A concussion is defined as a mild traumatic brain injury (mTBI) resulting from a jolt or blow to the head that temporarily disrupts normal brain function. A seizure is a sudden, uncontrolled electrical disturbance in the brain that causes changes in behavior, movements, feelings, or consciousness. Understanding the link between these two events is important for post-injury monitoring and recovery following head trauma. This article explores the connection between a concussion and the subsequent development of seizures.
The Direct Connection Between Brain Injury and Seizures
The physical trauma from a concussion can sometimes cause a seizure by disrupting the brain’s electrical stability. The sudden mechanical force on the brain tissue can result in an abnormal discharge of neurotransmitters, the chemical messengers between nerve cells. This process leads to a temporary state of neuronal hyperexcitability, which lowers the threshold for a seizure.
While a seizure can occur following an mTBI, the overall risk is relatively low compared to injuries classified as moderate or severe traumatic brain injury (TBI). The likelihood of developing seizures increases significantly with injury severity, especially those involving skull fractures or brain bleeding. Even a single, uncomplicated concussion carries a small risk of causing a seizure, necessitating careful observation.
Seizures Occurring Soon After Injury vs. Later
Post-traumatic seizures (PTS) are categorized based on the time elapsed since the initial injury, using the seven-day mark as the standard distinction. Seizures occurring within the first seven days following the concussion are classified as Early PTS. These are considered acute symptomatic events, meaning they are a direct consequence of immediate injury effects like swelling or chemical imbalances.
The occurrence of an Early PTS does not automatically mean a person will develop a long-term seizure disorder, though it does increase the risk. Medical professionals may treat these acute seizures, but preventing them with medication has not been shown to reduce the risk of developing long-term epilepsy. For many, these acute seizures represent a temporary complication that resolves as the initial injury heals.
Seizures happening more than seven days after the initial concussion are known as Late PTS. When a person experiences recurrent, unprovoked seizures in this timeframe, the condition is diagnosed as Post-Traumatic Epilepsy (PTE). Late seizures signify a permanent change in the brain’s structure or wiring, often involving scar tissue or chronic inflammation that creates a predisposition for abnormal electrical activity.
The prognosis differs significantly between the two types. Late PTS indicates a lasting neurological change and requires ongoing management. Studies suggest that a high percentage of individuals who experience Late PTS will develop PTE. This distinction highlights why the seven-day cutoff is important in determining the likelihood of a chronic seizure disorder.
Factors That Increase the Likelihood of Post-Concussion Seizures
While a concussion is a mild injury, specific characteristics of the trauma or the patient’s health history can elevate the risk of developing a seizure. The most significant factors relate to evidence of structural damage to the brain. This includes any sign of intracranial hematoma or contusion (bleeding or bruising on the brain tissue), which can be detected on initial imaging scans.
A depressed skull fracture, where a fragment of bone is pushed inward toward the brain cavity, also represents a substantial risk factor. Any penetrating head injury, even if not initially classified as severe, increases the chance of both early and late seizures. These injuries cause direct tissue damage, a primary driver of long-term seizure risk.
An individual’s personal or family history of epilepsy or seizures can lower their threshold for a post-traumatic seizure. The location of the injury matters, as trauma involving the cerebral cortex, particularly the temporal lobe, is associated with a higher risk of developing a chronic seizure focus. Young children and adults over 65 years old may also have heightened vulnerability following a TBI.
Recognizing the Signs and Medical Response
Identifying a seizure following a concussion requires immediate attention. Signs vary widely but often include sudden confusion or disorientation, uncontrolled muscle spasms, and loss of consciousness. Other indicators may involve staring spells, unusual sensory experiences (such as strange smells), or temporary changes in vision or hearing.
Any seizure or convulsion following a head injury is considered a “red flag symptom” and necessitates an emergency medical assessment. The medical response begins with patient stabilization and involves brain imaging, such as a CT scan or MRI, to check for structural changes like bleeding or swelling. These images help rule out severe underlying injuries that may be driving the seizure activity.
Electroencephalography (EEG) monitoring may be used to analyze the brain’s electrical activity and confirm the nature of the electrical disturbance. For acute management, anti-epileptic drugs (AEDs) like phenytoin or levetiracetam are administered to prevent further early seizures, especially in patients with high-risk injuries. For those diagnosed with Post-Traumatic Epilepsy, longer-term AED therapy is prescribed to manage and reduce the frequency of future episodes.