Seizure

Template:Short description Template:About Template:Use dmy dates Template:Infobox medical condition A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing.<ref name="Fisher2014">Template:Cite journal</ref><ref name="Fisher2005">Template:Cite journal</ref> Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, or consciousness. Symptoms vary widely. Some seizures involve subtle changes, such as brief lapses in attention or awareness (as seen in absence seizures), while others cause generalized convulsions with loss of consciousness (tonic–clonic seizures).<ref name="Berkowitz2022">Template:Citation</ref> Most seizures last less than two minutes and are followed by a postictal period of confusion, fatigue, or other symptoms.<ref name="Pottkämper2020">Template:Cite journal</ref> A seizure lasting longer than five minutes is a medical emergency known as status epilepticus.<ref name="Abou-Khalil2022">Template:Cite book</ref><ref name="Nardone2016">Template:Cite journal</ref>

Seizures are classified as provoked, when triggered by a known cause such as fever, head trauma, or metabolic imbalance, or unprovoked, when no immediate trigger is identified. Recurrent unprovoked seizures define the neurological condition epilepsy.<ref name="Fisher2014" /><ref name="Fisher2005" />

Clinical features

Seizure manifestations vary depending on the brain regions involved and the type of seizure. They may affect movement, sensation, autonomic functions, or cognitive and emotional processing. Motor symptoms can include muscle stiffening (tonic activity), rhythmic jerking (clonic activity), sudden muscle jerks (myoclonus), or sudden loss of muscle tone (atonia). Sensory disturbances may involve tingling, visual phenomena, or hallucinated sounds. Autonomic features can include changes in heart rate, respiration, or gastrointestinal sensations. Cognitive or emotional symptoms may manifest as confusion, fear, or altered perception.

Some individuals experience an aura before the seizure progresses, characterized by subjective sensations such as unusual smells, a sudden emotional shift, or feelings of déjà vu.

Most seizures last less than two minutes and are followed by a recovery phase known as the postictal state, which may include confusion, fatigue, or other neurologic symptoms.<ref name="Pottkämper2020" /> Seizures lasting more than five minutes, or occurring in rapid succession without recovery, are classified as status epilepticus, a medical emergency that can result in long-term brain injury or death.<ref name="Berkowitz2022" />

Classification

Seizures are classified according to their site of onset in the brain, clinical features, and level of awareness during the episode. In 2025, the International League Against Epilepsy (ILAE) released an updated classification to improve clarity, clinical relevance, and global applicability. The system distinguishes four major types: focal, generalized, unknown onset, and unclassified seizures. Seizures are further characterized based on whether awareness is preserved or impaired, as determined by responsiveness during the event.<ref name="Beniczky2025">Template:Cite journal</ref>

Focal seizures

Focal seizures originate within a network limited to one hemisphere of the brain.<ref name="Berg2010">Template:Cite journal</ref> They may arise from the cerebral cortex or subcortical structures. For a given seizure type, the site of onset tends to be consistent across episodes. Once initiated, the seizure may remain localized or spread to adjacent areas, and in some cases, may propagate to the opposite hemisphere (contralateral spread). Despite this potential for spread, the initial focus remains consistent.

They are subdivided based on whether consciousness is preserved or impaired, a classifier defined by awareness and responsiveness during the event:<ref name="Beniczky2025" />

• Focal preserved consciousness seizure: the person remains aware and responsive.
• Focal impaired consciousness seizure: awareness and/or responsiveness are affected.

They can manifest with motor, sensory, autonomic, cognitive, or emotional symptoms, depending on the regions involved. Some focal seizures can evolve into focal-to-bilateral tonic-clonic seizures, where abnormal brain activity spreads to both hemispheres.

Generalized seizures

Generalized seizures originate at a specific point within, and quickly spread across both hemispheres through interconnected brain networks. Generalized seizures can present in several forms, including:<ref name="Beniczky2025" />

• Absence seizures (brief lapses in awareness)
• Generalized tonic–clonic seizures (stiffening followed by rhythmic jerking)
• Other generalized seizures (a grouping term encompassing various motor and non-motor types)

Generalized tonic–clonic seizures are associated with the highest morbidity and mortality, and are the primary risk factor for sudden unexpected death in epilepsy (SUDEP).<ref>Template:Cite journal</ref>

Unknown (whether focal or generalized) seizures

When available information is insufficient to determine whether a seizure is focal or generalized, it is classified as unknown. These seizures may still be characterized based on consciousness and observable manifestations when possible.<ref name="Beniczky2025" />

