Epilepsy

An epileptic seizure is a temporary event caused by abnormal excessive or unusually synchronised electrical activity in the brain. Epilepsy describes an enduring tendency to have unprovoked seizures, not every isolated collapse or convulsion. Accurate diagnosis depends heavily on the history of what happened before, during and after each event.

What an epileptic seizure is Brain cells communicate through electrical and chemical signals. During an epileptic seizure, groups of brain cells become abnormally active in an excessive or unusually synchronised way. This temporary activity can alter awareness, sensation, movement, emotion, memory or behaviour. A seizure is an event rather than a diagnosis by itself. What epilepsy is Epilepsy is a neurological condition involving an enduring tendency to generate epileptic seizures. It is commonly diagnosed after two unprovoked seizures occurring more than 24 hours apart. A specialist can sometimes diagnose epilepsy after one unprovoked seizure when recurrence risk is high or an epilepsy syndrome is identified. The diagnosis also includes the cognitive, psychological and social effects that seizures can create. One seizure is not automatically epilepsy A single seizure can occur because of an acute illness or temporary disturbance. Some people have one unprovoked seizure and never experience another. The first event therefore requires investigation rather than an immediate lifelong label. Treatment after one seizure depends on the cause, examination, EEG, imaging and individual recurrence risk. Provoked seizures A provoked seizure is more precisely called an acute symptomatic seizure. It occurs in close association with an acute brain or body disturbance. Examples include severe hypoglycaemia, acute alcohol withdrawal, major electrolyte disturbance, acute stroke, head injury or central nervous system infection. Treating the provoking condition is central, although emergency seizure treatment may also be needed. Unprovoked seizures An unprovoked seizure does not occur because of an immediate reversible disturbance. The person can still have an underlying genetic tendency, old brain injury or structural lesion. Unprovoked does not mean that the event happened without any biological explanation. Repeated unprovoked seizures support an epilepsy diagnosis. Triggers are not the same as acute causes Sleep deprivation, stress, excess alcohol and missed medication can make seizures more likely in someone who is susceptible. They are often called triggers. Their presence does not necessarily reclassify an epileptic seizure as an acute symptomatic seizure. The specialist interprets the circumstances and underlying epilepsy together. Epilepsy can begin at any age Epilepsy can start during childhood, adolescence or adult life. Some genetic epilepsies begin during particular developmental periods. New epilepsy in later adulthood is more likely to have a structural cause such as previous stroke or another brain lesion. Age guides investigation but does not identify the cause alone. Genetic causes Some epilepsies arise mainly from genetic changes affecting brain networks or ion channels. The change may be inherited, newly occurring or not identified by current testing. Genetic epilepsy does not mean that every close relative will develop seizures. Structural causes A structural brain abnormality can create a region that generates seizures. Examples include previous stroke, traumatic brain injury, developmental malformation, tumour or scarring after infection. Finding a lesion does not prove that every later episode is epileptic. The event history, EEG and imaging pattern must fit together. Infectious, immune and metabolic causes Meningitis, encephalitis and other acute infections can provoke seizures. Autoimmune inflammation can occasionally produce new seizures or epilepsy. Severe abnormalities of glucose, sodium, calcium or other metabolic factors can also cause seizures. These causes may require urgent treatment beyond seizure control. Unknown cause For many people, testing does not identify one definite cause. The epilepsy remains real even when MRI and genetic testing are unrevealing. Future knowledge may explain mechanisms that current tests cannot detect. Classifying seizure onset Classification begins by asking where the seizure appears to start. A focal onset seizure begins within networks on one side or one region of the brain. A generalised onset seizure rapidly engages networks on both sides from the beginning. The onset remains unknown when available evidence cannot classify it confidently. Focal seizures Focal seizures can affect movement, sensation, emotion, memory or autonomic function. Possible experiences include tingling, a rising abdominal sensation, an unusual smell or sudden fear. One arm or one side of the face may jerk. Symptoms depend on the brain network involved and are not identical between people. Focal aware seizures During a focal aware seizure, the person remains aware of themselves and their surroundings. They may be unable to stop an unusual sensation or movement. An older term is simple partial seizure. Focal aware seizures still count as seizures and can affect driving regulations. Focal impaired awareness seizures During a focal impaired awareness seizure, awareness of the surroundings becomes reduced. The person may stare, respond incompletely or remember little afterwards. An older term is complex partial seizure. The event often lasts around one or two minutes, but duration varies. Automatisms Automatisms are repeated movements occurring without normal purposeful awareness. Examples include