Definition and epidemiology
A seizure is a transient occurrence of signs/symptoms from abnormal excessive or synchronous neuronal activity in the brain; epilepsy is a disease of enduring predisposition to recurrent unprovoked seizures. Seizures are common in childhood — roughly 1 in 10 children has at least one — while epilepsy affects about 0.5–1%, with a substantial share of the global burden in India and other LMICs where treatment gaps persist. Provoked (acute symptomatic) seizures — fever, electrolyte derangement, hypoglycaemia, CNS infection, trauma, toxins — must be distinguished from unprovoked seizures, since only the latter speak to an epilepsy diagnosis.
Clinical features
Presentation depends on seizure type. Focal-onset seizures begin in networks limited to one hemisphere and are classified by awareness (focal aware vs focal impaired awareness) and by motor vs non-motor onset; they may evolve to a bilateral tonic–clonic seizure. Generalised-onset seizures rapidly engage bilateral networks and include motor types (tonic–clonic, clonic, tonic, myoclonic, atonic, epileptic spasms) and non-motor (absence) types. When onset is not witnessed, classify as unknown onset. A careful semiology history — aura, lateralising features, automatisms, post-ictal state, duration, triggers and a description of the first event — is the highest-yield diagnostic tool and helps separate seizures from syncope, breath-holding, tics, parasomnias and non-epileptic events.
Diagnosis
Epilepsy is diagnosed (ILAE 2014 operational definition) by any one of: (1) ≥2 unprovoked (or reflex) seizures >24 hours apart; (2) one unprovoked seizure with a probability of further seizures similar to the general recurrence risk after two unprovoked seizures (≥60%) over the next 10 years; or (3) diagnosis of an epilepsy syndrome. Classification proceeds across three levels — seizure type, epilepsy type (focal, generalised, combined, or unknown), and epilepsy syndrome — with aetiology (structural, genetic, infectious, metabolic, immune, unknown) and comorbidities considered at every step. Investigations: EEG (and sleep-deprived/prolonged where standard is unrevealing), MRI brain for focal/refractory/early-onset cases, and targeted metabolic/genetic testing.
See the full criteria: Convulsive Disorder
Red flags
- Seizure >5 minutes or repeated seizures without recovery — status epilepticus
- Fever with altered sensorium, meningism, or focal deficit — CNS infection
- New focal neurological signs, raised ICP features (headache, vomiting, papilloedema)
- Neonatal seizures, or regression/developmental plateau
- Refractory seizures, or a first afebrile seizure with abnormal exam or focal onset
Management overview
For an acute convulsion lasting >5 minutes, follow a status epilepticus pathway: protect the airway, give a benzodiazepine first-line, escalate to a second-line antiseizure agent, and correct provoking factors (glucose, sodium, calcium, sepsis). For established epilepsy, choose monotherapy guided by seizure/epilepsy type and syndrome (some broad-spectrum agents for generalised epilepsies; certain sodium-channel agents can worsen absence/myoclonic seizures), with attention to adverse effects, adherence, comorbidities and — in adolescent girls — teratogenicity and contraception. A single provoked or unprovoked seizure with low recurrence risk often warrants counselling rather than drugs. Refer drug-resistant epilepsy (failure of two appropriate agents) for evaluation including epilepsy surgery, ketogenic diet, or neurostimulation. Counsel on seizure first aid, safety, driving/swimming precautions and SUDEP. (Specific doses omitted — use your formulary.)
References
- Fisher RS, et al. Epilepsia. 2017;58(4):522–530 (ILAE 2017 seizure classification).
- Fisher RS, et al. Epilepsia. 2014;55(4):475–482 (practical clinical definition of epilepsy).
- Scheffer IE, et al. Epilepsia. 2017;58(4):512–521 (ILAE classification of the epilepsies).
Decision support for qualified clinicians only — verify against current primary guidelines and your clinical judgement.