Unclassified seizures

Seizures are designated as unclassified when they are recognized as epileptic events, but insufficient information is available to assign them to any specific class. This is typically a temporary designation pending further clinical evaluation.<ref name="Beniczky2025" />

Causes

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}}Seizures can occur for many reasons and are broadly classified based on whether they are provoked (acute symptomatic) or unprovoked. Identifying the underlying cause is critical for guiding treatment and assessing the risk of recurrence.<ref name="Berkowitz2022" />

Provoked seizures

Provoked seizures, also known as acute symptomatic seizures, occur in direct response to an identifiable, transient cause affecting brain function. Common causes include:

• Metabolic disturbances: such as hypoglycemia (low blood sugar), hyponatremia (low sodium), or uremia.<ref name="Abou-Khalil2022">Template:Cite book</ref><ref name="Nardone2016"/>
• Central nervous system infections: including meningitis, encephalitis, or neurocysticercosis.<ref name="Berkowitz2022" />
• Acute brain injuries: such as stroke, traumatic brain injury, or hemorrhage.<ref name="Berkowitz2022" />
• Substance-related factors: including alcohol withdrawal, drug intoxication, or medication withdrawal.<ref name="Chen2015">Template:Cite journal</ref>
• Fever: particularly in children, leading to febrile seizures.<ref name="Berkowitz2022" /><ref name="Xixis2024">Template:Citation</ref><ref name="Graves2012">Template:Cite journal</ref>

Unprovoked seizures

Unprovoked seizures occur without an immediate precipitating event. These include spontaneous seizures and reflex seizures, which are consistently triggered by specific stimuli (e.g., flashing lights) but arise due to an enduring predisposition, not a transient cause.<ref name="Berg2010" />

They typically reflect an underlying neurological predisposition and are associated with a higher risk of recurrence,<ref name="Berkowitz2022" /> meeting the diagnostic criteria for epilepsy when there are either two or more unprovoked (or reflex) seizures occurring more than 24 hours apart, or one unprovoked (or reflex) seizure with a recurrence risk of at least 60% over the next 10 years based on clinical and diagnostic findings.

Causes and contexts for unprovoked seizures include:

• Structural brain abnormalities: such as brain tumors, malformations of cortical development, and chronic lesions from prior brain trauma.<ref name="Chen2022">Template:Cite journal</ref>
• Genetic epilepsies: mutations affecting neuronal excitability or network function. Examples include Dravet syndrome, Lennox–Gastaut syndrome, and juvenile myoclonic epilepsy.<ref name="Berkowitz2022" />
• Infectious etiologies: sequelae of central nervous system infections, such as neurocysticercosis or viral encephalitis.<ref name="Vezzani2015">Template:Cite journal</ref>
• Metabolic disorders: inborn errors of metabolism or mitochondrial diseases affecting neuronal function.
• Immune-mediated epilepsies: such as autoimmune encephalitis.
• Unknown etiologies: in some cases, no clear cause is found despite thorough investigation (termed idiopathic seizures).

Mechanism

Seizures are the result of abnormal, excessive, and hypersynchronous neuronal activity in the brain. At a cellular level, they reflect a disruption of the normal balance between excitatory and inhibitory neurotransmission. Under healthy conditions, excitatory neurotransmission (mainly mediated by glutamate) and inhibitory neurotransmission (primarily via GABA) maintain cortical stability. An excess of excitation or a failure of inhibition can tip this balance, promoting hypersynchronous neuronal firing characteristic of seizures.<ref name="Tatti2016">Template:Cite journal</ref><ref name="Sarlo2021">Template:Cite journal</ref><ref name="Treiman2001">Template:Cite journal</ref> The generation of a seizure—the transition from an interictal to an ictal state—is known as ictogenesis. This process involves a cascade of physiological and network-level changes that lead to the sudden onset of pathological activity.

In provoked seizures (e.g., due to trauma, metabolic insults, or infections), acute disturbances in ionic gradients, neurotransmitter release, and neuronal membrane stability may transiently lower the threshold for seizure activity.

