20.2 — Epilepsy and Seizures

Around 70 percent of people with epilepsy become seizure-free on medication, most on a single drug.

Which is a better outcome than most chronic neurological conditions, and it is frequently not the impression people have on diagnosis.

Around 1 in 100 people has epilepsy, and around 1 in 10 will have a seizure at some point in life — the two are not the same thing.

What a seizure is

A sudden, excessive, synchronised discharge of neurons.

Normally, neuronal activity is balanced between excitation — glutamate — and inhibition — GABA (Chapter 11.2).

A seizure is that balance tipping, and the excitation spreading.

Where it starts and how far it spreads determines what the seizure looks like — which is why the classification is by origin rather than by appearance.

The types

Focal — starting in one area.

With retained awareness — the person is conscious throughout. What it looks like depends entirely on the region involved: jerking of one limb from the motor cortex; tingling from the sensory cortex; a rising sensation in the stomach, an intense feeling of familiarity or unfamiliarity, or a strange smell from the temporal lobe (Chapter 11.5).

With impaired awareness — the person appears vacant, may perform automatic movements — lip-smacking, fumbling with clothes, wandering — and has no memory of it. Usually temporal lobe in origin.

And these are frequently mistaken for daydreaming, confusion, or psychiatric illness for years.

Focal to bilateral tonic-clonic — starting focally and spreading. The aura is the focal onset, which is why it is diagnostically useful.

Generalised — involving both hemispheres from the outset.

Tonic-clonic — the classic. Sudden loss of consciousness; a tonic phase with rigidity, sometimes a cry as air is forced through the larynx; then a clonic phase of rhythmic jerking; frequently tongue biting — characteristically the side of the tongue — and incontinence. Then a postictal phase of confusion and drowsiness lasting minutes to hours.

Absence — brief blank episodes, 5 to 20 seconds, with abrupt onset and offset and no postictal confusion. Mainly in children, occurring many times a day, and frequently mistaken for inattention or daydreaming. Hyperventilating for three minutes will often provoke one, which makes the diagnosis at the bedside.

Myoclonic — brief shock-like jerks. Juvenile myoclonic epilepsy characteristically causes morning jerks — spilling breakfast cereal is the classic history — and it is frequently not mentioned unless asked about specifically.

Atonic — sudden loss of tone, causing falls. Injury-prone.

What is not epilepsy

And distinguishing these matters, because misdiagnosis leads to years of unnecessary medication.

Syncope (fainting) — the commonest mimic.

The discriminating features: a prodrome of feeling hot, nauseated and vision greying out; pallor; rapid recovery within seconds to a minute; and a trigger — standing, pain, the sight of blood, a hot room.

And confusingly, brief jerking occurs in a substantial proportion of faints — "convulsive syncope" — which is why "he jerked, so it was a fit" is unreliable.

Postictal confusion lasting many minutes points to a seizure; immediate orientation points to a faint.

Non-epileptic attack disorder — episodes resembling seizures without epileptic discharge. A genuine and distressing condition, frequently associated with previous trauma, and it is not deliberate.

It is diagnosed by video-EEG, and treated psychologically rather than with anticonvulsants — and people with it are frequently on multiple anticonvulsants for years before the diagnosis is made.

Febrile convulsions — in children between 6 months and 5 years (Chapter 13.4). They do not cause brain damage and the risk of later epilepsy is only slightly above background.

And also: breath-holding attacks in toddlers, cardiac arrhythmias, sleep disorders, and migraine with aura.

What to do during a seizure

And this is worth knowing precisely.

Stay with them and note the time. The duration is the most important piece of information.

Protect the head — put something soft under it.

Move dangerous objects away.

Do not restrain them.

Do not put anything in the mouth. The idea that someone can swallow their tongue is anatomically impossible, and forcing objects into the mouth breaks teeth and injures fingers.

When the jerking stops, roll them into the recovery position and stay until they are fully alert.

Call an ambulance if:

The seizure lasts more than 5 minutes.A second seizure follows without recovery in between.It is their first seizure.They are injured.They do not regain consciousness.They have difficulty breathing afterwards.Or it happened in water.

And a person known to have epilepsy who has a typical seizure lasting under 5 minutes and recovers normally usually does not need an ambulance — which is worth knowing both to avoid unnecessary calls and to recognise when one is needed.

Status epilepticus

A seizure lasting more than 5 minutes, or repeated seizures without recovery between.

A medical emergency. Mortality rises with duration, and neuronal damage begins after around 30 minutes.

Treatment: a benzodiazepine first — buccal midazolam or rectal diazepam, which family members can be trained to give at home, and intravenous lorazepam in hospital. Then a second-line anticonvulsant, and anaesthesia if it continues.

Having a rescue medication and a plan is one of the more valuable things for someone with frequent or prolonged seizures, and it prevents a substantial number of emergency admissions.

