepsy in the general population is estimated at 0.5-2%, the incidence of PTS for all types of head injuries is 2-2.5% in civilian populations. This incidence increases to 5% in hospitalized neurosurgical patients. When only severe head injuries (usually Glasgow Coma Scale score <9) are considered, the incidence is 10-15% for adults and 30-35% for children. The incidence of PTS is as high as 50% in military series, as these studies include many patients with penetrating head injuries. The incidence of seizures (excluding early seizures) after uncomplicated mild head injury is the same in the military population as in the general population.
International
The data above are based on studies from the United States and Europe. In Japan, the occurrence of PTE is approximately 150,000 annually; this equals 10% of all hospitalized patients with head injury and 1% of all outpatients with head injury.
Mortality/Morbidity
Approximately 80% of first PTS occur within 2 years of the injury.
Age
In the United States, the incidence of brain injury is highest among young adults; this is reflected in the incidence of PTE in the relevant age group. Early PTS are more common in children, while late PTS are more common in adults.
Clinical
History
The seizures are usually partial (focal) or generalized tonic-clonic. Often, both types coexist. Most early PTS are partial seizures, whereas most late PTS, especially when part of PTE, are generalized and either primary or secondary.
Physical
No specific findings are noted on physical examination.
Causes
By definition, PTE is a result of injury to the brain. Recent data suggest that neuroimaging and genomic information (eg, haptoglobin genotypes, apolipoprotein E levels) may be helpful in predicting an individual's risk for PTE. Early PTSs are more common in children younger than 5 years, in patients with focal neurologic deficits, and in patients with a linear or depressed skull fracture than in others.
Factors that increase the risk of PTE are as follows:
- Severity of trauma
- Penetrating head injuries
- Intracranial hematoma
- Depressed skull fracture
- Hemorrhagic contusion
- Coma lasting more than 24 hours
- Early PTS
More on Posttraumatic Epilepsy |
 Overview: Posttraumatic Epilepsy |
| Differential Diagnoses & Workup: Posttraumatic Epilepsy |
| Treatment & Medication: Posttraumatic Epilepsy |
| Follow-up: Posttraumatic Epilepsy |
| References |
| Next Page » |
References
Angeleri F, Majkowski J, Cacchio G, et al. Posttraumatic epilepsy risk factors: one-year prospective study after head injury. Epilepsia. Sep 1999;40(9):1222-30. [Medline].
Annegers JF, Hauser WA, Coan SP, et al. A population-based study of seizures after traumatic brain injuries. N Engl J Med. Jan 1 1998;338(1):20-4. [Medline].
Beghi E. Overview of studies to prevent posttraumatic epilepsy. Epilepsia. 2003;44 Suppl 10:21-6. [Medline].
Chang BS, Lowenstein DH. Practice parameter: antiepileptic drug prophylaxis in severe traumatic brain injury: report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. Jan 14 2003;60(1):10-6. [Medline].
D'Ambrosio R, Perucca E. Epilepsy after head injury. Curr Opin Neurol. Dec 2004;17(6):731-5. [Medline].
Frey LC. Epidemiology of posttraumatic epilepsy: a critical review. Epilepsia. 2003;44 Suppl 10:11-7. [Medline].
Garga N, Lowenstein DH. Posttraumatic epilepsy: a major problem in desperate need of major advances. Epilepsy Curr. Jan-Feb 2006;6(1):1-5. [Medline].
Mori A, Yokoi I, Noda Y, Willmore LJ. Natural antioxidants may prevent posttraumatic epilepsy: a proposal based on experimental animal studies. Acta Med Okayama. Jun 2004;58(3):111-8. [Medline].
Schierhout G, Roberts I. Anti-epileptic drugs for preventing seizures following acute traumatic brain injury. Cochrane Database Syst Rev. 2001;CD000173. [Medline].
Temkin NR, Haglund MM, Winn HR. Causes, prevention, and treatment of post-traumatic epilepsy. New Horiz. Aug 1995;3(3):518-22. [Medline].
Temkin NR, Dikmen SS, Wilensky AJ. A randomized, double-blind study of phenytoin for the prevention of post-traumatic seizures. N Engl J Med. Aug 23 1990;323(8):497-502. [Medline].
Temkin NR, Dikmen SS, Anderson GD, et al. Valproate therapy for prevention of posttraumatic seizures: a randomized trial. J Neurosurg. Oct 1999;91(4):593-600. [Medline].
Further Reading
Keywords
PTE, head injury, head trauma, posttraumatic seizure, PTS, traumatic brain injury, TBI
