A seizure is a convulsion that is caused by sudden abnormal electrical activity in the brain. Most often seizures are caused by epilepsy. Seizures vary in type. Some forms do not cause a loss of consciousness. You are more likely to injure yourself from a fall due to seizure than from one due to fainting, because your protective reflexes are still at work during syncope.
Urination is more frequent with seizures.
You will regain your consciousness faster if you have fainted than if you have had a seizure. Mental confusion, headache and drowsiness are more common after seizures than after syncope. You probably will not recall having had presyncopal symptoms. Your doctor will take your medical history and perform a medical examination. As part of your history of fainting, he will be particularly interested in hearing bystander accounts.