What Are Seizures?
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A seizure is a burst of excessive brain activity that can cause uncontrolled movements and abnormal sensations, emotions, and behaviors. A wide range of factors can trigger seizures, including medications, lack of sleep, genetics, infection, brain inflammation, and injury, among others. They are most common among infants and children or those over 50 years old. Overall, it’s estimated between 2.2 and 41 out of 1,000 people experience seizures in their lifetime.
Seizure symptoms vary and depend on the part of the brain affected, Two or more seizures separated by 24 hours with no identifiable cause signify epilepsy, a neurological condition characterized by recurrent seizures. Treatment options for seizures depend on their type and frequency and differ based on if they're individual seizures or epilepsy.
Types of Seizure
There are two primary types of seizure—focal and generalized—and these are categorized based on the areas of the brain that are affected. Each of these is further sorted based on the specific symptoms that arise as well as the scope of the issue.
Focal Seizure
The brain has two sides, or hemispheres. A focal seizure is a burst of irregular neuronal firing in a specific area of one of these hemispheres. Also known as partial seizures, this type is typically less severe than generalized seizures and is more prevalent in both younger and older populations.
Generalized Seizure
With generalized seizures, there are bursts of rapid and abnormal activity in both hemispheres of the brain. This type generally has a more profound and severe effect, often leading to confusion and loss of awareness, among other symptoms. Researchers have found generalized seizures to represent about 26% of epilepsy cases.
Symptoms
Seizure symptoms range in severity, varying by type and individual case. Typically, seizures last anywhere from 30 seconds to a few minutes. In rare cases, they go on for 30 minutes or longer or arrive within minutes of each other, a condition called status epilepticus. Status epilepticus is a medical emergency, as it can cause lasting brain damage or even become fatal.
Focal Seizure Symptoms
Focal seizures, which affect only one side of the brain, cause a wide range of symptoms. Clinically, these signs serve to categorize this type further. Symptoms include:
Simple focal seizure: This is characterized by involuntary twitching and changes in sensation, causing you to experience unusual smells or strange tastes in your mouth.
Complex focal seizure: More severe, complex focal seizure leads to confusion and lack of awareness. You may feel dazed or unresponsive to questions or directions.
Secondary generalized seizure: This is a seizure that starts in one part of the brain and spreads to both sides. You'll experience symptoms of simple focal seizure at first, which then become more severe.
Generalized Seizure Symptoms
Generalized seizure symptoms tend to be more severe. Like focal seizures, the effects of this type serve to further categorize it. Symptoms include:
Absence seizure: Also known as a petit mal seizure, this type primarily causes rapid blinking or periods of staring off into space. This may or may not be accompanied by involuntary twitching.
Tonic seizure: This is characterized by stiffening of the muscles in the body, typically in the arms, legs, or back.
Clonic seizure: Clonic seizure affects both sides of the body, leading to jerky movements.
Myoclonic seizure: This type causes involuntary jerkiness, usually in the upper body.
Atonic seizure: Atonic seizure causes involuntary relaxation of the muscles, leading to a drooping of the head or falls.
Tonic-clonic seizure: Also called grand mal seizure, tonic-clonic seizures have a more profound effect, causing muscle spasms in the arms and legs, stiffness in the body, and loss of consciousness.
Causes
Neurons are the messengers in your body that transmit information from your brain to your nervous system and back. Seizures occur due to sudden, rapid bursts of neuron activity. Generally, this starts in a small area before affecting larger regions of the brain. This pattern has been attributed to two brain chemicals, or neurotransmitters: glutamate, which spurs cellular activity, and gamma-aminobutyric acid (GABA), which has the opposite effect. When these are out of balance, an electrical paroxysmal depolarization shift (PDS) occurs, which causes seizure activity.
