This type of seizure has a specific term called "focal to a bilateral tonic-clonic seizure. Other generalized tonic-clonic seizures are idiopathic, start in large networks involving both hemispheres, and have a presumed genetic cause. Precipitating factors include chemical and neurotransmitter imbalances and a genetically or situationally determined seizure threshold, both of which have been implicated. The seizure threshold can be altered by fatigue, malnutrition, lack of sleep or rest, hypertension, stress, diabetes, the presence of strobe-flashes or simple light/dark patterns, raised estrogen levels at ovulation, fluorescent lighting, rapid motion or flight, blood sugar imbalances, anxiety, antihistamines and other factors. Tonic–clonic seizures can also be induced deliberately with electroconvulsive therapy.In the case of symptomatic focal epilepsy, the cause is often determined by MRI or other neuroimaging techniques showing that there is some degree of damage to a large number of neurons. The lesions (i.e., scar tissue) caused by the loss of these neurons can result in groups of neurons forming a seizure "focus" area with episodic abnormal firing that can cause seizures if the focus is not abolished or suppressed via anticonvulsant drugs. Mechanism
Prodrome
Most generalized tonic–clonic seizures begin without warning and abruptly, but some epileptic patients describe a prodrome. The prodrome of a generalized tonic–clonic seizure is a sort of premonitory feeling hours before a seizure. This type of prodrome is distinct from stereotypic aura of focal seizures that become generalized seizures. Phases
A tonic–clonic seizure comprises three phases: the tonic phase, clonic phase and postictal phase. Tonic phaseThe tonic phase is usually the first phase.
Because the changes in the condition of the gums from one day to another are minimal, patients get used to the gums appearance and tend not to notice the recession visually. Receding gums may remain unnoticed until the condition starts to cause symptoms. The following signs and symptoms may indicate gum recession:

Tooth mobility
Dentin hypersensitivity (over-sensitive teeth) - short, sharp pain is triggered by hot, cold, sweet, sour, or spicy food and drink. If the cementum covering the root is not protected anymore by the gums, it is easily abraded exposing the dentin tubules to external stimuli. Teeth may also appear longer than normal (a larger part of the crown is visible if gums are receding)
The roots of the tooth are exposed and visible
The tooth feels notched at the gum line
Change in the tooth’s color (due to the color difference between enamel and cementum)
Spaces between teeth seem to grow (the space is the same, but it seems larger because the gums do not fill it any more)
Cavities below the gum lineIf the gum recession is caused by gingivitis, the following symptoms may also be present:

Puffy, red, or swollen (inflamed) gums
Gum bleeding while brushing or flossing
Bad breath (halitosis)In some cases, it is the treatment of gingivitis that reveals a gum recession problem, that was previously masked by the gums swelling.