Tonic-clonic seizure


A tonic-clonic (grand mal) seizure involves a loss of consciousness and violent muscle contractions. It's usually caused by epilepsy, but may have other triggers, such as extremely low blood sugar, high fever, or a stroke.


Many people will have only one such seizure. Others may need daily medications to control and prevent such seizures.

Last Updated Jun 13, 2017

Content from Mayo Clinic ©1998-2020 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. Terms of Use