What happens during a tonic-clonic seizure?

Tonic-clonic seizures are the type of seizure most people recognise and think of as a typical epileptic fit.

They happen in two stages, an initial ‘tonic’ stage shortly followed by a second ‘clonic’ stage.

Someone having a tonic-clonic seizure goes stiff, loses responsiveness, falls to the floor and begins to jerk or convulse. They may go blue around the mouth due to irregular breathing. Sometimes they may lose control of their bladder or bowels, and bite their tongue or the inside of their mouth.

Signs/symptoms

Tonic stage:

• Loss of responsiveness
• Stiff body
• May fall to the floor if they are standing

Clonic stage:

• Jerking movements
• Loss of bladder or bowel control
• Noisy, difficult breathing
• Grey/blue tinge around the mouth
• May bite their tongue or mouth
• Saliva or foam at the mouth which could be bloody if they have bitten their tongue or mouth

The seizure normally stops after a few minutes, but some last longer. Afterwards, the person may have a headache or difficulty remembering what happened and feel tired or confused.