A majority of seizures are the result of epilepsy, a neurological disorder characterized by multiple seizures separated by at least 24 hours. While many cases of epilepsy are due to unknown causes, this condition may be the result of:
Genetic predisposition, particularly mutations of the SCN1A gene
Developmental brain abnormalities
Infections, such as HIV, meningitis, and encephalitis
Traumatic brain injury (TBI)
Stroke or heart attack
Brain hemorrhage (brain bleed)
Abnormal brain vessel formation
In cases of seizures that aren’t linked to epilepsy, they can be attributed to specific causes. These are called provoked seizures. Triggers for this type include:
Alcohol consumption or withdrawal
Dehydration
Missing meals
Stress
Hormonal shifts, such as during your menstrual cycle
Related:Things That Can Trigger a Seizure Even If You Don't Have Epilepsy
Risk Factors
Some populations are more at risk for developing seizures and epilepsy. Risk factors include:
Young age (children and infants)
Age over 50
History of seizures, especially in childhood
Family history of epilepsy or seizures
Dementia
History of stroke or other blood vessel disorders
How Is Seizure Diagnosed?
When it comes to diagnosis, the primary goal is to identify the type of seizure you’re having, as this influences treatment. In addition, healthcare providers need to ensure your symptoms aren’t those of other conditions, such as convulsive concussion, convulsive syncope (a sudden drop in blood pressure that causes fainting), heart arrhythmia, and movement disorders, among others.
Alongside an evaluation of medical history, there are several diagnostic tests that can be used:
Neurological testing: A series of tests are used to determine motor skills, cognitive ability, and any changes in behavior.
Blood test: Blood tests are used to screen for underlying causes of seizures, such as metabolic or genetic disorders, infections, or other conditions.
Electroencephalogram (EEG): This type of imaging assesses abnormalities in brain waves to identify what types of seizures you're having and see if antiseizure medications can treat the condition.
Magnetoencephalogram (MEG): MEG tracks magnetic currents in the brain to see if there are abnormalities on the surface of the brain, which can help plan potential surgical interventions.
Computerized tomography (CT) scan: This form of X-ray imaging can produce detailed images of different areas in the body. It can be used to detect cysts or tumors that may be at the root of your seizures.
Magnetic resonance imaging (MRI): Like CT scans, MRIs produce three-dimensional images of the brain, which can identify cysts or tumors.
Positron emission tomography (PET) scan: This is a form of imaging that assess metabolism level in regions of the brain, which is helpful for detecting epilepsy as a cause of seizures.
Treatments for Seizure
Seizures can sometimes be isolated events that don’t require treatment. However, especially in cases of epilepsy where they come back, your healthcare provider (likely a neurologist, or a doctor who specializes in conditions of the brain, spinal cord, and nervous system) will have to decide on a course of treatment.
The goal of treatment is to stop seizures from returning while ensuring that side effects are kept to a minimum. To that end, there are several approaches, including medications, changing diet, surgery, and electrical stimulation.
Medications
There are many antiseizure drugs (also known as anticonvulsants) available. Healthcare providers weigh the expected benefits with potential side effects to determine the best course of treatment for each individual case. Anticonvulsants commonly prescribed for seizure include:
Tegretol (carbamazepine)
Trileptal (oxcarbazepine)
Lamictal (lamotrigine)
Vimpat (lacosamide)
Gabitril (tiagabine)
Sabril (vigabatrin)
Topamax (topiramate)
Felbatol (felbamate)
Spritam (levetiracetam)
Gralise (gabapentin)
Lyrica (pregabalin)
Valproic (valproic acid)
Benzodiazepines may also be considered, such as Valium (diazepam), Versed (midazolam), or Ativan (lorazepam).
Dietary Interventions
Certain types of seizures can be controlled by adjusting diet. Researchers have found adopting a high-fat, low-carbohydrate diet—called a ketogenic (keto) diet—to be effective for refractory cases, where medications aren’t yielding results.
