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Epilepsy is a neurological disorder that affects people of all ages; however, the incidence of seizures is higher in young children (estimated to occur in as many as 4 percent of all children) than in adults. It is unknown why the developing brain is more prone to seizures than the adult brain. When they occur repeatedly and are not provoked, a child is said to have epilepsy.
Causes
In most cases there is no specific acute cause of epilepsy. Some individuals may have minor brain injury present since birth or an inherited tendency towards having seizures. Sometimes, head trauma or a brain infection (meningitis or encephalitis) at an early age produces scarring of the brain that can cause seizures.
Symptoms
Seizures can cause a wide variety of symptoms such as strange sensations, changes in behavior or emotions, muscle spasms, convulsions, or a sudden loss of awareness or consciousness. When children have intractable epilepsy, they are at increased risk of physical injury during a seizure, adverse effects from antiepileptic drugs, disruption of family life, and impairment of learning and attention. Any or all of these reasons, accompanied by concerns about quality of life and future development, may lead a family to consider surgery.
Diagnosis
Diagnostic techniques, such as electroencephalograms (EEGs), video-EEG telemetry (vEEG), computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and single photon-emission computerized tomography (SPECT) are used to assess and visualize abnormalities and structural problems associated with epilepsy that may be targets for surgery. Functional testing, including neuropsychological testing, functional magnetic resonance imaging (fMRI), and WADA testing, may be used prior to surgery to define vital regions of the brain and limit risks associated with removal of the epileptic zone.
Treatment
Most children with epilepsy are well controlled with medication and develop normally with few limitations. However, some children experience uncontrolled seizures or intractable epilepsy despite aggressive treatment with antiepileptic therapy. In these children, epilepsy surgery or surgical removal of the “epileptic zone” of brain tissue is often considered. Although in the past, surgical treatment for epilepsy was considered only after a long period of seizures and multiple medication trials, individuals who will develop intractable epilepsy can now be identified earlier. A surgical evaluation will often be considered when a child has not responded to two or three antiepileptic medications. There is accumulating evidence that surgically curing epilepsy at an early age may provide a better quality of life.
Types of Epilepsy
There are many different types of epilepsy that are distinguished by causes, extent, and effects. Among these, there are two major types of epilepsy: generalized epilepsy, in which seizures affect the entire brain, and partial (or focal) epilepsy, in which seizures begin in a specific portion of the brain.
Generalized epilepsies have no defined area in the brain from which the seizures originate. There are two varieties of generalized epilepsies:
- Idiopathic, in which the brain behaves normally between seizures and the cause of seizures is unknown; and
- Symptomatic, in which there is a clear structural abnormality that contributes to the seizures.
The seizures caused by generalized epilepsy include:
- Absence, or petit mal, seizures
These seizures are characterized by a brief lapse in awareness that lasts a few seconds and causes the person to stare or have twitches in the eyelids or face muscles. These seizures, which may occur up to hundreds of times a day, commonly begin in before age two and end after childhood. - Tonic-clonic, or grand mal, seizures
These seizures are characterized by a sudden and complete loss of consciousness and a stiffening the arms and legs that causes the person to fall (called the tonic phase) before a rhythmic jerking (called the clonic phase) begins. When the seizing does not stop, it may become a status epilepticus seizure. This uncontrolled seizing requires immediate medical attention to prevent brain damage or death. - Tonic seizures
These seizures are similar to tonic-clonic seizures, but are not followed by a rhythmic jerking of the clonic phase. - Myoclonic seizures
These generalized seizures involve very brief, lightning-like jerks of any part of the body without a loss of consciousness. - Atonic seizures
People with these seizures experience a sudden loss of muscle tone resulting in collapse, sometimes head first, into the ground.
Partial (focal) epilepsy involve seizures that begin in a region of the most highly developed part of the brain’s hemispheres. While the seizures sometimes are localized, they can spread to become generalized seizures. The seizures caused by these epilepsies, which may spread and become generalized, include:
- Complex partial seizures (psychomotor attacks)
These seizures often begin with an aura, or a neurological warning, such as a sense of fear, an unpleasant smell, or change in perception. After the aura, consciousness may be altered; speech may stop and the person may perform automatic repetitive movements such as chewing, swallowing, hand fidgeting, or purposeless movement from place to place. - Simple partial seizures
These seizures typically affect the motor or sensory areas of the brain, causing jerking movements in the hand or facial muscles, or sensory symptoms such as flashing lights or a buzzing sound, but without altering consciousness.
