A seizure is a sudden surge of excessive brain activity that can cause uncontrolled movements and abnormal sensations, emotions, and behaviors. Many factors can trigger seizures, including medications, sleep deprivation, genetic influences, infections, brain inflammation, and injuries. Seizures are most common among infants, children, and adults over the age of 50. It is estimated that between 2.2 and 41 out of every 1,000 people experience seizures during their lifetime.

Seizure symptoms vary depending on the part of the brain affected. Two or more seizures occurring 24 hours apart without an identifiable cause signify epilepsy, a neurological disorder characterized by recurrent seizures. Treatment for seizures depends on the type and frequency of the seizures, and it differs if they are isolated incidents or part of epilepsy.

Types of Seizures

Seizures are classified into two primary types based on which areas of the brain are involved:

  • Focal Seizures:
    A focal seizure occurs when abnormal neuronal firing happens in a specific part of one hemisphere of the brain. Also called partial seizures, these tend to be less severe than generalized seizures and are common in both the young and elderly.
  • Generalized Seizures:
    Generalized seizures involve abnormal electrical activity across both hemispheres of the brain. They usually have more profound effects, including confusion and loss of awareness, and represent about a quarter of epilepsy cases.

Symptoms

Seizure symptoms range from mild to severe and vary by type and individual case. Seizures generally last from 30 seconds to a few minutes. In rare cases, they can last 30 minutes or more or occur in rapid succession, a condition known as status epilepticus, which is a medical emergency due to the risk of permanent brain damage or death.

Focal Seizure Symptoms:
Focal seizures, affecting only one side of the brain, may present with:

  • Simple focal seizures: Involuntary twitching, altered sensations, or experiencing unusual smells or tastes.
  • Complex focal seizures: Confusion, lack of awareness, and unresponsiveness to commands or questions.
  • Secondary generalized seizures: Start in one part of the brain with mild symptoms but spread and become more severe.

Generalized Seizure Symptoms:
 

Generalized seizures usually have more dramatic symptoms, including:

  • Absence seizures: Brief periods of staring or rapid blinking, sometimes with involuntary twitching.

  • Tonic seizures: Muscle stiffening, particularly in the arms, legs, or back.
  • Clonic seizures: Jerky movements on both sides of the body.
  • Myoclonic seizures: Sudden jerking movements, typically in the upper body.
  • Atonic seizures: Sudden loss of muscle tone leading to drooping or falls.
  • Tonic-clonic seizures: Intense muscle spasms, body stiffness, and loss of consciousness.

Causes

Seizures occur when neurons send out sudden, rapid bursts of signals. Normally, neurotransmitters like glutamate (which excites neurons) and GABA (which inhibits them) maintain a balance. When this balance is disrupted, abnormal electrical activity—called a paroxysmal depolarization shift—can lead to a seizure.

Many seizures are due to epilepsy, which may result from:

  • Genetic mutations
  • Developmental brain abnormalities
  • Infections like meningitis or encephalitis
  • Traumatic brain injury
  • Stroke or heart attack
  • Alzheimer’s disease
  • Brain hemorrhages
  • Abnormalities in brain blood vessels

Seizures not related to epilepsy are called provoked seizures, often triggered by factors like:

  • Alcohol use or withdrawal
  • Dehydration
  • Skipped meals
  • Stress
  • Hormonal changes, such as during menstruation

Risk Factors

Several groups have a higher risk of seizures or epilepsy, including:

  • Infants and young children
  • Adults over 50
  • Individuals with a personal history of childhood seizures
  • Those with a family history of epilepsy or seizures
  • People with dementia
  • Individuals with a history of stroke or blood vessel disorders

How Seizures Are Diagnosed

The first step in diagnosis is identifying the seizure type, as this informs treatment. Doctors also need to distinguish seizures from other conditions that can mimic them, like fainting spells or heart arrhythmias.

Diagnostic tools include:

  • Neurological exams: Assess motor skills, cognition, and behavior.
  • Blood tests: Identify metabolic, infectious, or genetic causes.
  • Electroencephalogram (EEG): Records brain wave activity to detect seizures and guide treatment.
  • Magnetoencephalogram (MEG): Tracks magnetic fields in the brain to locate abnormalities.
  • CT scans: Visualize potential structural causes like cysts or tumors.
  • MRI scans: Provide detailed images of the brain to identify tumors or other abnormalities.
  • PET scans: Measure brain metabolism to detect regions associated with epilepsy.

Treatment for Seizures

Some seizures are isolated and may not require treatment. However, in recurrent cases like epilepsy, treatment focuses on preventing seizures with minimal side effects. Options include:

Medications:
A wide range of anticonvulsant medications are available, such as:

  • Carbamazepine
  • Oxcarbazepine
  • Lamotrigine
  • Lacosamide
  • Tiagabine
  • Vigabatrin
  • Topiramate
  • Felbamate
  • Levetiracetam
  • Gabapentin
  • Pregabalin
  • Valproic acid

In some cases, benzodiazepines like diazepam, midazolam, or lorazepam are used.

Dietary Interventions:


A ketogenic diet—high in fat and low in carbohydrates—can help control seizures, particularly when medications are ineffective.

Surgery:
Surgical options include:

  • Lobectomy or lesionectomy: Removing the seizure focus.
  • Multiple subpial transection (MST): Cutting nerve fibers to prevent seizure spread without removing brain tissue.
  • Corpus callosotomy: Severing the connection between brain hemispheres, usually in severe cases.
  • Hemispherectomy: Removing a large portion of one brain hemisphere, mainly for severe cases in children.
  • Thermal ablation: Using heat to destroy seizure-causing brain tissue.

Deep Brain Stimulation:
Implantable devices can deliver electrical impulses to the brain when they detect signs of an impending seizure, helping reduce their frequency.

How to Prevent Seizures

Some seizures are preventable. Strategies include:

  • Preventing traumatic brain injury (TBI): Wearing helmets, using seat belts, and reducing fall risks at home.
  • Exercise: Maintaining physical activity reduces the risk of stroke and heart disease.
  • Healthy diet: Eating balanced meals helps prevent cardiac and metabolic conditions.
  • Quitting smoking: Reduces cardiovascular risk.
  • Vaccinations: Staying up to date to prevent infections that can lead to seizures.
  • Prenatal care: Proper care during pregnancy reduces epilepsy risk in newborns.
  • Food safety: Proper food handling helps prevent infection-induced seizures.

Comorbid Conditions

Seizures and epilepsy are associated with several other health issues, including:

  • Bone fractures: Due to falls during seizures and weakened bones from certain medications.
  • ADHD: Both conditions share overlapping neurological mechanisms.
  • Depression: Common among those living with epilepsy.
  • Hypertension: A complex relationship exists between high blood pressure and epilepsy.
  • Diabetes mellitus: Ongoing research is exploring connections between diabetes and seizure risk.

Living With Seizures

The outlook for living with seizures depends largely on the underlying cause. Seizures related to reversible factors, like alcohol use, are often manageable. After a first seizure, there is a 33% to 50% chance of another within five years, increasing to 75% after multiple seizures.

Serious complications include status epilepticus—seizures lasting over 30 minutes—and sudden unexplained death in epilepsy (SUDEP), which is rare but typically affects younger and middle-aged adults. With proper treatment, about 70% to 80% of people with epilepsy can effectively manage their condition.

Living with seizures presents challenges, but education, counseling, and support from advocacy groups like the American Epilepsy Society can make a significant difference.