seizure
Meaning of seizure: Most seizures stop by themselves within a couple of minutes, and the confusion that follows often lasts considerably longer than the event.
Definition of seizure
A seizure is a sudden, temporary burst of abnormal electrical activity in the brain that disrupts how nerve cells signal to one another. What it looks like depends on which part of the brain is involved: convulsive shaking, stiffening of the body, an odd smell or rising sensation, a brief blank stare, or altered behavior with no visible movement at all.
What are the main types?
| Type | Where it starts | What is seen |
|---|---|---|
| Focal aware | One area of one hemisphere | Twitching, tingling, an odd smell or taste; awareness preserved |
| Focal impaired awareness | One area, spreading further | Staring, lip smacking, fumbling; the person is unresponsive |
| Generalized tonic-clonic | Both hemispheres at once | Stiffening then rhythmic jerking, with loss of consciousness |
| Absence | Both hemispheres | Brief blank pauses, often mistaken for daydreaming in children |
| Myoclonic and atonic | Both hemispheres | Sudden jerks, or an abrupt loss of muscle tone causing a fall |
What provokes one?
A provoked seizure has an identifiable immediate trigger: a high fever in a young child, a marked chemical imbalance such as low sodium or low blood sugar, alcohol or sedative withdrawal, a head injury, lack of oxygen, or certain drugs. Remove the trigger and the tendency usually goes with it. An unprovoked seizure has no such explanation, and recurrent unprovoked seizures are what define epilepsy. The distinction is central, because a single provoked event carries a very different outlook from the start of a lasting condition.
What happens afterward?
A convulsive seizure is usually followed by a postictal state of drowsiness, confusion, headache and aching muscles that may last from minutes to hours, and temporary weakness of one side can occur. Tongue biting and loss of bladder control point toward a genuine seizure rather than a faint. Not every episode that looks like a seizure is one: fainting, certain heart rhythm disturbances, and functional nonepileptic seizures all mimic it, which is why an eyewitness account carries weight. Investigation typically pairs an electroencephalogram, which records abnormal electrical patterns, with brain imaging and blood tests.
Used in a sentence
The patient experienced a seizure that prompted an emergency evaluation and electroencephalogram.
Good to know
A single seizure related to a clear temporary trigger, such as a fever or an electrolyte imbalance, is evaluated differently from recurrent seizures without an identified trigger, which raise consideration of epilepsy.