Epilepsy and Seizures

A seizure is a sudden, brief storm of abnormal, hypersynchronous electrical activity in the brain. It is one of the most dramatic events in clinical medicine: a person who was talking to you a moment ago collapses, stiffens, and shakes, and then wakes minutes later remembering nothing. For most of human history this looked like possession by spirits. We now understand it as a disorder of electrical rhythm in networks of neurons — and that shift, from the supernatural to the electrical, is one of the great stories in neuroscience. This page teaches you how to recognize the different kinds of seizures, how to read what an EEG is telling you, how to manage the life-threatening emergency of status epilepticus, and how modern antiepileptic drugs actually work.

Understanding epilepsy matters far beyond the exam hall. Roughly 1 in 100 people live with epilepsy, and almost anyone can have a single provoked seizure under the right circumstances (fever, low sodium, alcohol withdrawal, a drug overdose). Knowing the difference between "a seizure" and "epilepsy," and between a benign faint and a dangerous emergency, changes how you counsel, investigate, and treat.

Learning Objectives

• Define seizure, epilepsy, and status epilepticus precisely, and distinguish provoked from unprovoked seizures.
• Classify seizures using the ILAE framework: focal (aware vs impaired awareness) versus generalized (tonic-clonic, absence, myoclonic, atonic).
• Explain what the EEG measures, recognize key epileptiform patterns, and understand its diagnostic limits.
• Manage generalized convulsive status epilepticus with a stepwise, time-critical protocol.
• Match major antiepileptic drugs to seizure types and know their key adverse effects and interactions.
• Trace the historical shift from demonic explanations to the electrical theory of seizures.

Quick Answer

A seizure is a transient episode of abnormal excessive or synchronous neuronal activity; epilepsy is the tendency to have recurrent unprovoked seizures (two or more, or one with high recurrence risk). Seizures are classified by where they start: focal (one part of one hemisphere) or generalized (both hemispheres from the outset). Focal seizures are subdivided by whether awareness is preserved; generalized ones include tonic-clonic, absence, myoclonic, and atonic types. The EEG records cortical electrical activity and helps classify and localize seizures but a normal EEG never excludes epilepsy. Status epilepticus — a seizure lasting more than 5 minutes or repeated seizures without recovery — is a neurological emergency treated with benzodiazepines first, then a loading antiseizure medication. Drug choice depends on seizure type: broad-spectrum agents (valproate, levetiracetam, lamotrigine) for generalized or uncertain cases, and agents like carbamazepine or lamotrigine for focal seizures.

Where It Came From

For thousands of years, seizures were read as a message from the gods or an invasion by demons. The convulsing body, the loss of control, the strange automatisms, and the amnesia afterward seemed to demand a supernatural explanation. Babylonian tablets from around 1000 BCE describe seizure types attributed to specific spirits. The Greeks called it the "sacred disease."

The first great intellectual break came with the Hippocratic treatise On the Sacred Disease (around 400 BCE), which argued bluntly that epilepsy was "no more divine nor more sacred than other diseases" but arose from the brain — a disorder of the same organ that governs thought and sensation. This was a radical claim: it located the problem in an organ, not in the heavens. Yet without tools to study the living brain, the idea stalled for two millennia, and the stigma of possession persisted.

The decisive shift was electrical. In the 1860s and 1870s the English neurologist John Hughlings Jackson, watching seizures that marched in an orderly way across the body (a twitch starting in the thumb, spreading up the arm — what we still call a "Jacksonian march"), reasoned that seizures were "occasional, sudden, excessive, rapid and local discharges of grey matter." He proposed, before anyone could measure it, that the cortex was electrically excitable and mapped somatotopically — an astonishing inference. Experiments by Fritsch and Hitzig (1870), stimulating the dog cortex and producing movements, confirmed that the cortex generated electricity and drove movement.