lip smacking, chewing, swallowing, picking at clothes or wandering. The same movements can occur in non epileptic conditions. Their sequence and associated awareness help the specialist interpret them. Focal to bilateral tonic clonic seizures A focal seizure can spread to involve networks on both sides of the brain. The person then develops a bilateral tonic clonic seizure. A preceding warning, head turn or one sided movement can provide evidence of focal onset. The modern term replaces the older phrase secondary generalisation. Generalised seizures Generalised seizures appear to involve networks on both sides from the beginning. They include absence, myoclonic, tonic, atonic and generalised tonic clonic seizures. A person can have more than one generalised seizure type within one epilepsy syndrome. Tonic clonic seizures During the tonic phase, awareness is lost and the body becomes stiff. During the clonic phase, repeated rhythmic jerking occurs. Breathing and colour can change temporarily, and saliva may collect around the mouth. The person is often confused, sleepy or sore afterwards. Generalised tonic clonic and bilateral tonic clonic are not identical labels A generalised tonic clonic seizure is generalised from its onset. A focal to bilateral tonic clonic seizure begins focally and then spreads. They can look similar once whole body stiffening and jerking begins. The earlier part of the event and investigation help distinguish them. Absence seizures An absence seizure causes a sudden brief interruption of awareness. The person may stop speaking, stare and then resume activity within seconds. Repeated eyelid movements can occur. Absences are more common in childhood and can be mistaken for daydreaming or inattention. Myoclonic seizures A myoclonic seizure causes a very brief shock like muscle jerk. Several jerks can occur close together, often after waking in some syndromes. Ordinary sleep starts and non epileptic muscle jerks are common. The wider pattern determines whether a jerk is epileptic. Tonic and atonic seizures A tonic seizure causes sudden sustained muscle stiffening. An atonic seizure causes sudden loss of muscle tone. Either can cause a fall and injury. Protective equipment and specialist treatment may be needed when drop attacks remain frequent. The postictal period Postictal describes the recovery period after some seizures. The person may be confused, sleepy, agitated, weak or unable to speak normally. Temporary weakness on one side is called Todd's paresis. Persistent weakness still requires urgent stroke assessment rather than assumption that it is postictal. Not every seizure includes convulsions Some seizures produce only altered awareness, unusual sensations or brief movements. A person may remain standing or appear to continue an activity. The public image of epilepsy as whole body shaking captures only part of the condition. Not every convulsion is epilepsy Fainting can include brief stiffening or jerking when blood flow to the brain falls. Functional seizures can involve prolonged shaking or unresponsiveness without epileptic electrical activity. Acute metabolic disturbances and some movement disorders can also resemble epileptic seizures. Status epilepticus Status epilepticus is a medical emergency involving a prolonged seizure or repeated seizures without adequate recovery. NICE treats generalised convulsive status epilepticus as a seizure lasting five minutes or more. The five minute threshold encourages treatment before the seizure becomes harder to stop. Non convulsive status can cause prolonged confusion or altered awareness and also needs urgent specialist assessment. Why status epilepticus is dangerous Prolonged convulsive activity can impair breathing, circulation and temperature control. It can cause injury, aspiration, metabolic disturbance and brain damage. The underlying cause may itself be life threatening. Rapid treatment improves the chance of stopping the seizure safely. Emergency management principles Emergency care begins with airway, breathing, circulation and blood glucose assessment. A prescribed individual emergency plan is followed when immediately available. A benzodiazepine is the usual first emergency medicine for convulsive status. Hospital teams use further intravenous antiseizure treatment and critical care when initial treatment fails. Seizure first aid Move dangerous objects away and cushion the person's head. Do not restrain their movements and do not put anything in their mouth. Time the seizure and stay with them. After convulsions stop, place them on their side when safe and monitor breathing until recovery. When to call 999 Call 999 when it is the person's first seizure. Call if the seizure lasts longer than usual or exceeds five minutes when the usual duration is unknown. Call when seizures repeat without recovery, serious injury occurs or breathing remains difficult. A personal care plan can give different instructions for someone with established epilepsy. Possible seizure triggers Common reported triggers include missed antiseizure medicine, sleep deprivation, illness and excess alcohol. Some people notice an association with stress or menstrual change. Many seizures have no identifiable immediate trigger. A diary can identify patterns without implying that every coincidence is causal. Alcohol Heavy drinking can disrupt sleep and lower seizure control. Abrupt withdrawal after sustained heavy use can provoke seizures and delirium. A person who may be dependent on alcohol should seek medical support before stopping suddenly. Moderation or abstinence advice should be individualised. Missed