Causes

And around half have no identified cause.

Genetic — many identified genes, mostly ion channels (Chapter 11.1).

Structural — stroke, tumour, trauma, malformations of cortical development, hippocampal sclerosis.

Metabolic — low sodium, low glucose, low calcium, kidney or liver failure.

Infection — meningitis, encephalitis, and neurocysticercosis, which is the leading cause of adult-onset epilepsy in many low-income countries (Chapter 17.3).

Autoimmune — increasingly recognised, and treatable with immunotherapy.

Alcohol withdrawal — and this one is worth knowing (Chapter 11.2).

Drugs.

Investigation: EEG — and a normal EEG does not exclude epilepsy, since it captures a short window; MRI; blood tests; and sometimes prolonged video-EEG monitoring.

Treatment

Drugs, and the choice is driven by seizure type as much as by side effects.

Broad-spectrum — sodium valproate, lamotrigine, levetiracetam, topiramate.

For focal seizures — carbamazepine, lamotrigine, levetiracetam.

For absence — ethosuximide, valproate.

And an important trap: carbamazepine, phenytoin and several others worsen absence and myoclonic seizures, which is why classifying the seizure type correctly matters.

Most work by stabilising sodium channels or enhancing GABA (Chapter 11.1).

Around 70 percent become seizure-free, around half on the first drug tried.

Side effects worth knowing:

Sodium valproate is highly teratogenic — around 10 percent major malformation and 30 to 40 percent neurodevelopmental impairment (Chapter 4.6). It is now restricted in women of childbearing potential, following inquiries in several countries into the delay in communicating this.

Lamotrigine can cause a severe rash including Stevens–Johnson syndrome (Chapter 14.5), which is why it is started at a very low dose and increased slowly — and why rapid escalation is dangerous.

Carbamazepine causes severe skin reactions in people carrying HLA-B*15:02, which is common in Han Chinese and Thai populations — and testing before prescribing is standard there (Chapter 3.3).

Enzyme-inducing drugs reduce the effectiveness of hormonal contraception, which is a common and consequential interaction.

And essentially all can cause drowsiness and cognitive slowing, which is the main quality-of-life issue.

For drug-resistant epilepsy — failing two appropriate drugs:

Surgery. In carefully selected patients, particularly temporal lobe epilepsy with hippocampal sclerosis, surgery renders 60 to 70 percent seizure-free — a far better result than adding a third drug, which succeeds in under 5 percent.

And it is substantially under-used, with typical delays of 15 to 20 years from drug resistance to referral.

Vagus nerve stimulation (Chapter 11.7).

Responsive neurostimulation — a device detecting seizure onset and delivering stimulation to abort it.

Ketogenic diet — very high fat, very low carbohydrate. Genuinely effective in some childhood epilepsies, particularly certain genetic syndromes, and demanding to follow.

Cannabidiol — approved for specific severe childhood epilepsies, with real trial evidence. This is a narrow, evidence-based indication and it does not support the broader claims made for cannabis products in epilepsy.

Living with epilepsy

Driving — restrictions apply everywhere, typically requiring a seizure-free period of 6 to 12 months for private licences. Rules vary and must be checked, and it is a legal obligation to inform the licensing authority.

Work — most occupations are open; a few are restricted.

Safety at home: showers rather than baths — drowning in a bath is a real cause of death in epilepsy; not swimming alone; caution with heights, heat and machinery.

Pregnancy — planned in advance where possible, with medication reviewed before conception and high-dose folic acid. Uncontrolled seizures are more dangerous to the pregnancy than most anticonvulsants, so stopping medication is not the answer (Chapter 4.6).

Sleep, alcohol and missed doses are the commonest precipitants, and addressing them is often as effective as changing medication.

SUDEP — sudden unexpected death in epilepsy — affects around 1 in 1,000 people with epilepsy per year, and more in those with frequent tonic-clonic seizures.

And the honest position: people should be told about it. Surveys show most want to know, and the main modifiable factor is seizure control — which makes it an argument for taking treatment seriously rather than a source of undirected fear. Night-time supervision and seizure alarms may reduce risk.

Stigma remains substantial in many parts of the world, and it affects employment, marriage and disclosure more than the condition itself does.

What is improving

Better drugs with fewer cognitive side effects.

Genetic diagnosis, which is increasingly identifying specific syndromes with specific treatments — and in some cases a drug that would otherwise never have been tried.

Surgery for drug-resistant epilepsy, under-used and highly effective in the right patients.

And devices, dietary treatment and immunotherapy for autoimmune causes, which have expanded the options for the 30 percent who do not respond to drugs.

What the next page fixes

Chapter 20.3 covers Parkinson's disease — a condition where the cause of the symptoms is understood better than almost any other neurodegenerative disease, and where treatment is genuinely effective.