Surgery
Surgeries are typically reserved for focal seizures that are unresponsive to other types of treatment or when there’s damage to an identified area of the brain. The following surgeries have been used to treat seizures:
Lobectomy or lesionectomy: When the seizures arise from one identified area of the brain, these procedures carefully remove that area.
Multiple subpial transection (MST): If it’s unsafe to remove an affected part of the brain, this procedure involves making cuts in the epileptic focus to prevent seizures from spreading.
Corpus callosotomy: This procedure involves severing the right and left hemispheres of the brain. It is usually reserved for severe cases in children.
Hemispherectomy: In this procedure, the cortex (outer layer) of one side of the brain is removed. This is also reserved for very severe cases in children.
Thermal ablation: This procedure involves using directed heat to destroy cells causing seizures. It is much less invasive than open surgery.
Deep Brain Stimulation
Newer therapies involve the use of devices implanted in the neck and in contact with the vagus nerve in the neck. These detect when seizures are coming on and send off bursts of electricity to the brain. This helps reduce seizures by 20 to 40%. It is generally attempted alongside other therapies.
Related:How Is Epilepsy Treated?
How to Prevent Seizure
In some cases, you can prevent seizures and epilepsy. Strategies include:
Preventing TBI: Wear bicycle or motorcycle helmets, fasten seat belts, and prevent falls at home by installing railings and removing trip hazards to prevent TBI.
Exercise: Ensure you’re staying active and get enough exercise to prevent stroke and heart attack, common causes of seizure.
Emphasize a good diet: Eat a nutritious, well-balanced diet that emphasizes healthy proteins, fruits, and vegetables to prevent cardiac issues.
Quit smoking: Among other health benefits, smoking cessation reduces stroke and heart attack risk.
Get vaccinated: Keep up to date on vaccines to prevent infections, which can induce seizures.
Keep up with prenatal health: Poor health during pregnancy or during labor can cause epilepsy in the child; follow your provider’s recommendations for prenatal health.
Food safety: To prevent seizures due to certain bacterial infections, make sure to wash your hands before cooking and store food safely.
Comorbid Conditions
The effects of seizures, and especially epilepsy, can increase the chances of developing a number of conditions, although more research is needed to confirm these comorbidities and better understand the extent in which they are related. The most common identified comorbidities include:
Bone fracture: Not only do seizures increase the risk of bone fracture due to falls, some anticonvulsive drugs affect bone health. Furthermore, bones are weaker among older adults, who are at increased risk of seizures.
Attention deficit hyperactivity disorder (ADHD): ADHD is characterized by difficulty concentrating, hyperactivity, and impulsiveness. Seizures and ADHD are known to share common underlying biological mechanisms.
Depression: Depression is more common in those with epilepsy, likely due to the burden of living with the condition.
Hypertension: Hypertension, or high blood pressure, often arises alongside epilepsy. They have an inverse relationship: one is more likely to contribute to the other.
Diabetes mellitus: Diabetes is an inability of the body to digest sugars. Researchers are still investigating the connection between diabetes and seizures, which may be caused by multiple physiological factors.
Living With Seizure
The outlook for those living with seizure very much depends on the underlying cause. When the issue is related to distinct factors, such as alcohol use, the condition can often be successfully managed. However, the chances of developing a second seizure after an initial episode is between 33 to 50% within five years. This rises to a 75% chance if you’ve had multiple seizures.
Of particular concern is status epilepticus, in which seizures last for 30 or more minutes, which can cause permanent disability or death. In addition, sudden unexplained death in epilepsy (SUDEP) is a fatal condition affecting younger or middle-aged people. That said, these conditions are rare, and 70 to 80% of those with epilepsy can successfully manage their condition with proper treatment.
Especially if you or a loved one has epilepsy, living with seizures can create many challenges and significantly impact your quality of life. However, learning about the condition and seeking support or counseling can ease the burden. In addition, advocacy organizations, such as the American Epilepsy Society (AES), can provide resources and connect you to research on therapies in development.
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