medication Missing doses can allow medicine levels to fall and increase breakthrough seizure risk. Stopping some medicines suddenly can provoke prolonged seizures. A missed dose should be managed using the product instructions or advice from a pharmacist or epilepsy team. Do not double doses unless specifically instructed. Sleep deprivation Insufficient sleep can increase seizure likelihood in many epilepsy syndromes. It can also cause faintness, poor concentration and non epileptic symptoms. Regular sleep supports seizure control but cannot replace effective medical treatment. Flashing lights Only a minority of people with epilepsy have photosensitive epilepsy. Specific flashing frequencies or high contrast patterns can provoke seizures in susceptible people. Ordinary screens are not a universal trigger. Individual testing and practical advice should avoid unnecessary restriction. Menstrual and hormonal patterns Some people notice seizures clustering at particular points in the menstrual cycle. This is sometimes called catamenial epilepsy. A diary can help identify a reproducible pattern. Treatment changes require specialist review because hormones and contraception can interact with antiseizure medicines. The eyewitness history is central A detailed account of the event is the most important diagnostic evidence. The person may not remember the episode, so witnesses can provide essential information. A safely recorded phone video can be valuable when available. The specialist examines what happened before, during and after the event. What to record before the event Useful details include posture, activity, sleep loss, illness and alcohol exposure. A warning such as déjà vu, an unusual smell or rising abdominal sensation can suggest focal onset. Feeling warm, sweaty, nauseated or light headed while standing can support vasovagal syncope. No single feature is definitive. What to record during the event Witnesses should note responsiveness, eye position, colour and breathing. They can describe stiffening, jerking, head turning and whether movements began on one side. Automatisms, duration and injuries also matter. Do not delay first aid to make a recording. What to record afterwards The specialist asks how quickly normal awareness returned. Prolonged confusion, muscle soreness or temporary weakness can support an epileptic seizure. Very rapid recovery after a brief collapse can support syncope. Neither pattern is absolute, so the whole event remains important. Initial medical assessment A first suspected seizure requires urgent specialist assessment, usually within two weeks under NICE guidance. Immediate care checks for injury, infection, pregnancy related emergencies and metabolic causes. A neurological examination and 12 lead ECG help identify alternative explanations. Blood tests are selected according to the circumstances. Electrocardiogram An ECG records the heart's electrical activity. Dangerous rhythm disorders can cause sudden loss of consciousness with jerking movements. An ECG cannot diagnose epilepsy. It is included because cardiac syncope can be mistaken for a seizure and may require urgent treatment. Electroencephalogram An electroencephalogram is shortened to EEG. Scalp electrodes record electrical activity generated by brain networks during the test. Epileptiform discharges can support epilepsy and help classify seizure type or syndrome. An EEG does not record every brain cell and is not a direct scan of brain structure. A normal EEG does not exclude epilepsy Epileptiform activity can be intermittent and absent during a short routine recording. NICE explicitly advises not using EEG to exclude epilepsy. A sleep deprived or ambulatory EEG may increase useful recording time when uncertainty remains. The diagnosis still depends primarily on the clinical event. An abnormal EEG does not diagnose every event Some people without seizures have non specific or epileptiform EEG findings. Movement, muscle activity and technical artefact can also create confusing patterns. The result must match the history and be interpreted by appropriately trained professionals. Timing of EEG When EEG is requested after a first seizure, NICE advises performing it as soon as possible. The ideal target is within 72 hours. This timing can increase the chance of detecting informative abnormalities. It does not make delayed testing useless. Brain imaging MRI provides detailed images of brain structure. NICE offers epilepsy protocol MRI to most people diagnosed with epilepsy unless a recognised generalised or self limited syndrome makes structural imaging unnecessary. CT is used when MRI is contraindicated or urgent imaging is needed. Imaging can identify a cause but cannot confirm that every reported event was epileptic. Blood tests and other investigations Blood glucose and electrolytes can identify acute metabolic causes. Pregnancy testing may affect diagnosis, imaging and medicine decisions where relevant. Toxicology, infection testing or lumbar puncture is used only when the clinical pattern indicates it. Genetic testing can support selected epilepsy syndromes. Syncope Syncope is a temporary loss of consciousness caused by reduced blood flow to the brain. Vasovagal syncope often follows prolonged standing, pain, heat or emotional distress. Warmth, sweating, nausea and dimming vision can precede the collapse. Brief stiffening or jerking can occur, so movements alone do not prove epilepsy. Features supporting syncope Syncope commonly occurs while standing and improves after lying flat. The person may look pale and recover orientation relatively quickly. A cardiac cause is more