The theory became visible in 1929, when the German psychiatrist Hans Berger recorded the first human electroencephalogram (EEG), demonstrating rhythmic electrical waves from the scalp. Within a few years, Frederic Gibbs and colleagues showed that seizures produced characteristic abnormal discharges — most famously the 3-per-second spike-and-wave of absence epilepsy. The electrical theory now had a recording. Treatment followed the science: bromides (1857), phenobarbital (1912), phenytoin (1938, deliberately screened for anticonvulsant action in animals), and the modern era of rationally targeted drugs.

Defining the Terms: Seizure, Epilepsy, Provoked vs Unprovoked

Precision here is examined constantly and matters clinically.

• A seizure is the event — the clinical manifestation of abnormal hypersynchronous discharge.
• Epilepsy is the disease — an enduring predisposition to generate seizures. The ILAE operational definition: (1) at least two unprovoked seizures more than 24 hours apart, OR (2) one unprovoked seizure plus a probability of further seizures of at least 60 percent (e.g. after a stroke or with clear epileptiform EEG), OR (3) diagnosis of an epilepsy syndrome.
• A provoked (acute symptomatic) seizure occurs in close temporal relation to an acute insult — hyponatremia, hypoglycemia, alcohol withdrawal, high fever in a child, eclampsia, a fresh head injury. Correcting the cause, not lifelong drugs, is the priority. A single provoked seizure is not epilepsy.

This distinction drives management: you do not diagnose epilepsy or start lifelong medication after a first seizure caused by a sodium of 118.

Classifying Seizures: Focal vs Generalized

The 2017 ILAE classification asks first: where does the seizure start?

Focal seizures begin in a network confined to one hemisphere. They are subdivided by awareness:

• Focal aware seizures (the old "simple partial"): consciousness is preserved. The patient can be a witness to their own seizure. Symptoms reflect the origin — a rising epigastric sensation and déjà vu (mesial temporal), unilateral limb jerking (motor cortex), flashing lights (occipital), or a strange smell (uncus).
• Focal impaired awareness seizures (the old "complex partial"): awareness is lost. Classic mesial temporal lobe seizures show a motionless stare, oral automatisms (lip-smacking, chewing), fumbling hand movements, and postictal confusion lasting minutes. These are the seizures most often mistaken for psychiatric events or drunkenness.
• A focal seizure can spread to become a focal to bilateral tonic-clonic seizure (formerly "secondary generalized").

Generalized seizures engage both hemispheres from the very onset:

• Tonic-clonic (grand mal): sudden loss of consciousness, a tonic phase (stiffening, sometimes a cry as air is forced past the larynx), then a clonic phase (rhythmic jerking), often with tongue-biting (lateral), incontinence, and a prolonged postictal state.
• Absence (petit mal): brief (5–10 second) blank stares with abrupt onset and offset, no aura, no postictal confusion, often dozens per day in a school-age child mislabeled as "daydreaming." The EEG signature is generalized 3 Hz spike-and-wave.
• Myoclonic: brief shock-like jerks, often of the arms on waking — the hallmark of juvenile myoclonic epilepsy (JME).
• Atonic ("drop attacks"): sudden loss of tone causing falls and injury.

Worked example

A 16-year-old drops her cereal spoon most mornings and one day, after a late night, has a full tonic-clonic convulsion. On questioning, she has had early-morning arm jerks for a year. This pattern — myoclonic jerks on waking, sleep-deprivation trigger, and a generalized tonic-clonic seizure — is juvenile myoclonic epilepsy. Recognizing it matters: it responds well to valproate or levetiracetam, but carbamazepine can worsen the myoclonus. The seizure type dictates the drug.

The EEG: What It Sees and What It Misses

The EEG records the summed electrical activity of cortical neurons through scalp electrodes, expressed as rhythmic waves (delta, theta, alpha, beta by frequency). It is the single most useful test for classifying epilepsy — but its power is often misunderstood.

