Seizures After a Brain Injury: Can TBI Cause Epilepsy?

Yes. Traumatic brain injuries can cause seizures, and some injured people later develop post-traumatic epilepsy. The risk is higher after more serious injuries involving bleeding in or around the brain, cerebral contusions, depressed skull fractures, penetrating trauma or other structural damage to brain tissue.

Seizures sometimes occur immediately after the injury, during the first week, or months or years later. The timing is important. A seizure in the first seven days after a traumatic brain injury is generally described as an early post-traumatic seizure. A seizure occurring more than seven days after the injury is a late post-traumatic seizure and raises concern that the damaged brain has developed an ongoing susceptibility to seizures.

For the injured person and their family, this can change nearly every part of recovery. A seizure disorder can affect driving, employment, independence, medication needs, supervision and future care. Our Ontario brain injury lawyers can represent individuals whose traumatic brain injuries resulted in seizures, epilepsy and other lasting neurological consequences.

What Is a Post-Traumatic Seizure?

Seizures occur when abnormal electrical activity in the brain temporarily disrupts normal brain function. After a traumatic brain injury, injured or irritated brain tissue can become the source of that abnormal electrical activity.

Not every seizure involves collapse and violent shaking in the way we commonly think of seizures. A post-traumatic seizure could mean stiffening or jerking of the limbs and loss of consciousness, but it can also present as a blank stare, sudden unresponsiveness, repetitive movements, interruption of speech, confusion, unusual sensations or a period of unexplained memory loss.

Following a seizure, the person can experience a postictal period. During that time, they can be exhausted, confused, unable to speak normally or unable to remember what occurred. Some people develop temporary weakness on one side of the body after a seizure, known as Todd’s paresis. Because confusion, speech problems or one-sided weakness can also suggest another neurological emergency, urgent medical assessment can be required.

In severe brain injury cases, seizures can also be non-convulsive. This means that the person does not necessarily shake or collapse. Instead, seizure activity can present as continuing confusion, agitation or reduced responsiveness. In a hospital or intensive-care setting, continuous EEG monitoring can be used to identify seizures that are not obvious from observation alone.

Early Seizures and Late Seizures After a Traumatic Brain Injury

Doctors distinguish between seizures occurring in the acute period after a traumatic brain injury and seizures developing later.

Early post-traumatic seizures occur within the first seven days after the injury. They can arise from the immediate effects of trauma, including brain bleeding, contusions, swelling and disruption of normal brain function.

Late post-traumatic seizures are seizures which occur more than seven days after the injury. They are more concerning for post-traumatic epilepsy because they arise after the immediate acute period has passed and can reflect lasting changes in injured brain tissue.

A person can appear to be recovering from a traumatic brain injury and then experience a first seizure months later. That delay does not mean the seizure is unrelated to the original accident. Post-traumatic epilepsy can develop after a period of apparent stability, particularly where the initial injury involved structural brain damage.

The medical literature on epilepsy after traumatic brain injury recognizes this distinction between early and late seizures and identifies structural injuries such as subdural hematoma, brain contusion, depressed skull fracture, penetrating injury and more severe TBI as factors associated with late post-traumatic seizures.

What Is Post-Traumatic Epilepsy?

Post-traumatic epilepsy is an enduring seizure disorder caused by traumatic brain injury. It arises when the damage from the trauma renders the brain susceptible to later unprovoked seizures.

This is not the same as a seizure that occurs during the first days of hospitalization. An early seizure can arise from the immediate effects of acute injury. Post-traumatic epilepsy concerns a longer-term neurological consequence of trauma.

After a first unprovoked late seizure following a serious traumatic brain injury, the risk of another seizure can be high. Whether the person is diagnosed and treated as having post-traumatic epilepsy is a medical determination made by the treating neurologist based on the injury, seizure history, imaging, EEG evidence and recurrence risk.

For someone who had begun recovering from a collision, a late seizure can mark a major change in the medical picture. It can introduce driving restrictions, ongoing medication, safety concerns at work and continuing fear of further seizures.

Which Traumatic Brain Injuries Are More Likely to Cause Seizures?

Most concussions and head injuries do not result in seizures. The risk is greater if the trauma has caused visible structural damage to the brain or bleeding within or around it.

In serious injury cases, relevant findings can include:

• cerebral contusions, particularly injuries involving the frontal or temporal lobes;

• subdural hematoma, where blood collects between the dura and the surface of the brain;

• intraparenchymal or intracerebral hemorrhage, where bleeding occurs within brain tissue;

• traumatic subarachnoid hemorrhage, where blood is present in the space surrounding the brain;

• depressed skull fracture;

• penetrating brain injury;

• significant brain swelling or permanent loss of brain tissue;

• a more severe initial traumatic brain injury.

A cerebral contusion is injured brain tissue, often accompanied by bleeding. Where trauma damages the cerebral cortex, the injured area can later become a source of abnormal electrical activity and seizures.

