In some 6 out of 10 cases, epilepsy is idiopathic — meaning the cause is unknown. In other cases, epilepsy can be traced to an abnormality of the structure or function of the brain. These abnormalities can arise from traumatic brain injuries, strokes and other vascular problems, infections of the nervous system (meningitis or encephalitis), congenital malformations, brain tumors or metabolic abnormalities.
Regardless, doctors can treat most epilepsy with medication, diet, nerve stimulation or, in some instances, surgery.
- Some epilepsies are caused by problems in the early formation of the fetal brain; others by inborn metabolic problems or early oxygen deprivation that leads to scarring.
- Other epilepsies occur as a result of brain trauma, stroke, infection, tumor or genetic susceptibility. Still others have no apparent cause.
- About 3 out of 10 people with epilepsy have structural changes in the brain that cause chronic seizures. These changes can be present at birth (congenital) or acquired later in life.
- Researchers are exploring the impact of genes in epilepsy but the association is complex, and genetic testing may not identify a specific cause.
GLUT-1 Deficiency Syndrome
GLUT-1 deficiency syndrome is an example of an epilepsy caused by a metabolic problem. GLUT-1 deficiency syndrome is characterized by problems in the transport of glucose to the brain. Speech may be particularly affected. A lumbar puncture can help diagnose the condition.
GLUT-1 deficiency can be treated with a ketogenic diet, one high in fat and protein and low in sugar and carbohydrates. Children who start the diet early and stick with it can see great improvement. If seizures still occur, the doctor may also prescribe medication.
As a fetus develops in the womb, cells called neurons migrate from the innermost parts of the brain and organize themselves to form the brain’s outer layer, or cortex. If this process occurs in an irregular way, cortical dysplasia cells can result. The misplaced neurons signal one another in abnormal ways, and the result is recurring seizures.
Treatment for seizures due to cortical dysplasia typically begins with anti-seizure medications. Surgery may be recommended if these medicines do not adequately control the seizures.
One rare example of cortical dysplasia is called hemimegalencephaly. Present at birth, this condition is characterized by one hemisphere (half) of the brain that is larger than the other. Hemimegalencephaly can cause frequent seizures and developmental delays.
Surgeons can remove the affected side of the brain, allowing the healthy hemisphere to adapt and assume the functions of the other side. This healing process is known as neuroplasticity, the ability of healthy brain tissue to compensate for damaged areas.
Mesial Temporal Sclerosis
The temporal lobe is a part of the brain under the temples on the side of the head. When scars form in the inner, or mesial, portion of the temporal lobe known as the hippocampus, the result is mesial temporal sclerosis.
Head trauma or brain infection can also interrupt the flow of oxygen to the temporal lobe, causing its brain cells to die. Scar tissue can form within the hippocampus and amygdala, areas in the brain that govern short-term memory and emotions. A person with this condition can develop a form of temporal lobe epilepsy with partial (focal) seizures that can spread and affect other areas of the brain.
Treatments can include anti-seizure medications, a low-carb diet, surgery or nerve stimulation.
Traumatic Brain Injury
People who have sustained head injuries from falls, car crashes, sports injuries and other accidents are more likely to experience seizures or epilepsy than those without a history of head injuries. The more times a person has had a trauma to the head, the more likely he or she is to have seizures. Genetics may also play a role in the development of post-traumatic epilepsy. Treatment may include medications, diet, surgery or neurostimulation.