What it can show:

• Interictal epileptiform discharges — spikes and sharp waves between seizures — support the diagnosis and help localize the focus (e.g. left temporal spikes).
• Characteristic patterns clinch specific syndromes: generalized 3 Hz spike-and-wave in childhood absence epilepsy; polyspike-and-wave in JME; hypsarrhythmia in infantile spasms.
• Localization to guide surgery in drug-resistant focal epilepsy.

Its crucial limits — high-yield for exams:

• A normal routine EEG does NOT exclude epilepsy. A single 30-minute recording is normal in up to half of people with genuine epilepsy, because it may simply not capture a discharge. Sensitivity rises with sleep deprivation, prolonged/ambulatory recording, and activation procedures (hyperventilation, photic stimulation).
• Minor nonspecific abnormalities are common in healthy people, so an EEG cannot on its own diagnose epilepsy — the diagnosis is clinical, supported by EEG.
• The gold standard for difficult or surgical cases is video-EEG telemetry, correlating the recorded event with the electrical trace, and the best way to distinguish epileptic seizures from psychogenic non-epileptic events.

Status Epilepticus: The Emergency

Status epilepticus is defined operationally as a convulsive seizure lasting 5 minutes or more, or two or more seizures without full recovery of consciousness between them. The old "30-minute" definition described when neuronal injury begins; the 5-minute threshold is when you must act, because most self-limiting seizures stop within 2–3 minutes. Convulsive status is a true emergency — mortality is significant, and prolonged seizures cause excitotoxic neuronal death and systemic complications (hyperthermia, rhabdomyolysis, aspiration, acidosis).

A stepwise, time-based protocol (align with local guidelines):

1. 0–5 min — Stabilize. Airway, breathing, circulation; high-flow oxygen; IV access; check capillary glucose (give glucose, with thiamine in adults at risk, if low); send electrolytes, calcium, magnesium, toxicology, and antiseizure drug levels.
2. 5–20 min — First-line: benzodiazepines. IV lorazepam (0.1 mg/kg), or IM midazolam if no IV access, or rectal diazepam. Under-dosing is the commonest error.
3. 20–40 min — Second-line: a loading antiseizure medication. IV levetiracetam, valproate, or fosphenytoin/phenytoin — the ESETT trial found these roughly equally effective, so choice depends on the patient and contraindications.
4. 40+ min — Refractory status: intubation and continuous infusion of midazolam, propofol, or thiopental in the ICU, with continuous EEG monitoring. Persisting despite anaesthesia is super-refractory status.

Always hunt for and treat the cause in parallel — hyponatremia, meningitis/encephalitis, eclampsia, hypoglycemia, drug toxicity, or a structural lesion.

Antiepileptic Therapy

The goal is no seizures with no side effects. Around two-thirds of patients achieve control on the first or second well-chosen drug; the rest have drug-resistant epilepsy (failure of two appropriately chosen, tolerated drugs) and warrant referral for surgery, vagus nerve stimulation, or a ketogenic diet.

Core principles:

• Match the drug to the seizure type. "Narrow-spectrum" sodium-channel blockers (carbamazepine, phenytoin, oxcarbazepine) are effective for focal seizures but can aggravate generalized absence and myoclonic seizures. "Broad-spectrum" agents (valproate, levetiracetam, lamotrigine, topiramate) cover both and are preferred when the type is uncertain or clearly generalized.
• Start low, go slow, aim for monotherapy at the lowest effective dose.

Drug	Main mechanism	Best for	Key adverse effects
Sodium valproate	Multiple (Na channels, GABA, T-type Ca)	Broad spectrum; generalized, JME	Weight gain, tremor, hepatotoxicity, highly teratogenic
Levetiracetam	Binds SV2A synaptic vesicle protein	Broad spectrum; safe in status	Irritability, mood change; few interactions
Lamotrigine	Na channel blockade	Focal and generalized; pregnancy	Rash (rarely Stevens-Johnson); titrate slowly
Carbamazepine	Na channel blockade	Focal seizures	Hyponatremia, enzyme inducer, worsens absence/myoclonus
Phenytoin	Na channel blockade	Focal, status (fosphenytoin)	Gum hypertrophy, ataxia, nonlinear kinetics
Ethosuximide	T-type Ca channel blockade	Absence seizures only	GI upset

A vital exam and clinical point: valproate is strongly teratogenic (neural tube defects, lower IQ, autism risk) and should be avoided in women of childbearing potential unless no alternative exists and with strict pregnancy prevention. For a young woman with generalized epilepsy, lamotrigine or levetiracetam is usually preferred.