Brief seizures, such as absence seizures lasting 5–10 seconds, do not cause observable brain damage.<ref name="Dingledine2014">Template:Citation</ref> More prolonged seizures have a higher risk of neuronal death.<ref name="Dingledine2014" /> Prolonged and recurrent seizures, such as status epilepticus, typically cause brain damage.<ref name="Dingledine2014" /> Scarring of brain tissue (gliosis), neuronal death, and shrinking of areas of the brain (atrophy) are linked to recurrent seizures.<ref name="Dingledine2014" /><ref name="Epi2008p483">Template:Cite book</ref> These changes may lead to the development of epilepsy, in a process called epileptogenesis.<ref name="Epi2008p483" />

Clinical evaluation

The clinical evaluation after a seizure event involves confirming if the episode was epileptic in nature, determining its type and cause, and distinguishing it from other conditions that can mimic seizures. A careful clinical history and targeted investigations are essential.<ref name="Berkowitz2022" /><ref name="Abou-Khalil2022" /> The antecedent events preceding seizure onset, as well as the clinical signs observed during the episode, are critical for accurately classifying the seizure type. However, because most individuals do not recall the details of their own seizures, obtaining eyewitness accounts is often essential for an accurate diagnosis.<ref name="Berkowitz2022" /><ref name="Abou-Khalil2022" /><ref name="Rowland2022">Template:Cite journal</ref> Video recordings, when available, provide valuable supplementary information, particularly in distinguishing epileptic seizures from mimics such as psychogenic nonepileptic seizures.<ref name="Abou-Khalil2022" />

The clinical history should include:

• Preictal symptoms (auras), such as unusual sensations, déjà vu, or fear
• Ictal features, including motor activity, awareness, automatisms, or autonomic signs
• Postictal symptoms, such as confusion, drowsiness, focal weakness (Todd’s paralysis), or headache

Medical history is also important, including:

• Previous neurological insults (e.g., traumatic brain injury, stroke, central nervous system infections)
• Developmental history in children
• Family history of epilepsy
• History of febrile seizures
• Use of medications, alcohol, or illicit substances

File:Bittentongue.JPG

An individual who has bitten the tip of their tongue while having a seizure

Physical examination

A focused neurological examination can yield additional diagnostic clues, particularly soon after a seizure. Findings may include:<ref name="Abou-Khalil2022" />

• Tongue or oral injuries, such as lateral tongue bites, which strongly suggest a generalized tonic–clonic seizure, though they occur in only about one-third of cases
• Postictal focal neurological signs, such as weakness or asymmetric reflexes
• Urinary or fecal incontinence, which, while not specific, can support the diagnosis of a generalized seizure

Between seizures, the neurological examination is often normal.<ref name="Abou-Khalil2022" />

Laboratory tests

Laboratory testing is often performed in the evaluation of a new-onset seizure, particularly when a provoked cause is suspected.<ref name="Berkowitz2022" /> Common investigations include:

• Serum glucose: to rule out hypoglycemia
• Electrolytes (sodium, calcium, magnesium): to identify metabolic disturbances<ref name="Winkel2022">Template:Cite book</ref>
• Renal and hepatic function panels: to assess for systemic dysfunction
• Toxicology screening: to detect alcohol, illicit substances, or prescription drug toxicity
• Infection markers (e.g., complete blood count, inflammatory markers): when infection is suspected

Laboratory findings can help identify treatable causes of seizures and guide management decisions.

File:EEG Recording Cap.jpg

An EEG can aid in locating the focus of the epileptic seizure.

Electroencephalography (EEG)

An electroencephalogram (EEG) records electrical activity in the brain and can help support a diagnosis of epilepsy.Interictal EEG may reveal epileptiform abnormalities, such as spikes, sharp waves, or spike-and-wave discharges. However, a normal EEG does not exclude epilepsy.

In certain cases, prolonged video EEG monitoring is used to capture seizures in real time and clarify seizure type, localization, or the diagnosis when psychogenic nonepileptic seizures are suspected.

Neuroimaging

Brain imaging is recommended in most cases of new-onset unprovoked seizures to identify structural abnormalities that may predispose to epilepsy. Imaging techniques include:<ref name="Abou-Khalil2022" />

• Magnetic resonance imaging (MRI): the preferred modality for detecting cortical dysplasia, tumors, mesial temporal sclerosis, and other lesions
• Computed tomography (CT): often used in emergency settings to exclude acute hemorrhage or trauma

Differential diagnosis

Several conditions can mimic epileptic seizures and must be considered:

• Syncope (transient loss of consciousness due to cerebral hypoperfusion)
• Psychogenic nonepileptic seizures (PNES)
• Transient ischemic attacks (TIAs)
• Paroxysmal movement disorders
• Migraine aura

Differentiating these conditions from epileptic seizures relies on careful history-taking, examination, EEG findings, and, when necessary, additional cardiac, metabolic, or psychiatric evaluations.

