Epilepsy is divided into 2 main varieties: idiopathic and symptomatic. Idiopathic epilepsy is most often generalized, and symptomatic – partial. This is due to different reasons for their occurrence. In the nervous system, signals from one nerve cell to another are transmitted by an electrical impulse, which is generated on the surface of each cell. Sometimes unnecessary excess impulses arise, but in a normally working brain they are neutralized by special antiepileptic structures. Idiopathic generalized epilepsy develops as a result of the genetic defect of these structures. In this case, the brain can not cope with excessive electrical excitability of cells, and it manifests itself in a convulsive readiness, which can at any time “grab” the cortex of both hemispheres of the brain and cause an attack.
With partial epilepsy, a focus is formed with epileptic nerve cells in one of the hemispheres. These cells generate an excessive electrical charge. In response to this, the remaining antiepileptic structures form a “protective shaft” around such a focus. Until a certain moment convulsive activity can be restrained, but the culmination moment arrives, and epileptic discharges break through the boundaries of the shaft and manifest as a first attack. The next attack, most likely, will not keep you waiting. “The track” has already been laid.
Such a focus with epileptic cells is formed, most often, against a background of some disease or pathological condition. Here are the main ones:
- Underdevelopment of brain structures – arises not as a result of genetic rearrangements (as in idiopathic epilepsy), but in the period of ripening of the fetus, and can be seen on an MRI;
- Tumors of the brain;
- The consequences of a stroke;
- Chronic use of alcohol;
- Infections of the central nervous system (encephalitis, meningeencephalitis, brain abscess);
- Craniocerebral injury;
- Drug addiction (especially from amphetamines, cocaine, ephedrine);
- Acceptance of certain medications (antidepressants, antipsychotics, antibiotics, bronchodilators);
- Some hereditary metabolic diseases;
- Antiphospholipid syndrome;
- Multiple sclerosis
Factors of epilepsy development
It happens that the genetic defect is not manifested in the form of idiopathic epilepsy and, the person lives without disease. But with the emergence of “fertile” soil (one of the above diseases or conditions), one of the forms of symptomatic epilepsy can develop. In this case, young people are more likely to develop epilepsy after traumatic brain injuries and alcohol or drug abuse, and in the elderly – against a background of brain tumors or after a stroke.