CT and MRI reports can therefore become important when investigating why a person developed seizures after an accident. Findings such as hemorrhagic contusions, subdural hematoma, residual blood products, encephalomalacia or gliosis can help neurologists assess whether later seizures are connected to permanent traumatic injury.

Can a Brain Bleed Cause Seizures After an Accident?

Yes. Traumatic brain bleeds increase the risk of seizures. Blood and damaged brain tissue can irritate the surrounding cortex and disrupt normal electrical activity. In the acute period, that can contribute to seizures during hospitalization. Over time, damaged tissue can heal with permanent structural changes that leave the person at risk of later seizures.

The type and location of the bleed is important. A hemorrhagic contusion affecting the frontal or temporal lobes can be particularly relevant because it directly involves cortical brain tissue. A subdural hematoma, intraparenchymal hemorrhage or traumatic subarachnoid hemorrhage can also form part of a serious injury associated with increased seizure risk.

A prior brain bleed does not prove that every later episode was a seizure or that every seizure was caused by the accident. The medical assessment requires consideration of the original trauma, the timing of the seizure, imaging, EEG testing, neurology evidence, medication history and other possible causes.

Can Seizures Start Months or Years After a Brain Injury?

Yes. A first seizure might not occur until months or years after a traumatic brain injury.

The brain can undergo changes after trauma as damaged tissue heals and reorganizes. The process through which injured brain tissue develops a tendency to generate recurring seizures is sometimes called epileptogenesis. That process can take time.

A person with a serious brain injury could leave hospital, participate in rehabilitation and attempt to return to ordinary life before experiencing a first late seizure. When that occurs, the medical consequences can be immediate: new medication, driving restrictions, neurology follow-up, workplace limitations and safety concerns around water, heights, machinery or being alone.

The possibility of delayed seizures is particularly relevant where the original injury involved a cerebral contusion, intracranial hemorrhage, depressed skull fracture, penetrating trauma or another serious structural injury documented on imaging.

How Are Seizures After a Brain Injury Investigated?

A person who experiences a suspected seizure after traumatic brain injury can require assessment by emergency physicians, neurologists and other specialists.

The medical investigation will usually examine both the seizure itself and the underlying brain injury.

EEG testing records electrical activity in the brain. It can identify epileptiform abnormalities or continuing seizure activity. A normal routine EEG does not necessarily rule out epilepsy, because abnormal activity is not always captured during the testing period.

CT or MRI imaging can identify injuries associated with seizure risk, including hemorrhage, contusions, chronic tissue loss and residual blood products from the original injury. New imaging can also be required where a seizure raises concern about a new bleed, swelling or another acute neurological event.

Neurology assessment addresses whether the episode was a seizure, whether it is connected to the traumatic brain injury, whether antiseizure medication is required and what restrictions should apply to driving, employment or higher-risk activities.

Medical records in these cases can refer to a focal seizure, generalized tonic-clonic seizure, postictal confusion, epileptiform discharges, seizure focus, antiseizure medication or post-traumatic epilepsy. These terms can become important evidence where a brain injury has resulted in continuing seizure risk or a permanent neurological disorder.

Are Anti-Seizure Medications Given After a Serious Traumatic Brain Injury?

In some moderate and severe traumatic brain injury cases, antiseizure medication is considered during the early period after the injury. The purpose is to address the risk of seizures during the acute stage while the brain is affected by bleeding, swelling or damaged tissue.

A 2024 Neurocritical Care Society guideline considered seizure prophylaxis in adults hospitalized with moderate-to-severe traumatic brain injury. It concluded that antiseizure medication or no antiseizure medication can be used in this population, based on a weak recommendation and low-quality evidence. Where medication is used, the guideline suggests levetiracetam over phenytoin or fosphenytoin and suggests a short duration of no more than seven days.

Sometimes medication used during the initial hospitalization addresses early seizure risk. That does not mean that a person will develop epilepsy. It also does not eliminate the possibility of late seizures developing months or years after the injury.

If someone experiences a late seizure or develops post-traumatic epilepsy, longer-term treatment decisions are made by the treating neurologist based on the nature of the original injury, the seizure history, recurrence risk and response to medication.

Can Someone Drive in Ontario After a Seizure Caused by a Brain Injury?

A seizure after a traumatic brain injury can affect the injured person’s ability to drive in Ontario. The Ministry of Transportation decides whether a person is medically fit to hold a driver’s licence. A seizure or diagnosis of epilepsy can result in medical reporting and review of the person’s licence. The outcome depends on the medical circumstances and the information provided to the Ministry.

For someone recovering from a serious brain injury, the inability to drive can be a significant additional loss. It can interfere with employment, treatment attendance, independence and family responsibilities. Where the person’s occupation involves commercial driving, machinery or regular travel, the effect can be especially severe.

Current information about medical driver review is available from the Ontario Ministry of Transportation. A person who has experienced a seizure should obtain medical advice from their treating physician or neurologist about driving and other safety restrictions.

Can Post-Traumatic Epilepsy Be Part of a Catastrophic Brain Injury Claim in Ontario?

