An epileptic seizure, formally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain.

Outward effects vary from uncontrolled shaking movements involving much of the body with loss of consciousness (tonic-clonic seizure), to shaking movements involving only part of the body with variable levels of consciousness (focal seizure), to a subtle momentary loss of awareness (absence seizure).

Most of the time these episodes last less than two minutes and it takes some time to return to normal.

Loss of bladder control may occur.

SpecialtyNeurology, emergency medicine
TypesProvoked, unprovoked
CausesProvoked: Low sugar, alcohol withdrawal, low , fever, brain infection, concussion
Unprovoked: Unknown, brain injury, brain tumor, previous stroke
Diagnostic methodBased on symptoms, tests, medical imaging, electroencephalography
Differential diagnosisSyncope, nonepileptic psychogenic seizure, tremor, migraine, transient ischemic attack
TreatmentLess than 5 min: Place person on their side, remove nearby dangerous objects
More than 5 min: Treat as per status epilepticus
Frequency~10% of people (at one point in time)

Seizures may be provoked and unprovoked. Provoked seizures are due to a temporary event such as low sugar, alcohol withdrawal, abusing alcohol together with prescription medication, low , fever, brain infection, or concussion.

Unprovoked seizures occur without a known or fixable cause such that ongoing seizures are likely.

Unprovoked seizures may be triggered by stress or sleep deprivation.

Diseases of the brain, where there has been at least one seizure and a long term risk of further seizures, are collectively known as epilepsy.

Conditions that look like epileptic seizures but are not include: fainting, nonepileptic psychogenic seizure and tremor.