For all the advances made by medical science against microorganisms that attack the body, the brain continues to closely hide its secrets. Cures for neurological conditions such as epilepsy remain elusive and effective treatments are often a moving target. Part of the challenge is that epilepsy isn’t one specific disorder. It encompasses a rainbow of brain disorders that range from mild to disabling and even potentially fatal.
The Nervous System
The nervous system is the most complex system of the human body. Its function is to transfer electrical impulses throughout the body. The main cells in nervous tissue are neurons. All cells exhibit electrical properties, but neurons are designed to transmit electrical impulses from one site in the body to another, and to receive and process information. The nervous system is divided into two parts: the central nervous system (CNS) and the peripheral nervous system.
The Central Nervous System
The main function of the central nervous system is to receive information from the body, interpret it, and then send out instructions. The brain controls the body’s systems and organs and keeps them working and interrelating properly. The brain enables us to think, remember, and imagine. In large part, the brain is what makes us human. The brain communicates with the rest of the body through the spinal cord and the nerves, which inform the brain about what was happening in the body. The brain is often compared to a computer because it is made up of complex electric circuitry that controls the majority of our body functions either directly or indirectly.
Normally, our inner electrical system is powered by approximately 80 pulses of energy per second that travel between nerve cells. An epileptic seizure occurs when these energy pulses go into hyper-drive and occur as much as 500 times per second for a short time. In essence, epilepsy causes the brain to short-circuit. This brief electrical surge can happen in just a small area of the brain, or it can affect the whole brain. When the normal pattern of neuronal activity is disturbed, it can cause both mental and physical reactions called seizures. Depending on the part of the brain that is affected, the surge of electrical energy can cause a variety of resulting seizures. Most people associate seizures with dramatic and frightening body convulsions. But seizures can be much more subtle such as unusual sensations of taste or smell, twitching, or memory loss. While epileptics suffer seizures, having a seizure does not mean an individual is suffering from a form of epilepsy. Any condition, illness, or injury that disrupts the usual pattern of neuron activity can cause seizures. In those cases, the seizures typically stop once the condition is corrected, illness cured, or injury healed. An epilepsy diagnosis is considered only after a patient suffers two or more seizures. Typical diagnostic tests for epilepsy include measuring the brain’s electrical activity, magnetic resonance imaging (MRI) brain scans, or computed tomography. Epileptic seizures vary in frequency; some people may experience only several seizures during their lifetime while others can suffer several seizures a day if the condition is left untreated. The type of epilepsy determines the current treatment protocol.
Types of Epilepsy
There are several types of epilepsy. • Idiopathic: there is no apparent cause. • Cryptogenic: there is a likely cause, but it has not been identified. • Symptomatic: a cause has been identified. • Generalized: the seizures are involving the whole brain at once. • Focal (or partial): the seizures begin in one area of the brain.
There are several theories on how epilepsy occurs including: • a defect or irregularity in the brain’s wiring; • an imbalance of neurotransmitters, brain chemicals that relay signals between neurons; • changes in brain cells called channels; or • some combination of these or other factors. Since each type of epilepsy has different causes and different symptoms, they also each have different treatments, which focus on controlling or prevent seizures, not curing them. According to the Epilepsy Foundation, “it can be very difficult to get complete control of seizures and medicines [only] control seizures in about 7 out of 10 people living with epilepsy.”
Current Medications Used to Treat Epilepsy
The most common medications used to treat epilepsy are:
One of the major challenges is controlling side effects by finding medication the individual patient can best tolerate. Side effects can range from relatively mild (decreased appetite, tiredness, dry mouth, irritability, and dizziness) to more severe (nausea, vomiting, and in the case of Felbatol, bone marrow or liver failure in isolated instances.) More than a dozen different antiepileptic drugs are currently available and each has different benefits and side effects. Choosing which drug to prescribe and its dosage depends on a variety of factors such as the type of seizures the patient experiences, their age, lifestyle, frequency of seizures, and for a woman, whether or not she is likely to become pregnant.
How Seizure Medicines Work
Most traditional epilepsy medications control seizures by slowing down how fast electrical signals fire between brain cells that can cause a seizure. The medications accomplish this in different ways. For example, some epilepsy medicines such as carbamazepine and phenytoin control seizures by blocking the brain channels used to transmit electrical impulses. Other medications including topiramate and tiagabine control seizures by increasing the activity of gamma-aminobutyric acid (GABA) in the brain. GABA is a neurotransmitter and increasing it can regulate and slow down the rapid-fire electrical signals that can cause seizures. Some epilepsy medications like levetiracetam work by attaching, or binding, to specific proteins called SV2A that are found in neurons. Once attached, levetiracetam may help reduce the abnormal spread of signals that lead to a seizure. By changing the way brain cells work or send messages, medicines can ideally stop how seizures begin and spread through the brain. Researchers are continually looking for biological pathways to control or stop seizures and developing medications based on that research. The goal is to give those who don’t respond to the older medicines a new treatment that does control their symptoms and enable them to live productive, seizure-free lives.References
Medical History, Epilepsy Foundation: www.epilepsy.com/learn/diagnosis/medical-history
Epilepsy Information Page, National Institutes of Neurological Disorders and Strike: www.ninds.nih.gov/disorders/epilepsy/epilepsy.htm
Epilepsy, U.S. National Library of Medicine: www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001714/