What To Do When Medicine No Longer Stops Your Epileptic Seizures
Surgery may lead to long-term complete seizure freedom in more than half of the drug-resistant patients with focal epilepsy.
Contributor: Imad Najm, MD
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Epilepsy is the fourth most common neurological disease, affecting at least 2.3 million adults and nearly 500,000 children in the United States. Each year, another 150,000 people are diagnosed with epilepsy. The disorder affects males and females and can develop at any age.
Epileptic seizures and epilepsies are classified as focal or generalized. Focal seizures begin in one particular region of the brain, while generalized seizures are the result of abnormal nerve cell firing that affects the whole brain from the beginning.
The first step in managing seizures is to confirm the diagnosis of epilepsy, as many patients suffer from what’s called psychogenic non-epileptic seizures, or PNES. This is usually done through recording brain waves during seizures in a specialized setting called an epilepsy monitoring unit.
More than 20 medications are approved in the United States for treating various types of epilepsies. More than two-thirds of patients with epilepsy can control their seizures with one or more medications.
Epilepsy is considered drug-resistant if seizures continue despite treatment with two or more anti-epileptic medications.
If a patient has drug-resistant focal epilepsy, surgery should be considered. Epilepsy surgery is an established and effective treatment option if the area of the brain from which the seizures start is adequately identified and safely resected.
Doctors at highly specialized epilepsy centers can identify the onset of seizures through the use of a series of tests. These tests include recording brain waves through an electroencephalogram (EEG) during the seizures in an epilepsy monitoring unit. The EEG may help identify the brain region where the seizures start.
A high resolution brain scan called magnetic resonance imaging (MRI) also is necessary to identify whether the brain has an area of structural abnormality.
The epilepsies have many possible causes, ranging from abnormal brain development to traumatic brain injury or illness. These malformations lead to abnormal brain wiring that occurs during brain development, an imbalance of neuron signaling chemicals called neurotransmitters, or a combination of these factors.
In some cases, inflammation and nerve cell damage that happen after a head injury, stroke, small vascular malformations or other trauma may lead to epilepsy. This happens when the brain tries to repair itself after injury, which inadvertently may generate abnormal nerve connections that lead to seizures.
Other tests may be needed to further assess the function of the seizure-generating areas and minimize the negative impact of the surgery on essential functions of the brain and increase the safety of the resection.
One of these tests is functional MRI to “map” language and memory zones before surgery. Another brain mapping technique called magnetoencephalography can pinpoint the seizure onset and to evaluate language processing and preserve key language zones during epilepsy surgery.
The most common type of surgery involves the removal of a seizure focus, the small area of the brain where seizures originate. This type of epilepsy surgery may lead to long-term complete freedom from seizures in more than half of the drug-resistant patients with focal epilepsy.
Other surgical procedures may be used in selected cases. They include corpus callosotomy, which is severing of the nerve fibers that connect the two sides of the brain, and hemispherectomy, which is removal of half of the brain.
Minimally invasive MRI-guided laser surgery is being increasingly used in large epilepsy centers to treat epilepsies associated with tumors, as well as small lesions. The technique involves drilling a very small hole in the skull, through which a thermal laser is inserted to ablate an epileptic area using guidance from the MRI.
Non-medical options include electrical stimulation of the brain or parts of the brain. The types of stimulation include: deep brain, intracranial cortical, peripheral nerve, vagal nerve and trigeminal nerve.
A promising application is development of implantable devices that can detect a seizure in the early stages. Once detected, the implanted device administers an intervention, like electrical stimulation, to prevent the seizure. One such device approved for use in the United States is the NeuroPace RNS system, known as responsive stimulation.
Epilepsy patient and surgery guides
This post is based on one of a series of articles produced by U.S. News & World Report in association with the medical experts at Cleveland Clinic.