A grand mal seizure — also known as a generalized tonic-clonic seizure — features a loss of consciousness and violent muscle contractions. It's the type of seizure most people picture when they think about seizures in general.
Grand mal seizure is caused by abnormal electrical activity throughout the brain. Most of the time grand mal seizure is caused by epilepsy. In some cases, however, this type of seizure is triggered by other health problems, such as extremely low blood sugar, high fever or a stroke.
Many people who have a grand mal seizure will never have another one. However, some people need daily anti-seizure medications to control and prevent future grand mal seizure.