concerning when collapse occurs during physical activity, while lying down or with palpitations. NICE blackout pathways use what the person describes, the examination and ECG to guide referral. Functional or dissociative seizures Functional seizures are real episodes involving altered movement, awareness or responsiveness. They are not caused by epileptic electrical discharges. Other terms include dissociative seizures and non epileptic attack disorder. They are part of functional neurological disorder and are not deliberate behaviour. Diagnosing functional seizures No single movement proves that an event is functional. Diagnosis requires a positive clinical pattern, often supported by video EEG recording of a typical episode. Some people have both epilepsy and functional seizures. A respectful explanation and appropriate neurological and psychological treatment are essential. Why misdiagnosis matters Treating syncope or functional seizures as epilepsy can expose someone to unnecessary medicines and restrictions. Missing epilepsy can leave seizures and safety risks untreated. Recurrent events despite apparently suitable treatment should prompt review of the diagnosis and seizure classification. Other mimics Migraine aura can cause sensory or visual symptoms developing over minutes. Panic attacks can cause shaking, breathlessness and altered perception. Sleep disorders can cause unusual movements or behaviours at night. Transient ischaemic attacks rarely cause isolated loss of consciousness and need a different urgent pathway. Starting antiseizure medicine NICE recommends starting antiseizure medicine once epilepsy is confirmed. Treatment can be considered after one unprovoked seizure when neurological deficit, epileptiform EEG or structural imaging raises recurrence risk. The person's view of an unacceptable recurrence risk also matters. Starting treatment is a shared specialist decision. Choosing a medicine Medicine choice depends on seizure type and epilepsy syndrome. Age, other illnesses, pregnancy potential, interactions, occupation and personal preference also matter. A medicine effective for one seizure type can worsen another. Treatment should not be selected from a general drug list without specialist assessment. Monotherapy NICE recommends one antiseizure medicine whenever possible. The dose is increased gradually to balance seizure control and adverse effects. When one medicine fails, the diagnosis and seizure type are reviewed before changing treatment. Combination treatment is considered when appropriate monotherapy is unsuccessful. Focal seizure treatment principle Lamotrigine or levetiracetam are common first line monotherapy options for focal seizures under current NICE guidance. Other medicines are used when these are unsuitable or unsuccessful. The exact choice depends on age, comorbidity, interactions and reproductive considerations. Generalised seizure treatment principle Generalised seizures often need a broad spectrum medicine chosen for the specific syndrome. Lamotrigine, levetiracetam and sodium valproate are options in several generalised pathways. Valproate has major reproductive restrictions and is not a routine unrestricted choice. Some narrow spectrum medicines can worsen absence or myoclonic seizures. Sodium valproate Sodium valproate can be highly effective for some generalised epilepsies. Exposure during pregnancy carries a high risk of major birth defects and neurodevelopmental harm. No one should stop valproate suddenly because uncontrolled seizures can also cause serious harm. Any concern requires prompt specialist review. Current valproate restrictions Valproate must not be used in women or girls able to have children unless other options are unsuitable and Pregnancy Prevention Programme requirements are met. The programme includes specialist review, clear risk discussion, effective pregnancy prevention where appropriate and documented risk acknowledgement. Current MHRA measures also restrict new valproate treatment in people under 55 unless two specialists agree that no effective tolerated alternative exists or the reproductive risks do not apply. Valproate and men MHRA advice also addresses possible reproductive risk when men take valproate around conception. Men are advised to use effective contraception during treatment and for three months after stopping. A man planning a family should discuss medicine options with the epilepsy team. He should not stop treatment independently. Pregnancy planning People with epilepsy can have healthy pregnancies. Pregnancy planning should begin before conception so seizure control and medicine risks can be reviewed. Women and girls who are pregnant or planning pregnancy need specialist epilepsy input coordinated with obstetric care. Antiseizure medicine should not be stopped without medical supervision. Treatment adherence Taking medicine consistently is one of the most important modifiable safety measures. Poor adherence increases seizure recurrence, status epilepticus and epilepsy related death risk. Side effects, cost, memory difficulty and stigma should be addressed rather than blamed. Medicine withdrawal A specialist may discuss gradual withdrawal after a sustained seizure free period. NICE recommends an individualised assessment rather than an automatic stop at one fixed time. Abrupt withdrawal can provoke seizures. Driving restrictions also apply during and after withdrawal. Drug resistant epilepsy Epilepsy is considered drug resistant when adequate trials of suitable tolerated medicines fail to achieve sustained seizure freedom. The diagnosis and classification should be reviewed. Tertiary