Why do people develop epilepsy?
This month’s episode of Epilepsy Explained focuses on the various possible causes of epilepsy with Dr. Manisha Patel, PhD, Professor at the University of Colorado, Anschutz and Past President of the American Epilepsy Society.
Video Transcript
How does a person get epilepsy?
Dr. Manisha Patel: Epilepsy has many causes and some patients do not know their cause. It is important to determine the cause of epilepsy, so that we can understand the triggers that a patient may face, what conditions co-occur with the epilepsy, and most importantly, understand how to treat the patient in the most effective manner. Epilepsy can be acquired with insults such as traumatic brain injury, stroke, or brain tumors, or it can be genetic. There are five potential known causes of epilepsy, structural, genetic, infectious, metabolic, and autoimmune.
What is meant by a structural cause of epilepsy?
Dr. Manisha Patel: A structural cause of epilepsy is when an abnormal structure in the brain is the main cause of the epilepsy syndrome. This is seen by imaging tests such as MRI together with other EEG type tests that can determine if the structure in the brain is the cause of the epilepsy. This really makes us understand if the patient should be referred to surgery after having failed some medications. Structural causes of epilepsy can be acquired by brain tumors, strokes, as well as other conditions. They may be abnormal brain development or they may be genetic.
What are the genetic causes of epilepsy?
Dr. Manisha Patel: Genetic causes of epilepsy are when a mutation in a specific gene is the cause or the suspected cause of the epilepsy syndrome. Genetic epilepsy can be inherited or run in families, but by far, many new epilepsy syndromes that we observe occur in the individual for the first time, so that previous generations do not have the mutations. There are many tests available to detect these genetic abnormalities. Detection of the genetic abnormality itself or the mutation is not sufficient, but has to be correlated with the symptoms that the patient has. It is important to remember that genetic does not equate to inherited, and that environmental factors also play a role in genetic epilepsy. For example, sleep disturbances, stress, and other illnesses.
How can an infection turn into epilepsy?
Dr. Manisha Patel: An infection to the brain can result in seizures and in epilepsy syndrome. This is a very prevalent cause of epilepsy throughout the world, particularly in developing countries. For example, neurocysticercosis is a type of epilepsy that’s transmitted through tapeworm found in pork. Cerebral malaria is another example of an infectious epilepsy caused by a parasite that is carried by mosquitoes. Other types of agents can cause infection-induced epilepsy, such as viruses that are more prevalent in the United States. Important thing to remember is that understanding this cause can allow the clinician to treat the epilepsy in a specific manner that is more appropriate for the patient.
What is a metabolic disorder and how does that cause epilepsy?
Dr. Manisha Patel: Metabolism is a set of reactions in our body that are catalyzed or conducted by a set of proteins known as enzymes. Sometimes, there is an error in one of these proteins or enzymes that can cause seizures in an individual. When the seizures are a prominent feature of such a disorder, then we call this a metabolic epilepsy. Metabolic epilepsy are fairly rare. They can be inherited by some error in metabolism, or they can be acquired due to deficiencies in certain nutrients such as folic acid. A good example of a metabolic epilepsy is glucose 1 transporter deficiency or GLUT-1 disorder. In this disorder, glucose transport to the brain and the spinal cord is defective. This is due to a decrease in the activity of a protein that allows the brain to use glucose as a nutrient. Glucose is really important as an energy source, and the individual who lacks this has a seizure disorder and epilepsy, which can be treated with ketogenic diets that provide an alternate source of energy for the individual.
What is auto-immune epilepsy?
Dr. Manisha Patel: Autoimmune epilepsy has been newly classified as a cause of epilepsy. Our bodies use certain proteins and cells in the immune system to fight any kind of invasion of microbes or foreign substances. Normally, our body protects itself from foreign substances that may attack it by producing antibodies through those. Sometimes, inadvertently, antibodies are generated to the body’s own proteins, and when these proteins are important for the brain’s function, this may cause an immune reaction, inflammation, and seizures. Examples of autoimmune epilepsy are NMDA receptor or LGI1. Sometimes, tumors can produce antibodies and also lead to autoimmune epilepsy. Autoimmune epilepsy can be detected by a combination of tests that include imaging of the brain together with sampling of the cerebrospinal fluid and detecting certain antibodies. These then can guide the treatment of the patient, so that the patient’s seizures can be controlled.
Are these all the ways that a person can get epilepsy?
Dr. Manisha Patel: No, some individuals have epilepsy that’s diagnosed, but the cause is unknown or yet to be determined. This is why research is really important to conduct, so that we understand all of these epilepsy causes and develop better treatments for epilepsy. Research also allows us to understand the conditions that occur with epilepsy that may be more disturbing to the patient, such as cognitive dysfunction memory lapses and sleep disturbances called the comorbidities of epilepsy. Epilepsy has many promising new treatments coming on in addition to the currently available treatments, which include anti-seizure medications, neurostimulation surgical approaches, and dietary approaches.
