Tonic-Clonic Seizure [TC]

Tonic-Clonic Seizures (formerly Grand Mal)

A generalized tonic-clonic seizure (GTC) is the sort most people think of when seizures are mentioned. Tonic-clonic seizures can be distressing to witness, especially when it is your child, but understanding what is happening does help us to cope with the situation.

In 60% of cases, the first seizure seen in Doose syndrome is a generalized tonic-clonic seizure and rarely the other types of generalized seizure (such as a myoclonic, myoclonic-atonic, or absence seizure). So, for most parents, a tonic-clonic seizure is the first symptom of MAE they will witness and it will strike completely out of the blue or sometimes accompany a fever.

What happens?

Initially, the child stiffens and simultaneously loses consciousness (so he/she is completely unaware of the event). Tonic (meaning stiff) refers to the stiffening stage and causes the child to fall to the ground. Typically, the eyes roll upwards, the head goes back, the back arches, and the arms and legs stiffen. The extension continues for what seems like a long time but rarely lasts more than thirty seconds. The brain cells are connected to other nerve cells through the spinal cord and during this tonic stage, all the muscles are contracted, including the chest muscles so it is difficult for the child to breathe. A combination of the face being flushed with the bluish blood of the veins and also the lack of oxygen causes the child to turn somewhat blue around the lips – a process called cyanosis. Excess saliva may cause a gurgling sound in the mouth or throat. The result of the muscles in the lungs contracting forces air out, sometimes making the child sound as though he/she is crying out. Occasionally, if the child’s bladder is full, he/she may lose bladder control.

After the tonic stage of a tonic-clonic seizure, the clonic (meaning jerk) phase of the seizure begins. The limbs jerk because now the muscles contract and relax in rapid succession. During this phase, the child may bite their tongue or the inside of their cheek. The fists are tightly clenched, the arms repeatedly flex at the elbows and then briefly relax. The legs flex at the hip and knee joint in a similar fashion; the head may flex and then fall backward. Initially, these movements occur rapidly but then gradually slow. The jerking becomes less intense and occurs at a slower rate, finally ceasing. Usually, a deep sigh signals the end of the jerking and normal breathing resumes.

The seizure is now over but the child is not awake and will not respond immediately. This recovery phase is called the postictal state when the brain can be thought of as exhausted from all its activity. The brain is quite active but its major activity is to inhibit (stop) the cells from firing. This inhibition has brought the seizure under control. This postictal stage or recovery time differs from child to child; it can last for a few minutes or longer, especially if the tonic-clonic seizure has been long. The child will probably feel like sleeping but can be roused and may feel tired, confused, agitated, or somewhat disorientated. Muscles will probably be sore. It is best to allow the child to rest until he/she is alert and fully recovered.