Epilepsy: Symptoms, Seizure Types, and Treatment — a Complete Overview

A single epileptic seizure — an episode of abnormal, excessive, or synchronized electrical activity of neurons in the brain — can occur under many circumstances (high fever in a child, severe dehydration, alcohol withdrawal, acute head injury) and does not by itself mean epilepsy. Epilepsy is a lasting tendency of the brain to generate seizures, and under the practical clinical definition it is usually diagnosed after at least two unprovoked seizures more than 24 hours apart, or after a single unprovoked seizure if the risk of another is similarly high as after two seizures (for example, with a clear structural abnormality on brain imaging).

This distinction has practical significance — a single convulsive seizure after a sleepless night and dehydration at a music festival is a completely different clinical situation than recurrent, unprovoked seizures in someone without a clear triggering factor. Epilepsy is one of the most common serious neurological conditions in the world, and its causes are remarkably varied: from genetic factors, through brain developmental abnormalities, stroke, tumors, and central nervous system infections, to epilepsy of unknown cause (idiopathic), where even thorough diagnostic work-up fails to identify a specific underlying condition.

The International League Against Epilepsy (ILAE) introduced an updated, operational classification of seizure types in 2017, organizing them by three main criteria: where the seizure begins (focal, generalized, or of unknown onset), the state of consciousness during a focal seizure (retained or impaired awareness), and the dominant symptoms at seizure onset (motor or non-motor).

In practice, this means, for example, that a focal seizure with retained awareness (formerly called "simple partial") may present solely as an unusual sensation, tingling in one limb, or a momentary smell disturbance, without loss of consciousness — something that can be wrongly dismissed by the patient themselves as "a strange feeling" rather than an epileptic seizure. Generalized tonic-clonic seizures (formerly "grand mal"), on the other hand, are the most recognizable — though not the only — form of epilepsy in popular awareness.

This diversity of clinical presentation is one reason epilepsy diagnosis is sometimes delayed, especially with focal seizures without loss of awareness or absence seizures in children, which those around the person may mistakenly interpret as a moment of inattention. Key to diagnosis is gathering a detailed, repeatable pattern of episodes — ideally also described by a witness, since the patient themselves often doesn't remember what happened during a seizure with impaired awareness.

The foundation of epilepsy diagnosis remains a detailed clinical history — a description of the seizures themselves, the circumstances in which they occur, and any possible triggering factors — supplemented by electroencephalography (EEG), which records the brain's electrical activity and can detect changes characteristic of epilepsy (e.g., spikes, sharp waves) even between seizures. A standard, routine EEG lasting 20-30 minutes detects epileptiform abnormalities in only some patients with epilepsy — a normal result from a single test does not rule out the diagnosis, which is why, with strong clinical suspicion, repeat testing, sleep-deprived EEG, or long-term video-EEG monitoring is used, especially in cases of diagnostic difficulty or when planning surgical treatment.

Brain MRI is recommended for most adults with newly diagnosed epilepsy to look for a structural cause of the seizures (e.g., hippocampal sclerosis, cortical malformation, effects of stroke or a tumor), which matters both for establishing prognosis and for choosing treatment — and in some cases for determining eligibility for surgical treatment. Blood tests are also typically done to rule out metabolic causes of seizures (electrolyte disturbances, hypoglycemia), which can mimic epilepsy without actually being it.

The choice of anti-seizure medication (anticonvulsant) depends primarily on the type of seizures and the type of epilepsy (focal vs. generalized), as well as on age, sex, coexisting conditions, and potential interactions with other medications. The goal of treatment is complete seizure control with as few side effects as possible — most patients achieve this with the first or second medication tried.

In generalized epilepsies, including idiopathic generalized epilepsies, valproate remains the medication with the most strongly documented efficacy — with an important caveat: due to the high risk of birth defects and neurodevelopmental disorders in the child, valproate is avoided where possible in women of childbearing age, in favor of alternatives such as lamotrigine or levetiracetam. The decision on which specific medication to use and at what dose always rests with the treating neurologist, who takes the individual patient's profile into account.

Although most patients achieve good seizure control with medication, in some — despite correctly chosen treatment — seizures persist. The International League Against Epilepsy has developed a precise, now widely used definition of this condition.

Epilepsy remains one of the most socially underestimated neurological conditions — partly because its clinical presentation is far broader than the popular image of convulsions and loss of consciousness suggests. Precise seizure classification, systematic diagnosis, and well-chosen first-line treatment allow most patients to lead fully active lives, and a clear definition of drug resistance provides a concrete, evidence-based point at which it's worth seeking further options rather than more trial and error.