If a traumatic brain injury was caused by a motor vehicle accident, post-traumatic seizures and epilepsy can form part of the medical picture in a catastrophic impairment claim. This is particularly important if the original trauma involved intracranial hemorrhage, cerebral contusions or other structural damage to the brain. A person dealing with recurring seizures can require continuing medication, neurological follow-up, supervision, driving restrictions and substantial changes to daily life.

A seizure disorder does not automatically mean that a person meets Ontario’s catastrophic impairment definition. For an adult applying under the traumatic brain injury criterion in the Statutory Accident Benefits Schedule, the injury must show positive findings on a CT scan, MRI or another medically recognized brain diagnostic technology indicating accident-related intracranial pathology. The person must also meet the required Glasgow Outcome Scale Extended, or GOSE, outcome at the applicable time after the accident. Catastrophic injury lawyers in Ontario can help those with brain injuries navigate this process.

Similar to hormonal disorders after a traumatic brain injury, seizures are a very important part of the overall medical and functional evidence. Where a serious traumatic brain injury has resulted in post-traumatic epilepsy, the consequences can affect personal safety, independence, employability, treatment needs and future care.

Why Seizures and Post-Traumatic Epilepsy Matter in an Ontario Brain Injury Claim

Seizure disorders fundamentally change the impact of a brain injury. A person with post-traumatic epilepsy can require continuing neurological treatment, antiseizure medication, monitoring, restrictions on driving and precautions around work, water, heights, machinery or living alone. Even where seizures are controlled for periods of time, the risk of recurrence can affect decisions about employment, independence and safety.

In serious injury cases, consequences can extend far beyond medication costs. Seizures can reduce earning capacity, interfere with career plans, increase dependence on others and create future-care or supervision needs. A person who previously drove for work, operated equipment or lived independently can face substantial restrictions after developing epilepsy

.

The medical connection between the traumatic brain injury and the seizures must be properly developed. Relevant evidence can include the original ambulance and hospital records, CT and MRI imaging, neurosurgical records, EEG findings, neurology opinions, medication history, Ministry of Transportation materials and evidence showing how seizure risk has changed the person’s daily life.

Foster Injury Law is an Ontario personal injury law firm able to represent people throughout Ontario whose lives have been altered by serious brain injuries and their neurological consequences. Our Ontario brain injury lawyers can review the medical evidence, assess the available compensation and treatment claims, and help build the evidence required to show the full impact of the injury.

We offer free consultations and do not charge legal fees unless the claim is resolved in a successful manner.

Frequently Asked Questions About Seizures After Traumatic Brain Injury

Can a traumatic brain injury cause seizures?

Yes. A traumatic brain injury can cause seizures, particularly where the injury involves brain bleeding, contusions, depressed skull fracture, penetrating trauma or other structural damage. Seizures can occur shortly after the accident or develop later.

What is the difference between an early seizure and a late seizure after brain injury?

An early post-traumatic seizure occurs within the first seven days after a traumatic brain injury. A late post-traumatic seizure occurs more than seven days after the injury and is more concerning for the development of post-traumatic epilepsy.

Can a brain bleed cause epilepsy?

Traumatic brain bleeds increase the risk of later epilepsy, particularly where the injury damages cortical brain tissue or forms part of a more serious traumatic brain injury. Whether a later seizure is connected to the original hemorrhage requires medical assessment.

Can seizures start months after a car accident brain injury?

Yes. A person can experience a first late seizure months or years after a traumatic brain injury. The risk is greater where the original injury involved intracranial hemorrhage, cerebral contusions, depressed skull fracture, penetrating trauma or serious structural damage.

Does one seizure after a traumatic brain injury mean the person has epilepsy?

Not always. A seizure during the first seven days after an injury could be an acute post-traumatic seizure. A seizure arising later is more concerning for post-traumatic epilepsy because the risk of recurrence can be high. Diagnosis and treatment decisions are made by the treating neurologist.

How are seizures after a brain injury investigated?

Investigations include emergency records, neurological assessment, EEG testing, CT or MRI imaging, medication history and witness descriptions of the episode. A normal routine EEG does not necessarily rule out epilepsy.

Can a person drive in Ontario after a seizure caused by a brain injury?

A seizure can lead to medical review of an Ontario driver’s licence. The Ministry of Transportation determines whether a person is medically fit to drive based on medical reporting and supporting information from treating professionals.

Does post-traumatic epilepsy automatically qualify as catastrophic impairment in Ontario?

No. Post-traumatic epilepsy is potentially an important consequence of a catastrophic brain injury, but seizures alone do not automatically satisfy Ontario’s catastrophic impairment definition. For an adult injured in a motor vehicle accident and applying under the traumatic brain injury criterion, the SABS requires positive findings on a CT scan, MRI or another medically recognized brain diagnostic technology indicating accident-related intracranial pathology, together with the applicable GOSE requirement.

By Lane Foster, Personal Injury Lawyer

Updated May 2026