A generalized tonic-clonic seizure involves disruption in the functioning on both sides of the brain. The disturbance transmits electrical indicators to the muscles, glands or nerves. These indicators can lead to loss of consciousness and severe muscular contractions.
There are 2 distinct stages in a generalized tonic-clonic seizure. In the tonic phase of the seizure, the muscles start to stiffen and the individual loses consciousness and might fall down. The clonic phase involves rapid muscular contractions or convulsions. An episode typically lasts for 1-3 minutes. If it lasts longer than 5 minutes, it is considered as a medical emergency.
Among those who have epilepsy, the individual might start to experience a generalized tonic-clonic seizure in later childhood or adolescence. Remember that this type of seizure is rarely seen among children below 2 years old.
The start of a generalized tonic-clonic seizure might be triggered by various health conditions. Some of the severe conditions including a brain tumor or a broken blood vessel in the brain that can lead to a stroke.
A head injury might also cause the brain to trigger a seizure. Other possible triggers for a generalized tonic-clonic seizure might include:
- Low level of sodium, glucose, calcium or magnesium in the body
- Injury or infection
- Drug or alcohol abuse or withdrawal
- Certain genetic conditions or neurological disorders
Oftentimes, the doctor might not be able to determine the exact trigger of the seizures.
Potential risk factors
An individual might be at risk for experiencing generalized tonic-clonic seizures if he/she has a family history of epilepsy.
A brain injury linked to a head trauma, stroke or infection also puts the individual at higher risk. Other factors that might increase the risk include the following:
- Deprivation of sleep
- Using alcohol or drugs
- Electrolyte imbalance due to other health conditions
Indications of a generalized tonic-clonic seizure
If an individual experiences a generalized tonic-clonic seizure, some or all of these symptoms might occur:
- Crying or screaming out involuntarily
- Strange sensation or feeling which is called an aura
- Severe headache after an episode
- Loss of bowel and bladder control either during or after a seizure
- Passing out and waking up feeling sleepy or confused
In most cases, an individual who experiences an episode stiffens and falls during the tonic phase. The limbs and the face appears to jerk rapidly as the muscles convulse.