Real-World Applications

• First-seizure clinics: deciding whether an event was truly a seizure (versus syncope or a psychogenic event), whether it was provoked, and whether the recurrence risk justifies treatment.
• Emergency medicine: the status epilepticus protocol above is one of the most time-critical algorithms a junior doctor must know cold.
• Everyday safety counselling: driving restrictions, avoiding swimming or heights alone, medication adherence, recognizing triggers (sleep deprivation, alcohol, flashing lights in photosensitive epilepsy), and — for anyone — basic seizure first aid: protect from injury, do NOT restrain, do NOT put anything in the mouth, turn to the side, and time the seizure.
• Preconception care: switching high-risk drugs and adding high-dose folic acid before pregnancy.

Common Mistakes

1. "A seizure means epilepsy." Wrong: a single provoked seizure (e.g. from hyponatremia or alcohol withdrawal) is not epilepsy. Correction: diagnose epilepsy only when the ILAE criteria for an enduring predisposition are met, and treat the provoking cause first.
2. "A normal EEG rules out epilepsy." Wrong: a routine EEG is normal in a large fraction of people with epilepsy. Correction: epilepsy is a clinical diagnosis; use sleep-deprived, prolonged, or video-EEG when the routine study is unrevealing, and never withhold treatment on the basis of a normal EEG alone.
3. "Restrain the patient and put something in their mouth." Wrong and dangerous: it causes injury (broken teeth, bitten fingers) and does not prevent tongue-swallowing, which cannot happen. Correction: cushion the head, remove hazards, turn to the recovery position, time it, and call for help if it exceeds 5 minutes.
4. (Bonus) Using a sodium-channel blocker in generalized epilepsy. Carbamazepine can worsen absence and myoclonic seizures. Correction: use a broad-spectrum agent when generalized seizures are present or the type is uncertain.

Comparison and Connections

Feature	Focal impaired awareness seizure	Absence seizure	Convulsive syncope
Typical age	Any; often adults	School-age children	Any
Duration	1–2 minutes	5–10 seconds	Seconds
Aura	Common (rising epigastric, déjà vu)	None	Lightheaded, greying vision
Automatisms	Yes (lip-smacking, fumbling)	Subtle or none	No
Postictal confusion	Yes, minutes	None (immediate recovery)	Rapid recovery, no confusion
EEG	Focal temporal discharges	3 Hz spike-and-wave	Normal

Seizures also connect to the wider neurology and physiology curriculum: the ionic basis of the action potential and neuronal excitability (see the physiology of nerve conduction), the glutamate/GABA balance central to both seizures and their drugs, and the vascular and structural causes (stroke, tumor, mesial temporal sclerosis) that provide the "focus." Compare with ../../26._Neurology/index.md for related disorders such as stroke and headache, and with ../../5._Pharmacology/index.md for the drug mechanisms.

Practice Questions

Recall

Q: State the ILAE operational definition of epilepsy. A: At least two unprovoked seizures more than 24 hours apart; OR one unprovoked seizure with a recurrence risk of at least 60 percent over 10 years; OR diagnosis of an epilepsy syndrome.

Understanding

Q: Why does a normal routine EEG not exclude epilepsy? A: A 30-minute recording samples only a brief window and may not capture an epileptiform discharge, which is intermittent. Sensitivity is limited, so the diagnosis remains clinical; sleep-deprived or prolonged/video-EEG recordings improve yield.

