Diagnosis
Diagnosis can be made definitively by video recordings of the seizures and Electroencephalography (EEG), which records the electrical activity of the brain. This is typically done after a seizure episode in a clinical setting with an attempt to "capture" a seizure while it happens. According to the "Harrisons Manual of Medicine," the EEG during the tonic phase will show a "progressive increase in low-voltage fast wave activity, followed by generalized high-amplitude, poly spike discharges." The clonic phase EEG will show "high amplitude activity that is typically interrupted by slow waves to create a spike-and-slow-wave pattern." Additionally, the postictal phase will show suppression of all brain activity, then slowing that gradually recovers as the patient awakens. Management
For a person experiencing a tonic–clonic seizure, first-aid treatment includes rolling the person over into the recovery position, which can prevent asphyxiation by preventing fluid from entering the lungs. Other general actions to take as recommended by the Epilepsy Foundation include staying with a person until a seizure is over, paying attention to length of seizure as a possible indication for status epilepticus and/or indication to give rescue medication and call for emergency help, moving close objects out of the way to prevent injury. It is also not recommended to hold a person down that is having a seizure, as that can lead to injury. Nor should anything be put in a persons mouth, as these items can become choking hazards and, depending on what is put in, can potentially break the persons teeth.
A generalized tonic–clonic seizure, or GTCS, previously known as a Grand mal seizure, is a type of generalized seizure that produces bilateral, convulsive tonic and then clonic muscle contractions. Tonic-clonic seizures are the seizure type most commonly associated with epilepsy and seizures in general and the most common seizure associated with metabolic imbalances. It is a misconception that they are the sole type of seizure, as they are the main seizure type in approximately 10% of those with epilepsy.These seizures typically initiate abruptly with either a focal or generalized onset, the former being known as focal to bilateral tonic-clonic seizure. The seizure itself includes tonic (sustained) and then clonic (repetitive short) contractions. In some seizures, the tonic phase may be preceded by brief, arrhythmic muscle jerks (myoclonus), by a clonic phase or by an absence seizure. After the GTCS, there is an extended postictal state where the person is unresponsive and commonly sleeping with loud snoring. There is usually pronounced confusion upon awakening. Causes
The vast majority of generalized tonic-clonic seizures have a focal origin they start as a smaller seizure that occurs solely on one side of the brain and is referred to as a focal (or partial) seizure. These unilateral seizure types (formerly known as simple partial seizure or a complex partial seizure and now referred to as focal aware seizure and focal impaired awareness seizure, respectively) can then spread to both hemispheres of the brain and cause a generalized tonic-clonic seizure.