assessment can consider surgery, vagus nerve stimulation, ketogenic dietary treatment or other specialist options. Referral should not wait indefinitely through repeated similar drug trials. Epilepsy surgery Surgery can remove or disconnect a well defined seizure generating brain region. Assessment requires detailed imaging, prolonged EEG and tests of memory, language and function. Surgery is suitable only when expected seizure benefit outweighs neurological risk. It can be life changing for selected focal epilepsies. Vagus nerve stimulation A device placed under the skin sends regular electrical impulses to the vagus nerve. It can reduce seizure frequency in selected drug resistant epilepsy. It does not usually eliminate the need for medicine. Ketogenic dietary treatment A ketogenic diet is a high fat, very low carbohydrate medical diet used in selected epilepsies. It requires specialist dietetic and medical supervision. It is not the same as an unsupervised commercial low carbohydrate diet. Sudden unexpected death in epilepsy Sudden unexpected death in epilepsy is shortened to SUDEP. It describes the sudden death of a person with epilepsy when trauma, drowning, status epilepticus and another clear cause do not explain the death. The mechanism is not fully understood and may involve breathing, heart rhythm and recovery after a seizure. SUDEP is uncommon, but it is a real risk that should be discussed honestly. Who has greater SUDEP risk Risk is higher with uncontrolled generalised tonic clonic or focal to bilateral tonic clonic seizures. Night time seizures, missed medicine, alcohol or drug misuse and living or sleeping alone can contribute. Risk varies substantially between people. Discussion should focus on modifiable factors rather than creating fear. Reducing SUDEP risk The most important step is improving control of tonic clonic seizures. Taking medicine as prescribed and attending reviews support this goal. People with higher risk sleep seizures can discuss night time supervision or monitoring with their team. No monitor guarantees prevention. Driving after a seizure A person must stop driving immediately after an epileptic seizure or unexplained blackout and notify DVLA. The rules apply to minor seizures, auras and events without complete loss of consciousness. The licence decision belongs to DVLA rather than the individual clinician alone. Northern Ireland uses a separate licensing agency. Group 1 driving rules For established epilepsy, the usual car and motorcycle requirement is twelve months free from every seizure. After a first isolated unprovoked seizure, relicensing may be possible after six months when investigations do not show a higher recurrence risk. A twelve month period is required when risk remains higher. Special rules exist for provoked seizures, sleep only seizures and seizures without functional impairment. Group 2 driving rules Bus and lorry standards are much stricter. Established epilepsy generally requires ten years without seizures and without antiseizure medicine before licensing can be considered. An isolated seizure usually requires five years without further seizure or medicine and specialist risk assessment. The current DVLA decision must always be checked for the individual. Bathing and showering A shower is generally safer than an unsupervised bath because water drains away. The bathroom door should remain unlocked, and another person may need to know when someone at higher risk is washing. Individual advice depends on seizure control and bathroom design. Swimming and water safety Swimming should not occur alone. A capable companion should know about the epilepsy and stay close enough to help. Open water activities require particular caution, suitable flotation and specialist safety planning. A seizure in water is a 999 emergency because inhalation injury can occur. Heights, heat and machinery Uncontrolled seizures increase risk near ladders, unguarded heights, open flames and hot surfaces. Cooking on rear hobs, using guards and choosing safer equipment can reduce injury. Workplace risk assessment should support reasonable adjustments rather than unnecessary exclusion. Pregnancy and parenting safety Pregnancy can alter medicine levels and seizure control. Specialist monitoring can protect both the pregnant person and baby. Advice can also cover bathing, feeding and carrying a baby when seizures remain possible. Planning should be individual and non judgemental. Prognosis Many people achieve long term seizure freedom with an appropriate medicine. Others need several treatments or specialist procedures. Some childhood syndromes remit, while other epilepsies remain lifelong. Good care addresses education, work, mood, memory, stigma and safety alongside seizure counts. What this lesson should not be used for This lesson cannot diagnose epilepsy from shaking, tongue biting or one abnormal EEG result. Do not restrain someone during a convulsion or put anything in their mouth. Do not start, stop or exchange antiseizure medicines without specialist advice. Do not drive after a seizure or blackout until DVLA requirements are satisfied. Call 999 for a first seizure, a seizure lasting five minutes, repeated seizures without recovery, serious injury or breathing difficulty.

A seizure is a temporary event caused by abnormal excessive or synchronised brain activity, while epilepsy is an enduring tendency to have unprovoked seizures. Diagnosis depends mainly on a detailed eyewitness account supported by EEG and imaging when appropriate. Treatment, safety planning, reproductive advice and driving restrictions must be individualised.