Application

Q: A 16-year-old has morning arm jerks and a tonic-clonic seizure after sleep deprivation. Which drug would you avoid and why? A: Avoid carbamazepine (a sodium-channel blocker), which can worsen the myoclonic and any absence seizures of juvenile myoclonic epilepsy. Use a broad-spectrum agent — levetiracetam or lamotrigine (valproate is effective but avoided in women of childbearing potential due to teratogenicity).

Analysis

Q: A patient has been convulsing for 7 minutes. IV lorazepam has been given twice without effect. Glucose is normal. What is the diagnosis and next step, and what is the underlying concern? A: This is established/convulsive status epilepticus refractory to first-line benzodiazepines. Next step: load a second-line antiseizure medication IV (levetiracetam, valproate, or fosphenytoin). The concern is that prolonged seizures cause excitotoxic neuronal injury and systemic complications, and progressively resist treatment as GABA receptors internalize, so rapid escalation toward ICU anaesthesia may be needed.

FAQ

Is epilepsy inherited? Some epilepsies have a strong genetic basis (many generalized epilepsies, several channelopathies), while others are acquired (after stroke, trauma, infection, or a tumor). Most cases have a mix of genetic susceptibility and other factors; having a relative with epilepsy modestly raises risk but most children of people with epilepsy never develop it.

Can someone swallow their tongue during a seizure? No — this is a myth. The tongue cannot be swallowed. Forcing objects into the mouth causes broken teeth and injury. Just protect the head and turn the person on their side.

Will medication cure epilepsy? Antiseizure drugs control seizures; they do not "cure" the underlying predisposition. Many people become seizure-free on medication, and some (especially certain childhood syndromes) can eventually stop drugs under specialist guidance after years free of seizures.

Are flashing lights dangerous for everyone with epilepsy? No. Only a minority (photosensitive epilepsy, more common in some generalized syndromes) are triggered by flickering light. It is not a feature of most epilepsy.

When can someone with epilepsy drive? Rules vary by country, but all require a seizure-free period (often 6–12 months) and legally mandate reporting to the licensing authority. This is a critical safety and medico-legal counselling point.

What is the difference between status epilepticus and a normal seizure? Most seizures stop within 2–3 minutes. Status epilepticus is a seizure lasting 5 minutes or more, or repeated seizures without recovery in between — a medical emergency requiring immediate drug treatment.

Quick Revision

• Seizure = the event; epilepsy = enduring tendency to unprovoked seizures. A single provoked seizure is not epilepsy.
• Classify by onset: focal (aware vs impaired awareness) or generalized (tonic-clonic, absence, myoclonic, atonic).
• Absence = 3 Hz spike-and-wave, no aura, no postictal phase; JME = morning myoclonus, worsened by carbamazepine.
• EEG supports but does not make the diagnosis; a normal EEG never excludes epilepsy.
• Status epilepticus = ≥5 min or repeated seizures without recovery → benzodiazepine first, then a loading agent, then ICU anaesthesia.
• Match drug to type: broad-spectrum (valproate, levetiracetam, lamotrigine) for generalized/uncertain; sodium-channel blockers for focal but they worsen generalized seizures.
• Valproate is teratogenic — avoid in women of childbearing potential where possible.
• History: sacred disease → Hippocrates (brain) → Hughlings Jackson & Berger's EEG (electrical theory).

Related Topics

Prerequisites

• Neuronal excitability and the action potential — ../../2._Physiology/index.md
• Neuroanatomy of the cortex and limbic system — ../../1._Anatomy/index.md

Related Topics

• Stroke, headache, and other neurological disorders — ../index.md
• Antiepileptic drug pharmacology — ../../5._Pharmacology/index.md

Next Topics

• Emergency management and status protocols — ../../23._Emergency_Medicine/index.md
• Psychogenic non-epileptic seizures and psychiatric comorbidity — ../../17._Psychiatry/index.md