A traumatic brain injury (TBI) may result from an event, such as an accident, that damages the structure of the brain and affects how it works. For every 10 people who have a TBI, between one and five of them may have a seizure. People who have their first seizure after a brain injury — called a post-traumatic seizure (PTS) — may continue to experience seizures, potentially for the rest of their lives. This is a type of acquired structural epilepsy known as post-traumatic epilepsy (PTE).
The brain is a sensitive and complex organ that controls almost every aspect of the body — including how our bodies function and how we move. That’s why the brain, and the blood vessels and nerve cells therein, are generally well-protected by the skull (bone), three layers of meninges (membranes), and the scalp (skin). Despite these many layers of protection, a person can still sustain brain injury and trauma.
Epilepsy is a type of seizure disorder that disrupts the normal electrical activity of the brain. In 60 percent of cases, there is no known cause for a person’s epilepsy. In 13 percent of all epileptic seizures with a known cause, TBI is the epileptogenesis. “Epileptogenesis” refers to the process that occurs after a brain injury or other aggravating factor, leading to recurrent seizures or epilepsy.
In 2014, TBI resulted in almost 2.9 million emergency department visits, hospitalizations, and deaths in America. Unintentional falls and motor vehicle accidents are the most commonly reported causes of TBI among people of all ages. Falls lead to nearly half of all TBI-related hospitalizations and were the most common cause of TBI in the most-at-risk age groups: the very young and the very old. Car accidents were the second leading cause of TBI. Assaults and sports injuries are other common causes of TBI that bring people to hospital.
Several actions or processes can cause traumatic injury of the brain. A primary TBI can result from the head directly hitting another object, which can create shockwaves and damage individual neurons (nerve cells) or blood vessels in the brain. A secondary TBI can result from illness or other injury. For example, edema, or swelling of the brain, can result from illness or another type of injury and can lead to the skull squeezing or putting pressure on the brain.
TBI can be visible to the naked eye or invisible with internal bleeding or microscopic internal injuries in and around the brain. According to the Epilepsy Foundation, traumatic injury to the brain can cause:
Traumatic brain injuries are categorized based on their severity. Mild TBI and concussions comprise most TBIs reported or treated in the emergency room or hospital. Despite its name, mild TBI is a serious cause for concern and has risks of short-term, long-term, and chronic outcomes, especially in children. Typically, more severe TBIs cause concussions, but mild TBI can cause seizures as well. You can have TBI with or without a concussion, but you can’t have a concussion without TBI. Symptoms of mild TBI include changes to how a person behaves, feels, learns, and sleeps.
Moderate and severe traumatic brain injuries can cause symptoms such as loss of consciousness (coma) or memory (amnesia). These injuries may also lead to long-term or lifelong health problems that can impact all aspects of day-to-day life. In some instances, moderate or severe TBI may require follow-up, ongoing, or long-term treatment to recover. The effects of severe and moderate TBI can be similar to those of a chronic disease. People who incur mild or moderate TBI are 50 times more likely to die from seizures than those who did not sustain a brain injury.
Following a TBI, when the body is trying to heal and recover, numerous short- and long-term processes can further harm the brain’s structure and function and contribute to the risk of seizures. These include short-term issues like:
In the long term, neurodegeneration (nerve loss), nerve regeneration (nerve regrowth), and remodeling (nerves making new connections) may also contribute to neurological circuit changes. These can become areas in the brain prone to epilepsy. Depending on the TBI severity, all of these types and outcomes of head trauma can cause PTS or epilepsy
About 10 percent of people who have had a TBI experience at least one seizure related to their head injury. PTS events are categorized by how long after the injury they occur: early or late. Some people who suffer TBI have a seizuere in the hours immediately after. However, some people may experience their first seizure episode months or even years later. PTE usually features focal seizures that originate at the site of the injury. Sometimes, focal seizures can spread to both sides of the brain, leading to generalized or tonic-clonic seizures.
Early PTS events happen within the first seven days after the traumatic brain injury. Most trauma-related seizures occur in this early phase. Twenty-five percent of early PTSs happen in the first hour following TBI. About half of early TBI seizures happen in the first 24 hours. Most concerning is that approximately 10 percent of people who experience early PTSs develop status epilepticus. Status epilepticus is an abnormally long seizure or bout of back-to-back seizures that lasts longer than five minutes and poses a huge risk of lasting damage; sometimes even death. The risk of death from status epilepticus is higher among young children.
Late PTS events are seizures that happen more than a week after the TBI. Around 80 percent of people who experience one late post-traumatic seizure will have at least one more seizure during their lifetime. For those who experience at least one late PTS, 1 in 50 people will develop PTE.
If a person has multiple seizures following a TBI, they are considered to have post-traumatic epilepsy. PTE is a seizure disorder of generalized and focal seizures caused by TBI. Approximately 1 in 50 people with TBI develop epilepsy. Among people ages 15 years and older with TBI, about 1 in 10 developed epilepsy in the three years following their injury.
Generally speaking, the risk of developing PTE drops over time after the TBI. That said, the risk can exist for quite a while — up to 15 years with more severe injuries. The risk of epilepsy following TBI is lowest in adults ages 25 to 65 years old who have no previous history of epileptic seizures. Older adults are at the greatest risk of PTE.
Not all post-traumatic seizures are epileptic seizures. Data suggests that dissociative spells are more common after mild TBI where the person has very few epilepsy risk factors. Dissociative spells are non-epileptic attacks that are often misdiagnosed for refractory PTE (seizures that are not controlled despite multiple different medications). They can look like epileptic seizures but do not stem from abnormal electrical signals in the brain and do not respond to antiepileptic drugs.