Management

Management of seizures depends on the clinical context, including whether the seizure is isolated or part of an ongoing epileptic disorder, and whether it is provoked or unprovoked.

First aid during a seizure

Basic first aid during a tonic-clonic seizure focuses on ensuring the person's safety and preventing injury:<ref name="Asadi-Pooya2022">Template:Cite journal</ref>

• Protect the person: Gently guide them to the ground if they are standing, and remove sharp or dangerous objects nearby.
• Do not restrain movements: Allow the seizure to occur without attempting to hold the person down.
• Do not place objects in the mouth: This can cause choking or injury.
• Turn onto the side: Once convulsions stop, or if vomiting occurs, gently roll the person onto their side into the recovery position to maintain an open airway and prevent aspiration.
• Stay calm and reassure: Stay with the person until they have regained full awareness.

For nonconvulsive seizures (such as absence seizures or focal impaired consciousness seizures), active physical first aid is often unnecessary. In these cases, observers should ensure the person is safe from harm, gently guide them away from danger if needed, and offer support and reassurance as they regain awareness.

Emergency medical treatment

If a convulsive seizure lasts longer than five minutes, or if repeated seizures occur without full recovery between events, the situation is classified as status epilepticus, a medical emergency requiring rapid intervention.<ref>Template:Cite journal</ref> In emergency care, the first-line therapy for status epilepticus is the administration of a benzodiazepine to terminate the seizure, with most guidelines recommending lorazepam, midazolam or diazepam. Early benzodiazepine treatment is associated with better seizure control and improved outcomes.<ref name="Abou-Khalil2022" />

If seizures persist despite benzodiazepine administration (second-line therapy), an intravenous antiseizure medication is given. Recommended options include fosphenytoin, valproate, or levetiracetam, depending on patient-specific factors and institutional protocols.<ref name="DeWaele2013">Template:Cite journal</ref> In cases of refractory status epilepticus (seizures continuing despite first- and second-line treatments), patients typically require intensive care unit management. This involves continuous EEG monitoring and administration of anesthetic agents such as propofol or continuous infusion of midazolam.<ref name="Abou-Khalil2022" />

Prompt recognition and treatment of status epilepticus are critical to prevent permanent neuronal injury, systemic complications, and death.

Management of provoked seizures

If a seizure is provoked by an acute reversible cause, treatment focuses on addressing the underlying condition. Long-term antiseizure medications are typically not needed once the acute cause has been resolved, unless seizures recur.

Management after unprovoked seizures

After a first unprovoked seizure, management depends on assessing the risk of recurrence. Antiseizure medication may be considered after a single event if risk factors for epilepsy are identified, such as epileptiform abnormalities on EEG or structural lesions on MRI. In other cases, careful observation may be appropriate.

Long-term management of epilepsy

Template:See also Long-term management applies to individuals diagnosed with epilepsy. The goals are seizure control, minimizing adverse effects, and optimizing quality of life.<ref name="Abou-Khalil2022" />

It is recommended to start with one anti-seizure medication.<ref name="Abou-Khalil2022" /><ref name="Liu2017" /> Another may be added if one is not enough to control the seizure occurrence.<ref name="Liu2017" /> Approximately 70% of people can obtain full control with continuous use of medication.<ref name="WHO2012">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The type of medication used is based on the type of seizure.<ref name="Abou-Khalil2022" /><ref name="Liu2017" />

Anti-seizure medications may be slowly stopped after a period of time if a person has just experienced one seizure and has not had any more.<ref name="Abou-Khalil2022" /> The decision to stop anti-seizure medications should be discussed between the doctor and patient, weighing the benefits and risks.

In severe cases where seizures are uncontrolled by at least two anti-seizure medications, brain surgery can be a treatment option.<ref name="Abou-Khalil2022" /><ref name="Liu2017" /> Epilepsy surgery is especially useful for those with focal seizures where the seizures are coming from a specific part of the brain.<ref name="Liu2017">Template:Cite journal</ref> The amount of brain removed during the surgery depends on the extent of the brain involved in the seizures. It can range from just removing one lobe of the brain (temporal lobectomy) to disconnecting an entire side of the brain (hemispherectomy).<ref name="Abou-Khalil2022" /> The procedure can be curative, where seizures are eliminated.<ref name="Abou-Khalil2022" /> However, if it is not curative, it can be palliative, reducing the frequency of seizures but not eliminating them.<ref>Template:Cite journal</ref>

