Seizures are one of the complications that may occur following a traumatic brain injury. Seizures are most frequently observed within the first week following the injury and can be seen in as many as 20% of patients with TBI. People at highest risk for TBI related seizures are those with moderate to severe brain injury, penetrating brain injuries, subdural hematomas and the young. Seizures may be obvious with uncontrolled jerking and shaking or subtle enough to only be detected by a special test called an electroencephalogram or EEG. For these reasons it is standard initial treatment for TBI patients to be placed on anti-convulsant medications immediately following the injury.
The peak time for onset of seizures is the first 48 hours following the injury. The clinical seizures, those that can be seen, occur in 5-15% of TBI patients whereas the incidence of EEG detected seizures is as high as 20%. More severe brain injuries are more likely to be associated with seizures. If the patient’s Glasgow Coma Scale is less than 8, if they experience brain swelling called cerebral edema or have an acute subdural hematoma the risk is higher. Seizures have been reported in as many as 30-40% of patients with a penetrating brain injury.
It is difficult to tell if seizures will become a long term problem, known as chronic epilepsy, for any particular patient. Patients with traumatic brain injury are at higher risk of developing chronic epilepsy than someone who has not had a brain injury. That risk is even higher if seizures occur early in the recovery. Some additional risk factors for chronic epilepsy include:
- penetrating missile injuries
- intracerebral hemorrhage
- diffuse injury
- prolonged post-traumatic amnesia
- depressed skull fracture
Early detection and intervention of conditions that contribute to seizure risk along with the use of anticonvulsants can lower the risk of post-traumatic seizures. Prompt treatment of seizures in the early stages of TBI will also reduce risk for continued seizures.