Around 81 percent to 89 percent of post-traumatic dissociative spells begin within the first 12 months after TBI. In fact, 20 percent of people diagnosed with refractory PTE actually have dissociative spells. Diagnostic delays due to misdiagnosis are dangerous as prolonging proper treatment can allow for seizures to do more lasting damage, hinder disease prognosis, and impact treatment outcomes.
Anyone can experience a TBI but not everyone will experience a seizure as a result of that trauma. About 10 percent of people who have had a TBI experience at least one seizure in the first week following their head injury. Not every person that experiences a singular PTS goes on to develop PTE. Several factors weigh into a person’s risk for PTE.
Both PTS and PTE are significantly more common in young children and older adults. This is likely because rates of TBI are higher among these age groups — very young children and older adults are at greater risk of injury from falls. Older adults are more likely to be hospitalized and die from a TBI than any other age group.
Traumatic brain injuries in children, or pediatric TBI, are highly concerning because the outcomes can be much more serious. A head injury, regardless of the severity, can disrupt proper brain development. Even mild TBI increases the likelihood of learning disabilities, psychiatric diagnoses, and other psychosocial challenges. Visits to the emergency room for TBI are highest among children 4 years old and younger, most commonly due to a fall. Younger children are at the highest risk for early PTS as well as status epilepticus.
A person who has experienced TBI before has an increased risk of having PTS and developing PTE with every additional injury. Approximately 5 percent of new epilepsy diagnoses (incident cases) and 20 percent of people living with epilepsy are thought to be linked to a previous TBI. A person who has a family seizure history of epilepsy is at higher risk of having seizures as a result of brain trauma.
The more severe a person’s brain injury or trauma is, the greater their risk of seizure and of developing epilepsy. One study found that TBI requiring two or more brain surgeries (to, for instance, remove blood clots, relieve swelling, or repair damage to the brain) has a seizure risk as high as 65 percent.
People who experience penetrating injuries (those that break through the brain’s protective layers) have the highest susceptibility to seizures from TBI. One study of U.S. veterans who had sustained penetrating TBI showed more than 50 percent developed epilepsy.
Drugs and alcohol are common contributing factors to TBIs and are also often predictors of PTS. Drugs and alcohol lower a person’s seizure threshold and greatly increase the likelihood of having a seizure after a TBI. Seizures that occur when a person is under the influence of drugs or alcohol are particularly dangerous because they may be more likely to cause the person to vomit and aspirate during the seizure. Drug- and alcohol-related seizures give a person less control over their gag and cough reflexes, which can lead to aspiration (inhaling stomach contents into the lungs). Aspiration can cause serious lung damage and can be fatal.
The type of treatment a person receives for a TBI will depend on the severity of the brain injury, the symptoms, the clinical exam, and test findings. For some people with a mild TBI, rest and observation at home may be all that is necessary. For others with moderate to severe TBI, emergency hospitalization, intensive care unit care, surgery, and other life-saving stabilization of injuries and treatments may be necessary.
Each person’s individual epilepsy treatment will be determined by their doctors or treatment team. Most first-line treatment for PTE usually comprises anti-seizure or antiepileptic drugs (AEDs) such as valproate, levetiracetam, or phenytoin. Approximately one-third of epilepsy will prove hard to treat with anticonvulsant medications or be refractory. More research is needed to understand if the underlying causes of epilepsy play any role in epileptic drug resistance. People who have dissociative spells also tend to be less responsive to AEDs. If PTE proves refractory, there are other treatment options including surgery that may help.
Vagus nerve stimulation (VNS) uses an implanted neurostimulation device (akin to a pacemaker) to send regular pulses of electrical energy to the brain through the vagus nerve. VNS is often used to help treat refractory epilepsy. Some research suggests that VNS may work better for PTE than non-TBI-related epilepsy; it reduced seizures by 73 percent after two years of treatment as compared to other seizure causes which saw a 57 percent reduction from VNS.
Research has shown a correlation between mental health conditions and the risk of PTS. Data suggests that people who have psychiatric diagnoses are more likely to experience a seizure within the two years after TBI compared to those who don’t have mental health diagnoses. In addition to physical outcomes like epilepsy, traumatic brain injury can affect a person’s behavioral, cognitive, and executive functioning — as well as their capacity to make important decisions.
Both TBI and epilepsy can also take a heavy emotional toll and impact a person’s quality of life. Heightened or chronic stress and not getting an adequate amount of high-quality sleep also lower the seizure threshold. Sometimes a person can experience a late-onset PTS years after a brain injury when they are under a great amount of pressure or feeling fatigued. Drug use and alcoholism profoundly affect a person’s quality of life and can also impact epilepsy treatment. Support from a medical team that is able to recognize and treat additional mental health diagnoses is vital to proper care for PTE.
TBI can happen to anyone and at any time. It often happens when you’re least expecting it. The best way to prevent PTE is to avoid the TBI that causes it. Luckily, we know more about activities that come with TBI risk and how better to protect ourselves from dangerous injuries.
Activities that come with a higher risk of accident and injury should be undertaken with all necessary safety precautions in place. In-home safety measures should be considered based on age, risk, and other TBI risk factors. Some TBI harm-reduction or protective measures to consider include:
If you do sustain a head injury or TBI, the following can help reduce the chances of resulting PTS and PTE:
It’s helpful to know how to recognize a seizure, and what to do if a person has PTE or experiences a seizure in your presence. The objective of seizure first aid is to prevent harm or injury until the seizure is over.
If a person is having a seizure, you should do the following:
You should never try to restrain the person when they are having a seizure or otherwise stop their movements Additionally, do not try to put anything in their mouth.
Most seizures do not require emergency or immediate medical attention. They usually end naturally within a few minutes after starting. If a person has a seizure that lasts longer than five minutes, or if they have three or more seizures in a row without coming to, seek immediate medical help.
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