Other

Helmets may be used to provide protection to the head during a seizure. Some claim that seizure response dogs, a form of service dog, can predict seizures.<ref name=Doh2007/> Evidence for this, however, is poor.<ref name=Doh2007>Template:Cite journal</ref> Cannabis has also been used for the management of seizures that do not respond to anti-seizure medications. Research on its effectiveness is ongoing, but current research shows that it does reduce seizure frequency.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> A ketogenic diet or modified Atkins diet may help in those who have epilepsy who do not improve following typical treatments, with evidence for its effectiveness growing.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

Prognosis

The prognosis after a first seizure depends on the underlying cause, seizure type, and patient-specific factors. In general, individuals who experience a single provoked seizure due to an acute and reversible cause (such as hypoglycemia or head trauma) have a low risk of recurrence once the underlying issue is treated. Following a first unprovoked seizure, the risk of more seizures in the next two years is around 40%.<ref name=":0">Template:Cite journal</ref> Starting anti-seizure medications reduces recurrence of seizures by 35% within the first two years. The greatest predictors of more seizures are problems either on the EEG or on imaging of the brain. Those with normal EEG and normal physical exam following a first unprovoked seizure had less risk of recurrence in the next two years, with a risk of 25%. In adults, after 6 months of being seizure-free after a first seizure, the risk of a subsequent seizure in the next year is less than 20% regardless of treatment.<ref>Template:Cite journal</ref>

Epidemiology

Seizures are relatively common neurological events, with an estimated lifetime risk of experiencing at least one seizure approaching 8-10% within the general population. However, not all seizures are indicative of epilepsy; numerous episodes are provoked by transient factors such as infections, metabolic abnormalities, or trauma. In adults, the risk of seizure recurrence within the five years following a new-onset seizure is 35%; the risk rises to 75% in persons who have had a second seizure.<ref name="Gavvala20162">Template:Cite journal</ref> In children, the risk of seizure recurrence within the five years following a single unprovoked seizure is about 50%; the risk rises to about 80% after two unprovoked seizures.<ref>Template:Cite journal</ref> In the United States in 2011, seizures resulted in an estimated 1.6 million emergency department visits; approximately 400,000 of these visits were for new-onset seizures.<ref name="Gavvala20162" />

Global variations exist, with higher rates of seizures and epilepsy reported in regions with elevated prevalence of risk factors such as central nervous system infections, traumatic brain injury, and limited access to perinatal care. Seizures contribute significantly to the global burden of neurological disease, affecting individuals' quality of life, social participation, and access to education and employment.

History

Seizures have been recognized throughout recorded history. Early descriptions date back to ancient Mesopotamia around 2000 BCE, where seizures were often attributed to supernatural causes or demonic possession.<ref name="Ali2015">Template:Cite journal</ref><ref name="Magiorkinis2009">Template:Cite journal</ref> Similar beliefs persisted across ancient cultures, including in Egypt, India, and Greece.<ref name="Ali2015" /> In the 5th century BCE, the physician Hippocrates challenged supernatural explanations in his treatise On the Sacred Disease, proposing that epilepsy was a disorder of the brain.<ref name="Ali2015" /> However, stigma surrounding seizures remained widespread for centuries.

Society and culture

Economics

Seizures result in direct economic costs of about one billion dollars in the United States.<ref name="AFP2012">Template:Cite journal</ref> Epilepsy results in economic costs in Europe of around €15.5 billion in 2004.<ref name="NChp1">Template:Cite book</ref> In India, epilepsy is estimated to result in costs of US$1.7 billion or 0.5% of the GDP.<ref name="WHO2012"/> They make up about 1% of emergency department visits (2% for emergency departments for children) in the United States.<ref name="emcna2011">Template:Cite journal</ref>

Research

Scientific work into the prediction of epileptic seizures began in the 1970s. Several techniques and methods have been proposed, but evidence regarding their usefulness is still lacking.<ref name=":2">Template:Cite journal</ref>

Two promising areas include: (1) gene therapy,<ref name=":3">Template:Cite journal</ref> and (2) seizure detection and seizure prediction.<ref name=":4">Template:Cite journal</ref>

Gene therapy for epilepsy consists of employing vectors to deliver pieces of genetic material to areas of the brain involved in seizure onset.<ref name=":3" />

Seizure prediction is a special case of seizure detection in which the developed systems are able to issue a warning before the clinical onset of the epileptic seizure.<ref name=":2" /><ref name=":4" />

Computational neuroscience has been able to bring a new point of view on the seizures by considering the dynamical aspects.<ref name="Depannemaecker 4–8">Template:Cite journal</ref>