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Tonic-Clonic (Grand Mal) Seizures

Tonic-clonic seizures (formerly known as grand mal seizures) can be one of the most frightening seizures to observe. There are two parts to a tonic-clonic seizure:

  • Tonic phase – The person initially stiffens and loses consciousness, causing them to fall to the ground. The person’s eyes roll back into their head as the muscles (including those in the chest, arms and legs) contract and the back arches. As the chest muscles tighten, it becomes harder for the person to breathe – the lips and face may take on a bluish hue, and the person may begin to make gargling noises. 

    Many observers have the misconception that the person is in danger of “swallowing their tongue,” so they attempt to put something in the person’s mouth. Swallowing your tongue is actually impossible, and any attempt to open the now tightly clenched jaw may cause more harm than good. The tonic phase will typically last no longer than a minute.

  • Clonic phase – Typically following the tonic phase, the clonic phase will start as the muscles begin to spasm and jerk. The elbows, legs and head will flex then relax rapidly at first, but the frequency of the spasms will gradually subside until they cease altogether. As the jerking stops, it is common for the person to let out a deep sigh, after which normal breathing resumes. The clonic phase will rarely last longer than a few minutes.

As the person transitions from the clonic phase to the post-seizure period, they’ll likely remain unconscious for a few minutes or more, depending on the severity of the seizure. During this time (known as the postictal period), the brain is extremely active trying to stop the cells from firing to bring the seizure under control. When the person wakes up, they may have sore muscles and be tired or confused. The observer’s best course of action is to be assuring and supportive.

Occasionally, it is possible to experience the tonic phase without the clonic phase and vice versa.

Treatment of tonic-clonic (grand mal) seizures

There is no one treatment method for any patient with a seizure disorder. Each treatment plan is tailored to the individual patient based on their diagnosis and symptoms. Treatment options may include medical therapy, nerve stimulation, dietary therapy, or surgery, as appropriate. Clinical trials may also be a valuable treatment alternative.

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For more information about tonic-clonic (grand mal) seizures or to meet with our doctors, request an appointment at the Epilepsy Center.

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