A stroke is caused by blood flow to the brain being cut off, while a seizure is caused by a sudden burst of abnormal electrical activity in the brain, often producing convulsions. One is a circulation problem, the other is an electrical one, though both are medical emergencies.
The core difference
A stroke is a loss of blood supply to the brain, while a seizure is abnormal electrical activity in the brain, common in epilepsy.
- stroke — a sudden loss of blood flow to part of the brain, which can cause lasting damage: he suffered a stroke in his early sixties but made a strong recovery.
- seizure — a sudden episode of abnormal electrical activity in the brain, often causing convulsions: she had two seizures in the night and was kept in for observation.
How to tell them apart
Think plumbing versus wiring: a stroke is a blood-supply problem, like a blocked or burst pipe feeding part of the brain, while a seizure is an electrical storm in the brain's wiring. That distinction is worth remembering because the two can look similar to an onlooker, but the underlying cause and treatment are different.
The words also drift outside medicine, which adds to the confusion. Stroke has everyday senses too, from a stroke of luck to a brush stroke in a painting, and seizure can simply mean the act of taking something by force or authority, as in the seizure of counterfeit goods at a border. Context usually makes clear which sense is meant.
