What are tonic-clonic (grand mal) seizures?

Updated: May 30, 2019
  • Author: David Y Ko, MD; Chief Editor: Selim R Benbadis, MD  more...
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Tonic-clonic seizures are commonly referred to as grand mal seizures. They consist of several motor behaviors, including generalized tonic extension of the extremities lasting for few seconds followed by clonic rhythmic movements and prolonged postictal confusion. On clinical evaluation, the only behavioral difference between these seizures and secondary generalized tonic-clonic seizures is that these seizures lack an aura, or there are partial seizure signs and symptoms. However, the aura preceding the partial seizure with secondary generalization is often forgotten because of postictal amnesia, and observers may not see partial seizure signs and come upon the patient in the grand mal phase.

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